Early weaning stress induces chronic functional diarrhea, intestinal barrier defects, and increased mast cell activity in a porcine model of early life adversity

The gut microbial metabolite indole-3-aldehyde alleviates impaired intestinal development by promoting intestinal stem cell expansion in weaned piglets

BACKGROUND

Weaning stress-induced diarrhea is widely recognized as being associated with gut microbiota dysbiosis. However, it has been challenging to clarify which specific intestinal microbiota and their metabolites play a crucial role in the antidiarrhea process of weaned piglets.

RESULTS

In this study, we first observed that piglets with diarrhea exhibited a lower average daily gain and higher diarrhea score, and elevated levels of lipopolysaccharide (LPS) and D-lactate (D-LA) compared to healthy piglets. Subsequently, we analyzed the differences in intestinal microbial composition and metabolite levels between healthy and diarrheal weaned piglets. Diarrheal piglets demonstrated intestinal microbiota dysbiosis, characterized primarily by a higher Firmicutes to Bacteroidota ratio, a deficiency of Lactobacillus amylovorus and Lactobacillus reuteri, and an increased abundance of Bacteroides sp.HF-5287 and Bacteroides thetaiotaomicron. Functional profiling of the gut microbiota based on Kyoto Encyclopedia of Genes and Genomes (KEGG) data was performed, and the results showed that tryptophan metabolism was the most significantly inhibited pathway in piglets with diarrhea. Most tryptophan metabolites were detected at lower concentrations in diarrheal piglets than in healthy piglets. Furthermore, we explored the effects of dietary indole-3-aldehyde (IAld), a key tryptophan metabolite, on intestinal development and gut barrier function in weaned piglets. Supplementation with 100 mg/kg IAld in the diet increased the small intestine index and improved intestinal barrier function by promoting intestinal stem cell (ISC) expansion in piglets. The promotion of ISC expansion by IAld was also confirmed in porcine intestinal organoids.

CONCLUSIONS

These findings revealed that intestinal microbial tryptophan metabolite IAld alleviates impaired intestinal development by promoting ISC expansion in weaned piglets.

Mechanism of JNK action in oxidative stress-enhanced gut injury by Clostridium perfringens type A infection

In piglets, oxidative stress can exacerbate gut injury caused by pathogens. C-Jun amino-terminal kinase (JNK) is associated with oxidative stress-induced damage to intestinal epithelial barrier. However, it is unclear whether oxidative stress can increase gut injury by Clostridium perfringens type A (CpA) and whether JNK mediates this process. We aimed to investigate if and how the JNK can regulate the effect of oxidative stress on gut injury induced by CpA infection. In this study, the oxidative stress in IPEC-J2 cells was modeled, and the changes in the susceptibility of IPEC-J2 cells to CpA were examined after treatment of oxidative stressed IPEC-J2 cells with JNK inhibitor (SP600125) and JNK siRNA. Pre-injection with the SP600125 solution was also carried out in oxidative stressed mice, followed by CpA infection. Results indicated that compared to that in the Control group, IPEC-J2 cells under oxidative stress showed reduced transmembrane resistance, degraded tight junction (TJ) proteins, increased membrane permeability, and enhanced CpA infection, all of which were reversed by inhibiting or interfering with JNK expression. Similarly, compared to that in the Control group, mice under oxidative stress showed degradation of jejunal TJ proteins, increased intestinal permeability and barrier damage by CpA, while mice pre-injected with the SP600125 solution showed alleviation of these alterations. These results suggested that oxidative stress enhanced the infection of IPEC-J2 cells and the gut injury caused by CpA, which was mediated by JNK. This study provides important insights regarding the mechanism by which oxidative stress enhanced intestinal damage by CpA.

Role of Sex and Early Life Stress Experience on Porcine Cardiac and Brain Tissue Expression of the Oxytocin and H2S Systems

Early life stress (ELS) significantly increases the risk of chronic cardiovascular diseases and may cause neuroinflammation. This post hoc study, based on the material available from a previous study showing elevated "serum brain injury markers" in male control animals, examines the effect of sex and/or ELS on the cerebral and cardiac expression of the H2S and oxytocin systems. Following approval by the Regional Council of Tübingen, a randomized controlled study was conducted on 12 sexually mature, uncastrated German Large White swine of both sexes. The control animals were separated from their mothers at 28-35 days, while the ELS group was separated at day 21. At 20-24 weeks, animals underwent anesthesia, ventilation, and surgical instrumentation. An immunohistochemical analysis of oxytocin, its receptor, and the H2S-producing enzymes cystathionine-β-synthase and cystathionine-γ-lyase was performed on hypothalamic, prefrontal cortex, and myocardial tissue samples. Data are expressed as the % of positive tissue staining, and differences between groups were tested using a two-way ANOVA. The results showed no significant differences in the oxytocin and H2S systems between groups; however, sex influenced the oxytocin system, and ELS affected the oxytocin and H2S systems in a sex-specific manner. No immunohistochemical correlate to the elevated "serum brain injury markers" in male controls was identified.

The effect of different weaning strategies on piglet growth, feed intake and gut health

The present study evaluated the effects of weaning strategy on piglet growth performance, onset of feed intake, and intestinal health. A total of 254 crossbred piglets were used and the experimental period lasted 45 days. The piglets were assigned to the fallowing treatments: early strategic weaning (ESW, n = 85), piglets weaned at 16 days of age and transferred to the pre-nursery unit; strategic segregated weaning (SSW, n = 85), piglets weaned at 21 days of age and kept in the farrowing crate until 24 days of age; and conventional weaning (CW, n = 84), piglet weaned at 24 days of age and transferred directly to the nursery unity; this experimental group was used as a control. Piglets from all treatments were transferred to the nursery unit at 24 days of age. For the nursery phase three periods of evaluation was considered: nursery phase I (0-7 d), nursery phase II (7-14 d), and nursery phase III (14-21 days). Piglets from the ESW and CW had greater (P < 0.001) ADG in the lactation period 16-21 days. The BW at 24 day of age was higher (P < 0.001) for piglets in the ESW and CW groups. In the nursery phase I, the ESW group had higher (P = 0.003) daily feed intake. Piglets from the ESW group had higher (P = 0.004) BW at the end of the experimental period. The ESW and SSW groups had a higher percentage of piglets (88% and 92%, respectively; P < 0,001) consuming feed in the first 24 h after transference to the nursery facility. When the total experimental period is considered, a reduction (P < 0.001) in the incidence of diarrhea was observed for ESW piglets. Overall, there was no effect of weaning strategy on intestinal permeability. In conclusion, the results of our study showed that the Segregated Strategic Weaning management can be used to mitigate the deleterious effects of early weaning.

Validation of an in vivo dual permeability marker technique to characterize regional gastrointestinal tract permeability in mid lactation Holstein cows during short-term feed restriction

This study evaluated the impact of short-term feed restriction in lactating dairy cows on regional permeability of the gastrointestinal tract (GIT), and the recovery of DMI, ruminal pH, and milk yield. In addition, sampling methods for a novel dual marker technique to characterize total GIT and post ruminal permeability were validated. Six ruminally cannulated lactating Holstein cows were blocked by parity (3 primiparous, 3 multiparous; 189 DIM ± 25.2) and enrolled in a crossover design. Experimental periods included a 5-d baseline phase (BASE), 5-d challenge phase (CHAL), and 2 weeks of recovery (REC1 and REC2). During CHAL cows received either 100% ad libitum feed intake (AL) or 40% of ad libitum feed intake (FR). To assess, total-tract and post-ruminal permeability, equimolar doses of Cr-EDTA and Co-EDTA were infused on d 3 of CHAL into the rumen and abomasum (0.369 mmol/kg BW). Following infusions, total urine and feces were collected every 8 h over 96 h, and blood samples were collected at h 0, 1, 2, 3, 4, 6, 8, 12, 16, 20, 24, 32, 40, 48, and 64. The plasma area under the curve (AUC) for Cr and Co were calculated. By design, DMI for FR was reduced by 60% during CHAL and remained 19% lower than AL during REC1 but was not different from AL in REC2. Mean ruminal pH for FR was greatest during CHAL and the least during REC1, with no differences detected between AL and FR in REC2. The duration that pH was < 5.8 was the least for FR during CHAL and greatest during REC1 which were different from AL and were no longer different between treatments in REC2. Milk yield was the least for FR during CHAL and REC1 and no longer different from AL in REC2. Feed restriction reduced milk fat, protein, and lactose yields by 26, 31% and 31%, respectively. Plasma Cr AUC was 34% greater and Co AUC tended to be 35% greater for FR than AL on d 3 of CHAL. Urinary Cr recovery after 48-h was not affected by treatment; however, urinary Co recovery was 36% greater for FR than AL. Positive correlations between plasma AUC and urinary recovery for Cr and Co were detected. It was determined that blood samples collected at h 2, 8, 20, 40, and 48 could predict the total plasma Cr and Co AUC within 1.9% and 6.2%, respectively. In summary, short-term FR in lactating dairy cows increases permeability of the total GIT and may increase permeability of the post-ruminal regions with more than 60% of the permeability occurring post-ruminally. After FR, cows experienced low ruminal pH and a sustained reduction in milk yield. When utilizing Cr- and Co-EDTA to evaluate regional GIT permeability, plasma AUC can be used as an alternate to urinary Cr and Co excretion. In addition, blood samples collected at h 2, 8, 20, 40, and 48 result in adequate prediction accuracy, at least when comparing GIT permeability for lactating dairy cows exposed to AL and FR.

The contribution of biological sex to heat stress-mediated outcomes in growing pigs

Heat stress (HS) negatively impacts a variety of production parameters in growing pigs; however, the impact of biological sex on the HS response is largely unknown. To address this, 48 crossbred barrows and gilts (36.8 ± 3.7 kg BW) were individually housed and assigned to one of three constant environmental conditions: (1) thermoneutral (TN) (20.8 ± 1.6 °C; 62.0 ± 4.7% relative humidity; n = 8/sex), (2) HS (39.4 ± 0.6 °C; 33.7 ± 6.3% relative humidity) for 1 d (HS1; n = 8/sex), or (3) or for 7 d (HS7; n = 8/sex). As expected, HS increased rectal temperature (Tr) following 1 d of HS (1.0 °C; P < 0.0001) and 7 d of HS (0.9 °C; P < 0.0001). By 7 d, heat-stressed gilts were cooler than barrows (0.4 °C; P = 0.016), despite identical heating conditions. There was a main effect of sex such that barrows had higher Tr than gilts (P = 0.031). Heat-stressed pigs on d 1 had marked reductions in feed intake and BW compared to TN (P < 0.0001). One day of HS resulted in negative gain to feed (G:F) in barrows and gilts and was reduced compared to TN (P < 0.0001). Notably, following 1 d of HS, the variability of G:F was greater in gilts than in barrows. Between 1 and 7 d of HS, G:F improved in barrows and gilts and were similar to TN pigs, even though HS barrows had higher Tr than gilts over this period. Heat stress for 1 and 7 d reduced empty gastrointestinal tract weight compared to TN (P < 0.0001). Interestingly, HS7 gilts had decreased gastrointestinal tract weight compared to HS1 gilts (2.43 vs 2.72 kg; P = 0.03), whereas it was similar between HS1 and HS7 barrows. Lastly, a greater proportion of gastrointestinal contents was in the stomach of HS1 pigs compared to TN and HS7 (P < 0.05), which is suggestive of decreased gastric emptying. Overall, HS barrows maintained an elevated Tr compared to HS gilts through the duration of the experiment but also maintained similar growth and production metrics compared to gilts, despite this higher temperature.

Modulation of pectin on intestinal barrier function via changes in microbial functional potential and bile acid metabolism

Weaning is one of the major factors that cause stress and intestinal infection in infants and in young animals due to an immature intestine and not fully developed immune functions. Pectin (PEC), a prebiotic polysaccharide, has attracted considerable attention in intestinal epithelial signaling and function via modulation of the microbial community. A total of 16 weaned piglets (21-d-old) were randomly assigned into two groups: control group and PEC group. Supplementation of 5% pectin improved intestinal mucosal barrier function by modulating the composition of the bile acid pool in piglets. Specifically, piglets in PEC group had less serum D-lactate content and alkaline phosphatase activity. In the ileum, dietary pectin increased the number of crypt PAS/AB-positive goblet cells and the mRNA expressions of MUC2, ZO-1, and Occludin. Piglets in PEC group displayed a decreased abundance of Enterococcus (2.71 vs. 65.92%), but the abundances of Lactobacillus (30.80 vs. 7.93%), Streptococcus (21.41 vs. 14.81%), and Clostridium_sensu_stricto_1 (28.34 vs. 0.01%) were increased. Elevated concentrations of bile acids especially hyocholic acid species (HCAs) including HCA, HDCA, and THDCA were also observed. Besides, correlation analysis revealed that dietary pectin supplementation may have beneficial effects through stimulation of the crosstalk between gut microbes and bile acid synthesis within the enterohepatic circulation. Thus, dietary pectin supplementation exhibited a further positive effect on the healthy growth and development of weaned piglets. These findings suggest pectin supplementation as the prebiotic is beneficial for gut health and improvement of weaned stress via regulating microbiota and bile acid metabolism.

Dietary glycerides of valerate ameliorate diarrhea and impact intestinal physiology and serum biomarkers in weaned piglets infected with enterotoxigenic Escherichia coli F18

In the commercial swine farm setting, the postweaning period is a critical window during which piglets are highly susceptible to infection and enterotoxigenic E. coli (ETEC)-associated diarrhea. Short-chain fatty acids and their glycerides are compounds that may influence intestinal health; however, valerate is one that has not been well-characterized for its role as a dietary supplement. Therefore, the major objective of this experiment was to investigate two forms of valerate glycerides on diarrhea, intestinal physiology, and systemic immunity of weaned pigs experimentally infected with ETEC F18. Dietary treatments included a control diet and three additional diets supplemented with 0.075% monovalerin, 0.1% monovalerin, or 0.1% trivalerin, respectively. Piglets were weaned (21 d to 24 d of age), individually housed, and experimental diets were fed through the 28-d trial period. After a 7-d period, all piglets were inoculated on three consecutive days with 1010 CFU ETEC F18/3 mL. Growth performance was monitored throughout the trial, and daily diarrhea scores were recorded. Rectal swabs were collected for bacterial culture to confirm the presence or absence of β-hemolytic coliforms throughout the trial. Serum samples were collected and analyzed for inflammatory biomarkers on days 0, 3, 6, and 21 postinoculation (PI) and untargeted metabolomics on day 6 PI. Intestinal mucosa and tissue sections were harvested from pigs sacrificed on day 7 PI for gene expression and histology analysis. All data, except for frequency of diarrhea and metabolomics, were analyzed by ANOVA using the PROC MIXED of SAS. Dietary trivalerin reduced (P < 0.05) the frequency of severe diarrhea over the entire trial period and the frequency of β-hemolytic coliforms on day 7 PI compared with the control. The intestinal villus height on day 7 PI in jejunum tissue was increased (P < 0.05) in pigs fed trivalerin. The mRNA expression of TNF-α was decreased (P < 0.05) in the trivalerin group, while that of ZO1 was increased (P < 0.05) compared with control. Throughout the trial, serum TNF-α was reduced in pigs fed trivalerin compared with control. Serum metabolites, adenosine, inosine, and shikimic acid were reduced (P < 0.05) on day 6 PI in all treatment groups compared with control. In conclusion, the present results indicate supplementing dietary valerate glycerides exhibited beneficial impacts on diarrhea, inflammation, and intestinal gene expression of piglets during the postweaning period.

Effects of supplemental citrulline on thermal and intestinal morphology parameters during heat stress and feed restriction in growing pigs

Study objectives were to characterize the effects of citrulline (CIT) on physiological and intestinal morphology metrics during heat stress (HS) and feed restriction. Forty crossbred gilts (30 ± 2 kg body weight [BW]) were assigned to one of five treatments: (1) thermoneutral (TN) fed ad libitum (AL) with control (CON) supplement (TNAL; n = 8), (2) TN pair-fed (PF) with CON (PF-CON; n = 8), (3) TN PF with CIT (PF-CIT; n = 8), (4) HS AL with CON (HS-CON; n = 8), and (5) HS AL with CIT (HS-CIT; n = 8). During the period (P) 1 (7 d), pigs were in TN conditions (23.6 °C) and fed AL their respective supplemental treatments. During P2 (2.5 d), HS-CON and HS-CIT pigs were fed AL and exposed to cyclical HS (33.6 to 38.3 °C), while TNAL, PF-CON, and PF-CIT remained in TN and were fed either AL or PF to their HS counterparts. Citrulline (0.13 g/kg BW) was orally administered twice daily during P1 and P2. HS increased rectal temperature (Tr), skin temperature (Ts), and respiration rate (RR) relative to TN pigs (0.8 °C, 4.7 °C, and 47 breaths/min, respectively; P < 0.01). However, HS-CIT had decreased RR (7 breaths/min, P = 0.04) and a tendency for decreased Tr (0.1 °C, P = 0.07) relative to HS-CON pigs. During P2, HS pigs had decreased feed intake (22%; P < 0.01) and a tendency for decreased average daily gain (P = 0.08) relative to TNAL pigs, and by experimental design, PF pigs followed this same pattern. Circulating lipopolysaccharide-binding protein tended to be decreased (29%; P = 0.08) in PF relative to TNAL pigs and was increased (41%; P = 0.03) in HS compared to PF pigs. Jejunum villus height was decreased in PF relative to TNAL pigs (15%; P = 0.03); however, CIT supplementation improved this metric during feed restriction (16%; P = 0.10). Jejunum mucosal surface area decreased in PF (16%; P = 0.02) and tended to decrease in HS (11%; P = 0.10) compared to TNAL pigs. Ileum villus height and mucosal surface area decreased in HS compared to TNAL pigs (10 and 14%, respectively; P ≤ 0.04), but both parameters were rescued by CIT supplementation (P ≤ 0.08). Intestinal myeloperoxidase and goblet cell area remained similar among treatments and intestinal segments (P > 0.24). In summary, CIT supplementation slightly improved RR and Tr during HS. Feed restriction and HS differentially affected jejunum and ileum morphology and while CIT ameliorated some of these effects, the benefit appeared dependent on intestinal section and stressor type.

A microencapsulated blend of botanicals supports weaning piglets during a lipopolysaccharide challenge by modulating liver inflammation and intestinal integrity

This study examined the action of a blend of botanicals (BOT) against lipopolysaccharide (LPS)-induced inflammation on cultured hepatocytes and weaning piglets. In vitro studies examined HepG2 cells treated with BOT and challenged with Escherichiacoli LPS for 8 d. BOT treatment reduced IL-6 concentration in cell culture media across time (P < 0.05) and decreased pro-inflammatory cytokine expression on days 1 and 8 of experiment (TNFα, IL-1β; P < 0.05). BOT also increased the expression of antioxidant enzymes (GPX-2, SOD, CAT) on day 8 (P < 0.05), which was supported by lowered reactive oxygen species concentration after LPS challenge (P < 0.1). The in vivo study was conducted with 72 weaning pigs, allotted into 24 pens and divided into 3 groups: a negative control (CTR-, basal diet), a challenged control (CTR+) that received an intraperitoneal injection of E. coli O55:B5 LPS on days 14 and 16, and a challenged treated group which received a diet containing 1.5 g/kg of microencapsulated BOT (BOT+) for the whole duration of the study. Growth performance was determined weekly and, on days 21 (1 animal per pen) and 28 (remaining animals), pigs were sacrificed to collect liver and jejunal tissues. After the challenge, BOT+ pigs had increased BW on days 21 (P < 0.05) and 28 (P < 0.1) compared to CTR+. Similar improvements in average daily gain and FCR on days 14 to 21 (P < 0.05) and 21 to 28 (P < 0.1) were also seen in BOT+ group. In the liver, compared to CTR+ pigs, BOT+ pigs had downregulated expression of TLR-4, IL-6, IFN-γ on day 21 (P < 0.05), and TLR-4, TNF-α, IL-8 on day 28 (P < 0.05). BOT+ also increased GPX-2 expression on days 21 and 28 (P < 0.05), while also upregulating SOD-1 and SOD-2 on day 21 (P < 0.05) and CAT on day 28 (P < 0.05) compared to CTR+. In the jejunum, BOT+ reduced inflammation by affecting cytokine expression (P < 0.05) and increasing the expression of tight-junction proteins, ZO-1 on day 21 and CLD-1 on day 28 (P < 0.05). Furthermore, BOT+ pigs had lower crypt depth on days 21 (P < 0.1) and 28 (P < 0.05), and increased villi-to-crypt ratio on days 21 and 28 (P < 0.05). By day 28, BOT+ intestinal measurements were restored to values similar to the CTR-. Finally, BOT+ also reduced mast cell activation on day 21 (P < 0.05) compared to CTR+. Considering all the findings, BOT controlled inflammatory activation and oxidative stress in liver cells, enhanced intestinal integrity, and as a result improved the growth performance of weaning piglets challenged with LPS.

Investigating intestinal mast cell dynamics during acute heat stress in growing pigs

Objectives were to examine the temporal pattern of intestinal mast cell dynamics and the effects of a mast cell stabilizer (ketotifen [Ket]) during acute heat stress (HS) in growing pigs. Crossbred barrows (n = 42; 32.3 ± 1.9 kg body weight [BW]) were randomly assigned to 1 of 7 environmental-therapeutic treatments: (1) thermoneutral (TN) control (TNCon; n = 6), (2) 2 h HS control (2 h HSCon; n = 6), (3) 2 h HS + Ket (2 h HSKet; n = 6); (4) 6 h HSCon (n = 6), (5) 6 h HSKet (n = 6), (6) 12 h HSCon (n = 6), or (7) 12 h HSKet (n = 6). Following 5 d of acclimation to individual pens, pigs were enrolled in two experimental periods (P). During P1 (3 d), pigs were housed in TN conditions (21.5 ± 0.8 °C) for the collection of baseline measurements. During P2, TNCon pigs remained in TN conditions for 12 h, while HS pigs were exposed to constant HS (38.1 ± 0.2 °C) for either 2, 6, or 12 h. Pigs were euthanized at the end of P2, and blood and tissue samples were collected. Regardless of time or therapeutic treatment, pigs exposed to HS had increased rectal temperature, skin temperature, and respiration rate compared to their TNCon counterparts (1.9 °C, 6.9° C, and 119 breaths/min; P < 0.01). As expected, feed intake and BW gain markedly decreased in HS pigs relative to their TNCon counterparts (P < 0.01). Irrespective of therapeutic treatment, circulating corticotropin-releasing factor decreased from 2 to 12 h of HS relative to TNCon pigs (P < 0.01). Blood cortisol increased at 2 h of HS (2-fold; P = 0.04) and returned to baseline by 6 h. Plasma histamine (a proxy of mast cell activation) remained similar across thermal treatments and was not affected by Ket administration (P > 0.54). Independent of Ket or time, HS increased mast cell numbers in the jejunum (94%; P < 0.01); however, no effects of HS on mast cell numbers were detected in the ileum or colon. Jejunum and ileum myeloperoxidase area remained similar among treatments (P > 0.58) but it tended to increase (12%; P = 0.08) in the colon in HSCon relative to TNCon pigs. Circulating lymphocytes and basophils decreased in HSKet relative to TN and HSCon pigs (P ≤ 0.06). Blood monocytes and eosinophils were reduced in HS pigs relative to their TNCon counterparts (P < 0.01). In summary, HS increased jejunum mast cell numbers and altered leukocyte dynamics and proinflammatory biomarkers. However, Ket administration had no effects on mast cell dynamics measured herein.

Changes in Rat Adrenal Cortex and Pineal Gland in Inverted Light-Dark Cycle: A Biochemical, Histological, and Immunohistochemical Study

Poor sleep standards are common in everyday life; it is frequently linked to a rise in stress levels. The adrenal gland interacts physiologically with the pineal gland in the stress response. Pineal gland is a small endocrine organ that modulates sleep patterns. This work aimed to evaluate the inverted light-dark cycle rhythm on the histological changes within the adrenal cortex and pineal gland in adult male albino rats. Twenty adult male albino rats were equally divided into two groups: For the first control group, animals were kept on daylight-darkness for 12-12 h. The second group was kept under an inverted 12- to 12-h light-darkness cycle for 4 weeks. Adrenal sections were subjected to biochemical, histological, and immunohistochemical study. Inverted light-dark cycle group recorded a significant elevation of plasma corticosterone, tissue malondialdehyde, tumor necrosis factor-α, and interleukin-1β (IL-1β) associated with a significant reduction of catalase and superoxide dismutase. Adrenal cortex showed biochemical and histological changes. Pineal glands also showed loss of lobular architecture. A significant upregulation in activated inducible nitric oxide synthase (iNOS) and B-cell lymphoma-associated X (Bax) immunohistochemical expression was recorded in adrenal cortex associating with downregulation in B-cell lymphoma 2 (Bcl-2). It could be concluded that subchronic inverted light-dark cycle exerted direct effects on adrenal cortex and the pineal glands.

Effects of Bacillus subtilis PB6 supplementation on production, metabolism, inflammatory biomarkers, and gastrointestinal tract permeability in transition dairy cows

Objectives were to evaluate the effects of Bacillus subtilis PB6 (BSP) on gastrointestinal tract permeability, metabolism, inflammation, and production parameters in periparturient Holstein cows. Multiparous cows (n = 48) were stratified by previous 305-d mature equivalent milk yield and parity and assigned to 1 of 2 top-dressed dietary treatments 21 d before expected calving through 63 DIM: (1) control (CON; 13 g/d calcium carbonate; n = 24) or (2) BSP (13 g/d BSP; CLOSTAT, Kemin Industries, Des Moines, IA; n = 24). Gastrointestinal tract permeability was evaluated in vivo using the oral paracellular marker chromium (Cr)-EDTA. Effects of treatment, time, and treatment × time were assessed using PROC MIXED of SAS version 9.4 (SAS Institute Inc.). Prepartum dry matter intake (DMI) was unaffected by treatment; however, BSP supplementation decreased postpartum DMI relative to CON (0.7 kg). Milk yield, energy-corrected milk (ECM), fat-corrected milk (FCM), and solids-corrected milk (SCM) increased in BSP cows compared with CON (1.6, 1.8, 1.6, and 1.5 kg, respectively). Decreased DMI and increased production collectively improved feed efficiency of milk yield, ECM, FCM, and SCM for BSP cows (6, 5, 5, and 5%, respectively). No treatment differences were observed for concentrations of milk fat, protein, total solids, somatic cell count, somatic cell score, body weight, or body condition score. Milk urea nitrogen concentrations decreased (5%), whereas milk protein and lactose yield increased (5 and 2%, respectively) with BSP supplementation. Prepartum fecal pH did not differ among treatments; conversely, postpartum fecal pH was increased with BSP supplementation (0.09 pH units). Prepartum fecal dry matter percentage, starch, acetic acid, propionic acid, butyric acid, and ethanol did not differ among treatments. Postpartum concentrations of the aforementioned fecal parameters were also unaffected by treatment, but fecal propionic acid concentration was decreased (24%) in BSP cows relative to CON. Circulating glucose, nonesterified fatty acids, l-lactate, and insulin were similar between treatments both pre- and postpartum. Prepartum β-hydroxybutyrate (BHB) did not differ between treatments, but postpartum BSP supplementation decreased (21%) circulating BHB relative to CON. Regardless of treatment, inflammatory markers (serum amyloid A and haptoglobin) peaked immediately following parturition and progressively decreased with time, but this pattern was not influenced by treatment. Postpartum lipopolysaccharide binding protein tended to be decreased on d 3 in BSP relative to CON cows (19%). Neither treatment nor time affected Cr-EDTA area under the curve. In summary, supplementing BSP had no detectable effects prepartum, but increased key postpartum production parameters. Bacillus subtilis PB6 consistently increased postpartum fecal pH and decreased fecal propionate concentrations but did not appear to have an effect on gastrointestinal tract permeability.

Interactions between corticotropin releasing factor signaling and prophylactic antibiotics on measures of intestinal function in weaned and transported pigs

The study objective was to evaluate the interaction between corticotrophin releasing factor (CRF) receptor signaling and prophylactic antibiotic administration on intestinal physiology in newly weaned and transported pigs. Pigs (n = 56; 5.70 ± 1.05 kg) were weaned (20.49 ± 0.64 d), a blood sample was taken, and then pigs were given an intraperitoneal injection of saline (SAL; n = 28 pigs) or a CRF receptor antagonist (CRFA; n = 28 pigs; 30 μg/kg body weight; Astressin B), and then were transported in a livestock trailer for 12 h and 49 min. A second and third intraperitoneal injection was given at 4 h 42 min and 11 h 36 min into the transport process, respectively. Following transport, 4 SAL and 4 CRFA pigs were blood sampled and euthanized. The remaining 48 pigs were individually housed and given dietary antibiotics [AB; n = 12 SAL and 12 CRFA pigs; chlortetracycline (441 ppm) + tiamulin (38.6 ppm)] or no dietary antibiotics (NAB; n = 12 SAL and 12 CRFA pigs) for 14 d post-transport. Blood was collected at 12 h and on d 3, 7, and 14, and then pigs were euthanized on d 7 (n = 24) and d 14 (n = 24) post-weaning and transport. Circulating cortisol was reduced (p = 0.05) in CRFA pigs when compared to SAL pigs post-weaning and transport. On d 7, jejunal villus height and crypt depth was greater overall (p < 0.05) in AB-fed pigs versus NAB-fed pigs. On d 14, ileal crypt depth was reduced (p = 0.02) in CRFA pigs when compared to SAL pigs. Jejunal CRF mRNA abundance tended to be reduced (p = 0.09) on d 7 in CRFA pigs versus SAL pigs. On d 14, jejunal tumor necrosis factor-alpha was reduced (p = 0.01) in AB-fed pigs versus NAB-fed pigs. On d 7, change in glucose short-circuit current tended to be increased (p = 0.07) in CRFA pigs fed the AB diet when compared to CRFA pigs fed the NAB diet. In conclusion, CRFA pigs and pigs fed AB had some similar biological intestinal function measures post-weaning and transport.

The impact of acute and chronic stress on gastrointestinal physiology and function: a microbiota-gut-brain axis perspective

The physiological consequences of stress often manifest in the gastrointestinal tract. Traumatic or chronic stress is associated with widespread maladaptive changes throughout the gut, although comparatively little is known about the effects of acute stress. Furthermore, these stress-induced changes in the gut may increase susceptibility to gastrointestinal disorders and infection, and impact critical features of the neural and behavioural consequences of the stress response by impairing gut-brain axis communication. Understanding the mechanisms behind changes in enteric nervous system circuitry, visceral sensitivity, gut barrier function, permeability, and the gut microbiota following stress is an important research objective with pathophysiological implications in both neurogastroenterology and psychiatry. Moreover, the gut microbiota has emerged as a key aspect of physiology sensitive to the effects of stress. In this review, we focus on different aspects of the gastrointestinal tract including gut barrier function as well as the immune, humoral and neuronal elements involved in gut-brain communication. Furthermore, we discuss the evidence for a role of stress in gastrointestinal disorders. Existing gaps in the current literature are highlighted, and possible avenues for future research with an integrated physiological perspective have been suggested. A more complete understanding of the spatial and temporal dynamics of the integrated host and microbial response to different kinds of stressors in the gastrointestinal tract will enable full exploitation of the diagnostic and therapeutic potential in the fast-evolving field of host-microbiome interactions.

A blend of selected botanicals maintains intestinal epithelial integrity and reduces susceptibility to Escherichia coli F4 infection by modulating acute and chronic inflammation in vitro

In the pig production cycle, the most delicate phase is weaning, a sudden and early change that requires a quick adaptation, at the cost of developing inflammation and oxidation, especially at the intestinal level. In this period, pathogens like enterotoxigenic Escherichia coli (ETEC) contribute to the establishment of diarrhea, with long-lasting detrimental effects. Botanicals and their single bioactive components represent sustainable well-recognized tools in animal nutrition thanks to their wide-ranging beneficial functions. The aim of this study was to investigate the in vitro mechanism of action of a blend of botanicals (BOT), composed of thymol, grapeseed extract, and capsicum oleoresin, in supporting intestinal cell health during inflammatory challenges and ETEC infections. To reach this, we performed inflammatory and ETEC challenges on Caco-2 cells treated with BOT, measuring epithelial integrity, cellular oxidative stress, bacterial translocation and adhesion, gene expression levels, and examining tight junction distribution. BOT protected enterocytes against acute inflammation: while the challenge reduced epithelial tightness by 40%, BOT significantly limited its drop to 30%, also allowing faster recovery rates. In the case of chronic inflammation, BOT systematically improved by an average of 25% the integrity of challenged cells (p < 0.05). Moreover, when cells were infected with ETEC, BOT maintained epithelial integrity at the same level as an effective antibiotic and significantly reduced bacterial translocation by 1 log average. The mode of action of BOT was strictly related to the modulation of the inflammatory response, protecting tight junctions' expression and structure. In addition, BOT influenced ETEC adhesion to intestinal cells (-4%, p < 0.05), also thanks to the reduction of enterocytes' susceptibility to pathogens. Finally, BOT effectively scavenged reactive oxygen species generated by inflammatory and H2O2 challenges, thus alleviating oxidative stress by 40% compared to challenge (p < 0.05). These results support the employment of BOT in piglets at weaning to help manage bacterial infections and relieve transient or prolonged stressful states thanks to the modulation of host-pathogen interaction and the fine-tuning activity on the inflammatory tone.

Early weaning and biological sex shape long-term immune and metabolic responses in pigs

During the early pre and postnatal life, host and environmental factors can impart a major influence on immune development, thus shaping lifelong disease resistance. Two major factors known to influence immune function and mortality in animals and people are early life stress and biological sex. How these two factors interact to shape long-term immune development and later life disease risk is poorly understood. Here we investigated how early weaning, a common early life stressor in pigs, and biological sex impacts long-term systemic inflammatory responses and hypothalamic-pituitary-adrenal axis (HPA axis) activation later in life. Ten-week-old female (F), intact-male (IM) and castrated-male (CM) pigs that were randomly assigned to early weaning (EW) and later weaning (LW) (at 15 or 28 days of age, respectively) were intramuscularly injected with either saline vehicle or lipopolysaccharide (LPS) to induce a systemic inflammatory response. Complete blood counts (CBC), proinflammatory cytokines, cortisol, testosterone, estradiol, and rectal temp were measured at 0 h, 2 h, and 4 h post-LPS challenge. At 4 h post-LPS, peritoneal fluid (PF) and white blood cells (WBC) were collected for differential analysis. LPS challenge significantly increased rectal temp and plasma cortisol level in all treatment groups. Together, the CBC results and immune cell counts in peritoneal cavity indicated that EW-F exhibited greater systemic immune response characterized by increased neutrophils to lymphocytes ratio (NLR) and enhanced neutrophil trafficking to the peritoneal cavity. Early weaning had an opposite effect on IM and CM pigs, which exhibited a suppressed LPS-induced neutrophil migration. Early weaning induced significantly greater cortisol responses only in IM pigs indicating a heightened HPA axis responses in EW-IM. how early weaning and biological sex affect immune and stress responses in pigs. Together, these results demonstrate that early weaning and biological sex and castration shape later life immune responses in pigs and provides insight into potential mechanisms driving sex differences in later life inflammatory disease risk and mortality.

Early life adversities and lifelong health outcomes: A review of the literature on large, social, long-lived nonhuman mammals

Social nonhuman animals are powerful models for studying underlying factors related to lifelong health outcomes following early life adversities (ELAs). ELAs can be linked to lifelong health outcomes depending on the species, system, sensitive developmental periods, and biological pathways. This review focuses on the literature surrounding ELAs and lifelong health outcomes in large, social, relatively long-lived nonhuman mammals including nonhuman primates, canids, hyenas, elephants, ungulates, and cetaceans. These mammals, like humans but unlike the most-studied rodent models, have longer life histories, complex social structures, larger brains, and comparable stress and reproductive physiology. Collectively, these features make them compelling models for comparative aging research. We review studies of caregiver, social, and ecological ELAs, often in tandem, in these mammals. We consider experimental and observational studies and what each has contributed to our knowledge of health across the lifespan. We demonstrate the continued and expanded need for comparative research to inform about the social determinants of health and aging in both humans and nonhuman animals.

Impact of Early Weaning on Development of the Swine Gut Microbiome

Considering that pigs are naturally weaned between 12 and 18 weeks of age, the common practice in the modern swine industry of weaning as early as between two and four weeks of age increases challenges during this transition period. Indeed, young pigs with an immature gut are suddenly separated from the sow, switched from milk to a diet consisting of only solid ingredients, and subjected to a new social hierarchy from mixing multiple litters. From the perspective of host gut development, weaning under these conditions causes a regression in histological structure as well as in digestive and barrier functions. While the gut is the main center of immunity in mature animals, the underdeveloped gut of early weaned pigs has yet to contribute to this function until seven weeks of age. The gut microbiota or microbiome, an essential contributor to the health and nutrition of their animal host, undergoes dramatic alterations during this transition, and this descriptive review aims to present a microbial ecology-based perspective on these events. Indeed, as gut microbial communities are dependent on cross-feeding relationships, the change in substrate availability triggers a cascade of succession events until a stable composition is reached. During this process, the gut microbiota is unstable and prone to dysbiosis, which can devolve into a diseased state. One potential strategy to accelerate maturation of the gut microbiome would be to identify microbial species that are critical to mature swine gut microbiomes, and develop strategies to facilitate their establishment in early post-weaning microbial communities.

Mast cell ontogeny: From fetal development to life-long health and disease

Mast cells (MCs) are evolutionarily ancient innate immune cells with important roles in protective immunity against bacteria, parasites, and venomous animals. They can be found in most organs of the body, where they also contribute to normal tissue functioning, for example by engaging in crosstalk with nerves. Despite this, they are most widely known for their detrimental roles in allergy, anaphylaxis, and atopic disease. Just like macrophages, mast cells were conventionally thought to originate from the bone marrow. However, they are already present in fetal tissues before the onset of bone marrow hematopoiesis, questioning this dogma. In recent years, our view of myeloid cell ontogeny has been revised. We now know that the first mast cells originate from progenitors made in the extra-embryonic yolk sac, and later get supplemented with mast cells produced from subsequent waves of hematopoiesis. In most connective tissues, sizeable populations of fetal-derived mast cells persist into adulthood, where they self-maintain largely independently from the bone marrow. These developmental origins are highly reminiscent of macrophages, which are known to have critical functions in development. Mast cells too may thus support healthy development. Their fetal origins and longevity also make mast cells susceptible to genetic and environmental perturbations, which may render them pathological. Here, we review our current understanding of mast cell biology from a developmental perspective. We first summarize how mast cell populations are established from distinct hematopoietic progenitor waves, and how they are subsequently maintained throughout life. We then discuss what functions mast cells may normally have at early life stages, and how they may be co-opted to cause, worsen, or increase susceptibility to disease.

Differential impact of yeast cell wall products in recovery of porcine intestinal epithelial cell barrier function following Lipopolysaccharide challenge

BACKGROUND

In swine intestinal barrier deterioration can be caused by exposure to harmful bacteria, toxins or contaminants that can lead to a leaky gut and post weaning diarrhoea. A leaky gut leads to increased infection, inflammation and poor nutrient absorption that can impair piglet growth and ultimately survival. Application of yeast cell wall (YCW) products may offer an opportunity to reduce the intestinal barrier damage caused by microbial challenge. A Mannan rich fraction (MRF) and three YCW products were compared by examining their impact on intestinal barrier function using a Jejunal model of intestine in response to a bacterial challenge using Salmonella LPS.

RESULTS

Trans epithelial electrical resistance (TEER) readings showed MRF had a significantly higher barrier function (P ≤ 0.05) over the positive control while YCW products A, B and C demonstrated no significant improvement to the positive control. Transcriptome analysis of the IPEC-J2 cells showed that differentially expressed genes associated with the gene ontology (GO) term for Structural molecule activity was significantly upregulated in the MRF treated cells over the positive control cells with 56 genes upregulated compared to product B (50 genes), Product C, (25 genes) and the negative control's 60 genes. Product A had no functional grouping under the structural molecule activity term. Both qPCR and western blotting analysis of tight junction associated genes showed that MRF treated cells demonstrated significantly higher Claudin 3 junctional gene expression (P ≤ 0.05) over the positive control and treatments A, B and C. Occludin expression was significantly higher in MRF treated cells (P ≤ 0.05) over the positive control and product B. A nonsignificant rise in TJP-1 gene expression was observed in the MRF treated cells when compared to the positive control. Protein abundances of Claudin 3, Occludin and TJP-1 were significantly (P ≤ 0.05) higher following MRF application to LPS challenged IPEC-J2 cells over the positive control.

CONCLUSIONS

The difference in each YCW products production and composition appeared to influence intestinal barrier integrity. The action of MRF demonstrates its potential ability to raise intestinal barrier integrity of IPEC-J2 intestinal cells on an in vitro level through significantly elevated intracellular connections.

RNA in extracellular vesicles during adolescence reveal immune, energetic and microbial imprints of early life adversity

Exposure to early life adversity (ELA), including childhood maltreatment, is one of the most significant risk factors for the emergence of neuropsychiatric disorders in adolescence and adulthood. Despite this relationship being well established, the underlying mechanisms remain unclear. One way to achieve this understanding is to identify molecular pathways and processes that are perturbed as a consequence of childhood maltreatment. Ideally, these perturbations would be evident as changes in DNA, RNA or protein profiles in easily accessible biological samples collected in the shadow of childhood maltreatment. In this study, we isolated circulating extracellular vesicles (EVs) from plasma collected from adolescent rhesus macaques that had either experienced nurturing maternal care (CONT) or maternal maltreatment (MALT) in infancy. RNA sequencing of RNA in plasma EVs and gene enrichment analysis revealed that genes related to translation, ATP synthesis, mitochondrial function and immune response were downregulated in MALT samples, while genes involved in ion transport, metabolism and cell differentiation were upregulated. Interestingly, we found that a significant proportion of EV RNA aligned to the microbiome and that MALT altered the diversity of microbiome-associated RNA signatures found in EVs. Part of this altered diversity suggested differences in prevalence of bacterial species in CONT and MALT animals noted in the RNA signatures of the circulating EVs. Our findings provide evidence that immune function, cellular energetics and the microbiome may be important conduits via which infant maltreatment exerts effects on physiology and behavior in adolescence and adulthood. As a corollary, perturbations of RNA profiles related to immune function, cellular energetics and the microbiome may serve as biomarkers of responsiveness to ELA. Our results demonstrate that RNA profiles in EVs can serve as a powerful proxy to identify biological processes that might be perturbed by ELA and that may contribute to the etiology of neuropsychiatric disorders in the aftermath of ELA.

The Effect of an Essential Oil Blend on Growth Performance, Intestinal Health, and Microbiota in Early-Weaned Piglets

Essential oils (EO) are promising feed additives for their antibacterial, antioxidant, and immune-enhancing abilities with low toxicity. Carvacrol, thymol, and cinnamaldehyde are commonly used to synthesize EO. However, few studies focus on combining these three EO in early-weaned piglets. In the present study, 24 piglets weaned at 21 d of age were randomly divided into 2 groups (6 replicate pens per group, 2 piglets per pen). The piglets were fed a basal diet (the control group) and a basal diet supplemented with 400 mg/kg EO (a blend consisting of carvacrol, thymol, and cinnamaldehyde, the EO group) for 28 days. At the end of the experiment, one piglet per pen was randomly chosen to be sacrificed. Growth performance, hematology, plasma biochemical indices, antioxidant capacity, intestinal epithelial development and immunity, colonic volatile fatty acids (VFA), and microbiota were determined. The results indicated that the diet supplemented with EO significantly improved average daily feed intake (ADFI, p < 0.01) and average daily gain (ADG, p < 0.05) in the day 0 to 28 period. EO supplementation led to a significant decrease in plasma lysozyme (p < 0.05) and cortisol levels (p < 0.01). Additionally, EO significantly promoted jejunal goblet cells in the villus, jejunal mucosa ZO-1 mRNA expression, ileal villus height, and ileal villus height/crypt depth ratio in piglets (p < 0.05). The ileal mucosal TLR4 and NFκB p-p65/p65 protein expression were significantly inhibited in the EO group (p < 0.05). Colonic digesta microbiota analysis revealed that bacteria involving the Erysipelotrichaceae family, Holdemanella genus, Phascolarctobacterium genus, and Vibrio genus were enriched in the EO group. In conclusion, these findings indicate that the EO blend improves ADG and ADFI in the day 0 to 28 period, as well as intestinal epithelial development and intestinal immunity in early-weaned piglets, which provides a theoretical basis for the combined use of EO in weaned piglets.

Asinine milk mitigates stress-mediated immune, cortisol and behavioral responses of piglets to weaning: A study to foster future interventions in humans

Introduction

The present study assessed whether asinine milk supplementation improved the immune and behavioral responses of piglets during an early life weaning stress event as a model for its future use in humans.

Methods

For this, 48 piglets from 4 different litters were used. At 20 days of age, piglets were weighed and allocated with their litter and dam into group pens until 28 days of age. Four piglets from each litter were then randomly assigned to either (1) asinine milk supplementation (n = 16) (2), skimmed cow milk supplementation (n = 16) or (3) no supplementation (n = 16; control group). The supplementations were voluntarily administered for 3 days preweaning and 3 days postweaning using a baby bottle. The effects on the weaning stress response were assessed through salivary cortisol measurements; behavioral tests such as the open field, novel object end elevated plus maze tests; and gene expression of HSD11B1, NR3C1 and IL1B in PBMCs, which was determined by RT-qPCR and normalized to GAPDH and UBB. To test the effect of the supplementations on weight, milk intake, gene expression, and behavior, a randomized block design was used with repeated measurements over time by the PROC MIXED procedure.

Results and discussion

The effects on salivary cortisol were determined using the ratio between the morning and afternoon concentrations, considering the time before and after the weaning event. Principal component analysis (PCA) and Fisher's test were performed to evaluate the behavior test data. When comparing salivary cortisol concentrations between the pre- and postweaning periods, there was a difference (p < 0.05) between the supplementation groups in the afternoon period, suggesting that piglets fed asinine milk had lower afternoon cortisol concentrations postweaning than their counterparts. For the behavioral tests, the supplementations had no measurable effects. No difference was between groups pre- and postweaning for the expression of HSD11B2, which codes for an enzyme that breaks down cortisol. However, the expression of NR3C1, which encodes the glucocorticoid receptor, was significantly upregulated in piglets supplemented with cow milk (mean 1.245; p < 0.05).

Conclusion

Asinine milk downregulated 1L1B gene expression, which codes for an inflammatory cytokine. In conclusion, these results suggest that supplementation with asinine milk may represent a strategy to diminish the damage associated with an early life event by modulating IL1B expression and reducing salivary cortisol levels in piglets undergoing weaning stress. Further transcriptomic and metabolomic studies may improve our understanding of the molecular pathways that mediate this systemic immune-mediated response.

Porcine blood cell and brain tissue energy metabolism: Effects of "early life stress"

Background: Early Life Stress (ELS) may exert long-lasting biological effects, e.g., on PBMC energy metabolism and mitochondrial respiration. Data on its effect on brain tissue mitochondrial respiration is scarce, and it is unclear whether blood cell mitochondrial activity mirrors that of brain tissue. This study investigated blood immune cell and brain tissue mitochondrial respiratory activity in a porcine ELS model. Methods: This prospective randomized, controlled, animal investigation comprised 12 German Large White swine of either sex, which were weaned at PND (postnatal day) 28-35 (control) or PND21 (ELS). At 20-24 weeks, animals were anesthetized, mechanically ventilated and surgically instrumented. We determined serum hormone, cytokine, and "brain injury marker" levels, superoxide anion (O₂ ^•¯) formation and mitochondrial respiration in isolated immune cells and immediate post mortem frontal cortex brain tissue. Results: ELS animals presented with higher glucose levels, lower mean arterial pressure. Most determined serum factors did not differ. In male controls, TNFα and IL-10 levels were both higher than in female controls as well as, no matter the gender in ELS animals. MAP-2, GFAP, and NSE were also higher in male controls than in the other three groups. Neither PBMC routine respiration and brain tissue oxidative phosphorylation nor maximal electron transfer capacity in the uncoupled state (ETC) showed any difference between ELS and controls. There was no significant relation between brain tissue and PBMC, ETC, or brain tissue, ETC, and PBMC bioenergetic health index. Whole blood O₂ ^•¯ concentrations and PBMC O₂ ^•¯ production were comparable between groups. However, granulocyte O₂ ^•¯ production after stimulation with E. coli was lower in the ELS group, and this effect was sex-specific: increased O₂ ^•¯ production increased upon stimulation in all control animals, which was abolished in the female ELS swine. Conclusion: This study provides evidence that ELS i) may, gender-specifically, affect the immune response to general anesthesia as well as O₂ ^•¯ radical production at sexual maturity, ii) has limited effects on brain and peripheral blood immune cell mitochondrial respiratory activity, and iii) mitochondrial respiratory activity of peripheral blood immune cells and brain tissue do not correlate.

The sex-dependent response to psychosocial stress and ischaemic heart disease

Stress is an important risk factor for modern chronic diseases, with distinct influences in males and females. The sex specificity of the mammalian stress response contributes to the sex-dependent development and impacts of coronary artery disease (CAD). Compared to men, women appear to have greater susceptibility to chronic forms of psychosocial stress, extending beyond an increased incidence of mood disorders to include a 2- to 4-fold higher risk of stress-dependent myocardial infarction in women, and up to 10-fold higher risk of Takotsubo syndrome-a stress-dependent coronary-myocardial disorder most prevalent in post-menopausal women. Sex differences arise at all levels of the stress response: from initial perception of stress to behavioural, cognitive, and affective responses and longer-term disease outcomes. These fundamental differences involve interactions between chromosomal and gonadal determinants, (mal)adaptive epigenetic modulation across the lifespan (particularly in early life), and the extrinsic influences of socio-cultural, economic, and environmental factors. Pre-clinical investigations of biological mechanisms support distinct early life programming and a heightened corticolimbic-noradrenaline-neuroinflammatory reactivity in females vs. males, among implicated determinants of the chronic stress response. Unravelling the intrinsic molecular, cellular and systems biological basis of these differences, and their interactions with external lifestyle/socio-cultural determinants, can guide preventative and therapeutic strategies to better target coronary heart disease in a tailored sex-specific manner.

Chitosan nanoparticles attenuate intestinal damage and inflammatory responses in LPS-challenged weaned piglets via prevention of IκB degradation

Chitosan nanoparticles (CNP), widely applied as oral drug/gene/vaccine carrier, were found to have anti-inflammatory properties. In this study, the effects of CNP on lipopolysaccharide (LPS)-induced intestinal damage in weaned piglets and the related mechanisms were investigated. Twenty-four weaned piglets (Duroc × Landrace × Yorkshire, 21 ± 2 day of age, initial mass: 8.58 ± 0.59 kg) were randomly assigned into four groups: control, LPS, CNP and CNP + LPS. The control and LPS groups were fed a corn-soybean meal-based control diet, whereas the CNP and CNP + LPS groups were fed a control diet supplemented with 400 mg/kg CNP. After 28 days of feeding, piglets in LPS and CNP + LPS groups were injected with LPS (100 μg/kg); meanwhile, the piglets in control and CNP groups were injected with sterile saline. After 4 h from the LPS challenge, pigs were sacrificed to collect the intestinal samples for analysis. The results showed that CNP could attenuate the intestinal damages and inflammatory response stimulated by LPS treatment. LPS induced dramatically higher levels of CD177⁺ neutrophils invasion in jejunum mucosa (p < 0.01), which accompanied by increased secretion of marks of inflammation (p < 0.01) compared with the control, whereas CNP administration obviously inhibited LPS-induced CD177⁺ neutrophils invasion (p < 0.01) and secretion of marks of inflammation, such as interleukin-8 (p < 0.05), intercellular adhesion molecule-1 (p < 0.05) secretion in jejunum mucosa compared with LPS group. Moreover, CNP was shown to inhibit IκB-α degradation in cytoplasm, which resulted in reduced nuclear translocation of NF-κB p65 in LPS-challenged piglets. These findings suggest that CNP attenuates intestinal damage and inflammatory responses in LPS-challenged weaned piglets by impairing the NF-κB signalling pathway.

Effects of mat feeding on the growth performance, removal, and mortality of pigs after weaning

Four experiments were conducted to determine the effect of mat feeding strategy on the growth performance, removal, and mortality of pigs after weaning. In exp. 1, 1,392 weanling pigs (initially 7.0 kg; approximately 24 d of age) were randomly allotted to 1 of 2 mat feeding treatments (mat feed vs. no mat feed). Overall, mat fed pigs had a tendency for improved ADG (P = 0.065) and G:F (P = 0.060) compared to pigs not offered mat feed. Mat fed pigs had fewer removals (P = 0.013) compared to pigs not offered mat feed. In exp. 2, 2,912 weanling pigs (initially 5.5 kg; approximately 21 d of age) were randomly allotted to 1 of 2 mat feeding treatments (mat feed vs. no mat feed). Overall, no differences in growth performance were observed. However, mat fed pigs had decreased (P < 0.026) final body weights compared to pigs not offered mat feed. This may be related to removal rates as mat fed pigs had fewer removals (P = 0.026). In exp. 3, 3,264 weanling pigs (initially 5.5 kg; approximately 21 d of age) were randomly allotted to 1 of 4 treatments in a 2 × 2 factorial with main effects of diet form (pellet or crumble) and mat feeding (mat feed vs. no mat feed). No interactions between diet form and mat feeding were observed. No differences were observed in overall growth performance for the main effect of mat feeding. Pigs offered pelleted feed had decreased overall ADFI (feed disappearance from the feeder and feed placed on the mat; P = 0.013) and improved G:F (P < 0.001) compared to pigs offered crumble feed. No differences were observed in removals or mortalities for the main effect of mat feeding or diet form. In exp. 4, 3,227 weanling pigs (initially 5.1 kg; approximately 21 d of age) were randomly allotted to 1 of 3 treatments consisting of mat feeding small (3.2 mm) pellets, mat feeding large (12.7 mm) pellets, or no mat feeding. Overall, no differences were observed in ADG or G:F. Mat fed pigs had increased ADFI (P < 0.001) compared to pigs not offered mat feed. Given the shorter duration of this experiment, the extra feed provided with mat feeding had a greater impact on overall feed usage than exp. 1, 2, and 3. No differences were observed in removals or mortalities. When combining the removal and mortality data for the four experiments, mat fed pigs had fewer removals (P = 0.002) compared to pigs not offered mat feed. In summary, mat feeding may encourage earlier feeding behavior, therefore reducing the removal rate of pigs post-weaning.

Weaning stress and intestinal health of piglets: A review

Weaning is considered to be one of the most critical periods in pig production, which is related to the economic benefits of pig farms. However, in actual production, many piglets are often subjected to weaning stress due to the sudden separation from the sow, the changes in diet and living environment, and other social challenges. Weaning stress often causes changes in the morphology and function of the small intestine of piglets, disrupts digestion and absorption capacity, destroys intestinal barrier function, and ultimately leads to reduced feed intake, increased diarrhea rate, and growth retardation. Therefore, correctly understanding the effects of weaning stress on intestinal health have important guiding significance for nutritional regulation of intestinal injury caused by weaning stress. In this review, we mainly reviewed the effects of weaning stress on the intestinal health of piglets, from the aspects of intestinal development, and intestinal barrier function, thereby providing a theoretical basis for nutritional strategies to alleviate weaning stress in mammals in future studies.

Pyrroloquinoline quinone regulates glycolipid metabolism in the jejunum via inhibiting AMPK phosphorylation of weaned pigs

Maintenance of intestinal metabolic function is important for optimal growth performance in post-weaning pigs. This study aimed to evaluate the effect of pyrroloquinoline quinone (PQQ) on maintaining intestinal glycolipid metabolism in weaned pigs. Seventy-two Duroc × Landrace × Yorkshire crossbred pigs were divided into two groups: pigs fed a basal diet (CTRL group) and pigs fed a basal diet supplemented with 3.0 mg kg^-1 PQQ (PQQ group). On d 14, serum was harvested from six pigs per group and the pigs were slaughtered to sample jejunal tissue. Compared with the CTRL group, pigs in the PQQ group had increased average daily gain (P < 0.05), decreased feed : gain (P < 0.05) and tended to have a reduced diarrhea ratio (P = 0.057). Jejunal villus height and villus height/crypt depth ratio were increased, and the crypt depth was decreased in the PQQ group (P < 0.01). The proteomics results showed that PQQ supplementation acted on three metabolic pathways, type I diabetes mellitus, the pancreatic secretion pathway and immune-related signalling. Compared with the CTRL group, PQQ supplementation increased (P < 0.05) serum insulin and jejunal mucosal pyruvate, triglyceride, total cholesterol and low-density lipoprotein cholesterol in the pigs. Jejunal mucosal lactic dehydrogenase and high-density lipoprotein cholesterol levels in the pigs were decreased by PQQ supplementation (P < 0.05). In addition, PQQ supplementation reduced glucose transporter 5 and phosphorylated-AMP-activated protein kinase expression in the jejunal mucosa of the pigs (P < 0.05). In conclusion, dietary supplementation with PQQ improved the growth performance and jejunal morphology and regulated glycolipid metabolism via inhibiting AMPK phosphorylation in weaned pigs.

Ameliorative effect and mechanism of Si-Ni-San on chronic stress-induced diarrhea-irritable bowel syndrome in rats

Background: Chronic stress-induced diarrhea is a common clinical condition, characterized by an abnormal bowel movement and loose stools, which lacks effective treatment in the clinic. Si-Ni-San (SNS) is a compound traditional Chinese medicine extensively used in China for stress-related diarrhea. However, the mechanism is unclear.

Methods: Male Wistar rats (200 ± 20 g) were placed in a restraint cylinder and fixed horizontally for 3 h once daily for 21 consecutive days to establish a chronic restraint stress (CRS) rat model. SNS (0.6944 g/kg or 1.3888 g/kg) was given by gavage 1 h before the restraint once daily for 21 consecutive days. We examined the fecal score, dopamine β hydroxylase (DβH), and c-fos expression in locus coeruleus, norepinephrine (NE) content in ileum and plasma, expression of α1 adrenergic receptors, MLCK, MLC, and p-MLC in the colon and mesenteric arteries, contraction of isolated mesenteric arteries, The expression of subunit δ of ATP synthase (ATP5D) in intestinal tissues, ATP, ADP, and AMP content in the ileum and colon, occludin expression between ileum epithelial cells, the number of enterochromaffin cells (ECs) and mast cells (MCs) in the ileum, and 5-hydroxytryptamine (5-HT) content in the ileum and plasma.

Results: After SNS treatment, the fecal score was improved. The increased expression of DβH and c-fos in locus coeruleus was inhibited. SNS suppressed the increased NE content in the ileum and plasma, down-regulated α1 adrenergic receptors in mesenteric arteries and MLCK, MLC, p-MLC in the colon and mesenteric arteries, and inhibited the contraction of mesenteric arteries. SNS also increased the ATP content in the ileum and colon, inhibited low expression of ATP5D in intestinal tissues, inhibited the decrease of ATP/ADP in the ileum and ATP/AMP in the colon, and up-regulated the occludin expression between ileum epithelial cells. In addition, SNS inhibited the increase of ECs and MCs in the ileum and the increase of 5-HT content in the ileum and plasma.

Conclusion: This study demonstrated that SNS could improve CRS-induced abnormal feces in rats. This effect was related to the inhibition of CRS-induced increased expression of DβH and c-fos in the locus coeruleus, NE content in the ileum and plasma, and the contraction of isolated mesenteric arteries; inhibition of energy metabolism abnormality and decreased occludin expression; inhibition of increased ECs and MCs in the ileum, and 5-HT content in the ileum and plasma.

Evaluation of a Dietary Grape Extract on Oxidative Status, Intestinal Morphology, Plasma Acute-Phase Proteins and Inflammation Parameters of Weaning Piglets at Various Points of Time

Reports of the underlying mechanisms of dietary grape extract (GE) in overcoming weaning challenges in piglets have been partly inconsistent. Furthermore, evaluations of the effects of GE at weaning in comparison to those of widely used therapeutic antibiotics have been scarce. To explore the mode of action of GE in selected tissues and plasma, we evaluated gut morphology, antioxidant and inflammation indices. Accordingly, 180 weaning piglets were allocated to three treatment groups: negative control (NC), NC and antibiotic treatment for the first 5 days of the trial (positive control, PC), and NC and GE (entire trial). The villus surface was positively affected by GE and PC on day 27/28 of the trial in the jejunum and on day 55/56 of the trial in the ileum. In the colon, NC tended (p < 0.10) to increase crypt parameters compared to PC on day 55/56. The PC group tended (p < 0.10) to increase catalase activity in the ileum and decrease Cu/Zn-SOD activity in the jejunum, both compared to NC. There were no additional effects on antioxidant measurements of tissue and plasma, tissue gene expression, or plasma acute-phase proteins. In conclusion, GE supplementation beneficially affected the villus surface of the small intestine. However, these changes were not linked to the antioxidant and anti-inflammatory properties of GE.

Socializing Models During Lactation Alter Colonic Mucosal Gene Expression and Fecal Microbiota of Growing Piglets

The enrichment of the social environment during lactation alleviates the stress of weaned piglets. It is significant to understand how the enriched social environment improves the weaning stress of piglets. RNA sequencing (RNA-seq) of colonic mucosa, 16S rRNA sequencing of feces, and short-chain fatty acids (SCFAs) of colonic content were used to determine the effects of social contact during lactation. In this study, thirty litter lactating piglets were divided into intermittent social contact (ISC) group that contacted with neighbors intermittently, continuous social contact (CSC) group that contacted with neighbors starting at day (D) 14 after birth, and control (CON) group in which piglets were kept in their original litter. The piglets were weaned at D35 and regrouped at D36. The colonic mucosal RNA-seq, fecal microbes, and SCFAs of colonic contents of 63-day-old piglets were analyzed. The results of RNA-seq showed that compared with the CON group, the pathways of digestion and absorption of minerals, protein, and vitamins of piglets were changed in the ISC group, whereas the pathways of retinol metabolism and nitrogen metabolism in the colonic mucosal were affected and stimulated the immune response in the CSC group. Compared with the CON group, the abundances of pernicious microorganisms (Desulfovibrio, Pseudomonas, Brevundimonas, etc.) in the CSC group and pernicious microorganisms (Desulfovibrio, Neisseria, Sutterella, etc.) and beneficial bacteria (Bifidobacterium, Megamonas, and Prevotella_9) in the ISC group were significantly higher (p < 0.05). The abundances of proinflammatory bacteria (Coriobacteriaceae_unclassified, Coprococcus_3, and Ruminococcus_2) in the CSC group were significantly increased (p < 0.05), but the abundances of SCFAs producing bacteria (Lachnospiraceae_UCG-010, Parabacteroides, Anaerotruncus, etc.) and those of anti-inflammatory bacteria (Eubacterium, Parabacteroides, Ruminiclostridium_9, and Alloprevotella) were significantly reduced (p < 0.05) in the CSC group. Compared with the CON group, the concentrations of microbial metabolites, acetate, and propionate in the colonic contents were reduced (p < 0.05) in the ISC group, whereas the concentration of acetate was reduced (p < 0.05) in the CSC group. Therefore, both ISC and CSC during lactation affected the composition of fecal microbes and changed the expression of intestinal mucosal genes related to nutrient metabolism and absorption of piglets.

Invited review: strategic adoption of antibiotic-free pork production: the importance of a holistic approach

The discovery of the use of antibiotics to enhance growth in the 1950s proved to be one of the most dramatic and influential in the history of animal agriculture. Antibiotics have served animal agriculture, as well as human and animal medicine, well for more than seven decades, but emerging from this tremendous success has been the phenomenon of antimicrobial resistance. Consequently, human medicine and animal agriculture are being called upon, through legislation and/or marketplace demands, to reduce or eliminate antibiotics as growth promotants and even as therapeutics. As explained in this review, adoption of antibiotic-free (ABF) pork production would represent a sea change. By identifying key areas requiring attention, the clear message of this review is that success with ABF production, also referred to as "no antibiotics ever," demands a multifaceted and multidisciplinary approach. Too frequently, the topic has been approached in a piecemeal fashion by considering only one aspect of production, such as the use of certain feed additives or the adjustment in health management. Based on the literature and on practical experience, a more holistic approach is essential. It will require the modification of diet formulations to not only provide essential nutrients and energy, but to also maximize the effectiveness of normal immunological and physiological capabilities that support good health. It must also include the selection of effective non-antibiotic feed additives along with functional ingredients that have been shown to improve the utility and architecture of the gastrointestinal tract, to improve the microbiome, and to support the immune system. This holistic approach will require refining animal management strategies, including selection for more robust genetics, greater focus on care during the particularly sensitive perinatal and post-weaning periods, and practices that minimize social and environmental stressors. A clear strategy is needed to reduce pathogen load in the barn, such as greater emphasis on hygiene and biosecurity, adoption of a strategic vaccine program and the universal adoption of all-in-all-out housing. Of course, overall health management of the herd, as well as the details of animal flows, cannot be ignored. These management areas will support the basic biology of the pig in avoiding or, where necessary, overcoming pathogen challenges without the need for antibiotics, or at least with reduced usage.

Gilt development to improve offspring performance and survivability

Methods for developing incoming replacement gilts can indirectly and directly influence survivability of their offspring. Indirectly, having proper gilt development reduces culling rates and mortality, which increases longevity and creates a more mature sow herd. Older sows are more likely to have greater immunity than gilts and therefore can pass this along to their pigs in both quantity and quality of colostrum and milk, thus improving piglet survivability. Directly, proper gilt development will maximize mammary gland development which increases colostrum and milk production leading to large, healthy pig. As for the developing gilt at birth, increasing colostrum intake, reducing nursing pressure, providing adequate space allowance, and good growth rate can increase the likelihood that gilts successfully enter and remain in the herd. Light birth weight gilts (<1 kg) or gilts from litters with low birth weight should be removed early in the selection process. Gilts should be weaned at 24 d of age or older and then can be grown in a variety of ways as long as lifetime growth rate is over 600 g/d. Current genetic lines with exceptional growth rate run the risk of being bred too heavy, reducing longevity. On the other hand, restricting feed intake at specific times could be detrimental to mammary development. In these situations, reducing diet amino acid concentration and allowing ad libitum feed is a possible strategy. Gilts should be bred between 135 and 160 kg and at second estrus or later while in a positive metabolic state to increase lifetime productivity and longevity in the herd. Once bred, gilts should be fed to maintain or build body reserves without becoming over-conditioned at farrowing. Proper body condition at farrowing impacts the percentage of pigs born alive as well as colostrum and milk production, and consequently, offspring performance and survivability. Combined with the benefit in pig immunity conferred by an older sow parity structure, gilt development has lasting impacts on offspring performance and survivability.

Biological sex: an understudied factor driving disease susceptibility in pigs

Biological sex is a major host factor influencing risk for infectious disease-associated mortality, and chronic inflammatory and metabolic diseases. Research in human and rodent models -has revealed sex differences that exist across organ systems during health and disease that may contribute to sex biases in disease risk. Despite the robust and growing literature on the role of sex as a risk factor in human disease, comparatively little attention has been focused on investigating the role of biological sex in disease susceptibility in agriculturally important animal populations such as the pig. To date, comparisons between sexes have focused on carcass composition, growth rate, and feed efficiency in pigs. However, there is a large gap in the literature regarding the effects of biological sex on other integral aspects of health and disease. The objective of this review is to highlight the available literature reporting sex differences in pig health and biology with an emphasis on sex differences in mortality, immunity, and gastrointestinal (GI) physiology and to address biological sex as a significant biological variable in disease risk and research study design. A basic overview of the biology of sex differences including the major hormonal and genetic/chromosomal mechanisms of sexual differentiation and the developmental periods in which sex differences emerge will be covered. This review will also discuss how production-relevant management and environmental factors (e.g., wean age, castration, stress, and nutrition) interact with biological sex to shape host immune and GI development and function. Perceived gaps in knowledge and areas of future research will also be discussed.

Impacts of weaning weights and mycotoxin challenges on jejunal mucosa-associated microbiota, intestinal and systemic health, and growth performance of nursery pigs

Background

This study aimed at investigating the effects of mycotoxin challenge on the growth and physiology of nursery pigs with different weaning weights.

Results

At weaning, 10 pigs were euthanized to collect jejunal mucosa and 90 pigs were assigned following a randomized complete block design in a 2 × 2 factorial arrangement of treatments with 3 pigs per pen. Factors were: weaning weight (light: body weight, BW < 7.5 kg or heavy: BW > 9.0 kg); and dietary mycotoxins (supplementation of 0.2 mg/kg aflatoxins, 2.0 mg/kg deoxynivalenol). All diets had titanium dioxide as an external marker at 0.5%. Growth performance and fecal score were recorded until pigs achieved 20 kg BW (light pigs average BW = 21.1 kg and heavy pigs average BW = 20.5 kg). Pigs were sampled for blood, ileal digesta, jejunal tissue and mucosa at 20 kg BW. Data were analyzed using the mixed procedure of SAS. At weaning, light pigs had decreased (P < 0.05) jejunal interleukin-8, increased (P < 0.05) tumor necrosis factor-α, and increased (P < 0.05) α-diversity indexes of jejunal mucosa-associated microbiota. At 20 kg of BW, light pigs had decreased (P < 0.05) average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G/F). Mycotoxins decreased (P < 0.05) BW, ADG, ADFI, and G/F. Light pigs tended to have increased fecal score on d 0 (P = 0.080), d 10 (P = 0.069), and increased (P < 0.05) fecal score at 20 kg. Mycotoxins decreased the apparent ileal digestibility of nitrogen (P < 0.05). Light pigs had increased (P < 0.05) intestinal malondialdehydes and interleukin 8. Mycotoxins tended to increase (P = 0.060) intestinal tumor necrosis factor-α.

Conclusions

Nursery pigs with light weaning weight were more susceptible to jejunal inflammation and had impaired intestinal health due to weaning stress, whereas mycotoxins diminished the health and growth of nursery pigs regardless of weaning weight.

Developmental alterations of intestinal SGLT1 and GLUT2 induced by early weaning coincides with persistent low-grade metabolic inflammation in female pigs

Early-life adversity (ELA) is linked with the increased risk for inflammatory and metabolic diseases in later life, but the mechanisms remain poorly understood. Intestinal epithelial glucose transporters sodium-glucose-linked transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) are the major route for intestinal glucose uptake but have also received increased attention as modulators of inflammatory and metabolic diseases. Here, we tested the hypothesis that early weaning (EW) in pigs, an established model of ELA, alters the development of epithelial glucose transporters and coincides with elevated markers of metabolic inflammation. The jejunum and ileum of 90-day-old pigs previously exposed to EW (16 days wean age), exhibited reduced SGLT1 activity (by ∼ 30%, P < 0.05) than late weaned (LW, 28 days wean age) controls. In contrast, GLUT2-mediated glucose transport was increased (P = 0.003) in EW pigs than in LW pigs. Reciprocal changes in SGLT1- and GLUT2-mediated transport coincided with transporter protein expression in the intestinal brush-border membranes (BBMs) that were observed at 90 days and 150 days of age. Ileal SGLT1-mediated glucose transport and BBM expression were inhibited by the β-adrenergic receptor (βAR) blocker propranolol in EW and LW pigs. In contrast, propranolol enhanced ileal GLUT2-mediated glucose transport (P = 0.015) and brush-border membrane vesicle (BBMV) abundance (P = 0.035) in LW pigs, but not in EW pigs. Early-weaned pigs exhibited chronically elevated blood glucose and C-reactive protein (CRP) levels, and adipocyte hypertrophy and upregulated adipogenesis-related gene expression in visceral adipose tissue. Altered development of intestinal glucose transporters by EW could underlie the increased risk for later life inflammatory and metabolic diseases.NEW & NOTEWORTHY These studies reveal that early-life adversity in the form of early weaning in pigs causes a developmental shift in intestinal glucose transport from SGLT1 toward GLUT2-mediated transport. Early weaning also induced markers of metabolic inflammation including persistent elevations in blood glucose and the inflammatory marker CRP, along with increased visceral adiposity. Altered intestinal glucose transport might contribute to increased risk for inflammatory and metabolic diseases associated with early-life adversity.

Characterization of Bacterial Microbiota Composition in Healthy and Diarrheal Early-Weaned Tibetan Piglets

The occurrence of diarrhea in Tibetan piglets is highly notable, but the microorganisms responsible are yet unclear. Its high incidence results in serious economic losses for the Tibetan pig industry. Moreover, the dynamic balance of intestinal microflora plays a crucial role in maintaining host health, as it is a prime cause of diarrhea. Therefore, the present study was performed to analyze the characteristics of bacterial microbiota structure in healthy, diarrheal and treated weaned piglets in Tibet autonomous region for providing a theoretical basis to prevent and control diarrhea. The study was based on the V3–V4 region of the 16S rRNA gene and gut microbiota functions following the metagenome analysis of fresh fecal samples (n = 5) from different groups. The Shannon and Simpson indices differed substantially between diarrheal and treated groups (p < 0.05). According to our findings, the beta diversities, especially between healthy and diarrheal groups, were found different. Firmicutes, Bacteroidetes and Proteobacteria were the dominant phyla in three groups. Furthermore, the abundance of Fusobacteria in the diarrheal group was higher than the other groups. The dominant genera in the diarrheal group were Fusobacterium, Butyricimonas, Sutterella, Peptostreptococcus, and Pasteurella. Moreover, Lactobacillus, Megasphaera and Clavibacter were distinctly less abundant in this group. It is noteworthy that the specific decrease in the abundance of pathogenic bacteria after antibiotic treatment in piglets was noticed, while the level of Lactobacillus was evidently increased. In conclusion, fecal microbial composition and structure variations were discovered across the three groups. Also, the ecological balance of the intestinal microflora was disrupted in diarrheal piglets. It might be caused by a reduction in the relative number of beneficial bacteria and an increase in the abundance of pathogenic bacteria. In the context of advocating for non-resistant feeding, we suspect that the addition of probiotics to feed may prevent early-weaning diarrhea in piglets. Moreover, our findings might help for preventing diarrhea in weaned Tibetan piglets with a better understanding of microbial population dynamics.

Assessing the Effectiveness of Providing Live Black Soldier Fly Larvae (Hermetia illucens) to Ease the Weaning Transition of Piglets

Weaning is a stressful event for piglets, involving substantial changes to their nutritional and social environment. Providing edible enrichment around weaning may ease the weaning transition by increasing pre-weaning feed intake and improving post-weaning performance, health, behavior, and affective state. In this study, we investigated the effects of providing live black soldier fly larvae (BSFL) as edible enrichment pre- and/or post-weaning. Pre-weaning, piglets received either only creep feed (Pre-C, n = 14 litters) or creep feed and live BSFL (Pre-L, n = 15 litters) ad libitum, and post-weaning piglets either had no access to live BSFL (Post-C, n = 24 pens) or they could rotate tubes that released BSFL (Post-L, n = 24 pens) at levels up to 20% of their expected daily dry matter intake, resulting in treatments CC, CL, LC, and LL. No interaction between pre- and post-weaning treatment was found for any of the measured parameters. Before weaning, Pre-L piglets preferred to interact with larvae over creep feed, and Pre-C piglets interacted more with creep feed than Pre-L piglets. Total time spent on feed-directed behaviors did not differ. Continuous larvae provisioning increased caecum length and proximal stomach digesta pH, while it decreased the passage of glucose and fluorescein isothiocyanate through the colon wall on d3 post-weaning (CC vs. LL, n = 12 piglets/treatment). Post-weaning diarrhea and final body weight were not affected by treatment. After weaning, Pre-C piglets tended to eat more and grew marginally faster than Pre-L piglets. Post-C piglets spent more time eating and had a higher feed intake post-weaning than Post-L piglets. Based on home-pen behavioral observations, Post-L piglets actively explored and ate the larvae. Post-C piglets spent more time on exploring the environment and nosing pen mates, and they spent more time on manipulating pen mates on d8 and played more on d8 & 15 compared to Post-L piglets. Piglet responses to a novel environment and an attention bias test on d4 & 5 post-weaning were not influenced by larvae provisioning. In conclusion, pre-weaning larvae provisioning did not improve pre-weaning feed intake and post-weaning performance, however post-weaning larvae provisioning did benefit piglet behavior as less manipulation of pen mates was observed.

Early social contact alters the community structure and functions of the faecal microbiome in suckling-growing piglets

Social contact during suckling, in an enriched social environment, can reduce the aggressive behaviours of piglets during regrouping at weaning, and improve their production performance and welfare. The aim of this study was to determine the possible impact of suckling social contact on gut microbes. We performed 16S rRNA sequencing to measure the faecal microbial structure and function in piglets experiencing social contact. Eighteen-litter piglets were allocated to two treatments: an early continuous social contact (CSC) group where piglets from adjacent pens shared a mutual pen starting at 14 days postpartum and a control (CON) group where piglets had no contact with individuals from adjacent pens during the suckling period. The piglets were regrouped at 36 days of age. The litter weights at 35 and 63 days of age were measured. Faecal samples were randomly collected at 16, 35, 42, and 63 days of age and faecal DNA was determined. The results showed that the litter weight of piglets in the CSC group was significantly decreased at 63 days compared with the CON group. Continuous social contact also significantly decreased the microbial richness at 16 and 35 days of age (P < 0.05). Firmicutes was the most abundant bacterial phylum in both groups at all detected time-points and the abundance increased with social contact. At the genus level, Lactobacillus was the most abundant bacterium after weaning and the abundance increased in the piglets with social contact. Compared with the faecal microbiota of control piglets, a total of 22 genera at 16 days, 20 genera at 35 days, 12 genera at 42 days, and 27 genera at 63 days in the faeces of CSC piglets were observed to be significantly different in abundance (linear discriminant analysis score > 3, P < 0.05). Furthermore, functional analysis of the microbial composition showed that the changes induced by early CSC mainly altered the relative abundance of metabolic and related pathways. The social contact notably had an effect on the abundance of microbial pathways for amino acid and carbohydrate metabolism. In conclusion, CSC changed the microbial composition in the faeces of piglets, which might have a negative effect on nutrient metabolism for the suckling-growing piglets. Our study provided new insight into the influence of social contact on the suckling-growing piglets.

Age-Dependent Intestinal Repair: Implications for Foals with Severe Colic

Colic is a leading cause of death in horses, with the most fatal form being strangulating obstruction which directly damages the intestinal barrier. Following surgical intervention, it is imperative that the intestinal barrier rapidly repairs to prevent translocation of gut bacteria and their products and ensure survival of the patient. Age-related disparities in survival have been noted in many species, including horses, humans, and pigs, with younger patients suffering poorer clinical outcomes. Maintenance and repair of the intestinal barrier is regulated by a complex mucosal microenvironment, of which the ENS, and particularly a developing network of subepithelial enteric glial cells, may be of particular importance in neonates with colic. Postnatal development of an immature enteric glial cell network is thought to be driven by the microbial colonization of the gut and therefore modulated by diet-influenced changes in bacterial populations early in life. Here, we review the current understanding of the roles of the gut microbiome, nutrition, stress, and the ENS in maturation of intestinal repair mechanisms after foaling and how this may influence age-dependent outcomes in equine colic cases.

Impacts of weaning age on dietary needs of whey permeate for pigs at 7 to 11 kg body weight

Background

Whey permeate is an effective lactose source for nursery pigs and the most benefits are obtained when pigs are at 7 to 11 kg BW. Altering weaning ages could cause different length of early-weaner phases until 7 kg BW and thus it would influence the dietary need of whey permeate during 7 to 11 kg BW of pigs. This study aimed to evaluate if weaning ages would affect the dietary needs of whey permeate for optimum growth performance of pigs at 7 to 11 kg BW.

Methods

A total of 1,632 pigs were weaned at d 21 (d 21.2 ± 1.3) or d 25 (d 24.6 ± 1.1) after birth. All pigs had a common early-weaner feeds until they reached 7 kg BW. When pigs reached 7 kg BW within a weaning age group, they were allotted in a randomized complete block design (2 × 4 factorial). Two factors were weaning age groups (21 and 25 d of age) and varying whey permeate levels (7.50%, 11.25%, 15.00%, and 18.75%). Data were analyzed using the GLM and NLIN procedures of SAS for slope-ratio and broken-line analyses to determine the growth response to whey permeate and optimal daily whey permeate intake for the growth of the pigs weaned at different ages.

Results

Pigs weaned at 21 d of age had a common diet for 11 d to reach 7 kg BW whereas pigs weaned at 25 d of age needed 2 d. The G:F of pigs weaned at 25 d of age responded to increased daily whey permeate intake greater (P < 0.05) than pigs weaned at 21 d of age. Breakpoints were obtained (P < 0.05) at 88 and 60 g/d daily whey permeate intake or 17.0% and 14.4% of whey permeate for G:F of pigs weaned at 21 and 25 d of age, respectively.

Conclusion

Pigs weaned at an older age with a short early-weaner phase had a greater growth response to whey permeate intake compared with pigs weaned at a younger age with a long early-weaner phase. Altering weaning ages affected dietary needs of whey permeate for optimum growth performance of pigs from 7 to 11 kg BW.

Resveratrol Improves Growth Performance, Intestinal Morphology, and Microbiota Composition and Metabolism in Mice

Background

Resveratrol (RSV) plays a vital role in alleviating various stresses and improving intestinal health. The current study was conducted to explore whether RSV alleviates weaning stress through improving gut health in a weaning mouse model. Forty 21-day-old weaned mice were randomly assigned to a control group without RSV treatment and three treatment groups with 10, 20, and 50 mg/kg RSV for 28 days.

Results

The results showed that RSV at a dose of 20 mg/kg improved total body weight, intestinal morphology (villus length and the ratio of villus length to crypt depth), and the levels of intestinal barrier proteins (claudin-1 and occludin), but had little effect on the food intake, crypt depth, and serum free amino acids of mice. Compared with the control group, mice supplemented with RSV had decreased mRNA expression of genes related to inflammatory cytokines (IL-6 and IL-1β), but increased mRNA expression of genes related to host defense peptides (Defa3, Defa5, Defa20, and Lyz) and short-chain fatty acids (SCFAs) production (propionic acid, isobutyric acid, butyric acid, and isovaleric acid). In addition, 16S rRNA sequencing results showed that RSV supplementation increased the richness indices of intestinal microbiota (Chao, ACE) and shaped the composition of intestinal microbiota (e.g., increased β-diversity of intestinal microbiota community). Meanwhile, RSV supplementation increased genes of Butyricicoccus, Ruminococcus_1, and Roseburia, which are producers of SCFAs. Furthermore, RSV supplementation significantly influenced the metabolism of intestinal microbiota, namely, amino acids metabolism, lipid metabolism, and defense mechanisms.

Conclusion

RSV can improve growth performance and intestinal morphology in weaning mice, possibly through improving gut immune response and microbiota function.

Biological Connection of Psychological Stress and Polytrauma under Intensive Care: The Role of Oxytocin and Hydrogen Sulfide

This paper explored the potential mediating role of hydrogen sulfide (H2S) and the oxytocin (OT) systems in hemorrhagic shock (HS) and/or traumatic brain injury (TBI). Morbidity and mortality after trauma mainly depend on the presence of HS and/or TBI. Rapid "repayment of the O2 debt" and prevention of brain tissue hypoxia are cornerstones of the management of both HS and TBI. Restoring tissue perfusion, however, generates an ischemia/reperfusion (I/R) injury due to the formation of reactive oxygen (ROS) and nitrogen (RNS) species. Moreover, pre-existing-medical-conditions (PEMC's) can aggravate the occurrence and severity of complications after trauma. In addition to the "classic" chronic diseases (of cardiovascular or metabolic origin), there is growing awareness of psychological PEMC's, e.g., early life stress (ELS) increases the predisposition to develop post-traumatic-stress-disorder (PTSD) and trauma patients with TBI show a significantly higher incidence of PTSD than patients without TBI. In fact, ELS is known to contribute to the developmental origins of cardiovascular disease. The neurotransmitter H2S is not only essential for the neuroendocrine stress response, but is also a promising therapeutic target in the prevention of chronic diseases induced by ELS. The neuroendocrine hormone OT has fundamental importance for brain development and social behavior, and, thus, is implicated in resilience or vulnerability to traumatic events. OT and H2S have been shown to interact in physical and psychological trauma and could, thus, be therapeutic targets to mitigate the acute post-traumatic effects of chronic PEMC's. OT and H2S both share anti-inflammatory, anti-oxidant, and vasoactive properties; through the reperfusion injury salvage kinase (RISK) pathway, where their signaling mechanisms converge, they act via the regulation of nitric oxide (NO).

Alginate oligosaccharide protects against enterotoxigenic Escherichia coli-induced porcine intestinal barrier injury

Alginate oligosaccharide (AOS) possesses various pharmaceutical benefits, making it an attractive candidate for biomedical applications. In the present study, we prepared AOS by depolymerising alginate; its degree of polymerisation mainly ranged from 2 to 8. We confirmed the enteroprotective potential of AOS against enterotoxigenic Escherichia coli (ETEC)-induced intestinal barrier injury in weaned pigs. Next, we illustrated the mechanisms underlying this effect of AOS using the porcine small intestinal epithelial cell line IPEC-J2. AOS potently reduced the binding of the bacteria-deprived endotoxin lipopolysaccharide (LPS) to the IPEC-J2 cell surface. Moreover, it suppressed the LPS-induced production of pro-inflammatory cytokines and the nuclear translocation of nuclear factor-κB (NF-κB) p65 in IPEC-J2 cells. These results indicate that AOS protects the intestinal epithelium from ETEC-induced inflammatory injury by preventing the activation of NF-κB, implying that AOS could be used as an anti-inflammatory agent for treating inflammation-related intestinal diseases in mammals.

Invited review: The influence of immune activation on transition cow health and performance-A critical evaluation of traditional dogmas

The progression from gestation into lactation represents the transition period, and it is accompanied by marked physiological, metabolic, and inflammatory adjustments. The entire lactation and a cow's opportunity to have an additional lactation are heavily dependent on how successfully she adapts during the periparturient period. Additionally, a disproportionate amount of health care and culling occurs early following parturition. Thus, lactation maladaptation has been a heavily researched area of dairy science for more than 50 yr. It was traditionally thought that excessive adipose tissue mobilization in large part dictated transition period success. Further, the magnitude of hypocalcemia has also been assumed to partly control whether a cow effectively navigates the first few months of lactation. The canon became that adipose tissue released nonesterified fatty acids (NEFA) and the resulting hepatic-derived ketones coupled with hypocalcemia lead to immune suppression, which is responsible for transition disorders (e.g., mastitis, metritis, retained placenta, poor fertility). In other words, the dogma evolved that these metabolites and hypocalcemia were causal to transition cow problems and that large efforts should be enlisted to prevent increased NEFA, hyperketonemia, and subclinical hypocalcemia. However, despite intensive academic and industry focus, the periparturient period remains a large hurdle to animal welfare, farm profitability, and dairy sustainability. Thus, it stands to reason that there are alternative explanations to periparturient failures. Recently, it has become firmly established that immune activation and the ipso facto inflammatory response are a normal component of transition cow biology. The origin of immune activation likely stems from the mammary gland, tissue trauma during parturition, and the gastrointestinal tract. If inflammation becomes pathological, it reduces feed intake and causes hypocalcemia. Our tenet is that immune system utilization of glucose and its induction of hypophagia are responsible for the extensive increase in NEFA and ketones, and this explains why they (and the severity of hypocalcemia) are correlated with poor health, production, and reproduction outcomes. In this review, we argue that changes in circulating NEFA, ketones, and calcium are simply reflective of either (1) normal homeorhetic adjustments that healthy, high-producing cows use to prioritize milk synthesis or (2) the consequence of immune activation and its sequelae.

Fructooligosaccharides improve growth performance and intestinal epithelium function in weaned pigs exposed to enterotoxigenic Escherichia coli

To explore the protective effect of Fructooligosaccharides (FOS) against Enterotoxigenic Escherichia coli (ETEC)-induced inflammation and intestinal injury, twenty-four weaned pigs were randomly assigned into three groups: (1) non-challenge (CON, fed with basal diet), (2) ETEC-challenge (ECON, fed with basal diet), and (3) ETEC challenge + FOS treatment (EFOS, fed with basal diet plus 2.5 g kg-1 FOS). On day 19, the CON group was orally infused with sterilized culture while pigs in the ECON group and EFOS group were orally infused with ETEC (2.5 × 1011 colony-forming units). After 3 days, pigs were slaughtered for sample collection. We showed that ETEC challenge significantly reduced average daily gain (ADG); however, FOS improved the ADG (P < 0.05), apparent digestibility of crude protein (CP), gross energy (GE), and ash and reduced the diarrhea incidence (P < 0.05). FOS reduced plasma concentrations of IL-1β and TNF-α and down-regulated (P < 0.05) the mRNA expression of IL-6 and TNF-α in the jejunum and ileum as well as IL-1β and TNF-α in the duodenum. The concentrations of plasma immunoglobulin A (IgA), immunoglobulin M (IgM) and secreted IgA (SIgA) in the jejunum (P < 0.05) were elevated. Interestingly, FOS elevated the villus height in the duodenum, and elevated the ratio of villus height to crypt depth in the duodenum and ileum in the EFOS group pigs (P < 0.05). Moreover, FOS increased lactase activity in the duodenum and ileum (P < 0.05). The activities of sucrase and alkaline phosphatase (AKP) were higher in the EFOS group than in the ECON group (P < 0.05). Importantly, FOS up-regulated the expressions of critical genes in intestinal epithelium function such as zonula occludens-1 (ZO-1), L-type amino acid transporter-1 (LAT1), and cationic amino acid transporter-1 (CAT1) in the duodenum and the expressions of ZO-1 and glucose transporter-2 (GLUT2) in the jejunum (P < 0.05). FOS also up-regulated the expressions of occludin, fatty acid transporter-4 (FATP4), sodium glucose transport protein 1 (SGLT1), and GLUT2 in the ileum (P < 0.05). FOS significantly increased the concentrations of acetic acid, propionic acid and butyric acid in the cecal digesta. Additionally, FOS reduced the populations of Escherichia coli, but elevated the populations of Bacillus and Bifidobacterium in the caecal digesta (P < 0.05). These results suggested that FOS could improve the growth performance and intestinal health in weaned pigs upon ETEC challenge, which was associated with suppressed inflammatory responses and improved intestinal epithelium functions and microbiota.