Nutrition and pathology of weaner pigs: Nutritional strategies to support barrier function in the gastrointestinal tract

Effects of dietary yeast mannan-rich fraction supplementation on growth performance, intestinal morphology, and lymphoid tissue characteristics in weaned piglets challenged with Escherichia Coli F4

We evaluated the effects of supplementing yeast mannan-reach-fraction on growth performance, jejunal morphology and lymphoid tissue characteristics in weaned piglets challenged with E. Coli F4. A total of 20 crossbred piglets were used. At weaning, piglets were assigned at random to one of four groups: piglets challenged and fed the basal diet supplemented with yeast mannan-rich fraction (C-MRF, n = 5); piglets challenged and fed the basal diet (C-BD, n = 5); piglets not challenged and fed the basal diet supplemented with yeast mannan-rich fraction (NC-MRF, n = 5), and piglets not challenged and fed the basal diet (NC-BD). Each dietary treatment had five replicates. On days 4, 5 and 10, piglets were orally challenged with 108 CFU/mL of E. Coli F4. C-MRF piglets had higher BW (p = 0.002; interactive effect) than C-BD piglets. C-MRF piglets had higher (p = 0.02; interactive effect) ADG in comparison with C-BD piglets. C-MRF piglets had higher (p = 0.04; interactive effect) ADFI than C-BD piglets. The diameter of lymphoid follicles was larger (p = 0.010; interactive effect) in the tonsils of C-MRF piglets than C-BD piglets. Lymphoid cells proliferation was greater in the mesenteric lymphnodes and ileum (p = 0.04 and p = 0.03, respectively) of C-MRF piglets. A reduction (p > 0.05) in E. Coli adherence in the ileum of piglets fed MRF was observed. In conclusion, the results of the present study demonstrate that dietary yeast mannan-rich fraction supplementation was effective in protecting weaned piglets against E. Coli F4 challenge.

Effects of Dietary Glutamine Supplementation on the Modulation of Microbiota and Th17/Treg Immune Response Signaling Pathway in Piglets after Lipopolysaccharide Challenge

BACKGROUND

Glutamine (Gln) has an important effect on the growth performance and immune function of piglets. However, the effect of Gln on intestinal immunity in piglets through modulating the signaling pathways of the helper T cells 17 (Th17)/regulatory T cells (Treg) immune response has not been reported.

OBJECTIVE

This study aimed to determine the effect of Gln on piglet growth performance and immune stress response and its mechanism in piglets.

METHODS

Twenty-four weaned piglets were randomly assigned to 4 treatments with 6 replicates each, using a 2 × 2 factorial arrangement: diet (basal diet or 1% Gln diet) and immunological challenge [saline or lipopolysaccharide (LPS)]. After 21 d, half of the piglets on the basal diet and 1% Gln diet received the intraperitoneal injection of LPS and the other half received the same volume of normal saline.

RESULTS

The results showed that Gln increased average daily feed intake and average daily weight gain in comparison with the control group (P < 0.05). Dietary Gln increased the villus height, villus height-to-crypt depth ratio, and the abundance of Bacteroidetes, Lactobacillus sp., and Ruminococcus sp. while reducing the abundance of Firmicutes, Clostridium sensu stricto 1 sp., and Terrisporobacter sp. (P < 0.05). Furthermore, Gln increased the concentration of short-chain fatty acids in the colon and the expression of genes of interleukin (IL)-10, transforming growth factor-beta-1, forkhead box P3 while downregulating the expression of genes of IL-6, IL-8, IL-1β, tumor necrosis factor-α, IL-17A, IL-21, signal transducer and activator of transcription 3, and rar-related orphan receptor c in ileum (P < 0.05). Correlation analysis demonstrated a strong association between colonic microbiota, short-chain fatty acids, and ileal inflammatory cytokines.

CONCLUSIONS

These results suggest that dietary Gln could improve growth performance and attenuate LPS-challenged intestinal inflammation by modulating microbiota and the Th17/Treg immune response signaling pathway in piglets.

Probiotic, Paraprobiotic, and Hydrolyzed Yeast Mixture Supplementation Has Comparable Effects to Zinc Oxide in Improving Growth Performance and Ameliorating Post-weaning Diarrhea in Weaned Piglets

A total of 150 21-day-old weaned piglets [(Yorkshire × Landrace) × Duroc] were randomly assigned to 3 groups (CON, TRT1, TRT2) to evaluate the effects of dietary supplementation of probiotic, paraprobiotic, and hydrolyzed yeast mixture (PPY) on growth performance, nutrient digestibility, fecal bacterial counts, fecal calprotectin contents, and diarrhea rate in a 42-day experiment (phase 1: days 1-14; phase 2: days 15-42). There were 10 replicate pens per treatment with 5 pigs per pen (three gilts and two barrows). Pigs in CON were only provided with a basal diet. Pigs in TRT1 were provided with a basal diet + 3000 mg/kg zinc oxide during phase 1 and a basal diet during phase 2. Pigs in TRT2 were provided with a basal diet + 200 mg/kg probiotic (Saccharomyces cerevisiae boulardii) + 800 mg/kg paraprobiotic (inactivated yeast strains of Saccharomyces cerevisiae and Cyberlindnera jadinii) + 10 g/kg hydrolyzed yeast mixture during phase 1, and a basal diet + 100 mg/kg probiotic + 400 mg/kg paraprobiotic mixture during phase 2. Pigs in TRT1 and TRT2 were significantly heavier at day 14 and 42 than CON pigs. Growth rate during days 1-14, 15-42, and 1-42 and feed efficiency during days 1-14 were similarly affected by treatment while feed efficiency was significantly higher for TRT2 pigs between 15-42 and 1-42 days. Moreover, nitrogen and energy digestibility in both TRT1 and TRT2 were higher than that in CON. During experimental periods, diarrhea rate in TRT1 and TRT2 was lower than that in CON. Therefore, we demonstrated that PPY supplementation had comparable effects as ZnO in improving growth performance and nutrient digestibility as well as ameliorating post-weaning diarrhea in weaned piglets.

Variability in feed intake the first days following weaning impacts gastrointestinal tract development, feeding patterns, and growth performance in nursery pigs

The present study investigated the effects of voluntary feed intake (FI) the first days after weaning on gastrointestinal development and protein fermentation the first week after weaning and growth performance and feeding patterns during the nursery phase. A total of 144 mixed-sex weaned pigs (24 ± 2 d old; 7.2 ± 0.8 kg body weight [BW]) were allocated to 12 pens with 12 pigs/pen. Each pen was equipped with an electronic feeding station for monitoring individual FI during a 40-d study. Pigs were classified based on their cumulative FI over the initial 3 d after weaning (FId1-3) being above or below their pen median FId1-3 (high = 919 ± 244 g or low = 507 ± 222 g FId1-3). Similarly, weaning BW classes (BW0; high = 7.72 ± 0.59 kg or low = 6.62 ± 0.88 kg BW) were created to study interactions with FId1-3. Two female pigs with either a high or a low FId1-3 per pen (n = 24) were selected for sampling at d6 and were used to study gastrointestinal development and fermentation products in the small intestine. Feeding patterns per day, FI, and growth performance were measured individually. Low FId1-3 pigs had lower (P < 0.05) daily FI during d0 to d8, d8 to d15, and d22 to d28, BW on d15, d22, d29, and d40, and average daily gain during d0 to d8, d22 to d29, and d29 to d40 compared to high FId1-3. High FId1-3 pigs increased (P < 0.05) the number of visits to the feeder between d1 to d13 and d31 to d35, and the time spent per visit only for d1 to d4 (P < 0.05). The daily rate of FI (g/min) was higher (P < 0.05) for High FId1-3 pigs on d6, d8, d9, and d10, and again several days later (d20 to d39). In addition, the high FId1-3 × high BW0 interaction improved daily FI during d18 to d40 compared to low FId1-3 × low BW0 class (P < 0.05). For the sampling on d6, low FId1-3 pigs had a lighter small intestine, colon, and pancreas, and reduced villi length, smaller villi surface area, and a lower number of goblet cells size in jejunum (P < 0.05), while concentrations of lactic acid, histamine, and cadaverine in small intestinal content were increased (P < 0.05). In conclusion, pigs with high FId1-3 became faster eaters with higher FI and growth rates toward the second half of the nursery, which was similar and additive for pigs with higher weaning BW. High FId1-3 was also associated with greater development of the gastrointestinal tract and a reduced protein fermentation 1-wk after weaning.

Piglet growth performance improved by dietary supplementation of porous or nano particles of zinc oxide may be related to the gut microbiota

Previous studies on porous or nano particles zinc oxide (ZnO) in the piglets have mainly focused on growth performance and intestinal inflammation, but have scarcely explored the efficacy on gut microbiota. In addition, the efficacy of nano particles ZnO, which is related to its product quality, remains undefined. This study aimed to determine the efficacy of dietary 500 mg/kg porous or nano particles ZnO on the growth performance and gut microbiota of the weaned piglets. A total of 128 weaned piglets were randomly assigned to the dietary groups: NC (basal diet), PC (basal diet + 3,000 mg/kg conventional ZnO), 500HiZ (basal diet + 500 mg/kg porous particles ZnO), and 500ZNP (basal diet + 500 mg/kg nano particles ZnO). Compared with the NC diet group, both 500HiZ and 500ZNP increased (P < 0.05) average daily feed intake (1 to 28 d) and average daily gain (1 to 28 d), and the 500ZNP tended to decrease feed to gain ratio (F:G ratio, 1 to 28 d) (P = 0.09). Both 500HiZ and 500ZNP decreased crypt depth of the ileum and increased claudin-2 in the duodenum and zonula occludens-1 in the ileum (P < 0.05). Moreover, both 500HiZ and 500ZNP decreased IL-1β and tumor necrosis factor-α (TNF-α) in the jejunum and decreased TNF-α and IL-6 in the ileum (P < 0.05). Both 500HiZ and 500ZNP increased microbial β-diversity index in the ileum and microbial α-diversity indices in the colon of piglets (P < 0.05). The probiotic genera Coprococcus (500ZNP) and Blautia (500HiZ) were positively correlated with the F:G ratio (1 to 28 d) in colon of piglets (P < 0.05). In addition, 500HiZ promoted mitochondrial fusion protein 1 (MFN1) and zinc transporter-1 (ZnT-1) in the jejunum (P < 0.05), whilst 500ZNP decreased MFN1 in the jejunum and ZnT-1 in the ileum (P < 0.05). In summary, both 500HiZ and 500ZNP improved the growth performance of piglets, which is likely via the genera Blautia and Coprococcus, respectively. Both 500HiZ and 500ZNP improved barrier function and inflammation of the intestine, and 500HiZ achieved better efficacy than 500ZNP on intestine mitochondrial functions.

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.

Effect of N-Carbamylglutamate Supplementation on Growth Performance, Jejunal Morphology, Amino Acid Transporters, and Antioxidant Ability of Weaned Pigs

Weaning is an important period that affects the performance of piglets. However, the regulation of dietary amino acid levels is considered to be an effective way to alleviate the weaning stress of piglets. N-carbamylglutamate (NCG) plays an important role in improving the growth performance and antioxidant capacity of animals. A total of 36 weaned piglets were randomly assigned to two treatment groups, a control group (CON) and a 500 mg/kg NCG group (NCG), and the experiment lasted for 28 days. The results show that the NCG treatment group showed an increased 0-28 days average weight gain and average daily feed intake, and also increased contents of GLU and HDL, and lower SUN in serum, and an upregulation of the expression of the amino acid transporters SNAT2, EAAC1, SLC3A1, and SLC3A2 mRNA in the jejunum (p < 0.05), as well as an increased villus length and VH:CD ratio, and claudin-1, occludin, and ZO-1 mRNA expression in the jejunum (p < 0.05). The NCG treatment group showed an increased content of GSH-Px in serum and T-AOC and SOD in the jejunum, and a lower content of MDA (p < 0.05); and the upregulation of the mRNA expression related to antioxidant enzymes (CAT, SOD1, Gpx4, GCLC, GCLM and Nrf2, AhR, CYP1A1) in the jejunal mucosa (p < 0.05). In addition, compared with the control group, the NCG treatment group saw an upregulation in the mRNA expression of IL-10 and a decrease in the expression of IL-1β and IL-4 in the jejunal mucosa (p < 0.05). In summary, the results of this study suggest that NCG improved growth performance and jejunal morphology, improved the jejunal transport of amino acids related to the ornithine cycle, and improved the antioxidant capacity in weaned pigs.

Effect of postweaning feed intake on performance, intestinal morphology, and the probability of diarrhoea in piglets

Changes in gastrointestinal architecture, high incidence of diarrhoea, and low feed intake (FI) are commonly observed around weaning of pigs, but the relationship between postweaning FI and diarrhoea is unclear. This study aimed to determine the effect of low or high FI during the first days after weaning on growth performance, diarrhoea probability, intestinal permeability, and morphology in pigs until postweaning day (PWD) 28. A total of 120 pigs (7.20 ± 0.26 kg) weaned at 28 days of age (PWD 0) were randomly allocated to five diets and housed individually until PWD 28. Two diets differed in CP and three diets differed in threonine and tryptophan levels. At PWD 4, pigs with the 25% lowest accumulated FI (LOW; n = 30) and 25% highest accumulated FI (HIGH; n = 30) were selected for the study. Faecal consistency was evaluated daily using a 4-scale visual scoring system. Blood was collected at PWD 4, 14, 21 and 28, and small intestinal and colonic tissue was obtained at slaughter on PWD 28. Until PWD 4, LOW pigs consumed approximately 20% (35.7 ± 5.9 g/day) of the FI of HIGH pigs (181 ± 5.75 g/day; P < 0.05) and their average daily gain (ADG) was -103 ± 15.1 g/day. At PWD 28, average daily feed intake, ADG, and feed conversion ratio were still negatively affected by the FI level (P < 0.05) and pigs in the LOW group were on average 4.4 kg lighter than HIGH pigs. Pigs in the HIGH group showed a 55% higher probability of diarrhoea compared with LOW pigs during PWD 0-28. The number of antibiotic treatment days against diarrhoea was 2.38 days higher for HIGH compared with LOW pigs (P = 0.04). The intestinal permeability markers diamine oxidase and D-lactate in plasma were unaffected by the level of FI (P > 0.10). The systemic inflammatory markers haptoglobin and C-reactive protein were higher for HIGH pigs at PWD 4 (P = 0.005), but not affected in the following periods (P > 0.10). Pigs in the HIGH group had an increased area of acidic mucin-producing cells in the small intestine compared with LOW pigs (P < 0.05), but other intestinal morphology measurements at PWD 28 were unaffected by the level of FI. In conclusion, high FI just after weaning was associated with higher growth performance but also higher probability of diarrhoea and more frequent use of antibiotics until PWD 28.

Summary of methodology used in enterotoxigenic Escherichia coli (ETEC) challenge experiments in weanling pigs and quantitative assessment of observed variability

Postweaning diarrhea in pigs is often caused by the F4 or F18 strains of enterotoxigenic Escherichia coli (ETEC). To evaluate interventions for ETEC, experimental infection via a challenge model is critical. Others have reviewed ETEC challenge studies, but there is a lack of explanation for the variability in responses observed. Our objective was to quantitatively summarize the responses and variability among ETEC challenge studies and develop a tool for sample size calculation. The most widely evaluated response criteria across ETEC challenge studies consist of growth performance, fecal consistency, immunoglobulins, pro-inflammatory cytokines, and small intestinal morphology. However, there is variation in the responses seen following ETEC infection as well as the variability within each response criteria. Contributing factors include the type of ETEC studied, dose and timing of inoculation, and the number of replications. Generally, a reduction in average daily gain and average daily feed intake are seen following ETEC challenge as well as a rapid increase in diarrhea. The magnitude of response in growth performance varies, and methodologies used to characterize fecal consistency are not standardized. Likewise, fecal bacterial shedding is a common indicator of ETEC infection, but the responses seen across the literature are not consistent due to differences in bacterial enumeration procedures. Emphasis should also be placed on the piglet's immune response to ETEC, which is commonly assessed by quantifying levels of immunoglobulins and pro-inflammatory cytokines. Again, there is variability in these responses across published work due to differences in the timing of sample collection, dose of ETEC pigs are challenged with, and laboratory practices. Small intestinal morphology is drastically altered following infection with ETEC and appears to be a less variable response criterion to evaluate. For each of these outcome variables, we have provided quantitative estimates of the responses seen across the literature as well as the variability within them. While there is a large degree of variability across ETEC challenge experiments, we have provided a quantitative summary of these studies and a Microsoft Excel-based tool was created to calculate sample sizes for future studies that can aid researchers in designing future work.

Dietary Supplementation with Puerarin Improves Intestinal Function in Piglets Challenged with Escherichia coli K88

The objective of this study was to investigate the effect of puerarin supplementation on the growth performance and intestinal function of piglets challenged with enterotoxigenic Escherichia coli (ETEC) K88. Twenty-four ternary crossbred piglets were randomly assigned to three treatment groups: control group, ETEC group (challenged with ETEC K88 on day 8), and ETEC + Puerarin group (supplemented with 5 mg/kg puerarin and challenged with ETEC K88 on day 8). All piglets were orally administered D-xylose (0.1 g/kg body weight) on day 10, and blood samples were collected after 1 h. Subsequently, piglets were killed and intestinal samples were collected for further analysis. The results showed that puerarin supplementation significantly decreased the adverse effects of ETEC K88-challenged piglets; significantly improved growth performance; increased the number of Bifidobacterium in the colon and Lactobacillus in the jejunum, cecum and colon; decreased the number of Escherichia coli in the jejunum and cecum; reduced the hydrogen peroxide content in the jejunum and myeloperoxidase activity in the jejunum and ileum; and increased the activities of catalase and superoxide dismutase in the jejunum and ileum. In addition, puerarin supplementation alleviated ETEC K88-induced intestinal injury in piglets, significantly downregulated the mRNA level of Interleukin-1β and upregulated the mRNA levels of intercellular cell adhesion molecule-1, myxovirus resistance protein 1, myxovirus resistance protein 2, and guanylate-binding protein-1 in the small intestine of piglets. In conclusion, dietary supplementation with puerarin could attenuate ETEC K88-induced intestinal injury by increasing the antioxidant and anti-inflammatory capacity and the number of beneficial intestinal bacteria in piglets.

Effects of Weaning Age and Creep Feed Type on Growth Performance and Gut Maturation in Weaned Piglets

The objective was to study the effects of weaning in week 5 (W5) vs. week 4 (W4), as well as liquid (LF) vs. dry feed (DF), on growth performance, disaccharidase activity and nutrient transporter expression after weaning. The experiment included 12,923 pigs fed LF or DF in the pre-weaning period and a subpopulation of 15 pigs from each group, W4DF, W4LF, W5DF and W5LF, which were weighed and euthanized five days after weaning. The proximal part of the small intestine was analyzed for maltase, lactase and sucrase activity and the expression of SGLT-1, GLUT-2 and PepT-1. Pigs fed LF displayed less maltase activity (2100 vs. 2729 U/mg protein, p < 0.05) but an increased expression of SGLT-1 (∆Ct: 5.22 vs. 6.21, p = 0.01). Pigs weaned in W5 were heavier than those weaned in W4 (9.35 vs. 7.11 kg BW, p ≤ 0.05), and pigs fed LF were heavier than those fed DF (8.55 vs. 7.91 kg BW, p ≤ 0.05) five days after weaning in the subpopulation. LF pigs (21.8 kg) were heavier than DF pigs (20.6 kg) (SE 0.108, p < 0.0001), and W4 pigs (21.0 kg) were lighter than W5 pigs (21.5 kg) (SE 0.108, p = 0.01) at nine weeks. LF increased weight gain in the early post-weaning period and at nine weeks, although this was apparently not explained by accelerated gut maturation.

Effects of different stocking density and various phytogenic feed additives dosage levels on growing-finishing pigs

This study was to investigate the effects of different phytogenic feed additives (PFA) dosage levels in growing- finishing pigs stressed by high stocking density. A total of 72 mix sexed 12 weeks growing pigs ([Landrace × Yorkshire] × Duroc) with initial body weight (BW) of 49.28 ± 4.58 kg were used for 8 weeks. There were 3 replicate pens in each treatment group, with 3 pigs per pen. The dietary treatment groups consisted of basal diets in animal welfare density (negative control [NC]), basal diet in high stocking density (positive control [PC]), PC + 0.04% essential oil (ES1), PC + 0.08% essential oil (ES2), PC + 0.10% bitter citrus extract & essential oil (CES1), PC + 0.20% bitter citrus extract & essential oil (CES2), PC + 0.05% grape pomace extract (GP1), PC + 0.10% grape pomace extract (GP2). The reduction of space allowance decreased (p < 0.05) average daily gain, feed efficiency, and digestibility of dry matter, crude protein, and gross energy. Also, the fecal score of PC groups increased (p < 0.05) compared with other groups. Basic behaviors (feed intake, standing, lying) were inactive (p < 0.05) and singularity behavior (biting) was increased (p < 0.10) under high stocking density. There was no difference in blood profile. However, the supplementation of PFA alleviated the negative effects such as reduced growth performance, nutrient digestibility, and some increasing stress indicators in th blood (cortisol) and animal behavior (biting). In conclusion, the negative effect of high stocking density was most effectively mitigated by the normal dosage of the mixture of bitter citrus extract and essential oil additive (CES1).

Maternal supplementation with glycerol monolaurate improves the intestinal health of suckling piglets by inhibiting the NF-κB/MAPK pathways and improving oxidative stability

Glycerol monolaurate (GML) is a food safe emulsifier and a kind of MCFA monoglyceride that has been proven to confer positive benefits in improving animal health, production and feed digestibility as a feed additive. This study aims to evaluate whether supplementation of a sow diet with GML could affect the intestinal barrier function and antioxidant status of newborn piglets and to explore its regulatory mechanism. A total of 80 multiparous sows were divided into two groups, which were fed a basal diet or a basal diet supplemented with 0.1% GML. The results indicated that maternal supplementation with GML significantly increased fat, lactose and protein in sow colostrum, as well as fat and protein in sow 14-day milk (P < 0.05). The results showed that GML significantly reduced the concentrations of IL-12 in the duodenum, TNF-α, IL-1β and IL-12 in the jejunum, and IL-1β in the ileum of piglets (P < 0.05). Higher concentrations of T-AOC, T-SOD, GSH and GSH-Px and lower MDA in the intestine were observed in the GML group than in the control group. Correspondingly, the villi height, crypt depth and the ratio of villi height to crypt depth (V/C) in the jejunum and the V/C in the ileum in the GML group were significantly higher than those in the control group (P < 0.05). Moreover, the GML group displayed significantly increased protein abundance of zonula occludens (ZO)-1, occludin, and claudin-1 in the small intestine (P < 0.05), mRNA expression of mucins (MUCs) in the small intestine (MUC-1, MUC-3 and MUC-4), and mRNA expression of porcine beta defensins (pBDs) in the duodenum (pBD1 and pBD2), jejunum (pBD1, pBD2 and pBD129) (P < 0.05), and ileum (pBD2, pBD3 and pBD114) (P < 0.05). Further research showed that GML significantly reduced the phosphorylation of the NF-κB/MAPK pathways in the small intestine (P < 0.05). In addition, the results of 16S rDNA sequencing showed that maternal supplementation with GML altered the colonic microbiotic structure of piglets, and reduced the relative abundance of Escherichia shigella. In summary, a sow diet supplemented with GML enhanced the offspring's intestinal oxidative stability and barrier function and attenuated the offspring's intestinal inflammatory response, possibly by suppressing the activation of the NF-κB/MAPK pathways.

Increased Proportion of Fiber-Degrading Microbes and Enhanced Cecum Development Jointly Promote Host To Digest Appropriate High-Fiber Diets

Previous study found that appropriate high-fiber diet (containing 19.10% total dietary fiber [TDF], treatment II) did not reduce apparent fiber digestibility of Chinese Suhuai finishing pigs and increased the yield of short-chain fatty acids (SCFAs), but too high-fiber diet (containing 24.11% TDF, treatment IV) significantly reduced apparent fiber digestibility compared with normal diet (containing 16.70% TDF, control group). However, characteristics of microbiota at the species level and histological structure in pigs with the ability to digest appropriate high-fiber diets were still unknown. This study conducted comparative analysis of cecal physiology and microbial populations colonizing cecal mucosa. The results showed intestinal development indexes including cecum length, densities of cecal goblet cells, and renewal of cecal epithelial cells in treatment II and IV had better performance than those in the control. Paludibacter jiangxiensis, Coprobacter fastidiosus, Bacteroides coprocola CAG:162, Bacteroides barnesiae, and Parabacteroides merdae enriched in treatment II expressed large number of glycoside hydrolase (GH)-encoding genes and had the largest number of GH families. In addition, pathogenic bacteria (Shigella sonnei, Mannheimia haemolytica, and Helicobacter felis) were enriched in treatment IV. Correlation analysis revealed that the intestinal development index positively correlated with the relative abundance of cecal mucosal microbiota and the amount of digested fiber. These results indicated that increased proportions of fiber-degrading microbes and enhanced intestinal development jointly promote the host to digest an appropriate high-fiber diet. However, although too-high fiber levels in diet could maintain the adaptive development of cecal epithelium, the proportions of pathogenic bacteria increased, which might lead to a decrease of fiber digestion in pigs. IMPORTANCE Although studies about the effects of dietary fiber on fiber digestion and intestinal microbiota of pigs were widely in progress, few studies have been conducted on the dynamic response of intestinal microbiota to dietary fiber levels, and the characteristics of intestinal microbiota and intestinal epithelial development adapted to high-fiber diet s were still unclear. Appropriate high fiber promoted the thickness of large intestine wall, increased the density of cecal goblet cells, and promoted the renewal of cecal epithelial cells. In addition, appropriate high fiber improves the microbial abundance with fiber-digesting potential. However, excessive dietary fiber caused an increase in the abundance of pathogenic bacteria. These results indicated that an increased proportion of fiber-degrading microbes and enhanced intestinal development jointly promote host to digest appropriate high-fiber diets. However, although too-high fiber levels in diet could maintain the adaptive development of cecal epithelium, the proportions of pathogenic bacteria increased, which might lead to a decrease of fiber digestion in pigs. Our data provided a theoretical basis for rational and efficient utilization of unconventional feed resources in pig production.

Protein Content in the Diet Influences Growth and Diarrhea in Weaning Piglets

The aim of this research has been to assess the effect of the dietary protein level on piglet growth and post-weaning diarrhea (PWD) incidence. Piglet fecal microbiota and feces composition were also assessed. The experiment was carried out on 144 weaned piglets (Duroc × Large White; 72 piglets per treatment) and lasted from weaning (at 25 days of age) until the end of the post-weaning phase (at 95 days). Two dietary protein levels were compared: high (HP; 17.5% crude protein on average, during the experiment) and low (LP; 15.5% on average). Lower (p < 0.01) average daily gain and feed conversion ratio were observed in LP piglets in the first growth phase. However, at the end of the post-weaning period, the growth parameters were not significantly different in the two diets. Diarrhea scores were lower in piglets fed LP diets than in piglets fed HP diets (28.6% of the total vs. 71.4% in the HP piglets). Fibrobacteres, Proteobacteria, and Spirochaetes were more abundant in the feces of the piglets fed LP diets. Feces nitrogen content was lower in piglets fed LP diets. In conclusion, low protein levels in the diet can reduce the incidence of PWD while only marginally affecting growth parameters.

Analysis of serum antioxidant capacity and gut microbiota in calves at different growth stages in Tibet

Introduction

The hypoxic environment at high altitudes poses a major physiological challenge to animals, especially young animals, as it disturbs the redox state and induces intestinal dysbiosis. Information about its effects on Holstein calves is limited.

Methods

Here, serum biochemical indices and next-generation sequencing were used to explore serum antioxidant capacity, fecal fermentation performance, and fecal microbiota in Holstein calves aged 1, 2, 3, 4, 5, and 6 months in Tibet.

Results and Discussion

Serum antioxidant capacity changed with age, with the catalase and malondialdehyde levels significantly decreasing (p < 0.05), and superoxide dismutase levels significantly increasing (p < 0.05) with age. No significant differences (p > 0.05) in total volatile fatty acid levels were noted between the groups. In all groups, Firmicutes, Bacteroidetes, and Actinobacteria were the three most dominant phyla in the gut. Gut microbial alpha diversity significantly increased (p < 0.05) with age. Principal coordinate analysis plot based on Bray-Curtis dissimilarity revealed significant differences (p = 0.001) among the groups. Furthermore, the relative abundance of various genera changed dynamically with age, and the serum antioxidant capacity was associated with certain gut bacteria. The study provides novel insights for feeding Holstein calves in high-altitude regions.

Effect of 3-caffeoylquinic acid on growth performance, nutrient digestibility, and intestinal functions in weaned pigs

Phenolic acid like with the 3-caffeoylquini acid (3-CQA) is formed by caffeic acid and qunic acid. This study was conducted to explore the effect of 3-CQA on growth performance and intestinal functions in weaned pigs. A total of 180 weaned pigs were randomly allocated into five treatments with 6 replicate pens per treatment (6 pigs per pen). Pigs in the control group (CON) were fed with basal diet (BD), and the others in the experimental groups were fed with BD and supplemented with 12.5, 25, 50, and 100 mg/kg 3-CQA. On day 43, the blood sample-collected pigs in the CON and optimal-dose group (only based on growth performance) were picked, and housed in metabolism cages (a total of 12 pigs, N = 6). 3-CQA increased the feed efficiency from days 21 to 42 of the trial and throughout the trial (P < 0.05). 3-CQA increased the serum concentrations of total protein, albumin, and total cholesterol (P < 0.05). Moreover, 3-CQA supplementation at 25 mg/kg increased the apparent digestibility of DM, energy, and ash (P < 0.05). Interestingly, 3-CQA decreased the crypt depth but increased the ratio of villus height to crypt depth in the jejunum and ileum (P < 0.05). Moreover, 3-CQA also increased the activities of sucrase, lactase, and catalase in the jejunal mucosa, and increased the activities of alkaline phosphatase and superoxide dismutase in the ileal mucosa (P < 0.05). 3-CQA also increased the abundance of secretory immunoglobulin A in the ileal mucosa (P < 0.05). Importantly, 3-CQA not only elevated the expression levels of critical functional genes such as the zonula occludens-1 , occludin, solute carrier family 7 , and nuclear factor erythroid 2-related factor 2 (Nrf2) in the duodenum but also elevated the expression levels of divalent metal transporter-1 and Nrf2 in the jejunum (P < 0.05). These results suggested a positive effect of 3-CQA supplementation on the growth and intestinal functions of weaned pigs. The mechanisms of action may be associated with elevated anti-oxidant capacity and improved intestinal barrier functions.

Plant-oriented microbiome inoculum modulates age-related maturation of gut-mucosal expression of innate immune and barrier function genes in suckling and weaned piglets

In the immediate time after weaning, piglets often show symptoms of gut inflammation. The change to a plant-based diet, lack of sow milk, and the resulting novel gut microbiome and metabolite profile in digesta may be causative factors for the observed inflammation. We used the intestinal loop perfusion assay (ILPA) to investigate jejunal and colonic expression of genes for antimicrobial secretion, oxidative stress, barrier function, and inflammatory signaling in suckling and weaned piglets when exposed to "plant-oriented" microbiome (POM) representing postweaning digesta with gut-site specific microbial and metabolite composition. Two serial ILPA were performed in two replicate batches, with 16 piglets preweaning (days 24 to 27) and 16 piglets postweaning (days 38 to 41). Two jejunal and colonic loops were perfused with Krebs-Henseleit buffer (control) or with the respective POM for 2 h. Afterward, RNA was isolated from the loop tissue to determine the relative gene expression. Age-related effects in jejunum included higher expression of genes for antimicrobial secretions and barrier function as well as reduced expression of pattern-recognition receptors post- compared to preweaning (P < 0.05). Age-related effects in the colon comprised downregulation of the expression of pattern-recognition receptors post- compared to preweaning (P < 0.05). Likewise, age reduced the colonic expression of genes encoding for cytokines, antimicrobial secretions, antioxidant enzymes, and tight-junction proteins post- compared to preweaning. Effect of POM in the jejunum comprised an increased the expression of toll-like receptors compared to the control (P < 0.05), demonstrating a specific response to microbial antigens. Similarly, POM administration upregulated the jejunal expression of antioxidant enzymes (P < 0.05). The POM perfusion strongly upregulated the colonic expression of cytokines and altered the expression of barrier function genes, fatty acid receptors and transporters, and antimicrobial secretions (P < 0.05). In conclusion, results indicated that POM signaled via altering the expression of pattern-recognition receptors in the jejunum, which in turn activated the secretory defense and decreased mucosal permeability. In the colon, POM may have acted pro-inflammatory via upregulated cytokine expression. Results are valuable for the formulation of transition feeds for the immediate time after weaning to maintain mucosal immune tolerance towards the novel digesta composition.

Dietary medium-chain fatty acid and Bacillus in combination alleviate weaning stress of piglets by regulating intestinal microbiota and barrier function

The present study evaluated the effects of dietary medium-chain fatty acid (MCFA) and Bacillus on growth performance, nutrient digestibility, antioxidant capacity, colonic fermentation, and microbiota of weaning piglets. A total of 400 weaned piglets were randomly divided into 4 treatments, with 10 replicates per treatment and 10 pigs per replicate. The treatment included: basal diet (control, CON), basal diet with 0.588 g/kg MCFA (MCF), basal diet with 1.3 × 109 CFU/kg Bacillus (BAC), and basal diet with 0.588 g/kg MCFA and 1.3 × 109 CFU/kg Bacillus (SYN). Compared with CON group, the average daily gain of MCF and SYN in the early (1 to 9 d) and whole stage (1 to 36 d) of trail were improved (P < 0.05), the feed to gain ratio of MCF in later (10 to 36 d) and whole stage of trial were decreased (P < 0.05), and the diarrhea rate of SYN in the early stage (1 to 9 d) of trial decreased (P < 0.05). The digestibility of dry matter, ether extract, acid detergent fiber digestibility of MCF were decreased (P < 0.05) compared with CON. The serum d-lactic acid in MCF, BAC, and SYN were lower (P < 0.05) compared with CON group. Compared with CON group, the contents of total antioxidant capacity, superoxide dismutase, and glutathione peroxidase were greater (P < 0.05), whereas the content of malondialdehyde and the contents of colonic isobutyrate and isovalerate were lower (P < 0.05) in MCF. The microbial Shannon and Simpson diversity was lower in MCF (P < 0.05) than that in BAC and SYN. The relative abundance of Prevotella was greater (P < 0.05), whereas the Treponema and Oscillibacter were lower (P < 0.05) in MCF than that in BAC and SYN. In addition, the metabolic pathways of bacteria such as pentose phosphate pathway, adenosine nucleotides degradation II were enhanced (P < 0.05), whereas the pathways such as incomplete reductive TCA cycle, and TCA cycle IV (2-oxoglutarate decarboxylase) were decreased (P < 0.05) in MCF compared with BAC. The results indicated that dietary MCFA and Bacillus in combination improved the intestinal barrier function of piglets by changing the intestinal microbiota and its metabolic function, and finally alleviated the diarrhea rate in early weaning stage and improved growth performance in whole trial period. In addition, MCFA was effective in improving feed efficiency and antioxidant capacity of piglets.

Effects of dietary supplementation with purple garlic powder and oregano essential oil on intestinal health in post-weaning piglets from commercial farms

This work studied the effects of the inclusion of Purple Garlic Powder (PGP) and Oregano Essential Oil (OEO) in the feed, at different doses and combinations, on intestinal health and the growth performance of 140 and 3000 piglets, respectively, weaned at 21 days of age. Seven dietary treatments were used: a negative control group (basal diet), a positive control group with ZnO (3000 mg/Kg of feed), two groups with OEO at 0.4% and 1.2% respectively, two groups with PGP at 0.4% and 2% respectively and one group with OEO at 1.2% combined with PGP at 2%. Only the positive control group received ZnO in the diet. Each group of piglets received the treatment for seven weeks, from weaning, and were later sacrificed to obtain jejunum and ileum samples for counting of goblet cells, intraepithelial lymphocytes, and IgA-producing cells. The growth performance were measured at the beginning and at the end of the seven weeks. In jejunum and ileum, the number of goblet cells increased in the groups with ZnO, PGP 2%, OEO 1.2% and PGP 2% + OEO 1.2%, presenting significant differences with the rest of the groups. The results obtained for the intraepithelial lymphocyte count were in line with those obtained for the count of goblet cells. Regarding IgA-producing cells, the groups that showed significantly favourable results in the jejunum and ileum were OEO 1.2%, PGP 2% and their combination, but the groups that showed the most similar means to ZnO were the OEO 0.4% and the PGP 0.4%. Regarding the growth performance, PGP 2%, OEO 1.2% and their combination had similar results to ZnO. The intestinal health of piglets could be improved, without harming the growth performance, by means of the supplementation of PGP 2%, OEO 1.2% and PGP 2% + OEO 1.2% offering a natural alternative to the use of ZnO.

Dietary fibers with low hydration properties exacerbate diarrhea and impair intestinal health and nutrient digestibility in weaned piglets

Background

This study aimed to investigate the hydration properties of different-source fibrous materials by comparing their water-binding capacity (WBC), water swelling capacity (WSC), viscosity, and in vivo effects of selected samples on growth performance, nutrient digestibility, diarrhea, and intestinal health in weaned piglets.

Methods

A total of 13 commercially available fibrous materials were first compared in chemical composition and in vitro hydration property. Subsequently, 40 weaned piglets were randomized to five experimental dietary groups (8 piglets per group): control diet (a basal diet without dietary fiber, CON), basal diet supplemented with 5% microcrystalline cellulose (MCC), 5% wheat bran (WB), 5% Moringaoleifera leaf powder (MOLP), or 5% sugar beet pulp (SBP), followed by analyzing their growth performance and diarrhea rate in a 28-d experiment. After the feeding experiment, anaesthetized piglets were killed, and their intestinal and colon content or plasma samples were analyzed in nutrient digestibility, intestinal morphology, intestinal barrier, short-chain fatty acids (SCFAs), and bacterial population.

Results

In vitro studies showed low hydration properties for WB and MCC, while medium hydration properties for MOLP and SBP. In vivo studies indicated that compared with medium hydration property groups, low hydration property groups showed (1) exacerbated diarrhea, impaired intestinal health, and reduced apparent fecal digestibility of dry matter, gross energy, acid detergent fiber, and neutral detergent fiber; (2) decreased SCFAs concentration and relative levels of Lactobacillus and Bifidobacterium, but increased levels of Escherichia coli and Brachyspira hyodysenteriae in colon contents. Additionally, SBP showed optimal performance in reducing diarrhea and increasing SCFAs production. Correlation analysis revealed a positive correlation of fiber hydration properties with in vitro SCFAs production, and diarrhea index and nutrient digestibility were negatively and positively correlated with SCFAs levels in the colon contents of weaned piglets, respectively.

Conclusions

Different-source dietary fibers varied in their hydration properties and impacts on diarrhea, microbial composition and SCFAs production in weaned piglets. WB and MCC could exacerbate diarrhea and impair nutrient digestibility, probably because their low hydration properties were detrimental to gut microbial homeostasis and fermentation. Our findings provide new ideas for rational use of fiber resources in weaned piglets.

Effects of a Novel Protease on Growth Performance, Nutrient Digestibility and Intestinal Health in Weaned Piglets

This experiment was conducted to evaluate the effects of different protease levels on performance, diarrhea rate, nutrient digestibility, blood metabolites, digestive enzyme activities, and intestinal health of weaned piglets. A total of 96 weaned piglets (Duroc × Landrace × Yorkshire, 28 d of age, initial average BW = 6.55 ± 0.17 kg) were divided into four groups (4 pigs/pen and 6 replicates/group) according to a completely random block design. Piglets were fed different levels of protease (0, 150, 300 or 600 mg/kg of diet) for 28 d. The results showed that the addition of protease had no significant effect on the growth performance of weaned piglets (p > 0.05), and the addition of 300 mg/kg protease significantly increased the apparent total intestinal digestibility (ATTD) of nutrients and the apparent ileal digestibility (AID) of amino acids in weaned piglets (p < 0.05), while the addition of 150 mg/kg and 600 mg/kg protease had no significant effect on the digestibility (p > 0.05). The nutrient digestibility of dry matter (DM), organic matter (OM), crude protein (CP) and total energy (GE) showed a trend of increasing and then decreasing with increasing protease concentration (p < 0.05). Adding 300 and 600 mg/kg protease significantly decreased serum ALB/GLO levels (p < 0.05) and duodenal pH (p < 0.05) and increased duodenal villus height (p < 0.05). The addition of protease significantly increased jejunal trypsin and chymotrypsin activities (p < 0.01) and duodenal and jejunal mucosal tight junction proteins in piglets. The mRNA expression levels of ZO-1 and CLAUDIN-1 in the duodenum together with ZO-1 and OCCLUDIN in the jejunum of piglets in the 300 and 600 mg/kg protease supplementation groups were significantly higher than those in the control group (p < 0.05). The results showed that, compared with the control group, protease could promote nutrient absorption, improve small intestine morphology and enhance digestive enzyme activity in weaned piglets. The suitable addition amount was 150−300 mg/kg in the present study.

Supplementing oat hulls to the diet of suckling piglets altered their intestinal tract and colonic microbiota development

Current study evaluated the effect of a fine and coarsely ground insoluble dietary fibre source on the gastrointestinal development of suckling pigs. Oat hulls (OH) were selected as a model feedstuff, rich in cellulose, lignin, and insoluble dietary fibre. Three experimental supplemental diets were formulated: a finely ground, low fibre and nutrient dense diet served as control (CON). For the 2 high fibre diets, 15% heat-treated starch in CON was exchanged with OH, either finely (OH-f) or coarsely ground (OH-c). Litters of 10 primi- and multiparous sows (mean litter size 14.6 ± 0.84) were used. Within a litter, experimental diets were allotted to triplets of 4 piglets. From approximately 12 d of age, piglets' individual feed intakes were recorded 2 times per day when separated from their dam for 70 min. Piglets could suckle with their dam for the remainder of the day. On d 24 and 25, from the total pool of 120 piglets, seven healthy well-eating piglets per treatment were selected for post-mortem evaluation, resulting in 14 replicates per treatment. Consumption of OH-c and OH-f did not impede clinical health and production performance of piglets. The full stomach weights tended to be greater for OH-c compared to OH-f whereas CON was intermediate (P = 0.083). Supplementing OH significantly increased ileal villus height and caecal dry matter concentration (P < 0.05). For the colon, OH increased its length, contents weight, short-chain fatty acid concentration and reduced total bacterial count as well as γ-proteobacteria count and proportion (P < 0.05). The OH-c treatment specifically increased full gastrointestinal tract weight and caecum contents weight compared to piglets fed CON and OH-f. Furthermore, OH-c reduced colonic crypt depth when compared to OH-f (P = 0.018). In conclusion, supplementing OH to a diet for suckling piglets exerted subtle developmental effects on gastrointestinal morphology and colonic microbial community. These effects were largely independent from the particle size of the OH.

Dietary Crude Protein Levels Alter Diarrhea Incidence, Immunity, and Intestinal Barrier Function of Huanjiang Mini-Pigs During Different Growth Stages

Huanjiang mini-pig is an indigenous pig breed in China; however, the optimal dietary crude protein (CP) levels for this pig breed during different growth stages has not been standardized yet. This study investigated the effects of different CP levels on diarrhea incidence, immunity, and intestinal barrier function in pigs. A total of 360 Huanjiang mini-pigs were assigned to three independent trials and fed the following CP diets: 5−10 kg stage, 14, 16, 18, 20, and 22%; 10−20 kg stage, 12, 14, 16, 18, and 20% and 20−30 kg stage, 10, 12, 14, 16, and 18%. In the 5−10 kg stage, the 22%; diet increased the plasma IL-1β, IL-6, IL-8, and TNF-α concentrations compared to the 14−20% diets and decreased IL-10 and TGF-β; however, these results were fluctuated in the later stages, including the decrease of IL-1β and IL-8 in the 20% group, TNF-α in the 18−20% groups, and the increase of IFN-γ in the 20% group at the 10−20 kg stage and the decrease of TNF-α in the 16% group at the 20−30 kg stage. The 20% diet increased the jejunal and ileal IL-10 concentration compared to the 14% diet at the 5−10 kg stage, as well as in the 16% diet compared to the 12% diet at the 10−20 kg stage. In addition, ileal IL-10 concentration was increased in the 16% diet compared to the 10, 12, and 18% diets at the 20−30 kg stage. Furthermore, the 18% diet at the 5−10 kg stage and the 16% diet at the 10−20 kg stage decreased jejunal IL-6 expression, whereas the 20% diet increased the TNF-α and IFN-γ at the 5−10 kg stage. The 20% diet increased the Claudin, Occludin, ZO-1, ZO-2, Mucin-1, and Mucin-20 expressions at the 5−10 kg stage, as well as TLR-2, TLR-4, and NF-κB in the 22 and 20% diets at the 5−10 and 10−20 kg stages, respectively. Collectively, these findings suggest optimal dietary CP levels of 16, 14, and 12% for Huanjiang mini-pigs during the 5−10, 10−20, and 20−30 kg growth stages, respectively; and provide the guiding significance of dietary CP levels for Huanjiang mini-pigs during different growth stages.

Effects of dietary supplementation with essential oils and protease on growth performance, antioxidation, inflammation and intestinal function of weaned pigs

This experiment evaluated the impacts of essential oils (EO) and protease (PRO), independently or in combination, on growth performance, antioxidation, inflammation and intestinal function of weaned pigs. One hundred and sixty weaned pigs (21 d of age, BW of 6.74 ± 0.20 kg) were randomly divided into 4 treatments with 8 replicate pens of 5 pigs per pen. Dietary treatments included the following: 1) control diet (CON), 2) CON with 300 mg/kg essential oils (EO), 3) CON with 500 mg/kg protease (PRO), 4) CON with 300 mg/kg essential oil and 500 mg/kg protease (EO + PRO). On d 8, one pig from each pen was selected for sampling. The remaining pigs were fed for an additional week and growth performance was monitored during this period. Dietary treatments had no marked effects (P > 0.05) on the growth performance of pigs. However, pigs receiving EO diet had higher (P < 0.05) serum glutathione peroxidase (GSH-Px) activity, and tended to decrease (P = 0.063) serum concentration of tumor necrosis factor-α (TNF-α). In addition, pigs receiving EO diet had higher (P < 0.05) abundances of phylum Actinobacteria, and genera Bifidobacterium, and lower (P < 0.05) phylum Bacteroidetes and genera Alloprevotella in colonic digesta. Pigs receiving PRO diet decreased (P < 0.05) the serum concentration of malondialdehyde (MDA) and diamine oxidase activity, increased (P < 0.05) the villus height and the ratio of villus height to crypt depth in duodenum, increased sucrase activity in jejunal mucosa, and also increased the abundance of phylum Actinobacteria in colonic digesta. Furthermore, the synergistic effects of EO and PRO was observed (P < 0.05) for pigs with decreasing serum TNF-α concentration and increasing serum GSH-Px activity. Collectively, the results indicated that dietary supplementation of EO and PRO had no significant effects on growth performance of weaned pigs. EO diet appeared to improve antioxidant activity and intestinal microbiota, while PRO diet improved intestinal morphology and digestive enzyme activity, and there was a synergistic effect of EO and PRO on reducing inflammatory parameters in weaned pigs.

Effects of Protein Restriction and Succedent Realimentation on Jejunal Function and Bacterial Composition of Different Colonic Niches in Weaned Piglets

Recent studies have proved that protein succedent realimentation could rescue the loss of growth performance in weaning piglets caused by a prior protein restriction. However, how the protein restriction and succedent realimentation influence the jejunal function and bacterial composition of different colonic niches microbiota in weaning piglets needs a further investigation. After protein succedent realimentation, we found that the treatment group (TRE) piglets had a higher IGF-1 content and IGF-1R gene expression level in jejunal mucosa than the control group (CON) piglets. The ZO-1 gene expression level was up-regulated in the jejunal mucosa of TRE piglets during protein restriction and succedent realimentation, while the jejunal permeability of TRE piglets was only decreased after protein succedent realimentation. In addition, we found that protein restriction and succedent realimentation increased the gene expression of Pept-1 and the fecal apparent digestibility of crude protein in TRE piglets, but decreased the fecal nitrogen content. After 16S rRNA MiSeq sequencing of bacteria in different colonic niches (mucosa and digesta), TRE piglets had a higher relative abundance of beneficial bacteria and a lower relative abundance of potential pathogens than CON piglets in different colonic niches after protein restriction and succedent realimentation. Our data showed that protein restriction and succedent realimentation decreased the concentrations of branch chain fatty acids and ammonia-N in the colon of TRE piglets. In addition, protein succedent realimentation increased the concentration of total short chain fatty acids in the colon of TRE piglets. All these findings demonstrated that the strategy of protein restriction and succedent realimentation is an effective way to improve intestinal health of weaning piglets, and provided new insights into the nutrition management of piglets during the weaning period.

Effect of Bacillus subtilis C-3102 Spores as a Probiotic Feed Supplement on Growth Performance, Nutrient Digestibility, Diarrhea Score, Intestinal Microbiota, and Excreta Odor Contents in Weanling Piglets

It has been well-documented that the dietary supplementation of Bacillus subtilis could improve piglet performance. The present study was conducted to investigate the effect of Bacillus subtilis C-3102 spores as a probiotic feed supplement on growth performance, nutrient digestibility, fecal score, intestinal microbiota, and excreta odor contents in weanling piglets. A total of 150 crossed ((Yorkshire × Landrace) × Duroc) weanling piglets (28-days-old), with an average initial body weight of 7.53 ± 1.23 kg, were divided into two treatment groups according to sex and initial body weight (BW) for a 6-week experiment. In each group, fifteen replicate pens consisting of five piglets per pen (three gilts and two barrows) were used in a randomized complete block design. Treatments consisted of (1) CON, a basal diet; (2) BSC, a diet of CON + 300 g Bacillus subtilis (B. subtilis) C-3102 spores per ton of feed. Supplementation with the B. subtilis C-3102 spores in the diet increased the BW, average daily gain (ADG), and gain-to-feed ratio (G:F) throughout the whole trial (p < 0.05). Weanling piglets that were fed B. subtilis C-3102 spores had increased dry matter (DM), crude protein (CP), and energy (E) digestibility compared to the CON group (p < 0.05). Lower diarrhea scores were observed in the B. subtilis C-3102 spores group on Day 7 (p < 0.05). Taken together, our results suggest that dietary supplementation with B. subtilis C-3102 spores could benefit the BW, ADG, and G:F of weanling piglets and improve the apparent total tract digestibility (ATTD) of the DM, CP, and E.

Effects of Bacillus-based probiotics on growth performance, nutrient digestibility, and intestinal health of weaned pigs

Bacillus is characterized by the formation of spores in harsh environments, which makes it suitable for use as a probiotic for feed because of thermostability and high survival rate, even under long-term storage. This study was conducted to investigate the effects of Bacillus-based probiotics on growth performance, nutrient digestibility, intestinal morphology, immune response, and intestinal microbiota of weaned pigs. A total of 40 weaned pigs (7.01 ± 0.86 kg body weight [BW]; 28 d old) were randomly assigned to two treatments (4 pigs/pen; 5 replicates/treatment) in a randomized complete block design (block = BW and sex). The dietary treatment was either a typical nursery diet based on corn and soybean meal (CON) or CON supplemented with 0.01% probiotics containing a mixture of Bacillus subtilis and Bacillus licheniformis (PRO). Fecal samples were collected daily by rectal palpation for the last 3 days after a 4-day adaptation. Blood, ileal digesta, and intestinal tissue samples were collected from one pig in each pen at the respective time points. The PRO group did not affect the feed efficiency, but the average daily gain was significantly improved (p < 0.05). The PRO group showed a trend of improved crude protein digestibility (p < 0.10). The serum transforming growth factor-β1 level tended to be higher (p < 0.10) in the PRO group on days 7 and 14. There was no difference in phylum level of the intestinal microbiota, but there were differences in genus composition and proportions. However, β-diversity analysis showed no statistical differences between the CON and the PRO groups. Taken together, Bacillus-based probiotics had beneficial effects on the growth performance, immune system, and intestinal microbiota of weaned pigs, suggesting that Bacillus can be utilized as a functional probiotic for weaned pigs.

Impact of zinc oxide, benzoic acid and probiotics on the performance and cecal microbiota of piglets

Background

Intestinal health remains a key factor in animal production because it is essential for digestion, absorption and bacterial fermentation. Feed additives have been used to attenuate the weaning stress such as Zinc Oxide (ZnO) and benzoic acid (C₇H₆O₂). The objective of this study was to evaluate the impact of of benzoic acid and probiotics (BA + P) on performance, diarrhea and cecal microbiota of piglets in the nursery phase (23 to 65 days).

Results

One hundred and sixty weaned piglets with an initial weight of 6.335 ± 0.698 kg and 23 days of age were submitted to four treatments: supplementation with 2500 ppm of Zinc oxide (ZnO), supplementation with a commercial blend of benzoic acid and probiotics (Bacillus licheniformis, Bacillus subtilis and Enterococcus faecium NCIMB 10415; Vevogut P®) (BA + P), supplementation with Zinc oxide plus benzoic acid and probiotics (ZnO + BA + P), and controls receiving only the basal diet without any supplementation. At 65 days of age, 32 piglets (n = 8 per treatment) were slaughtered for the evaluation of the cecal microbiota. Supplementation with ZnO and BA + P were associated with better feed conversion (P < 0.05) in the early stage (23 to 49 days) and with an improvement in all performance parameters over the entire experimental period. The occurrence of diarrhea was lower (P < 0.05) in the BA + P group. The 4 most abundant phyla along with unclassified bacteria represented 93% of all sequences. Firmicutes dominated the cecal microbiota of all groups, followed by Bacteroidetes. Richness represented by the observed number of genera and by the Chao index were statistically lower in ZnO and ZnO + BA + P supplemented animals compared to controls. The beta diversity analysis that compares similarities between bacterial communities demonstrated formation of two distinct clusters containing samples with and without supplementation with ZnO, confirming a strong influence of ZnO on the intestinal microbiota.

Conclusion

The use of Benzoic acid with probiotics yields similar performance results with lower impact on the gut microbiota compared to ZnO, and it should be considered as a potential alternative in swine production.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-021-00151-y.

Understanding host-microbiota interactions in the commercial piglet around weaning

Weaning is a critical period in the life of pigs with repercussions on their health and welfare and on the economy of the swine industry. This study aimed to assess the effect of the commercial early weaning on gut microbiota, intestinal gene expression and serum metabolomic response via an integrated-omic approach combining 16S rRNA gene sequencing, the OpenArray gene expression technology and ¹H-NMR spectroscopy. Fourteen piglets from different litters were sampled for blood, jejunum tissue and caecal content two days before (− 2d), and three days after (+ 3d) weaning. A clearly differential ordination of caecal microbiota was observed. Higher abundances of Roseburia, Ruminococcus, Coprococcus, Dorea and Lachnospira genera in weaned piglets compared to prior to weaning showed the quick microbial changes of the piglets’ gut microbiota. Downregulation of OCLN, CLDN4, MUC2, MUC13, SLC15A1 and SLC13A1 genes, also evidenced the negative impact of weaning on gut barrier and digestive functions. Metabolomic approach pinpointed significant decreases in choline, LDL, triglycerides, fatty acids, alanine and isoleucine and increases in 3-hydroxybutyrate after weaning. Moreover, the correlation between microbiota and metabolome datasets revealed the existence of metabolic clusters interrelated to different bacterial clusters. Our results demonstrate the impact of weaning stress on the piglet and give insights regarding the associations between gut microbiota and the animal gene activity and metabolic response.

Effect of fiber source and crude protein level on nursery pig performance and fecal microbial communities

Reduction in dietary crude protein and addition of fiber could mitigate the incidence and severity of post-weaning diarrhea, a common gastrointestinal condition in newly weaned pigs. Therefore, 360 weanling pigs, initially 5.0 ± 0.10 kg, were used to evaluate the effects of crude protein (CP) level and fiber source on growth performance and fecal microbial communities. At weaning, pigs were randomly assigned to pens and allotted to 1 of 8 dietary treatments in a 2 × 4 factorial with main effects of CP (21 or 18%) and fiber source (none, coarse wheat bran, oat hulls, or cellulose). There were 5 pigs per pen and 9 pens per treatment. Experimental diets were formulated in two dietary phases from d 0 to 10 and 10 to 24, with a common post-treatment diet fed from 24 to 45. The 21% CP diets contained 1.40% standardized ileal digestible (SID) Lys in phase 1 and 1.35% SID Lys in phase 2. By using a maximum SID Lys:digestible CP ratio of 6.35%, the 18% CP diets contained 1.25% SID Lys in both phases. Diets containing a fiber source were formulated to the level of insoluble fiber provided by 4% coarse wheat bran, resulting in the addition of 1.85% oat hulls and 1.55% cellulose. No fiber source × CP level interactions (P > 0.05) were observed. Decreasing CP (and subsequently SID lysine) decreased (P = 0.05) ADG and G:F during the experimental period. From d 0 to 45, ADG decreased (P = 0.05) for pigs fed 18% CP diets compared to pigs fed 21% CP. No effect of fiber source was observed for growth performance. Fecal DM on d 17 increased (P < 0.001) for pigs fed 18% CP diets compared to pigs fed 21% CP diets. Pigs fed diets with added cellulose had increased (P < 0.05) fecal dry matter during the experimental period compared to pigs fed no fiber source or wheat bran. Bacterial community structure was investigated by sequencing the V4 region of the 16S rRNA gene. Analysis indicated a significant difference between CP content at d 24 (P = 0.023) using a Weighted UniFrac distance matrix. Further investigation identified five differential Amplicon Sequence Variants associated with CP content at d 24. In conclusion, reducing crude protein (and subsequently SID Lys) decreased growth performance but increased fecal dry matter content. The source of dietary fiber in nursery diets had no impact on growth performance; but pigs fed added cellulose had increased fecal DM compared with other treatments. Microbial analysis identified differential taxa associated with CP content.

Effects of early weaning on intestinal morphology, digestive enzyme activity, antioxidant status, and cytokine status in domestic pigeon squabs (Columba livia)

The aim of this study was to explore the effects of early weaning on growth performance, intestinal morphology, digestive enzyme activity, antioxidant status, and cytokine status in domestic pigeon squabs (Columba livia). The conclusion is based on body weight (BW) and average daily gain (ADG), length index and weight index of small intestine, small intestinal morphology, activity of digestive enzymes in duodenum content, the concentrations of jejunal antioxidant status and cytokines. A completely randomized design with 2 treatments, the control group (CON) and early weaning (EW) group, was utilized. Eight squabs per treatment were sampled at the age of 25 d. The results showed that early weaning reduced BW (P < 0.05), ADG (P < 0.05), ileac length index (P < 0.05), and weight index (P < 0.01). Compared with the CON group, small intestinal morphology was altered in the EW group. Ileac crypt depth (CD) increased significantly (P < 0.01). The villus area was decreased in the duodenum (P < 0.05), jejunum (P < 0.01), and ileum (P < 0.05). The ileac ratio of villus height to crypt depth (VCR) in the EW group was lower than the ileac ratio of villus height to VCR in the CON group (P < 0.01). The activity of trypsin (P < 0.05), sucrase (P < 0.01) and aminopeptidase-N (APN) (P < 0.01) in the duodenum was reduced. Jejunal malondialdehyde (MDA) (P < 0.01) was increased and total superoxide dismutase (T-SOD) (P < 0.01) was reduced significantly. Early weaning decreased the concentrations of interferon-γ (IFN-γ) (P < 0.01), interleukin-4 (IL-4) (P < 0.05) and interleukin-10 (IL-10) (P < 0.01) but induced significant upregulation of interleukin-2 (IL-2) (P < 0.05). In conclusion, our results suggested that early weaning did harm the BW and ADG, intestinal length index and weight index, intestinal morphology, activity of digestive enzymes, and antioxidant and cytokine status.

Modulation of intestinal morphology and microbiota by dietary Macleaya cordata extract supplementation in Xuefeng Black-boned Chicken

Antibiotics are commonly overused to prevent livestock from diseases and to increase production performance. As potential substitutes of antibiotics, plant extracts have attracted the attention of researchers. It was known to all that addition of Macleaya cordata extract (MCE) to the food could advance immunity, intestinal health and animal performance. Thus, it was conducted to investigate the influence of MCE (0, 100, 150 and 200 mg/kg, with six replicate pens/treatment and 24 hens/pen) on intestinal morphology and microbial diversity in different intestinal segments in Xuefeng black-boned chicken in this study. The results showed that MCE supplement (100, 150 and 200 mg/kg) significantly diminished (P < 0.05) the crypt depth of the jejunum as compared to basal diet group. The 100 mg/kg group displayed a marked increase (P < 0.05), compared with 0 and 200 mg/kg group, in ileum microbial diversity as represented by the Shannon's index. In the cecum, treatment of MCE significantly decreased (P < 0.01) the Firmicutes, but Deferribacteres in 200 mg/kg MCE group were significantly raised (P < 0.05). In conclusion, we found that MCE improved intestinal morphology and reduced the crypt depth in jejunum. Together, addition of 200 mg/kg MCE modulated intestinal microbiota, increased beneficial bacteria such as Lactobacillus. Adding 100 mg/kg MCE to diet increased bacterial community diversity and relative abundance in jejunum and ileum, but had no effect on cecum microbial diversity.

Effect of Fiber and Fecal Microbiota Transplantation Donor on Recipient Mice Gut Microbiota

Both fecal microbiota transplantation (FMT) and dietary fiber intervention were verified as effective ways to manipulate the gut microbiota, whereas little is known about the influence of the combined methods on gut microbiota. Here, we constructed "non-industrialized" and "industrialized" gut microbiota models to investigate the donor effect of FMT and diet effect in shaping the gut microbiota. Mice were transplanted fecal microbiota from domestic pig and received a diet with low-fiber (D) or high-fiber (DF), whereas the other two groups were transplanted fecal microbiota from wild pig and then received a diet with low-fiber (W) or high-fiber (WF), respectively. Gut microbiota of WF mice showed a lower Shannon and Simpson index (P < 0.05), whereas gut microbiota of W mice showed no significant difference than that of D and DF mice. Random forest models revealed the major differential bacteria genera between four groups, including Anaeroplasma or unclassified_o_Desulfovibrionales, which were influenced by FMT or diet intervention, respectively. Besides, we found a lower out-of-bag rate in the random forest model constructed for dietary fiber (0.086) than that for FMT (0.114). Linear discriminant analysis effective size demonstrated that FMT combined with dietary fiber altered specific gut microbiota, including Alistipes, Clostridium XIVa, Clostridium XI, and Akkermansia, in D, DF, W, and WF mice, respectively. Our results revealed that FMT from different donors coupled with dietary fiber intervention could lead to different patterns of gut microbiota composition, and dietary fiber might play a more critical role in shaping gut microbiota than FMT donor. Strategies based on dietary fiber can influence the effectiveness of FMT in the recipient.

Effects of the supplementation of a calcium soap containing medium-chain fatty acids on the fecal microbiota of pigs, lactating cows, and calves

Medium-chain fatty acids (MCFAs) have antialgal, antibacterial, antifungal, antiprotozoan, and antiviral activities. However, antibacterial activities of MCFAs in the hindgut of pigs and cattle are still unknown. We report the effects of the supplementation of MCFAs on fecal bacteria of pigs, lactating cows, and Japanese Black calves. Lactobacillus spp., Bifidobacterium spp., eaeA(+) Escherichia coli, Salmonella spp., Campylobacter jejuni, and Clostridium perfringens in the feces of animals were quantified by real-time PCR assay. There was no significant increase or decrease in Lactobacillus spp. and Bifidobacterium spp. in the three animals. In the pig feces, eaeA(+) E. coli was reduced to less than a third in the treatment group (P < 0.01). C. jejuni in the pig feces was also significantly less in the treatment group compared with the control (P < 0.01). In the lactating cow, eaeA(+) E. coli was reduced to one fifth of that in the control (P < 0.01). Salmonella spp. was halved in calf feces (P < 0.01). Thus, a reduction in Gram-negative pathogenic bacteria was observed. In conclusion, supplementation of a MCFA calcium soap in the diet would be beneficial to growing pigs, lactating cow, and calves by reducing pathogenic bacteria.

Effects of Total Dietary Fiber on Cecal Microbial Community and Intestinal Morphology of Growing White Pekin Duck

The current study was to investigate the effects of total dietary fiber (TDF) on growth performance, cecal structure, cecal microbial community, and short-chain fatty acids (SCFAs) profiles in the cecum of growing White Pekin ducks. A total of 108 male Pekin ducks of 14-days-old were randomly allocated and fed diets containing 12.4, 14.7, and 16.2% TDF for 35 days. Each dietary treatment consisted of six replicates with six birds each. The results showed that 14.7 and 16.2% TDF treatments promoted growth performance relative to 12.4% TDF treatments (P < 0.05). A total of 14.7 and 16.2% TDF treatments significantly elevated villus height, the ratio of villus height to crypt depth and muscle layer thickness of cecum, and lowered crypt depth compared with 12.4% TDF treatment (P < 0.05). Simultaneously, 14.7 and 16.2% TDF treatments up-regulated Claudin-1 mRNA expression of barrier genes in the cecum compared with 12.4% TDF (P < 0.05). Butyrate-producing bacteria like Oscillopiraceae affiliating to the phyla Firmicutes were observed as a biomarker in the 16.2% TDF. Higher concentration of butyrate in the cecum was obtained in the 14.7% TDF compared with 12.4 and 16.2% TDF (P < 0.05). The concentrations of isobutyrate, valerate, and isovalerate in the cecum were significantly increased in the 16.2% TDF compared with 12.4 and 14.7% TDF (P < 0.05). Meanwhile, the abundance of genus UCG-005 and Enterococcus was positive correlations with isobutyrate and valerate (P < 0.05). However, the concentration of propionate in the cecum significantly decreased in 14.7 and 16.2% TDF treatments relative to 12.4% TDF treatments (P < 0.05). In summary, increasing TDF levels improved growth performance, cecal histomorphology, and barrier function of meat ducks and it might be mediated by the changes of microbiota communities, especially bloom of SCFAs-producing bacteria, which facilitated the interaction between intestinal mucosa and microbiota.

Use of 25-hydroxyvitamin D3 in diets for sows: A review

Dietary supplementation with 25-hydroxyvitamin D₃ (25OHD₃), as an alternative source of vitamin D, is becoming increasingly popular due to its commercialization and more efficient absorbability. The addition of 25OHD₃ rather than its precursor vitamin D₃ can circumvent the 25-hydroxylation reaction in the liver, indicating that supplementation of 25OHD₃ can rapidly improve the circulating vitamin D status of animals. Emerging experiments have reported that maternal 25OHD₃ supplementation could increase sow performances and birth outcomes and promote circulating vitamin D status of sows and their offspring. Increased milk fat content was observed in many experiments; however, others demonstrated that adding 25OHD₃ to lactating sow diets increased the contents of milk protein and lactose. Although an inconsistency between the results of different experiments exists, these studies suggested that maternal 25OHD₃ supplementation could alter milk composition via its effects on the mammary gland. Previous studies have demonstrated that adding 25OHD₃ to sow diets could improve the mRNA expressions of insulin-induced gene 1 (INSIG1) and sterol regulatory element-binding protein 1 (SREBP1) in the mammary gland cells from milk and increase the mRNA expressions of acetyl-CoA carboxylase α (ACCα) and fatty acid synthase (FAS) in the mammary gland tissue. Maternal 25OHD₃ supplementation promotes skeletal muscle development of piglets before and after parturition, and improves bone properties including bone density and bone breaking force in lactating sows and their piglets. Interestingly, 25OHD₃ supplementation in sow diets could improve neonatal bone development via regulation of milk fatty acid composition related to bone metabolism and mineralization. In this review, we also discuss the effects of adding 25OHD₃ to sow diets on the gut bacterial metabolites of suckling piglets, and propose that butyrate production may be associated with bone health. Therefore, to better understand the nutritional functions of maternal 25OHD₃ supplementation, this paper reviews advances in the studies of 25OHD₃ for sow nutrition and provides references for practical application.

Protective effect of Bombyx mori gloverin on intestinal epithelial cells exposure to enterotoxigenic E. coli

Bombyx mori gloverin A2 (BMGlvA2) is an induced antimicrobial insect protein isolated from Bombyx mori. This study was conducted to explore the effect and potential mechanisms of BMGlvA2 on inflammatory responses and cellular functions in intestinal epithelial cells (IPEC-J2) exposure to enterotoxigenic E. coli (ETEC). IPEC-J2 cells pretreated with or without BMGlvA2 (12.5 μg/mL) were challenged by ETEC K88 (1×106 CFU/well) or culture medium. We show that BMGlvA2 pretreatment increased the cell viability and improved the distribution and abundance of tight junction protein ZO-1 in IPEC-J2 cells exposure to ETEC (P < 0.05). Interestingly, BMGlvA2 not only decreased the expression levels of inflammatory cytokines such as the tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), but also decreased the expression level of Caspase3 and the apoptosis rate in the ETEC-challenged cells (P < 0.05). Importantly, BMGlvA2 decreased the protein abundances of two critical inflammation-associated signaling proteins, phosphorylated nuclear factor-kappa-B inhibitor alpha (p-IκBα) and phosphorylated nuclear factor-kappa B (p-NF-κB), in the ETEC-challenged cells. These results indicate that BMGlvA2 attenuates ETEC-induced inflammation in the IPEC-J2 cells by regulating the NF-κB signaling pathway, resulting in decreased secretion of inflammatory cytokine and reduced cell apoptosis.

Effect of xylanase and live yeast supplementation on growth performance, nutrient digestibility, and gut microbiome diversity of pigs

Effect of xylanase (Xyl) and live yeast (LY) supplementation on gut microbiome composition, growth performance, and nutrient digestibility of weanling pigs was determined. A total of 180 weanling pigs were assigned to five treatments from weaning to market. Treatments were designated based on whether Xyl, LY, or their combination were fed in the first 2 wk postweaning or thereafter until finishing at day 141 postweaning. Treatments were (days 1–15; days 15–141): control–control, control–Xyl, Xyl–Xyl, LY–Xyl, Xyl + LY–Xyl. Xylanase was added at 16 000 BXU·kg−1 and LY at 1 kg·t−1. Pigs fed with LY and LY + Xyl from days 0–15 had greater body weight and average daily gain at day 15 compared with control (P < 0.05). Glucose transporter 2 mRNA was higher in LY and LY + Xyl groups on day 15 compared with control (P < 0.05). Xylanase supplementation from week 2 postweaning increased apparent total tract nutrient digestibility of gross energy, nitrogen, and phosphorus on day 43. Live yeast with or without Xyl improved growth performance in the first 2 wk after weaning; Xyl + LY–Xyl and control–Xyl groups had improved overall feed efficiency. In conclusion, LY and Xyl supplementation improved performance of weanling pigs in the first 2 wk after weaning with no effects on long-term growth performance.

In-Feed Supplementation of Resin Acid-Enriched Composition Modulates Gut Microbiota, Improves Growth Performance, and Reduces Post-Weaning Diarrhea and Gut Inflammation in Piglets

The weaning process represents a delicate phase for piglets, and is often characterized by lower feed intake, lower weight gain, diarrhea, and ultimately increased mortality. We aimed to determine the effects of RAC supplementation in diets on improving piglet growth and vitality, reducing post-weaning diarrhea, and enhancing gut health. In a 2 × 2 × 2 factorial experiment, we selected forty sows and their piglets. Piglets were followed until seven weeks of age. There were no significant differences found between RAC treated and control piglets until weaning (p = 0.26). However, three weeks after weaning, RAC treated piglets had higher body weight and average daily growth (ADG) than the control piglets (p = 0.003). In addition, the piglets that received RAC after weaning, irrespective of mother or prior creep feed treatment, had lower post-weaning diarrhea (PWD) and fecal myeloperoxidase (MPO) level than control piglets. Gut microbiota analysis in post-weaning piglets revealed that RAC supplementation significantly increased Lachnospiraceae_unclassified, Blautia, Butyricicoccus, Gemmiger and Holdemanella, and decreased Bacteroidales_unclassified. Overall, RAC supplementation to piglets modulated post-weaning gut microbiota, improved growth performance after weaning, reduced post-weaning diarrhea and reduced fecal myeloperoxidase levels. We therefore consider RAC to be a potential natural feed supplement to prevent enteric infections and improve growth performance in weaning piglets.

Growth performance and gut health of Escherichia coli-challenged weaned pigs fed canola meal-containing diet

An experiment was conducted to evaluate the effects of including canola meal (CM) in diets for weaning pigs challenged with a F18 strain of Escherichia coli on growth performance and gut health. A total of 36 individually housed weaned pigs (initial body weight [BW] = 6.22 kg) were randomly allotted to one of the three diets (12 pigs/diet). The three diets were corn-soybean meal (SBM)-based basal diet (control diet) and the basal diet with 0.3% zinc oxide, 0.2% chlortetracycline, and 0.2% tiamulin (antibiotic diet) or with 20% CM diet. The diets were fed in two phases: Phase 1: days 0 to 7 and Phase 2: days 7 to 20. All pigs were given an oral dose of 2 × 109 CFU of F18 strain of E. coli on day 7. Fecal score was assessed daily throughout the trial. Dietary antibiotics increased (P < 0.05) overall average daily gain (ADG) and average daily feed intake (ADFI) compared by 48% and 47%, respectively. Dietary CM increased (P < 0.05) overall ADG and ADFI by 22% and 23%, respectively; but the ADG and ADFI values for CM-containing diet did not reach those for the antibiotics-containing diet. Dietary antibiotics reduced (P < 0.05) fecal score; however, dietary CM unaffected fecal score. Dietary antibiotics decreased (P < 0.05) liver weight per unit live BW by 16% at day 20, whereas dietary CM did not affect liver weight per unit live BW (29.2 vs. 28.6). Also, dietary antibiotics increased (P < 0.05) serum triiodothyronine and tetraiodothyronine levels for day 14, whereas dietary CM did not affect the serum level of these hormones. Dietary antibiotics reduced (P < 0.05) the number white blood cells and neutrophils by 38% and 43% at day 20, respectively, whereas dietary CM tended to reduce (P = 0.09) the number white blood cells by 19% at day 20. The number white blood cells for CM diet tended to be greater (P < 0.10) than that for antibiotics diet. The dietary antibiotics decreased (P < 0.05) the concentration of individual volatile fatty acids and hence of total volatile fatty acid in cecum by 61% at day 20, whereas dietary CM decreased (P < 0.05) cecal butyric acid concentration by 61% and tended to reduce (P < 0.10) total volatile fatty acid concentration by 30% at day 20. In conclusion, the dietary inclusion of 20% CM improved ADG and tended to reduce white blood cell counts. Thus, inclusion of CM in antibiotics-free corn-SBM-based diets for weaned pigs that are challenged with F18 strain of E. coli can result in their improved performance partly through a reduction of the inflammatory response.

Effectiveness of Two Plant-Based In-Feed Additives against an Escherichia coli F4 Oral Challenge in Weaned Piglets

This study evaluates the efficacy of two plant-based feed supplementations to fight colibacillosis in weanlings. A total of 96 piglets (32 pens) were assigned to four diets: a control diet (T1) or supplemented with ZnO (2500 ppm Zn) (T2) or two different plant supplements, T3 (1 kg/t; based on essential oils) and T4 (T3 + 1.5 kg/t based on non-volatile compounds). After one week, animals were challenged with ETEC F4, and 8 days after, one animal per pen was euthanized. Performance, clinical signs, microbial analysis, inflammatory response, intestinal morphology, and ileal gene expression were assessed. ZnO improved daily gains 4 days after challenge, T3 and T4 showing intermediate values (96, 249, 170, and 157 g/d for T1, T2, T3, and T4, p = 0.035). Fecal lactobacilli were higher with T3 and T4 compared to ZnO (7.55, 6.26, 8.71, and 8.27 cfu/gFM; p = 0.0007) and T3 increased the lactobacilli/coliforms ratio (p = 0.002). T4 was associated with lower levels of Pig-MAP (p = 0.07) and increases in villus/crypt ratio (1.49, 1.90, 1.73, and 1.84; p = 0.009). Moreover, T4 was associated with an upregulation of the REG3G gene (p = 0.013; p_FDR = 0.228) involved in the immune response induced by enteric pathogens. In conclusion, both plant supplements enhanced animal response in front of an ETEC F4 challenge probably based on different modes of action.

Factors affecting performance response of pigs exposed to different challenge models: a multivariate approach

Factors associated with the severity with which different challenge models (CMs) compromise growth performance in pigs were investigated using hierarchical clustering on principal components (HCPC) analysis. One hundred seventy-eight studies reporting growth performance variables (average daily gain [ADG], average daily feed intake [ADFI], gain:feed [GF], and final body weight [FBW]) of a Control (Ct) vs. a Challenged (Ch) group of pigs using different CMs (enteric [ENT], environmental [ENV], lipopolysaccharide [LPS], respiratory [RES], or sanitary condition [SAN] challenges) were included. Studies were grouped by similarity in performance in three clusters (C1, C2, and C3) by HCPC. The effects of CM, cluster, and sex (males [M], females [F], mixed [Mi]) were investigated. Linear (LRP) and quadratic (QRP) response plateau models were fitted to assess the interrelationships between the change in ADG (∆ADG) and ADFI (∆ADFI) and the duration of challenge. All variables increased from C1 through C3, except for GF, which decreased (P < 0.05). LPS was more detrimental to ADG than ENV, RES, and SAN models (P < 0.05). Furthermore, LPS also lowered GF more than all the other CMs (P < 0.05). The ∆ADG independent of ∆ADFI was significant in LPS and SAN (P < 0.05), showed a trend toward the significance in ENT and RES (P < 0.10), and was not significant in ENV (P > 0.10), while the ∆ADG dependent on ∆ADFI was significant in ENT, ENV, and LPS only (P < 0.05). The critical value of ∆ADFI influencing the ∆ADG was significant in pigs belonging to C1 (P < 0.05) but not C2 or C3 (P > 0.10). The ∆ADG independent of duration post-Ch (irreparable portion of growth) was significant in C1 and C2 pigs, whereas the ∆ADFI independent of duration post-Ch (irreparable portion of feed intake) was significant in C1 pigs only (P < 0.05). Moreover, the time for recovery of ADG and ADFI after Ch was significant in pigs belonging to C1 and C2 (P < 0.05). Control F showed reduced ADG compared with Ct-M, and Ch-F showed reduced ADFI compared with Ch-M (P < 0.05). Moreover, the irreparable portion of ΔADG was 4.8 higher in F (-187.7; P < 0.05) compared with M (-39.1; P < 0.05). There are significant differences in growth performance response to CM based on cluster and sex. Furthermore, bacterial lipopolysaccharide appears to be an appropriate noninfectious model for immune stimulation and growth impairment in pigs.

Effects of dietary inactivated probiotics on growth performance and immune responses of weaned pigs

This experiment was performed to verify whether dietary heat-killed Lactobacillus rhamnosus (LR) improves growth performance and modulates immune responses of weaned pigs. Ninety-six weaned pigs ([Landrace × Yorkshire] × Duroc; 6.95 ± 0.25 kg body weight [BW]; 28 d old) were randomly allocated to four treatments: 1) a basal diet without heat-killed LR (CON), 2) T1 (CON with 0.1% heat-killed LR), 3) T2 (CON with 0.2% heat-killed LR), and 4) T3 (CON with 0.4% heat-killed LR). Each treatment had six pens with four pigs (6 replicates per treatment) in a randomized completely block design. The heat-killed LR used in this study contained 1 × 10⁹ FU/g of LR in a commercial product. Pigs were fed each treatment for four weeks using a two-phase feeding program to measure growth performance and frequency of diarrhea. During the last week of this study, all diets contained 0.2% chromic oxide as an indigestible marker. Fecal sampling was performed through rectal palpation for the consecutive three days after the four adaptation days to measure apparent total tract digestibility (ATTD) of dry matter, crude protein, and gross energy (GE). Blood sampling was also performed on day 1, 3, 7, and 14 after weaning to measure immune responses such as serum tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), C-reactive protein (CRP), and cortisol. The heat-killed LR increased (p < 0.05) growth rate, feed efficiency, and ATTD of GE for overall experimental period compared with CON, but reduced (p < 0.05) post-weaning diarrhea. In addition, pigs fed diets contained heat-killed had lower concentrations of serum TNF-α (d 7; p < 0.05), TGF-β1 (d 7; p < 0.10), and cortisol (d 3 and 7; p < 0.05) than pigs fed CON. In conclusion, dietary heat-killed LR improved growth rate, modified immune responses of weaned pigs, and alleviated post-weaning diarrhea.