Short-chain fatty acids modulate the IPEC-J2 cell response to pathogenic E. coli LPS-activated PBMC

Intestinal disorders can affect pigs of any age, especially when animals are young and more susceptible to infections and environmental stressors. For instance, pathogenic E. coli can alter intestinal functions, thus leading to altered nutrient adsorption by interacting with local cells through lipopolysaccharide (LPS). Among several compounds studied to counteract the negative effects on the intestine, short-chain fatty acids (SCFA) were demonstrated to exert beneficial effects on gut epithelial cells and resident immune cells. In this study, acetate and propionate were tested for their beneficial effects in a co-culture model of IPEC-J2 and porcine PBMC pre-stimulated with LPS from E. coli 0111:B4 aimed at mimicking the interaction between intestinal cells and immune cells in an inflammatory/activated status. IPEC-J2 viability was partially reduced when co-cultured with activated PBMC and nitric oxide concentration increased. IPEC-J2 up-regulated innate and inflammatory markers, namely BD-1, TLR-4, IL-8, TNF-α, NF-κB, and TGF-β. Acetate and propionate positively modulated the inflammatory condition by sustaining cell viability, reducing the oxidative stress, and down-regulating the expression of inflammatory mediators. TNF-α expression and secretion showed an opposite effect in IPEC-J2 depending on the extent of LPS stimulation of PBMC and TGF-β modulation. Therefore, SCFA proved to mediate a differential effect depending on the degree and duration of inflammation. The expression of the tight junction proteins (TJp) claudin-4 and zonula occludens-1 was up-regulated by LPS while SCFA influenced TJp with a different kinetics depending on PBMC stimulation. The co-culture model of IPEC-J2 and LPS-activated PBMC proved to be feasible to address the modulation of markers related to anti-bacterial immunity and inflammation, and intestinal epithelial barrier integrity, which are involved in the in vivo responsiveness and plasticity to infections.

Bifidobacterium infantis and 2'-fucosyllactose supplementation in early life may have potential long-term benefits on gut microbiota, intestinal development, and immune function in mice

The health benefits of nutritional interventions targeting the gut microbiota in early life are transient, such as probiotics, prebiotics, and synbiotics. This study sought to determine whether supplementation with Bifidobacterium infantis 79 (B79), 2'-fucosyllactose (2'-FL), or both (B79+2'FL) would lead to persistent health benefits in neonatal BALB/c mice. We found that at postnatal day (PND) 21, Ki67 and MUC2 expression increased, while total serum IgE content decreased in the B79, 2'-FL, and B79+2'-FL groups. The gut microbiota structure and composition altered as well. The levels of propionic acid, sIgA, and IL-10 increased in the 2'-FL group. Moreover, butyric acid content increased, while IL-6, IL-12p40, and tumor necrosis factor-α decreased in the B79+2'-FL group. At PND 56, Ki67 and MUC2 expression increased, whereas the gut microbiota remained altered in all 3 groups. The serum total IgG level increased only in the B79+2'-FL group. In conclusion, our study suggests that early-life supplementation with B79, 2'-FL, or their combination persistently alters the gut microbiome and promotes intestinal development; the immunomodulatory capacity of B79 and 2'-FL occurs during weaning, and their combination may persist into adulthood.

Comparative efficacy of a novel Bacillus subtilis-based probiotic and pharmacological zinc oxide on growth performance and gut responses in nursery pigs

In this study, we assessed the efficacy of a novel Bacillus subtilis probiotic in improving growth performance and gut responses in comparison to pharmacological zinc oxide (ZnO) in nursery pigs. A total of 96 piglets were randomly assigned to four groups: Negative control (NC), Positive control (PC, 3000 mg Zn /kg feed), B.subtilis low dose (BS9-L, 2 × 10⁷ CFU/pig) and B.subtilis high dose (BS9-H, 2 × 10⁹ CFU/pig). Growth performance, diarrhea rate, gut mucosal gene expression and fecal microbial populations were evaluated. B.subtilis administration did not improve piglet bodyweight. BS9-L showed (P < 0.05) higher average daily gain (ADG) in Period 2 (D14-D28). BS9 groups had (P < 0.001) lower feed conversion ratio (FCR) in Period 2 (D14-D28) and overall. Like the ZnO-group, BS9 groups had lower (P < 0.01) diarrhea rate. A significant reduction (P < 0.05) in fecal E. coli, total coliforms, and an increase in lactic acid bacteria and Bacillus spp. in BS9 groups was observed. BS9 group had reduced (P < 0.05) mRNA levels of intestinal IL-8 and higher levels of MUC-1 and occludin and TJP-1 compared to negative control. These findings suggest that probiotic BS9, may promote growth performance, and ameliorate various indicators of intestinal health in piglets. Hence, it may serve as a prospective alternative to ZnO growth promoter in commercial swine production.

Effects of different short-chain fatty acids (SCFA) on gene expression of proteins involved in barrier function in IPEC-J2

Background

Gut microbial anaerobic fermentation produces short-chain fatty acids (SCFA), which are important substrates for energy metabolism and anabolic processes in mammals. SCFA can regulate the inflammatory response and increase the intestinal barrier integrity by enhancing the tight junction protein (TJp) functions, which prevent the passage of antigens through the paracellular space. The aim of this study was to evaluate the effect of in vitro supplementation with SCFA (acetate, propionate, butyrate, and lactate) at different concentrations on viability, nitric oxide (NO) release (oxidative stress parameter) in cell culture supernatants, and gene expression of TJp (occludin, zonula occludens-1, and claudin-4) and pro-inflammatory pathway-related mediators (β-defensin 1, TNF-α, and NF-κB) in intestinal porcine epithelial cell line J2 (IPEC-J2).

Results

The SCFA tested showed significant effects on IPEC-J2, which proved to be dependent on the type and specific concentration of the fatty acid. Acetate stimulated cell viability and NO production in a dose-dependent manner (P < 0.05), and specifically, 5 mM acetate activated the barrier response through claudin-4, and immunity through β-defensin 1 (P < 0.05). The same effect on these parameters was shown by propionate supplementation, especially at 1 mM (P < 0.05). Contrarily, lactate and butyrate showed different effects compared to acetate and propionate, as they did not stimulate an increase of cell viability and regulated barrier integrity through zonula occludens-1 and occludin, especially at 30 mM and 0.5 mM, respectively (P < 0.05). Upon supplementation with SCFA, the increase of NO release at low levels proved not to have detrimental effects on IPEC-J2 proliferation/survival, and in the case of acetate and propionate, such levels were associated with beneficial effects. Furthermore, the results showed that SCFA supplementation induced β-defensin 1 (P < 0.05) that, in turn, may have been involved in the inhibition of TNF-α and NF-κB gene expression (P < 0.05).

Conclusions

The present study demonstrates that the supplementation with specific SCFA in IPEC-J2 can significantly modulate the process of barrier protection, and that particularly acetate and propionate sustain cell viability, low oxidative stress activity and intestinal barrier function.

Effects of Brewer Grain Meal with Enzyme Combination on Growth Performance, Nutrient Digestibility, Intestinal Morphology, Immunity, and Oxidative Status in Growing Pigs

This study investigated the effects of supplementing feed with various levels of brewer grain meal (BGM) and enzymes (amylase, xylanase, β-glucanase, lipase, cellulase, β-mannanase, phytase, and pectinase) on growth performance, nutrient digestibility, intestinal morphology, immunity, and oxidative status in growing pigs. Eighty growing pigs were subjected to four feed treatments (five replicates per treatment), based on a corn-soybean basal diet: feeds with 0.1% enzyme combination supplementation (PC), no enzyme supplementation (NC), 20% BGM with 0.1% enzyme combination (BGM20), and 40% BGM with 0.1% enzyme combination (BGM40). Supplementing the feed with both BGM-supplemented diets significantly increased final body weight, average daily gain, the digestibility of crude protein and ash, serum concentration of total proteins, superoxide dismutase activity, villus height in the duodenum and jejunum, and duodenal villus height to crypt depth ratio; however, it did not significantly increase blood urea nitrogen, tumor necrosis factor-alpha, malondialdehyde levels, and duodenal crypt depth compared to the NC diet (p < 0.05). Furthermore, a lower hindgut pH in the middle of the colon was detected following the BGM-supplemented diet compared to PC treatment (p = 0.005). Increased levels of triglycerides and albumin were detected in BGM20-fed pigs, whereas increased levels of glucose, total antioxidant capacity, and glutathione peroxidase but decreased interleukine-6 levels were observed in the BGM40 compared with the NC group (p = 0.05). No differences were observed in the average daily feed intake and gain to feed ratio, in the serum levels of aspartate aminotransferase or immunoglobulins (p > 0.05). The addition of up to 40% BGM combined with 0.1% enzyme supplementation positively promotes the growth performance, nutrient utilization, and intestinal health of growing pigs.

Microbial sensing in the neonatal pig gut: effect of diet-independent and diet-dependent factors1

There is considerable agreement that the gastrointestinal microbiota contributes to the performance and health of the neonate, and this relationship includes an ability of the host animal to “sense” changes in the microbial community. Identifying the mechanisms used by the host to sense microbiota is one approach to developing methods to manipulate the microbiota to improve pig health and performance. Diet-independent microbial products are molecules unique to the microbial community and sensed by host pattern recognition receptors stimulating inflammation. Common among all members of the microbial community, their presence is unaffected by diet, but the nature of the response does depends on factors affecting the microenvironment in which the molecule is detected. Diet-dependent microbial products arise as products of fermentation of dietary components and include short-chain fatty acids, ammonia, phenols, hydrogen sulfide, amines, and many other compounds. A plethora of sensing mechanisms exists that include enzymatic metabolism as well as membrane receptors that have evolved to respond to microbial products (e.g., short-chain fatty acid receptors), or simply cross-react with microbial products. This review focuses on host mechanisms used to sense the intestinal microbiota and attempts to establish practical considerations for neonatal gut health based on current understanding.

Activation of a Specific Gut Bacteroides-Folate-Liver Axis Benefits for the Alleviation of Nonalcoholic Hepatic Steatosis

A beneficial gut Bacteroides-folate-liver pathway regulating lipid metabolism is demonstrated. Oral administration of a Ganoderma meroterpene derivative (GMD) ameliorates nonalcoholic hepatic steatosis in the liver of fa/fa rats by reducing endotoxemia, enhancing lipid oxidation, decreasing de novo lipogenesis, and suppressing lipid export from the liver. An altered gut microbiota with an increase of butyrate and folate plays a causative role in the effects of GMD. The commensal bacteria Bacteroides xylanisolvens, Bacteroides thetaiotaomicron, Bacteroides dorei, and Bacteroides uniformis, which are enriched by GMD, are major contributors to the increased gut folate. Administration of live B. xylanisolvens reduces hepatic steatosis and enhances the folate-mediated signaling pathways in mice. Knockout of the folate biosynthetic folp gene in B. xylanisolvens blocks its folate production and beneficial effects. This work confirms the therapeutic potential of GMD and B. xylanisolvens in alleviating nonalcoholic hepatic steatosis and provides evidence for benefits of the gut Bacteroides-folate-liver pathway.

Infusion of short chain fatty acids in the ileum improves the carcass traits, meat quality and lipid metabolism of growing pigs

Short chain fatty acids (SCFA) are the main products of indigestible carbohydrates undergoing bacterial fermentation in the hindgut, which are related to some physiological functions. This study was designed to investigate the effects of SCFA infusion by ileum on the carcass traits, meat quality and lipid metabolism of growing pigs. In a 28-day study, 24 growing barrows fitted with a T-cannula in distal ileum were divided into 4 treatments: 1) Control, 2) antibiotics (AB), 3) AB + 300 mL of SCFA1 solution (ABS1), 4) AB + 300 mL of SCFA2 solution (ABS2). The concentrations of acetate, propionate and butyrate in SCFA1 solution were respectively 61.84, 18.62 and 12.55 mmol/L, and in SCFA2 were respectively 40.08, 15.41 and 9.78 mmol/L. The results showed that the SCFA infusion increased the average daily feed intake and average daily gain of pigs (P < 0.05). Meanwhile, the SCFA treatments increased longissimus dorsi area (P < 0.05) and carcass weight (P = 0.058), decreased the drip loss of longissimus dorsi (P = 0.059), and reduced serum concentrations of triglyceride, total cholesterol and urea nitrogen (P < 0.05). Besides, the SCFA administration inhibited the mRNA expressions of fatty acid synthase (FAS) and acetyl-CoA carboxylase in longissimus dorsi (P < 0.05), the mRNA expression of FAS in the liver (P < 0.05), and the mRNA expression of hormone-sensitive lipase in abdominal fat (P < 0.05). Short chain fatty acid infusion also enhanced the mRNA expression of carnitine palmitoyltransferase-1α in the liver (P < 0.05), the mRNA expressions of peroxisome proliferator activated receptor gamma and lipoprotein lipase in abdominal fat (P < 0.05), and the mRNA expressions of free fatty acid receptor 2, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon (P < 0.05). These results suggested that SCFA administration in the ileum could improve the carcass traits and meat quality of growing pigs, which was possibly due to the fact that SCFA modulated lipid metabolism.

Exogenous infusion of short-chain fatty acids can improve intestinal functions independently of the gut microbiota

The present experiment was conducted to investigate the effects of exogenously infused short-chain fatty acids (SCFAs) on the growth development and intestinal functions in a germ-free (GF) pig model. Twelve hysterectomy-derived newborn piglets were reared in six sterile isolators. All piglets were hand-fed Co60-γ-irradiated sterile milk powder for 21 d and then were switched to sterile feed for another 21 d. During the second 21-d period, GF piglets (n = 6) were orally infused with 25 mL/kg sterile saline per day, and SCFA piglets (n = 6) were orally infused with 25 mL/kg SCFAs mixture (acetic, propionic, and butyric acids, 45, 15, and 11 mM, respectively) per day. We observed the concentrations of SCFAs in serum and intestine, and the messenger ribonucleic acid (mRNA) abundance of G-protein-coupled receptor-43 in the ileum was increased (P < 0.05) in the SCFA group. Meanwhile, oral infusion of SCFAs enhanced (P < 0.05) the contents of glucagon-like peptide-2 in the jejunum and serum and tended to increase the villi height in the ileum (P < 0.10). Besides, the activities of lipase, trypsin, sucrase, lactase, Na+-K+-adenosine triphosphatase ([ATPase] P < 0.05), and Ca2+-Mg2+-ATPase (P < 0.10) were stimulated and the mRNA expressions of solute carrier family 7 (SLC7A1) and regeneration protein (REG)-ΙΙΙ γ in the jejunum (P < 0.05) were upregulated in the SCFA group. Additionally, SCFAs infusion downregulated the mRNA abundances of interleukin (IL)-1β and IL-6 in the jejunum, ileum, or colon (P < 0.05) and increased the counts of white blood cell, neutrophils, and lymphocyte in the blood (P < 0.05). Collectively, exogenous infusion of SCFAs might improve intestinal health through promoting intestinal development and absorption function, and enhancing intestinal immune function, and these effects were occur independently of the gut microbiota.

Free Fatty Acid Receptors 2 and 3 as Microbial Metabolite Sensors to Shape Host Health: Pharmacophysiological View

The role of the gut microbiome in human health is becoming apparent. The major functional impact of the gut microbiome is transmitted through the microbial metabolites that are produced in the gut and interact with host cells either in the local gut environment or are absorbed into circulation to impact distant cells/organs. Short-chain fatty acids (SCFAs) are the major microbial metabolites that are produced in the gut through the fermentation of non-digestible fibers. SCFAs are known to function through various mechanisms, however, their signaling through free fatty acid receptors 2 and 3 (FFAR2/3; type of G-coupled protein receptors) is a new therapeutic approach. FFAR2/3 are widely expressed in diverse cell types in human and mice, and function as sensors of SCFAs to change several physiological and cellular functions. FFAR2/3 modulate neurological signaling, energy metabolism, intestinal cellular homeostasis, immune response, and hormone synthesis. FFAR2/3 function through Gi and/or Gq signaling, that is mediated through specific structural features of SCFAs-FFAR2/3 bindings and modulating specific signaling pathway. In this review, we discuss the wide-spread expression and structural homologies between human and mice FFAR2/3, and their role in different human health conditions. This information can unlock opportunities to weigh the potential of FFAR2/3 as a drug target to prevent human diseases.

Early Intervention Using Fecal Microbiota Transplantation Combined with Probiotics Influence the Growth Performance, Diarrhea, and Intestinal Barrier Function of Piglets

Early intervention with fecal microbiota transplantation (FMT) improves the growth performance and intestinal barrier function of piglets. Accelerating intestinal oxygen concentration is beneficial for symbiotic bacterial colonization. Saccharomyces boulardii (SB) is an aerobic fungus, which may contribute to the colonization of anaerobic symbiotic bacteria by competing for oxygen. Clostridium butyricum (CB) improves intestinal barrier function and performance, via regulating the gut microbiota composition of piglets. The objective of this study was to investigate the effect of early intervention with FMT combining CB and SB on growth performance, diarrhea, and intestinal barrier function in piglets. A total of 77 litters of neonatal piglets assigned to one of six treatments, which treated with antibiotics (AB), placebo (CON), and FMT (FMT), FMT-added CB (FMT+C), FMT-added SB (FMT+S), and FMT-added CB and SB (FMT+C+S), respectively. FMT+C+S treated piglets had higher body weight (BW) and average daily gain (ADG) both in weaning and finial period, and it significantly increased the levels of fecal mucin-2 (MUC2), fecal short-chain fatty acids (SCFAs), and relative abundance of fecal Lactobacillus spp., and Bifidobacterium genus. Moreover, early intervention with FMT+C+S reduced the diarrhea rate during the experiment. FMT+C+S also decreased the level of plasma diamine oxidase (DAO) and D-lactate (D-LA), and relative abundance of fecal E. coli during the suckling period. In summary, early intervention with FMT combining CB and SB improved the growth performance, intestinal barrier function, fecal SCFAs concentration, and fecal Lactobacillus and Bifidobacterium of piglets.

Short chain fatty acids could prevent fat deposition in pigs via regulating related hormones and genes

Short chain fatty acids (SCFAs) are produced when indigestible carbohydrates, such as fiber and resistant starch, undergo fermentation by specific microbiota in the hindgut.

Imbalance in the force: the dark side of the microbiota on stroke risk and progression

The composition of the gut microbiota depends on many factors, including our lifestyle, diet, metabolism, antibiotic use and hygiene. The contribution of these factors in shaping the gut microbiota and the subsequent effects on the prevention and development of stroke has been under intense investigation. Furthermore, several reports have uncovered the impact of stroke on intestinal dysfunction and gut dysbiosis, highlighting the delicate interplay between the brain, gut and microbiome following this acute brain injury. Despite our growing appreciation of the gut microbiota in shaping brain health, the immune system, host metabolism and disease progression, its therapeutic capability in stroke is yet to be fully exploited. This review will explore the microbiota-gut-brain axis in stroke, and examine the potential role of the gut microbiota in the onset, progression and recovery phase of stroke.

Protein restriction and succedent realimentation affecting ileal morphology, ileal microbial composition and metabolites in weaned piglets

Dietary protein restriction is one of the effective ways to reduce post-weaning diarrhoea and intestinal fermentation in piglets, but it may also reduce growth performance. The compensatory growth induced by subsequent protein realimentation may solve the issue. However, little research has been done on the impact of protein realimentation on the gut. In this study, the effects of protein restriction and realimentation on ileal morphology, ileal microbial composition and metabolites in weaned piglets were investigated. Thirty-six 28-day-old weaned piglets with an average body weight of 6.47 ± 0.04 kg were randomly divided into a control group and a treatment group. The CP level in the diet of the control group was 18.83% for the entire experimental period. The piglets in the treatment group were fed 13.05% CP between days 0 and 14 and restored to a diet of 18.83% CP for days 14 to 28. On day 14 and 28, six pigs from each group were sacrificed and sampled. It was found that the abundance of Lactobacillus and Salmonella in the ileal digesta was significantly lower in the treatment group than the control group on day 14, whereas the abundance of Clostridium sensu stricto 1, Streptococcus, Halomonas and Pseudomonas significantly increased in the ileal digesta of the treatment group on day 14 compared with the control group. In addition, reduced concentrations of lactic acid, total short-chain fatty acids (total SCFAs), total branched chain fatty acids, ammonia and impaired ileal morphology and mucosal barrier were observed in the treatment group on day 14. However, diarrhoea levels decreased in the treatment group throughout the experiment. During the succedent protein realimentation stage, the treatment group demonstrated compensatory growth. Compared with the control group, the treatment group showed increased abundance of Lactobacillus and reduced abundance of Salmonella, Halomonas and Pseudomonas in the ileum on day 28. The concentrations of lactic acid and total SCFAs increased significantly, whereas the concentration of ammonia remained at a lower level in the treatment group on day 28 compared with the control group. Overall, protein realimentation could improve ileal morphology and barrier functions and promote ileal digestive and absorptive functions. In conclusion, ileal microbial composition and metabolites could change according to dietary protein restriction and realimentation and eventually influence ileal morphology and barrier functions.

Cecal Infusion of Sodium Propionate Promotes Intestinal Development and Jejunal Barrier Function in Growing Pigs

Simple Summary

Microbial-derived short-chain fatty acids can exert influence on intestinal development and intestinal barrier function. Usually, it is well known that short-chain fatty acid butyrate provides energy for the colonic cell turnover and maintains the integrity of the colonic epithelium. However, the effect of short-chain fatty acid propionate on intestinal development and jejunal barrier function is given less attention. In this study, we found that cecal infusion of propionate promoted development of the jejunum and colon, and selectively enhanced jejunal tight junction protein expression. These results suggest that propionate by microbial fermentation in the hindgut has an important role in intestinal development and gut health.

Abstract

Short-chain fatty acids (SCFAs) produced by microbial fermentation facilitate the differentiation and proliferation of intestinal epithelium. However, the role of individual SCFAs, such as propionate, on intestinal development is still unclear. In the present study, sixteen barrows fitted with a cecal fistula were randomly divided into two groups for cecal infusion of either saline (control group) or sodium propionate (propionate group). After 28 days, the length and the relative weight of intestinal segments were calculated, the intestinal morphology was assessed, and the expression of tight junction protein was measured using qPCR and Western blotting. Compared to the saline group, the length of the colon was significantly increased in the propionate group (p < 0.05). The jejunal villi length and villi/crypt ratio in the propionate group were significantly higher than in the saline group (p < 0.05). Furthermore, propionate infusion significantly upregulated the mRNA levels of Claudin-4 and the expression of Claudin-1, Claudin-4, and Occludin protein in the jejunal mucosa (p < 0.05). Collectively, these findings revealed that the short-chain fatty acid propionate in the hindgut contributed to intestinal development, and selectively enhanced jejunal tight junction protein expression.

Effects of Intravenous Infusion With Sodium Butyrate on Colonic Microbiota, Intestinal Development- and Mucosal Immune-Related Gene Expression in Normal Growing Pigs

This study aimed to investigate effects of intravenous infusion with sodium butyrate (SB) on colonic microbiota, intestinal mucosal immune and intestinal development in normal growing pigs. Twelve crossbred barrows (Duroc × Landrace × Large White) fitted with a medical polyethylene cannula via internal jugular vein were daily infused with 10 ml SB (200 mmol/l) or the same volume of physiological saline for 7 days. Results showed that SB infusion had no effects on the short-chain fatty acids concentrations and the number of total bacteria, but significantly increased the microbial richness estimators (ACE and Chao1), and the abundance of genera related to Clostridiales order in the colonic digesta (P < 0.05). SB infusion significantly up-regulated the mRNA expression of monocarboxylate transporter 1 (MCT1) in the colon, while no change was found in the ileum. Only the relative mRNA of pro-inflammatory cytokine IL-6 gene was decreased significantly in the ileum by SB infusion. On the contrary, in the colon, SB infusion significantly decreased the gene expression of histone deacetylase 1 (HDAC1) and pro-inflammatory cytokines IL-6, IL-18, IL-12p40, and TNF-α (P < 0.05), but significantly increased the secretory immunoglobulin A (sIgA) concentration, the gene expression of anti-inflammatory cytokine IL-10, and the expression of intestinal development-related gene zonula occludens-1 (ZO-1), occludin, and epidermal growth factor (EGF) (P < 0.05). The results suggest that systemic SB can modify colonic microbial composition, regulate the inflammatory cytokine- and intestinal development-related gene expression in pigs under the normal physiological condition. This study may provide an alternative strategy for improving the intestinal health of normal piglets.