Background: Compared with oral antibiotics(primarily disrupt foregut microbiota), the present study used antibiotics with ileum terminal infusion to disrupt the hindgut microbiota, and investigated the changes in specific bacterial composition and immune indexes in the jejunum and colon, and serum of growing pigs. Twelve barrows(45 d of age, 12.08 ± 0.28 kg) fitted with a T-cannula at the terminal ileum, were randomly assigned to two groups and infused either saline without antibiotics(Control) or with antibiotics(Antibiotic) at the terminal ileum. After 25 d experiment, all pigs were euthanized for analyzing bacterial composition and immune status.Results: Ileum terminal antibiotic infusion(ITAI) altered dominant bacteria counts, with a decrease in Bifidobacterium, Clostridium cluster IV and Clostridium cluster IV in the colon(P < 0.05), and an increase in Escherichia coli in the jejunum(P < 0.05). ITAI decreased(P < 0.05) short-chain fatty acids concentrations in the colon. ITAI decreased interleukin-8(IL-8), IL-10 and secretory immunoglobulin A(sIgA) concentrations, and down-regulated IL-10, Mucin-1(MUC1), Mucin-2(MUC2) and zonula occludens-1(ZO-1) mRNA expression in the colonic mucosa(P < 0.05). In the jejunal mucosa, ITAI decreased interferon-γ(IFN-γ), tumor necrosis factor-α(TNF-α), s IgA and IgG levels together with down-regulation of IFN-γ, TNF-α, MUC2 and ZO-1 mRNA expression(P < 0.05). Furthermore, ITAI decreased IL-10, INF-γ, TNF-α, IgA and IgG concentrations in serum(P < 0.05). Correlation analysis revealed that the change in intestinal microbiota was correlated with alterations of Ig and cytokines.Conclusions: ITAI affected jejunal and colonic specific bacteria counts, and altered some immune markers levels in the jejunal and colonic mucosa and serum. These findings implicate the potential contribution of hindgut bacteria to immune response in the intestinal mucosa and serum of growing pigs.
Backgroud： This study aimed to determine the effects of early antibiotic intervention（EAI） on subsequent blood parameters, apparent nutrient digestibility, and fecal fermentation profile in pigs with different dietary crude protein（CP） levels. Eighteen litters of piglets（total 212） were randomly allocated to 2 groups and were fed a creep feed diet with or without in-feed antibiotics（olaquindox, oxytetracycline calcium and kitasamycin） from postnatal d 7 to d 42. On d 42, the piglets within the control or antibiotic group were mixed, respectively, and then further randomly assigned to a normal-（20%, 18%, and 14% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively） or a low-CP diet（16%, 14%, and 10% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively）, generating 4 groups. On d 77（short-term） and d 185（long-term）, serum and fecal samples were obtained for blood parameters, microbial composition and microbial metabolism analysis.Results： EAI increased（P 〈 0.05） albumin and glucose concentrations in low-CP diet on d 77, and increased（P 〈 0.05） urea concentration in normal-CP diet. On d 185, EAI increased（P 〈 0.05） globulin concentration in normal-CP diets, but decreased glucose concentration. For nutrient digestibility, EAI increased（P 〈 0.05）digestibility of CP on d 77. For fecal microbiota, the EAI as well as low-CP diet decreased（P 〈 0.05） E. coli count on d 77. For fecal metabolites, on d 77, EAI decreased（P 〈 0.05） total amines concentration but increased skatole concentration in low-CP diet. On d 185, the EAI increased（P 〈 0.05） putrescine and total amines concentrations in low-CP diets but reduced（P 〈 0.05） in the normal-CP diets. The low-CP diet decreased the concentrations of these compounds.Conclusions： Collectively, these results indicate that EAI has short-term effects on the blood parameters and fecal microbial fermentation profile. The effects of EAI varied between CP levels, which was
To reduce nitrogen excretion and lower feeding costs,low crude protein(CP)diets are sometimes pro-posed,however,a great reduction of dietary CP concentration(>4%reduction vs.recommended con-centration),even supplemented with essential and nonessential amino acids(AA)can detrimentally affect small intestinal barrier function and immunity,possibly due to the excessive lack of peptides.Here we hypothesize that with an extremely low CP concentration diet,protein-derived peptides,rather than AA supplementation,can improve intestinal barrier development and health.To test this hypothesis,21 growing pigs(19.90±1.00 kg body weight)were randomly assigned to 3 treatments with control diet(16%CP),or low CP diets(13%CP)supplemented with AA(LCPA)or casein hydrolysate(LCPC)for 28 days.In comparison with the control diet,the LCPA diet decreased the protein expression level of jejunal barrier factor zonula occludens-1(ZO-1)and stem cell proliferation factor leucine-rich repeat-containing G-protein-coupled receptor-5,whereas the LCPC diet enhanced intestinal barrier function by increasing the protein expression level of jejunal occludin and ZO-1 and ileal mucin-2.The LCPA diet reduced Lactobacillus counts,whereas the LCPC diet increased Lactobacillus counts and reduced Escherichia coli counts in the ileum.The LCPA diet also increased protein expression levels of pro-inflammatory cytokine interleukin-6(IL-6)and IL-22,whereas the LCPC diet decreased protein expression levels of pro-inflammatory IL-1β,IL-17A and tumor necrosis factor-αin the ileum.Collectively,the casein hydroly-sate supplementation of low CP diets showed beneficial effects on the small intestinal barrier,bacterial community,and immunity in pigs,pointing to the important role of protein-derived peptides in small intestinal health in cases of low crude protein diets.
High-protein diet could cause an increase in protein fermentation in the large intestine, leading to an increased production of potentially detrimental metabolites. We hypothesized that an increase in corn resistant starch content may attenuate the protein fermentation. The aim of this study was to evaluate the effect of resistant starch on protein fermentation by inocula from large intestine of pigs using in vitro cultivation. Fermentation patterns were analyzed during a 24-h incubation of cecal and colonic digesta with varying corn resistant starch contents, using casein protein as sole nitrogen source. The results showed that the concentration of short-chain fatty acids(SCFA) and cumulative gas production were significantly increased(P < 0.05), while ammonia-nitrogen(NH_3-N) and branched-chain fatty acids(BCFA), which indicated protein fermentation, decreased when the corn resistant starch levels increased(P < 0.05). The copies of total bacteria, Bifidobacterium and Lactobacillus were significantly increased with the increased corn resistant starch levels after incubation(P < 0.05). The copies of the Bifidobacterium and Lactobacillus in cecum were significantly higher than those in colon(P < 0.05). We conclude that the addition of corn resistant starch weakens the protein fermentation by influencing microbial population and reducing protein fermentation in the cecum and colon in vitro.
Background:High-protein diets can increase the colonic health risks.A moderate reduction of dietary crude-protein(CP)level can improve the colonic bacterial community and mucosal immunity of pigs.However,greatly reducing the dietary CP level,even supplemented with all amino acids(AAs),detrimentally affects the colonic health,which may be due to the lack of protein-derived peptides.Therefore,this study evaluated the effects of supplementation of casein hydrolysate(peptide source)in low-protein(LP)diets,in comparison with AAs supplementation,on the colonic microbiota,microbial metabolites and mucosal immunity in pigs,aiming to determine whether a supplementation of casein hydrolysate can improve colonic health under very LP level.Twenty-one pigs(initial BW 19.90±1.00 kg,63±1 days of age)were assigned to three groups and fed with control diet(16%CP),LP diets(13%CP)supplemented with free AAs(LPA)or casein hydrolysate(LPC)for 4 weeks.Results:Compared with control diet,LPA and LPC diet decreased the relative abundance of Streptococcus and Escherichia coli,and LPC diet further decreased the relative abundance of Proteobacteria.LPC diet also increased the relative abundance of Lactobacillus reuteri.Both LP diets decreased concentrations of ammonia and cadaverine,and LPC diet also reduced concentrations of putrescine,phenol and indole.Moreover,LPC diet increased total short-chain fatty acid concentration.In comparison with control diet,both LP diets decreased protein expressions of Toll-like receptor-4,nuclear factor-κB,interleukin-1βand tumor necrosis factor-α,and LPC diet further decreased protein expressions of nucleotide-binding oligomerization domain protein-1 and interferon-γ.LPC diet also increased protein expressions of G-protein coupled receptor-43,interleukin-4,transforming growth factor-β,immunoglobulin A and mucin-4,which are indicators for mucosal defense activity.Conclusions:The results showed that supplementing casein hydrolysate showed beneficial effects on the colonic microbiota and mucosal immunit
