Supplemental N-acyl homoserine lactonase alleviates intestinal disruption and improves gut microbiota in broilers challenged by Salmonella Typhimurium

Background Salmonella Typhimurium challenge causes a huge detriment to chicken production.N-acyl homoserine lactonase(AHLase),a quorum quenching enzyme,potentially inhibits the growth and virulence of Gram-negative bacteria.However,it is unknown whether AHLase can protect chickens against S.Typhimurium challenge.This study aimed to evaluate the effects of AHLase on growth performance and intestinal health in broilers challenged by S.Typhimurium.A total of 240 one-day-old female crossbred broilers(817C)were randomly divided into 5 groups(6 replicates/group):negative control(NC),positive control(PC),and PC group supplemented with 5,10 or 20 U/g AHLase.All birds except those in NC were challenged with S.Typhimurium from 7 to 9 days of age.All parameters related to growth and intestinal health were determined on d 10 and 14.Results The reductions(P<0.05)in body weight(BW)and average daily gain(ADG)in challenged birds were alleviated by AHLase addition especially at 10 U/g.Thus,samples from NC,PC and PC plus 10 U/g AHLase group were selected for further analysis.S.Typhimurium challenge impaired(P<0.05)intestinal morphology,elevated(P<0.05)ileal inflammatory cytokines(IL-1βand IL-8)expression,and increased(P<0.05)serum diamine oxidase(DAO)activity on d 10.However,AHLase addition normalized these changes.Gut microbiota analysis on d 10 showed that AHLase reversed the reductions(P<0.05)in several beneficial bacteria(e.g.Bacilli,Bacillales and Lactobacillales),along with increases(P<0.05)in certain harmful bacteria(e.g.Proteobacteria,Gammaproteobacteria,Enterobacteriaceae and Escherichia/Shigel a)in PC group.Furthermore,AHLase-induced increased beneficial bacteria and decreased harmful bacteria were basically negatively correlated(P<0.05)with the reductions of ileal IL-1βand IL-8 expression and serum DAO activity,but positively correlated(P<0.05)with the increased BW and ADG.Functional prediction revealed that AHLase abolished S.Typhimurium-induced upregulations(P<0.05)of certain pathogenicity-related pathways such as lipopolysaccharide biosynthesis,shigellosis,bacterial invasion of epithelial cells and pathogenic Escherichia coli infection of gut microbiota.Conclusions Supplemental AHLase attenuated S.Typhimurium-induced growth retardation and intestinal disruption in broilers,which could be associated with the observed recovery of gut microbiota dysbiosis.

N-acyl homoserine lactonase attenuates the virulence of Salmonella typhimurium and its induction of intestinal damages in broilers

This study aimed to investigate the potential mitigating effects of N-acyl homoserine lactonase(AHLase)on the virulence of Salmonella typhimurium and its induction of intestinal damages in broilers.In vitro study was firstly conducted to examine if AHLase treatment could attenuate the virulence of S.typhimurium.Then,an in vivo experiment was performed by allocating 240 broiler chicks at 1 d old into 3 groups(8 replicates per group):negative control(NC),positive control(PC),and PC supplemented with 10,000 U/kg AHLase.All chicks except those in NC were orally challenged by S.typhimurium from 8to 10 d of age.Parameters were measured on d 11 and 21.The results showed that treatment with 1 U/mL AHLase suppressed the biofilm-forming ability(including biofilm biomass,extracellular DNA secretion and biofilm formation-related gene expression),together with swarming motility and adhesive capacity of S.typhimurium.Supplemental 10,000 U/kg AHLase counteracted S.typhimurium-induced impairments(P<0.05)in broiler growth performance(including final body weight,average daily gain and average daily feed intake)during either 1-11 d or 12-21 d,and increases(P<0.05)in the indexes of liver,spleen and bursa of Fabricius on d 11,together with reductions(P<0.05)in ileal villus height and its ratio to crypt depth on both d 11 and 21.AHLase addition also normalized the increased(P<0.05)m RNA expression of ileal occludin on both d 11 and 21 in S.typhimurium-challenged broilers.However,neither S.typhimurium challenge nor AHLase addition altered(P>0.05)serum diamine oxidase activity of broilers.Noticeably,S.typhimurium challenge caused little change in the mRNA expression of ileal inflammatory cytokines except for an increase(P<0.05)in interleukin-8 expression on d 11,whereas AHLase addition normalized(P<0.05)this change.In conclusion,AHLase treatment could attenuate the virulence and pathogenicity of S.typhimurium,thus contributing to alleviate S.typhimurium-induced growth retardation and intestinal damages in broilers.

Effect of dietary supplementation with protease on growth performance,nutrient digestibility, intestinal morphology, digestive enzymes and gene expression of weaned piglets

This study was conducted to investigate the effect of dietary protease supplementation on the growth performance, nutrient digestibility, intestinal morphology, digestive enzymes and gene expression in weaned piglets. A total of 300 weaned piglets(21 days of age Duroc x Large White x Landrace; initial BW = 6.27 ± 0.45 kg) were randomly divided into 5 groups. The 5 diets were: 1) positive control diet(PC), 2) negative control diet(NC), and 3) protease supplementations, which were 100, 200, and 300 mg per kg NC diet. Results indicated that final BW, ADG, ADFI, crude protein digestibility, enzyme activities of stomach pepsin, pancreatic amylase and trypsin, plasma total protein, and intestinal villus height were higher for the PC diet and the supplementations of 200 and 300 mg protease per kg NC diet than for the NC diet(P < 0.05). Supplementations of 200 and 300 mg protease per kg NC diet significantly increased the ratio of villus height to crypt depth(VH:CD) of duodenum, jejunum and ileum compared with NC diet(P < 0.05). Feed to gain ratio, diarrhea index, blood urea nitrogen, and diamine oxidase were lower for the PC diet and supplementations of 200 and 300 mg protease per kg NC diet than for the NC diet(P < 0.05). Piglets fed the PC diet had a higher peptide transporter 1(PepTl) mRNA abundance in duodenum than piglets fed the NC diet(P < 0.05), and supplementations of 100, 200 and 300 mg protease per kg NC diet increased the PepTl mRNA abundance in duodenum(P < 0.05) comparing with the NC diet. Piglets fed the PC diet had a higher b0,+AT mRNA abundance in jejunum than piglets fed the NC diet(P < 0.05), and supplementations of 200 and 300 mg protease per kg NC diet increased the b0,+AT mRNA abundance in jejunum and ileum comparing with the NC diet(P < 0.05). In summary, dietary protease supplementation increases growth performance in weaned piglets, which may contribute to the improvement of intestinal development, protein digestibility, nutrient transport efficiency, and health status of piglets when fed low digestible protein sources.

Inclusion of wheat aleurone in gestation diets improves postprandial satiety,stress status and stillbirth rate of sows

This study investigated the effects of different amounts of wheat aleurone(WA)(0,15%,30%)inclusion in gestation diets on the reproductive performance,postprandial satiety,stress status and stereotypic be-haviors of sows.A total of 84 Landrace×Yorkshire sows(parity 4.87±1.32)at breeding were randomly allotted to one of the three isoenergetic and isonitrogenous dietary treatments based on parity and body weight.The results showed that,compared with the control(0),sows fed the WA diet had a higher serum concentration of peptide YY(PYY)(P<0.05)and glucagon like peptide-1(GLP-1)(P<0.05)and a lower concentration of saliva cortisol(P<0.01).Importantly,compared with the control group,only the 15%WA group had a higher concentration of the total antioxidant capacity(T-AOC)(P<0.05),lower pro-portions of sitting(P=0.05)and stillbirth rates(P<0.01).Accordingly,the production cost per piglet born alive($6.9 vs.$7.6)or per piglet born healthy($7.4 vs.$7.9)declined in the 15%WA group versus the control group.Overall,15%WA inclusion in gestation diets contributed to enhancing postprandial satiety,alleviating stress status and decreasing stillbirth rate of sows.This study provides a reference for the application of WA as a partial substitute for conventional feed ingredients to improve sows'repro-ductive performance.