| Weaning is a critical period in pig production systems.At the transition period,piglets suffer from many great challenges,such as reduced growth performance,serious diarrhea and poor disease resistance,which may lead to heavy diseases or even death.Antibiotics have been widely used in the diet of piglets to enchance growth performance and reduce the incidence of diarrhea.Recently,antibiotics draw much attention because of the public concerns,including drug residue and resistance of pathogenic bacteria.It is urgent to seek the alternatives.Numerous studies have shown that probiotics presented potential benefits on growth performance,diarrhea incidence and intestinal ecology of weaning piglets.This study aimed to investigate feeding Lactobacillus plantarum in weaning piglets on growth performance,andintestinal mucosa function and the microbiota community,and then based on the probiotic properties to isolate and identify lactic acid bacteria from swine.1 Effects of Lactobacillus plantarum on growth performance,diarrhea incidence and serum biochemical indices of weaning pigletsThe objective of this study was to evaluate the effects of on Lactobacillus plantarum the growth performance,organ weight,and serum biochemical and antioxidant indexes of weaned piglets,and to explore the mechanisms of Lactobacillus plantarumon the transition of weaning stress.A total of 144 Suhuai weaned piglets(9.34±0.33 kg)at age of 28 days were randomly divided into 3groups,including control group(basal diet),antibiotics group(basal diet supplemented with antibiotics)and Lactobacillus plantarum group(basal diet supplemented with Lactobacillus plantarum).Each group had 6 replicates and 8 piglets per replicate.The experiment started on day 32 and ended on day 59 after birth.On day 59,one piglet from each replicate was slaughtered for sampling.Results showed that Lactobacillus plantarum significantly increased the average daily gain(ADG)and average daily feed intake(ADFI),decreased feed/gain(F/G)and diarrhea rate after weaning compared with control group(P<0.05),and it also significantly increased the weight of spleen and the concentration of serum TP and GLO(P<0.05),decreased the concentration of MDA in serum(P<0.05).Compared with antibiotics group,Lactobacillus plantarum significantly increased the concentration of serum TP and GLO(P<0.05),and Lactobacillus plantarum have no significant effect on other indexes.The findings imply that the Lactobacillus plantarum contribute to improve the growth performance,decrease diarrhearate,increase the organ weight and alter the concentration of TP,GLO and MDA in serum which may benefit torelive weaning stress of piglets.Potentially,the probiotics would be the alternatives of antibiotics for the weaning transition of piglets.2 Effects of Lactobacillus plantarum on intestinal mucosa function and the microbiota community of weaning pigletsThe experiment aims to investigate the effects of Lactobacillus plantarum on intestine morphology,genes of transport channels and tight junction protein in small intestine mucosa,and microbial populations of weaned piglets.The experimental design,feeding programme and slaughter were the same as experiment.However,on the day of slaughter,the tissue and mucosa samples of duodenum,jejunum,and digesta samples of stomach,jejunum,ileum,cecum and colon were collected,respectively.Compared with control group,Lactobacillus plantarum improved villus development of duodenum,reduced V/C of duodenum,jejunum and ileum after weaning(P<0.05),compared with antibiotics group,it also significantly increased villus height of duodenum(P<0.05).Compared with control group,the Lactobacillus plantarum treatment increased mRNA relative expression of PepT1 induodenum(P<0.01),SGLT-1,PepTl in jejunum and SGLT-1 in ileum(P<0.01).Compared with control and antibiotics treatments,Lactobacillus plantarum increased mRNA relative expression of Occludin in duodenum,and Occludin,ZO-1 in jejunum and ileum(P<0.01).Compared with control the group,Lactobacillus plantarum significantly decreased pH(P<0.05),significantly increased the concentration of buyrate(P<0.05)and significantly decreased the population of Escherichia coli in cecum and colon(P<0.05),significantly increased the concentration of lactic acid incecum(P<0.05),the population of Lactobacillus and Clostridium cluster XIVa in colon(P<0.05).Compared with antibiotics treament,Lactobacillus plantarum significantly decreased pH of cecum(P<0.05),increased lactic acid concentration in cecum and butyrate,lactic acid concentration in colon(P<0.05),it also significantly increased the population of Lactobacillus in cecum and colon(P<0.05).The results suggest that the administration of Lactobacillus plantarum could maintain the intestine healthy and relive weaning stress of piglets by improving intestine morphology,triggering transport channels and tight junction protein in small intestine mucosa,decreasing pH,increasing the VFAs and lactic acid concentration,promoting the proliferation of Lactobacillus and Clostridium cluster XIVa and the decrease of Escherichia coli population in intestine.3 Isolation,identification of Lactic Acid Bacteria from swine and investigation of their biological propertiesThis study was to isolate and identify lactic acid bacteria(LAB)from the intestinal digesta,mucosa and feces of piglets,and investigate their lactate production in vitro,resistance to low pH and bile salt,and antimicrobial properties to explore the potential probiotic stains for the swine production.The sample diluents were cultured in agar culture-medium for 48h to isolate and identify purified LAB strains with high lactate production by conventional measures.Then the isolates were identified by the conventional biochemical methodand bacterial 16S rRNA sequence,and assessed the resistance to low pH and bile salt,and antimicrobial properties.Results implied that a total of 155 LAB was isolated,and 4 isolates with high lactate production were obtained,the 4 LAB isolates(L45,L47,L63,L79)Lactobacillus reuteri,Lactobacillus plantarum,Lactobacillus johnsonii and Enterococcus facium strain were identified based on lactate production at 8 h(>100 mmol/L)and final pH values at 90 h(<3.9).We revealed that the 4 isolates were able to grow rapidly in vitro.Results of this 4 strains resistance to low pH and bile salt showed that L47 and L79 isolates presented stronger tolerance against pH 2.5 than other two strains,while L47 could resistant to 0.5%bile salts.As the 4 isolates were co-cultured with E.coli K88 and Salmonella,the growth of E.coli K88 and Salmonella was inhibited.The finding indicated the L47 isolate demonstrated stronger inhibition effect than other three isolates.L47 strain presented a higher lactate production,better growth,higher tolerance against pH 2.5 and 0.5%bile salt,and stronger antimicrobial effect on E.coli K88 and Salmonella,indicating that L47 isolate may have the potential probiotic properties for swine production. |
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