The Effect Of Fructooligosaccharide On Protein Fermentation And Microbial Community In Porcine Large Intestine

Protein in hindgut of porcines can fennente by microbial,the metabolites often do harms to procines' health,also,pollute the environment.Fructooligosaccharide is a kind of high-quality prebiotics,its promoting effect to pig health has been studied extensively,but its effect on the protein's fermentation character was rarely reported.This thesis consists of three chapters,First of all,we evaluated the fermentation characteristics of porcine colonic microbes under different protein levels(In Vitro),then evaluate the effect of different concentrations of fructooligosaccharide on protein fermentation and microbiota in porcinelarge intestine(In Vitro),at last,we conducted an experiment evaluated the effect of perfusing fructooligosaccharide on protein metabolism and microbial community in porcine large intestine(in vivo),in order to provide basis for promoting pig intestinal health and reduce pig intestinal harmful metabolites.1 Effects of Different Levels of Protein Substrates on Fermentation Characteristics and Microbial Protein Synthesis Ability of Porcine large Intestine Microbiota-In VitroThis study evaluated the fermentation characteristics of porcine colonic microbes under different protein levels in vitro,aiming to determine the fermentation pattern of protein by porcine colon microbiota.Porcine colon digesta was used as microbial inoculum,0 g(group C),0.1 g(group L),0.25 g(group H)casein was added into microbial fermentation broth.At different time points,cumulative gas production,pH,microbial protein,ammonia nitrogen and volatile fatty acid were determined.The results showed that at 3 h,6 h and 12 h fermentation,the pH of group L and group H was significantly lower than the control group(P<0.05),and pH at 3 h was significantly higher than 6 h;Protein level significantly increased cumulative gas production(P<0.05);The concentration of microbial protein in group L and group H was significantly higher than that of control group(P<0.05),at 6 h group H was significantly higher than group L(P<0.05);With the increase of protein level,the concentration of ammonia nitrogen increased significantly(P<0.05);The concentration of SCFA and BCFA increased with the fermentation time,and increased with the protein level.Results suggest that adding protein substrates promotes intestinal microbial protein synthesis,but excessive protein cannot further increase microbial protein synthesis,instead,increase microbial fermentation.2 Effects of Fructooligosaccharide on the Fermentation Characteristics of Protein in Porcine Large Intestine-in vitroThis experiment was conducted to evaluate the effect of different concentrations of fructooligosaccharide on protein fermentation and microbiota in porcinelarge intestine.Porcine intestinal contents were used as the inoculums.The amount of 0,0.25,0.5,0.75 g FOS were added into cecal and colonic microflora fermentation broth respectively,as groups MC,ML,MM,MH(cecal microbial inoculation fluid)and groups JC,JL,JM,JH(colon microbial inoculation fluid).The amount of 0.25 g casein hydrolysate was added as protein substrate.At different time points,cumulative gas production,microbial protein,ammonia nitrogen and volatile fatty acid were determined.At the end of fermentation,samples were also collected for the analyses of microbial community by PCR-DGGE and real-time PCR.Results showed that FOS significantly increased gas production and the concentration of MCP(P<0.05),while the concentrations of ammonia and SCFA were significantly reduced with the addition of FOS(P<0.05).FOS significantly(P<0.05)increased the number of microbes in both intestinal segments.The microbial composition in both segments was also shifted by FOS and the microbial diversity in colon was increased by FOS as well(P<0.05).Results indicated that FOS could improve the growth of microbes and the synthesis of microbial protein in hindgut and thus reduce the production of ammonia and BCFA,which are the fermentation products of protein in the hindgut.3 In vivo Study the Effect of Fructooligosaccharide on Protein metabolism and Microbial Community in Porcine Large IntestineThis experiment evaluated the effect of perfusing fructooligosaccharide on protein metabolism and microbial community in porcine large intestine.The amount of 10 Duroc×Yorkshire×Landrace castrated boars(40 days old,12±0.5 kg)with fistula at distal ileum were randomly divided into 2 groups according to body weight as control group(group C,n=4)and test group(group F,n=6).Fructooligosaccharide solution and saline solution were perfused through the fistula to groups F and C,respectively for 16 days at 8:00 and 20:00 daily.At 0,7,16 days,fecal samples was collected before morning feeding for the determination of microbial protein,ammonia nitrogen,biogenic amines,indole,skatole concentration and microbial community by PCR-DGGE and real-time PCR.The results showed that fructooligosaccharide significantly increased fecal microbial protein(P<0.05),while significantly decreased the ammonia nitrogen(P<0.05).The concentrations of cadaverine,putrescine,spermidine,indole,skatole were significantly(P<0.05)reduced by FOS at day 16.DGGE results showed that the the microbial community was shifted by fructooligosaccharide,which was revealed by the separate cluster of each group.The microbial diversity also significantly(P<0.05)increased by FOS.Real-time PCR results showed that fructooligosaccharide significantly increased the number of Bifidobacteria and Lactobacillus(P<0.05).Results suggested that fructooligosaccharide significantly increased microbial protein synthesis,and thus reduced the fermentation products of protein.It also changed the intestinal microbial community and increased the number of probiotics.