| This experiment was aimed to study the effects of yeast cell wall polysaccharide on growth performance,small intestinal mucosa morphology,intestinal flora,peripheral blood and gut immunity of weaned piglets(21 day).This experiment was conducted to study the effects of dietary yeast cell wall polysaccharide on growth performance and small intestinal mucosa morphology in weaned piglet.One-factor design was used.One hundred and eighty piglets with the similar genetic background and health condition weaned at 21 days of age were randomly divided into four treatments,with five replicates in each treatment and nine piglets in each replicate.Four treatments were fed control diet,0.15%,0.30% and 0.45% yeast cell wall polysaccharides diet,respectively.The experiment lasted for 21 days.Experiment 1: Calculate the average daily feed intake(ADFI),daily gain(ADG),feed weight ratio(F/G)and the rate of diarrhea.After killing piglets,shearing piglet duodenum,jejunum,ileum in 4% formaldehyde solution fixed more than 24 h in jars,paraffin section HE dyeing observation piglets intestinal mucosal morphology.The results showed that:1)compared with the control group,yeast cell wall polysaccharide significantly increased average daily gain(ADG)and average daily feed intake(ADFI)(P<0.05),and had the trend to decrease diarrhea incidence and the radio of weaned piglets,although there were no significant differences(P>0.05).2)Compared with the control group,diets added with yeast cell wall polysaccharide significantly increased the ratio of villus height to crypt depth(V/C)in jejunum of weaning piglets(P<0.05).and diets added with 0.45% yeast cell wall polysaccharide significantly increased villus height in jejunum and V/C in duodenum of weaning piglets(P<0.05).Accordingly,the yeast cell wall polysaccharide can enhance the growth performance,and improve the small intestinal mucosa morphology of weaning piglets.By considering the growth performance,small intestinal mucosa morphological,0.30% yeast cell wall polysaccharide is a optimum addition level in the piglet feed.Experiment 2: The ileum content can be determined through weather chromatograph acetic acid,propionic acid,butyric acid,isobutyric acid,valeric acid,isovaleric acid content,and calculate the total volatile fatty acid content.Plate culture method is used to determine the cecum contents of e-coli,salmonella,bifidobacterium,lactobacillus,and the total number of bacteria.The results showed as follows: 1)compared with control group,dietary supplementation of 0.15%,0.30% and 0.45% yeast cell wall polysaccharides significantly increased colon acetic acid content of pigs(P<0.05),and 0.30% and 0.45% yeast cell wall polysaccharides also significantly enhance the contents of propionic acid,butyric acid and total volatile fatty acids(TVFA)in colon(P<0.05),but there were no significant differences between both(P>0.05).2)Compared with control group,dietary supplementation of 0.15%,0.30% and 0.45% yeast cell wall polysaccharides significantly decreased the amounts of cecum salmonella and Escherichia coli(P<0.05),but there were no significant differences between pigs receiving 0.30% and 0.45% yeast cell wall polysaccharides(P>0.05).These findings indicate that yeast cell wall polysaccharides can increase the intestinal volatile fatty acids and improving intestinal flora in weaned piglets,By considering intestinal volatile fatty acids countent and improve intestinal microbial flora of weaned piglets,0.30% yeast cell wall polysaccharide is a optimum addition level in the piglet feed.Experiment 3: After 21 days,the piglets were killed and the samples of cecum content were collected.Total bacterial DNA of 20 samples of pigs per group was extracted,and used to amplify PCR for 16 Sr RNA gene V4 tag fragment and sequence using high-throughput MiSeq technique.Based on the QIIME platform,the microbial community diversity in cecum content was compared.The results showed as follows: 1)There were no significant differences on bacterial diversity in piglets receiving control diets and yeast cell wall polysaccharide.To a certain extent,dietary supplementation yeast cell wall polysaccharides can change the bacterial diversity,and without considering the abundance of each species,0.30% yeast cell wall polysaccharide cecum flora is the most abundant.2)Bacteroidetes,Firmicutes,Spirochaetes and Proteobacteria were the dominant phyla in cecum content of piglets.Compared with the control group,dietary supplementation of 0.30% yeast cell wall polysaccharide significantly decreased Bacteroidetes(P<0.05),0.30% and 0.45% yeast cell wall polysaccharides significantly increased the amounts of Firmicutes.Added 0.45% yeast cell wall polysaccharide can significantly increase the Tenericutes of cecum,in addition,Yeast cell wall polysaccharide can reduce the Proteobacteria of cecum,but there were no significant differences(P=0.066).3)Prevotella were the dominant genus in cecum content of piglets.The yeast cell wall polysaccharide enhance(P<0.05)Anaerovibrio,Ruminococcus,Coprococcus and Phascolarctobacterium,and reduced the Streptococcus of cecum(P<0.05).Accordingly,diets with yeast cell wall polysaccharide in short feeding-period can improve the cecum bacteria structure of weaned piglets.Diets with yeast cell wall polysaccharide can enhance the Advantage bacterium of cecum,such as Firmicutes,Ruminococcus,Coprococcus,etc.Experiment 4: After the test,before the vena cava blood and shearing ileum.Measurement the concentration of serum IgG,IgM and IgA,IL-2,IL-6,IL-10,IFN-γ,TNF-α,using immunohistochemical observation ileum CD4,CB8,CD20 lymphocytes distribution.The results showed as follows: 1)compared with control group,dietary supplementation of yeast cell wall polysaccharide significantly increased serum immunoglobulin A of pigs(P<0.05).0.30% and 0.45% yeast cell wall polysaccharides enhance(P<0.05)the immunoglobulin G in serum of piglet,but there were no significant differences between both(P>0.05).2)Compared with control group,dietary supplementation of yeast cell wall polysaccharide significantly decreased the amounts of serum IFN-γ(P<0.05),0.30% yeast cell wall polysaccharide significantly increased the amounts of serum IL-10(P<0.05).3)Compared with control group,dietary supplementation of 0.45% yeast cell wall polysaccharide significantly increased ileum CD4~+ T lymphocytes(P<0.05).dietary supplementation of yeast cell wall polysaccharide can enhance the ileum CD8~+ and CD20~+ cells to a certain extent,although there were no significant differences(P>0.05).These findings indicate that yeast cell wall polysaccharide may enhance the peripheral blood and gut immunity in weaned piglets,relieve the weaning stress of the piglets. |
