Effects Of Dietary Bacillus Subtilis And Streptococcus Faecalls On Growth Performance And Intestinal Health Of Weaned Piglets

Weaning stress can directly increase intestinal health stress and disease risk in piglets.Probiotics can improve the intestinal environment,maintain homeostasis,relieving weaning stress,promote intestinal health and growth of piglets.This experiment was conducted to investigate the effects of dietary supplementation of Bacillus subtilis,Streptococcus faecalis,and the hybrid supplementation on growth performance and intestinal health of weaning piglets,trying to provide scientific basis for adding Bacillus subtilis and Streptococcus faecalis to the diets of weaned piglets.This study is composed two trails.Exp.1 Effects of dietary Bacillus subtilis and Streptococcus faecalis on production performance,digestion and absorption function of weaned pigletsTwo-hundred-forty Duroc×Landrace×Yorkshire of 21-day-age weaned piglets were randomly allotted to 4 groups with 6 replicates per groups and 10 piglets per replicate.The four groups are control group,Bacillus subtilis supplementation group,Streptococcus faecalis supplementation group,and hybrid supplementation group.Piglets of group control were fed basal diet,Piglets of group Bacillus subtilis were fed basal diet supplemented with Bacillus subtilis(dietary viable content of Bacillus subtilis are 5×10~6CFU/g),Piglets of group Streptococcus faecalis were fed basal diet supplemented with Streptococcus faecalis(dietary viable content of Streptococcus faecalis are 4×10~5CFU/g),Piglets of group hybrid supplementation group were fed basal diet supplemented with Streptococcus faecalis and Bacillus subtilis(dietary viable content of Bacillus subtilis are 5×10~6CFU/g;dietary viable content of Streptococcus faecalis are 4×10~5CFU/g).Piglets were weaned and weighed at21d.At day49 in the trial,piglets were weighed and the fecal samples,duodenum,jejunum and ileum segments were collected.The results showed as follows:Dietary Bacillus subtilis and Streptococcus faecalis had synergistic effect on the weight of d49,and the average daily gain and average daily feed intake form d21 to d49 trended to increase(P<0.1).Dietary supplementation with Streptococcus faecalis increased the ileum villi height(P<0.05);Sreptococcus faecalis and Bacillus subtilis hybrid supplementation had synergistic effect on the ratio of villi height to crypt depth of duodenum.Dietary supplementation with Streptococcus faecalis improved the apparent digestibility of lysine,histidine,isoleucine,leucine,phenylalanine and threonine(P<0.05);Dietary supplemention with Bacillus subtilis improved the apparent digestibility of lysine,isoleucine,leucine,phenylalanine and valine(P<0.05);Sreptococcus faecalis and Bacillus subtilis hybrid supplementation had synergistic effect on the digestibility of histidine,aspartic acid and glutamate increase(P<0.05).The results show that supplementation with Bacillus subtilis and Streptococcus faecalis to diet could promote the development of intestinal,improve the digestibility of amino acids.Dietary Sreptococcus faecalis and Bacillus subtilis had synergistic effect on the improve the growth performance of piglets.Exp.2 Effects of dietary Bacillus subtilis and Streptococcus faecalis on intestinal barrier function of weaned pigletsAt 42d in the trial,the digestas of duodenum,jejunum,ileum and cecum were collected to perform macrogene sequencing and determine the contents of short-chain fatty acids by gas chromatography.In addition,the mucosa of jejunum was collected to determine the relative expression of tight junction protein(Claudin-1,ZO-1,Occludin),the cytokines(TNF-?,IL-2,IL-6)by RT-q PCR.The results showed as follows:Dietary supplementation with Bacillus subtilis and Streptococcus faecalis had little effect on the microflora of duodenum and cecum revealing that the microflora of duodenum and cecum were stable.But dietary supplementation with Bacillus subtilis could improve microbial composition of jejunum.The relative abundances of Lactobacillus and Veillonella were increased and the relative abundances of Leishmania were reduced respectively in jejunum with the supplemented of Bacillus subtilis.The results of KEGG prediction showed that dietary supplementation with Bacillus subtilis increaesed the abundance of amino acid metabolism,carbohydrate metabolism,energy metabolism,immune system,lipid metabolism,cellulose metabolism in jejunal digesta.Dietary supplementation with Streptococcus faecalis increased the relative contents of propionic acid and isobutyric acid in jejunal digesta(P<0.05);Dietary supplementation with Bacillus subtilis increased the relative content of isovaleric acid in jejunal digesta(P<0.05).Dietary supplementation with Bacillus subtilis and Streptococcus faecalis have no significant effect of intestinal immune factor and intestinal compact junction protein on jejunum(P>0.05).The results show that supplementation with Bacillus subtilis to diet could improve the composition of jejunal microflora.Supplementation with Bacillus subtilis and Streptococcus faecalis to diet could increase the content of short chain fatty acids in jejunum.The present results show that supplementation with Bacillus subtilis and Streptococcus faecalis to diet could promote the development of intestinal,and improve the digestibility of amino acids.Supplement with Bacillus subtilis to diet could improve the composition of jejunal microflora,increase the content of short chain fatty acids in jejunum.Dietary Sreptococcus faecalis and Bacillus subtilis had synergistic effect on the development of intestine,improve the digestibility of amino acids and the growth performance of piglets.