Study On Intestinal Microbial Structure And Fecal Metabolomics In Diarrheic Piglets

Piglet diarrhea is the main factor affecting the growth and development of suckling or weaning piglets,which has brought great economic losses to the pig industry.In recent years,studies have shown that gut microbiota is an important cause of piglet diarrhea,and imbalance of intestinal flora is mutually causal with diarrhea.In this study,we selected weaned piglets of Wannan black pig as the research object,which is the excellent local pig breed in Anhui,exploring the microbial structure and diversity of healthy piglets in different gut segments,differences in microbial structure and diversity of diarrheic and healthy piglets in different intestinal segments,and differences in the metabolic profiles of feces between diarrheic and healthy piglets.i)The differences in intestinal microbial composition and abundance in different intestine segments of healthy pigletsCompared with the colon and fecal flora,the jejunal microorganisms in healthy piglets had the lowest α diversity and the highest β diversity,while the colon and stool groups had no significant differences in various diversity index;Rothia and Lactobacillus are the core microbiota in the jejunum of healthy piglets;Blautia is the core flora in the colon of healthy piglets;Prevotellaceae,Ruminoccoccaceae and Muribaculaceae are the core flora in the feces of healthy piglets.ii)Clear difference between the structure of intestinal flora in diarrhea and healthy pigletsa.There is no significant difference on jejunal microbial diversity between the diarrhea and healthy piglet;the unidentified Solibacterales at family level is the core flora in the healthy piglet jejunum,and Acinetobacter nosocomial is the core flora in the diarrhea piglet jejunum(LDA> 2);compared with the healthy group,the content of Armatimonadetes,Blyobacter,Bacillus,unidentified Rhizobiaceae in the jejunum of diarrhea piglets was significantly reduced(p <0.05).b.Compared with healthy piglets,the ACE and observed species index of diarrheal piglet significantly reduced in the colon,and there was no significant difference in other αdiversity index and β diversity;Muribaculaceae and unidentified Clostridiales are the core flora in the colon of healthy piglets,and Campylobacter is the core flora in the colon of diarrhea piglets(LDA> 4);Compared with the healthy group,unidentified Bacteria and Campylobacter in the colon of diarrhea piglets increased significantly(p <0.05),the contents of Chloroflexi,Gemmatimonadetes,unidentified Ruminococcaceae,unidentified Clostridiales,and Peptostreptococcus decreased significantly(p <0.05).c.There is no significant difference in the diversity of fecal flora between diarrhea and healthy piglets;Muribaculaceae,Streptococcus gallolyticus subsp macedonicus bacteria are the core flora in the feces of healthy piglets,Campylobacter is the core flora in the feces of diarrhea piglets(LDA> 4);compared with the healthy group,the contents of unidentified Bacteria and Campylobacter in the feces of diarrheic piglets increased significantly(p < 0.05);Bacteroidetes,Parabacteroides and unidentified Unidentified Prevotellaceae reduced significantly(p <0.05).d.Comprehensive analysis of diarrhea and various intestinal segments of healthy piglets shows that Streptococcus gallolyticus subsp macedonicus and Muribaculaceae are the core flora in the intestines of healthy piglets.Campylobacter is the core flora in the intestines of diarrhea piglets(LDA> 4);compared with the healthy group,the contents of unidentified Bacteria and Campylobacter in the intestines of diarrhea piglets increased significantly(p<0.05),Chloroflexi,Gemmatimonadetes and Terrisporobacter,unidentified Prevotellaceae content was significantly reduced(p <0.05);correlation analysis of each genus showed that Campylobacter,Fusobacterium,Anaerovibrio,Helicobacter,etc.were positively correlated(r> 0.6,p <0.05),but negatively correlated with Streptococcus,Bacillus,and Bifidobacterium(R <-0.6,p <0.05).iii)The significant differences in fecal metabolite contents between diarrhea piglets and healthy pigletsA total of 186 differential metabolites were screened in the positive ion mode,of which49 were up-regulated and 137 were down-regulated;a total of 127 differential metabolites were screened in the negative ion mode,of which 32 were up-regulated and 95 were down-regulated.These differential metabolites mainly including tryptophan metabolites such as serotonin,kynuric acid,xanthurenic acid,indole and their derivatives,cholic acid metabolites such as deoxycholic acid,7-ketodeoxycholic acid,amino acids and their metabolites such as L-histidine,L-lysine,methionine,glycine,spermine,spermidine and other metabolites such as biliverdin and stercobilin.Differential metabolites are significantly enriched in arginine and proline metabolism,porphyrin and chlorophyll metabolism,β-alanine metabolism,cysteine and methionine metabolism,tryptophan metabolism,glutathione metabolism.In summary,the diversity of jejunum flora in healthy piglets is lower than that in colon and fecal groups,and the structure of colon and fecal flora is similar;diarrhea has less effect on the structure and diversity of intestinal flora in weaned piglets.Increased Campylobacter and decreased probiotic content such as Streptococcus gallolyticus subsp macedonicus and Bifidobacterium may be the main reason for the occurrence of diarrhea in weaned piglets;the contents of spermine and spermidine in the stool of diarrhea piglets increased significantly and related metabolic disorder of arginine and proline,β alanine,cysteine and metabolic disorder may be the potential molecular mechanism to induce diarrhea in weaned piglets.