Study On The Relationship Between Intestinal Microbiota Structure And Fat Deposition In Pigs

Animal intestinal microbiota and their metabolites short-chain fatty acids(SCFAs)play an important regulatory role in host energy metabolism and lipid deposition.In this study,Jinhua pigs with high body fat content and good meat quality were used as the research model,using 16 S r RNA gene sequencing technology to explore the composition of the gut microbes of Jinhua pigs at the developmental stage,and to explore the relationship between gut microbiota and fat deposition.Using the selected Jinhua pigs with different body fat phenotypes as models to further analyze the correlation between intestinal microbes and fat deposition,it provides a theoretical basis for regulating fat deposition and improving meat quality in pigs.The research is divided into three parts:Part 1,this experiment aims to study the relationship between the developmental changes in the structure of the small intestinal microbiota of Jinhua pigs and the expression of fat metabolism-related genes and fat deposition.In the experiment,4 health y Jinhua pigs of 45,90,150,and 270 days old with similar body weight were selected,and their body weight and backfat thickness were measured.The expression of fatty acid binding protein(FABP)gene in ileal mucosa was detected by fluorescence quantitative PCR.The structure of Jinhua pig ileum microbiota was analyzed by high-th-roughput sequencing based on 16 S r RNA gene.The results showed that the dominantphyla of Jinhua pig ileum were Firmicutes and Bacteroidetes;the microbiota structureshowed developmental changes at the genus level.The dominant genus were Clostridium sensu stricto 1,Lactobacillus,Terrisporobacter,Romboutsia and Streptococcus.T he relative abundance of Epulopiscium and Mycoplasma is positively correlated with F ABP1,FABP2 and FABP4 gene expression levels and backfat thickness.Part 2,this experiment aims to analyze the relationship between the developmental changes in the structure of the coliform microbiota of Jinhua pigs and the expression of fat metabolism-related genes and fat deposition.In the experiment,4 healthy Jinhua pigs of 45,90,150 and 270 days old with similar weight were selected.After slaughter,the cecal contents were collected to extract their genomic DNA,and the structure of the cecal microbiota of Jinhua pigs was analyzed by high-throughput sequencing technology,and fluorescence was used.Quantitative PCR method was used to quantitatively analyze the key functional genes of butyrate production in the caecal microbiota;gas chromatography(GC)was used to determine the content of SCFAs.The results showed that with the increase of age,the diversity of intestinal microbiota in Jinhua pigs increased significantly;the dominant bacteria in the cecum of Jinhua pigs belonged to the phylum Bacteroides and Firmicutes;Prevotella,Prevotella NK3B31,Alloprevotella,Lactobacillus,and Bacteroides are the main dominant genera of the cecum of Jinhua pigs.The structure of the cecum microbiota and the metabolism of short-chain fatty acids in Jinhua pigs show developmental changes.At 270 days of age,the content in the cecum of Jinhua pigs was lower than that of other days,and the relative abundance of butyryl-Co A:acetate-Co A transferase in the microbiota was positively correlated with the butyrate content.Part 3,in order to further reveal the effects of pig intestinal microbiota and metabolites on body fat deposition,Jinhua pigs with different body fat phenotypes were used as the research object to compare the microbiota a structure and metabolism of the entire intestinal segment of pigs with two different body fat phenotypes product difference.The microbial diversity and abundance of the large intestine(cecum,colon)of Jinhua pigs is higher than that of the small intestine(duodenum,jejunum,and cecum),and the dominant bacteria phyla of each intestine segment are Firmicutes and Bacteroides.There are certain differences in the gut microbiota of Jinhua pigs with high and low body fat phenotypes.In the jejunum and ileum of Jinhua pigs in the high-fat group,the relative abundance of Firmicutes is higher than that of the Jinhua pigs in the low-fat group,while the relative abundance of Bacteroides was on the contrary;at the same time,the relative abundance of Prevotella 1 and Anaerovibrio in the cecum and colon was significantly higher than that of the low-fat group Jinhua pigs,while the relative abundance of Clostridium 1 was on the contrary.For short-chain fatty acids,which are metabolites of microbiota,the contents of propionate and butyrate in the cecum and colon of Jinhua pigs in the high-fat group were significantly lower than those in the low-fat Jinhua pigs.The structural developmental changes of Jinhua pig intestinal microbiota are positively correlated with the expression of lipid metabolism-related genes and fat deposition.Porcine intestinal microbiota may regulate fat deposition through short-chain fatty acid metabolism,which indicates to a certain extent the intestinal microbiota and metabolism.There is a certain correlation between the product and fat deposition.