Differences In Butyric Acid Metabolism In Jinhua Pigs With Different Body Fat Phenotypes And Regulation Of Butyric Acid On Fat Metabolism In Mice

Fat deposition affects human health and the quality of meat from economic animals.Gut microbes have a regulatory role in fat metabolism,with butyric acid being one of the main products of gut microbial metabolism.Disturbances in lipid metabolism caused by disturbances in the gut flora are one of the factors that promote the development of obesity.In this experiment,Jinhua pigs with different body fat phenotypes were used to analyse the differences in butyric acid metabolism and to explore the correlation between butyric acid and fat metabolism.Using C57BL/6J mice as experimental subjects,the effects of butyric acid on intestinal flora and intestinal gene expression were analysed by 16 S r RNA gene sequencing technology and transcriptome technology to reveal the regulation of fat metabolism and the ameliorative effect of butyric acid on fat metabolism and obesity.Experiment 1.Differences in relative abundance and metabolism of butyric acidproducing bacteria in intestinal tract of Jinhua pigs with different body fat phenotypesIn this experiment,5 Jinhua pigs with high body fat(H group)and 5 Jinhua pigs with low body fat(L group)were selected to collect ileal and colonic tissues and contents,and the relative abundance of butyric acid-producing bacteria,key genes of butyric acid production and butyric acid content in ileum and colon of Jinhua pigs with different body fat phenotypes were determined,and the results showed that the relative abundance of butyric acid-producing bacteria in ileum and colon of Jinhua pigs with high body fat was generally lower than that of Jinhua pigs with low body fat.The relative abundance of Oscillospira and Roseburia in the ileal contents of H group and of Blautia,Butyricicoccus and Faecalibacterium in the colonic contents was significantly lower than in L group(P<0.05).However,the relative abundance of Oscillospira was significantly higher in the colon than in the L group(P<0.05).Correlation analysis showed the butyryl CoA: acetate CoA transferase gene in the ileum was positively correlated with Faecalibacterium(P<0.05),while the key gene producing butyric acid in the colon was negatively correlated with Fusobacterium and Oscillospira(P<0.05).There was a significant positive correlation between butyric acid key genes in ileum and colon and butyric acid content in Jinhua pigs with different body fat phenotypes(P<0.05).In conclusion,there were significant differences in intestinal butyrate-producing bacteria and butyric acid metabolism among Jinhua pigs with different body fat.Experiment 2.Effect of butyric acid on body fat phenotype and gut microbiota in high-fat diet-induced obese miceIn this experiment,15 C57BL/6J mice were randomly divided into 3 groups with5 mice in each group.The control group(Ctrl)was given normal diet and 200 μL normal saline,mice in high-fat diet group(HFD)were fed with high-fat diet and 200μL normal saline,while mice in butyric acid group(Buty)were fed with high-fat diet and 200 μL butyric acid(200 mg/kg).Drink freely during the experiment.The mice were sacrificed under anaesthesia after 15 weeks of rearing,and blood,adipose tissue,ileal and colonic tissues,and ileal and colonic contents were collected.The results showed that after high-fat diet treatment,the weight,adipose tissue,fasting blood glucose,fasting insulin,total cholesterol and triglycerides of the mice increased significantly(P<0.05),whereas after butyric acid intervention,the weight,adipose tissue,fasting blood glucose,fasting insulin and triglycerides of the high-fat dietinduced obese mice were significantly reduced(P<0.05).Using 16 S r RNA gene sequencing technology,it was found that high-fat diet significantly affected ileal flora diversity and colonic flora richness in mice,while butyric acid significantly affected ileal flora richness and diversity in mice.The high-fat diet altered the microflora structure of the ileum and colon of mice,but butyric acid had little effect on the flora structure of mice on the high-fat diet.At the phylum level,the abundance of Firmicutes in ileum and colon increased after high-fat diet treatment,while that of Bacteroidetes decreased.At the genus level,the abundance of Faecalibaculum,Lachnospiraceae＿uncultured,Lactococcus in ileum and Alistipes in colon increased significantly(P<0.05),while the abundance of Allobaculum,Bacteroidales S24-7group＿norank in ileum and Parasutterella in colon decreased significantly after highfat diet(P<0.05).After butyric acid intervention in mice fed a high-fat diet,the abundance of Lactobacillus in the ileum and colon decreased significantly(P<0.05),while the abundance of Blautia in the colon increased significantly(P<0.05).In addition,ileal LEfse analysis showed that Candidatus Arthromitus and Intestinibacter had a positive effect on lipid metabolism in mice.Experiment 3.Effects of butyric acid on the intestinal transcriptome of high-fat diet-induced obese miceThe difference in intestinal gene expression among the 3 groups of mice was detected by transcriptome technique.The results showed that the effect of high fat diet and butyric acid on the gene expression of ileum was more significant than that of colon in mice.After high-fat diet treatment,GPIHBP1,ADRB3 and IGF1 genes in ileum were significantly down-regulated(P<0.05),while ANGPTL4,FABP4,FADS2 and ELOVL7 genes in ileum and colon were significantly up-regulated(P<0.05),which was beneficial to reduce fat decomposition and promoted fat deposition.After butyric acid intervention,TRARG1,PLIN1,LPL,STEAP4,ADIPOQ and LEP genes in ileum were significantly up-regulated(P<0.05)and SGK1 genes in colon were significantly down-regulated(P<0.05),which was conducive to increasing fatty acid oxidation,improving fat metabolism and reducing the effects of obesity.