Gut Microbial Community And Its Correlation With Fat Deposition In Jinhua Pigs

The deposition of animal body fat is of great significance for keeping body health and improving the quality of meet product.The objective of this study was to investigate the gut microbiota of obese-type Jinhua pigs and its correlation with fat deposition.Three experiment were included.Experiment 1.Gut microbial diversity and the core microbiota of the Jinhua pig,were examined from a total of 105 fecal samples collected from 6 groups of pigs at 3 weaning ages that originated from 2 strains and were raised on 3 different pig farms.The bacterial community was analyzed following high-throughput pyrosequencing of 16S rRNA genes,and the fecal concentrations of short-chain fatty acids(SCFAs)were measured by gas chromatograph.Our results showed that Firmicutes and Bacteroidetes were the dominant phyla,and Lactobacillus,Streptococcus,Clostridium,SMB53,and Bifidobacterium were the most abundant genera.Fifteen predominant genera present in every Jinhua pig sample constituted a phylogenetic core microbiota and included the probiotics Lactobacillus and Bifidobacterium,and the SCFA-producing bacteria Clostridium,Prevotella,Bacteroides,Coprococcus,Roseburia,Ruminococcus,Blautia,and Butyricicoccus.Comparisons of the microbiota compositions and SCFA concentrations across the 6 groups of pigs demonstrated that genetic background and weaning age affected the structure of the gut microbiota more significantly than the farm.The relative abundance of the core genera in the pigs,including Lactobacillus,Clostridium,Prevotella,Bacteroides,Roseburia,Ruminococcus,Blautia,and Butyricicoccus varied dramatically in pigs among the 2 origins and 3 weaning ages(P<0.05),while Oscillospira,Megasphaera,Parabacteroides,and Cotynebacterium differed among pigs from different farms(P<0.05).Interestingly,there was a more significant influence of strain and weaning age than of rearing farm on the SCFA concentrations and pH.Experiment 2.Using the lean-type Landrace pig as an animal comparative model,we compared the differences in fat deposition and in bacterial community structure throughout the intestinal tract in two breeds(Landrace and Jinhua)of pigs with distinct phenotypes.Ten 240-day-old pigs were respectively selected from Jinhua pigs and Landrace pigs that had been reared in the same conditions.The body fat phenotype such as the backfat thickness and long-distance muscle fat content,serum biochemical markers related to lipid metabolism,and the expression of genes associated with adipogenesis and differentiation in gut,liver,and abdominal adipose tissue were analyzed to investigate the differences in fat deposition between Jinhua pigs and Landrace pigs by using 16S rRNA gene sequencing.The results showed that the weight of Jinhua pigs at the same age was significantly lower than that of Landrace pigs(P<0.05),while the backfat thickness,longissimus muscle fat content,and serum triglyceride concentrations were all higher than Landrace pigs(P<0.05).The liver cell triglyceride content,abdominal fat cell size,and liver and abdominal fat synthesis-related gene expression levels in Jinhua pigs were significantly higher than Landrace pigs(P<0.05).However,the FIAF expression levels of liver,adipose tissue and intestinal tract were significantly lower than Landrace pigs(P<0.05).we revealed that the bacterial communities are more diverse in the duodenum,jejunum,and cecum of Jinhua pigs than in those of Landrace pigs(P<0.05);whereas the ileal and colonic microbiota show a similar complexity between the two breeds.Therefore,the relative fat content of Jinhua pigs was higher than that of Landrace pigs.Experiment 3.In order to fully understand the differences in metabolic characteristics and gut microbial community structure between Jinhua pigs and Landrace pigs and their correlations,we selected the fresh feces from a 240-day-old Jinhua and Landrace sow to produce a bacterial suspension.The antibiotic-treated mice were gavaged by the bacterial suspension of Jinhua and Landrace,respectively.The microbial community structure of recipients mice was analyzed and the fat metabolism phenotype was measured to further elucidate the relationship between intestinal flora and fat deposition in Jinhua pigs from the perspective of mouse models.Results showed that there were differences in the bacterial community structure between Jinhua pig and Landrace pig fecal donors.The relative abundance of Clostridium and Treponema in Jinhua pig feces is relatively higher,while that of Lactobacillus and Escherichia coli in Landrace pigs is higher.There were also significant differences in the intestinal microbiota structure of recipient mice with different fecal microbiota.The Relative abundance of Firmicutes in cecum of Jinhua pig fecal microbiota-related mice(JM)was higher than that in Landrace pig fecal microbiota-related mice(LM)(P<0.05),whereas the abundance of Verrucomicrobia was opposite(P<0.05).At the genus level,the relative abundance of Lactobacillus and Parabacteroides was higher in JM group(P<0.05),while the relative abundance of Akkermansia was significantly higher in LM group(P<0.05).Triglyceride content and LPL activity were significantly higher in JM than LM(P<0.05).In addition,the expression of genes related to fat synthesis in the liver and abdomen was also significantly higher in JM than in LM,whereas the expression of FIAF in the abdominal fat and intestine was significantly lower than that in LM.It is suggested that the transplantation of pig fecal microbiota into mice can transfer the fat deposition metabolic phenotype of pigs to some extent.These finding shows that 15 predominant genera present in every Jinhua pig sample and formed the core microbiota.the relative abundances of these genera was mainly affected by its strain and weaning age in Jinhua pig under the same feed conditions.There was a significant difference in the intestinal microbial community structure between Jinhua pig and Landrace pig.At the same time,the gut microbiota of Jinhua pigs is positively correlated with the expression of genes related to fat deposition,which reflects a certain association with fat deposition in the body.