Metagenomic Analysis Of Intestinal Microflora In Goose And Its Relation With Fatty Liver Formation

Gut microbes can affect metabolism and function of liver by participating in the degradation of nutrients,producing various metabolites and changing the barrier function of the intestine,and play an important role in the occurrence and development of fatty liver in animals.The livers of humans and various animals often suffer from irreversible inflammation and fibrosis during severe steatosis,which harmfully affects human health and animal production.On the contrary,although the weight of fatty liver can be increased by 8 times more than that of normal liver in goose,but no obvious pathological symptoms occur with severe steatosis,so it may have an unique mechanism underlying its formation.Our previous studies showed that,compared with the normal feeding group,the composition of gut microbes changed significantly in the overfed Landes geese,however,the underlying mechanism by which gut microbes affect the formation of goose fatty liver remains unclear.In this study,75 healthy male Landes geese with similar body weight at 70 days old were randomly divided into the control group(n=48)and the overfeeding group(n=32).The control group was fed normally,while the overfeeding group was overfed with energy-rich corn.At the age of 70,82 and 94,15 geese from each group(exceptionally,only 16 from the control group at the age of 70)were sacrificed for each time point,and the internal contents from jejunum,ileum,and cecum were collected.16S rDNA sequencing analysis was performed to investigate the effect of overfeeding on the composition of gut microbes in the experimental geese.Based on the 16S rDNA sequencing data,some of the samples were selected for metagenomics analysis,and the effect of overfeeding on the composition and function of gut microbes was further determined.Finally,60 male Landes geese with similar body weight at 70 days were randomly divided into four groups(15 each group):the control group,the control group with supplement of Lactobacillus,the overfeeding group,and the overfeeding group with supplement of Lactobacillus.After 24 days of overfeeding,body weight was measured.Liver weight,spleen weight,and abdominal fat weight were also measured upon slaughter.The effect of Lactobacillus supplement to diet on the formation of goose fatty liver was investigated.According to the results from the experiments,the following conclusions are drawn here:(1)The composition of gut microbes across different intestinal tracts was different during the period of overfeeding.In the process of overfeeding,the relative abundance of the main microbes including Phylum Firmicutes,Proteobacteria and Bacteroidetes was changed at different degrees;(2)The composition of gut microbes across different intestinal tracts was obviously different after overfeeding,and the genera of microbes from different intestinal segments were unique;(3)Metagenomics analysis showed that lipid metabolism,carbohydrate metabolism and amino acid metabolism were enhanced in the overfed geese;(4)The abundance of beneficial microbes represented by Lactobacillus was increased after overfeeding;(5)Lactobacillus could ameliorate goose fatty liver to a certain extent.In conclusion,this study demonstrated that gut microbes got adapted to overfeeding process by changing its own composition and increasing the abundance of bacteria related to lipid metabolism and carbohydrate metabolism during formation of goose fatty liver,thus alleviating the steatosis in the liver.