Paper
Chickens represent a specific case in lipid metabolism that liver is the main site of lipid synthesis. As ovipara, their gut microbiota could be strongly influenced by environment and diets after hatching. The aim of this study is to elucidate the linkage of gut microbiota and fat synthesis in broilers. The broilers were subjected to dietary treatments of combined probiotics (Clostridium butyrate 4x108 cfu/kg, Bifidobacterium 2x108 cfu/kg, Lactobacillus plantarum 2x108 cfu/kg and Lactococcus faecalis 2x108 cfu/kg, PB) and guar gum (1 g/kg, GG). The result showed that dietary supplementation of PB and GG changed the cecal microbiota diversity, altered short chain fatty acids (SCFAs) contents, and suppressed lipogenesis in liver and abdominal fat tissues. In intestinal epithelial cells (IECs), acetate, propionate, and butyrate upregulated the expression of glucagon-like peptide-1 (GLP-1) via MAPK pathways, especially via the ERK and p38 MAPK pathways. GLP-1 suppressed lipid accumulation in primary hepatocytes with the involvement of AMPK/ACC signaling. In conclusion, the result suggests that SCFAs-induced GLP-1 secretion links the regulation of gut microbiome on hepatic lipogenesis in chickens. IMPORTANCEIntestinal microbes metabolize SCFAs and stimulate intestinal epithelium L cells to produce GLP-1. Recent evidence showed that GLP-1 reduced fat deposition by reducing appetite and increasing satiety. However, how SCFAs stimulate the secretion of GLP-1 and whether GLP-1 directly affects fat metabolism is not clear. Poultry adipocytes have limited ability to produce fat, and 90% of carcass fat is synthesized in the liver. In addition, large intake of feeds easily leads to fatty liver diseases in chickens. The aim of this study is to investigate how SCFAs mediate secretion of GLP-1 and whether GLP-1 could directly affect hepatic deposition in broiler chickens. The hepatic lipogenesis regulated by the intestinal microbiota of chickens is of great significance to the study of intestinal microbiota and fat deposition in poultry, and this work could provide reference for intestinal microorganism and fat metabolism in mammals and humans.
