Chicken cecal microbiota reduces abdominal fat deposition by regulating fat metabolism

Abstract Background: Rapidly developed broilers are often accompanied by excessive fat deposition and markedly decreased feed utilization, which is a severe problem in the poultry industry. Recent studies established that gut microbiota significantly alters chicken fat deposition. However, what kind of cecal bacteria can regulate fat deposition and how they control fat deposition remains unclear. Results: The abdominal fat weight and index, and average diameter of adipocytes were markedly higher in high than in low abdominal fat deposition chickens at different time points (1, 4, and 12 months). The higher expression levels of fat synthesis related genes (ACSL1, FADS1, CYP2C45, ACC, and FAS) and a lower expression of fat catabolism genes (CPT-1, and PPARα) in the liver and abdominal fat of high abdominal fat deposition chickens, indicated that an unbalanced fat metabolism leads to excessive abdominal fat deposition. Parabacteroides, Parasutterella, Oscillibacter, and Anaerofustis were found higher in high abdominal fat deposition chickens, while Bacteroides and Sphaerochaeta were higher in low abdominal fat deposition chickens at different time points. Further, Spearman correlation analysis indicated that the relative abundance of Parabacteroides, Parasutterella, Oscillibacter, and Anaerofustis was positively correlated with abdominal fat weight and index, and the expression level of fat anabolism genes, yet the relative abundance of Bacteroides and Sphaerochaeta was negatively correlated with these factors. Furthermore, transferring fecal microbiota from adult chickens with low abdominal fat deposition into one-day-old chicks significantly decreased Parabacteroides, abdominal fat weight and index, and fat anabolism genes, while markedly increased Bacteroides and Sphaerochaeta and fat catabolism genes. Conclusion: Our findings highlighted that Bacteroides and Sphaerochaeta might reduce abdominal fat deposition, yet Parabacteroides Parasutterella, Oscillibacter, and Anaerofustis could promote abdominal fat deposition by regulating fat metabolism.