Supplemental Modulates Lipid Metabolism Through Shaping Gut Microbiota and Bile Acid Profile of Aged Laying Hens

Probiotic could affect lipid metabolism in broilers. However, it is not clear whether could improve lipid metabolism through shaping gut microbiota and bile acid (BA) profile of laying hens. We aimed to evaluate the contributions of gut microbiota and BA profile to the potential effect of on lipid metabolism of aged laying hens. A total of 192 60-week-old Hy-Line Brown laying hens were divided into two groups (eight replicates per group). Birds were fed a basal diet supplemented with 0 or 2.7 g/kg (1.0 × 10 CFU/g). Samples were collected at the end of week 8 of the experiment. The results showed elevated ( < 0.05) concentrations of glucagon-like peptide 1, insulin and thyroid hormones in serum responded to addition, which also decreased ( < 0.05) hepatic free fatty acids contents, as well as increased ( < 0.05) the expression of hepatic acyl-CoA oxidase, farnesoid X receptor (FXR) and PPARα. addition increased ( < 0.05) abundance but tended to decrease ( < 0.10) abundance in the ileum. Besides, addition resulted in higher ( < 0.05) abundances of () and , concurrent with an increasing trend ( < 0.10) of abundance and decreased the abundances of several harmful bacteria such as ( < 0.05). Regarding ileal BA profile, there was a reduced ( < 0.05) content of tauro-α-muricholic acid, increased ( < 0.05) contents of tauroursodeoxycholic acid and lithocholic acid, along with increasing trends ( < 0.10) of glycochenodeoxycholic acid and hyodeoxycholic acid contents due to addition, which also increased ( < 0.05) ileal FXR expression. Collectively, supplemental accelerated hepatic fatty acid oxidation, and shaped gut microbiota and BA profile, thus reducing fat deposition in the liver of aged laying hens.