This experiment was conducted to evaluate the effects of bile acids (BAs) on the growth performance and lipid metabolism of broilers fed with different energy level diets. 480 one-day-old Arbor Acres broilers (45.01 ± 0.26 g) were allotted to a 2 × 2 factorial design with 2 levels of energy (basal or high-energy level) and 2 levels of BAs (with or without BAs supplementation), resulting in 4 groups of 8 replicates; the experiment lasted 42 d. High-energy diets decreased the feed/gain ratio (F/G) from 1 to 21 d (P0.05), and increased the liver index and abdominal fat percentage at 42 d (P0.05). The serum total triglyceride (TG) and high-density lipoprotein cholesterol at 42 d were increased by high-energy diets (P0.05), while the hepatic lipoprotein lipase (LPL) activity at 21 and 42 d was decreased (P0.05). BAs supplementation increased the body weight at 21 d and decreased the F/G during entire period (P0.05), as well as improved the carcass quality reflected by decreased abdominal fat percentage at 42 d and increased breast muscle percentage at 21 and 42 d (P0.05). The serum TG at 21 and 42 d were decreased by BAs (P0.05), and the hepatic LPL activity at 42 d was increased (P0.05). In addition, high-energy diets increased the expression of sterol regulatory element binding transcription factor 1, acetyl-CoA carboxylase, and fatty acid synthase (P0.05), while BAs diets decreased these genes expression (P0.05). Moreover, BAs supplementation also increased the expression of carnitine palmitoyltransferase 1 (P0.05), which was increased in high-energy groups (P0.05). In conclusion, BAs supplementation could increase growth performance, elevate carcass quality, and improve lipid metabolism in broilers.
