Dietary manganese supplementation decreases hepatic lipid deposition by regulating gene expression and enzyme activity involved in lipid metabolism in the liver of broilers

This study aimed to characterize the effects of different dietary forms of supplemental manganese (Mn) on hepatic lipid deposition, gene expression, and enzyme activity in liver fat metabolism in 42-d-old broiler chickens. In total 420 one-day-old Arbor Acres (AA) broilers (rooster:hen = 1:1) were assigned randomly based on body weight and sex to 1 of 6 treatments (10 replicate cages per treatment and 7 broilers per replicate cage) in a completely randomized design using a 2 (sex) x 3 (diet) factorial arrangement. The 3 diets were basal control diets without Mn supplementation and basal diets supplemented with either Mn sulfate or Mn proteinate. No sex x diet interactions were observed in any of the measured indexes; thus, the effect of diet alone was presented in this study. Dietary Mn supplementation increased Mn content in the plasma and liver, adipose triglyceride lipase (ATGL) activity, and ATGL mRNA and its protein expression in the liver by 5.3% to 24.0% (P < 0.05), but reduced plasma triglyceride (TG), total cholesterol, and low-density lipoprotein (LDL-C) levels, liver TG content, fatty acid synthase (FAS) and malic enzyme (ME) activities, mRNA expression of sterol-regulatory element-binding protein 1 (SREBP1), FAS, stearoyl-coA desaturase (SCD), and ME, as well as the protein expression of SREBP1 and SCD in the liver by 5.5% to 22.8% (P < 0.05). No differences were observed between the 2 Mn sources in all of the determined parameters. Therefore, it was concluded that dietary Mn supplementation, regardless of Mn source, decreased hepatic lipid accumulation in broilers by inhibiting SREBP1 and SCD expression, FAS and ME activities, and enhancing ATGL expression and activity.