Effects of high dietary iron on the lipid metabolism in the liver and adipose tissue of male broiler chickens

Abstract

Iron overload is associated with the obesity and type 2 diabetes in humans. To investigate its effects on lipid metabolism in the liver and adipose tissue of broiler chickens, a total of 320 1-day-old male broiler chickens were assigned to 2 groups with 8 replicate pens (20 birds per pen). The broiler chickens were fed diets containing either 139 mg Fe/kg (adequate dietary iron; control) or 609 mg Fe/kg (high dietary iron; high-iron) by FeSO4 supplement (dry matter basis). After 21 days, the samples of blood, liver, and abdominal adipose tissue were collected. High dietary iron decreased body weight (BW), abdominal adipose tissue weight, and the percentage of abdominal adipose tissue weight relative to BW (P < 0.01). Adipocyte size and DNA content in abdominal adipose tissue were also lower (P < 0.001) in the high-iron treatment group than in the control group. High dietary iron decreased the concentrations of triglyceride (TAG) and total fatty acids in the liver, and the concentration of very-low-density lipoprotein in the serum, the major vehicle for TAG from the liver to the peripheral tissues. In the liver, the activities of lipogenic enzymes including acetyl-coenzyme A carboxylase, fatty acid synthase (FAS), and stearoyl-coenzyme A desaturase 1 (SCD1) were lower in the high-iron treatment group than in the control group (P < 0.05). High dietary iron decreased the activities of lipolytic enzymes such as adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) in the abdominal adipose tissue (P < 0.05). Simultaneously, high dietary iron decreased the mRNA abundance of FAS, SCD1, and sterol regulatory element–binding transcription factor (SREBP) 1 in the liver and that of peroxisome proliferator–activated receptor γ, CCAAT/enhancer-binding protein (C/EBP) α, and C/EBPβ in the abdominal adipose tissue (P < 0.05). These results suggested that high dietary iron reduced abdominal adipose fat deposition and hepatic TAG accumulation in broiler chickens, which was at least partly due to the reduction in hepatic de novo lipogenesis in broiler chickens.