Abstract
Objective: The objective of this study was to determine whether a dietary vitamin E (VE) supplement could alleviate any detrimental effects of aged corn on lipid metabolism and antioxidant status in laying hens.
Methods: The experiment consisted of a 2 × 3 factorial design with two corn types (normal corn and aged corn (stored for 4 yr) and three concentrations of VE (0, 20 and 100 IU/kg). A total of 216 Lohmann laying hens (50 wk of age) were randomly allocated into six treatment diets for 12 wk. Each treatment had 6 replicates of 6 hens per replicate.
Results: The results show that aged corn significantly decreased the content of low-density lipoprotein cholesterol (LDL-C) (P< 0.05), and reduced chemokine-like receptor 1 (CMKLR1) mRNA expression (P< 0.05) in the liver compared to controls. Diet with VE did not alter the content of crude fat and cholesterol (P> 0.05), or acetyl-CoA carboxylase (ACC), lipoprotein lipase (LPL), fatty acid synthase (FAS) or CMKLR1 mRNA expression (P> 0.05) in the liver among treatment groups. Aged corn significantly increased the content of malondialdehyde (MDA) (P< 0.05) and decreased superoxide dismutase (SOD) activity (P< 0.05) in the liver. VE increased the content of MDA (P< 0.05) but decreased glutathione peroxidase (GSH-PX) activity in serum (P< 0.01) and in the ovaries (P< 0.05). Adding VE at 20 and 100 IU/kg significantly increased GSH-PX activity (P< 0.05) in liver and in serum (P< 0.01), 100 IU/kg VE significantly increased SOD activity (P< 0.05) in serum. Aged corn had no significant effects on GSH-PX mRNA or SOD mRNA expression (P< 0.01) in the liver and ovaries. Addition of 100 IU/kg VE could significantly increase SOD mRNA expression (P< 0.01) in the liver and ovary.
Conclusion: Aged corn affected lipid metabolism and decreased the antioxidant function of laying hens. Dietary VE supplementation was unable to counteract the negative effects of aged corn on lipid metabolism. However, addition of 100 IU/kg VE prevented aged corn-induced lipid peroxidation in the organs of laying hens.