Synergistic effects of copper and bile acids on cholesterol reduction in eggs of laying hens

This study investigates the combined effects of copper (Cu) and bile acids (BA) on production performance, lipid metabolism, and antioxidant capacity in laying hens. During a 67-day trial, a total of 300 Jingfen 8 laying hens aged 160 days were randomly allocated into four treatment groups: Control (basal diet), Cu (25 mg/kg Cu), BA (500 mg/kg BA), and Mix (a combination of 25 mg/kg Cu and 500 mg/kg BA). The results indicated that the Mix group experienced a significant decrease in egg cholesterol levels, particularly in the yolk cholesterol content, along with an enhancement in the total antioxidant capacity. Additionally, the liver cholesterol metabolism was modulated by upregulation of CYP7A1 and ABCG5, alongside downregulation of SREBP-2 and HMGCR. While Cu and BA individually showed minimal effects on production, their combination yielded a synergistic impact on lipid metabolism and antioxidant defense. However, the Mix group showed reduced liver zinc content, suggesting a Antagonistic relationship between Cu and Zn. These findings suggest that Cu and BA supplementation may enhance egg quality and metabolic health in laying hens, highlighting the importance of maintaining balanced trace element ratios in poultry diets.