Effect of supplementary dietary L-carnitine and yeast chromium on lipid metabolism of laying hens

Two hundred and eighty-eight 21-week-old Hyline Brown laying hens were randomly allotted to 9 treatments, 32 birds for each treatment. A 3 x 3 (chromium x L-carnitine) factorial experiment was designed to investigate the single and interactive effects of adding yeast chromium (0, 400 and 600 mug/kg) and L-carnitine (0, 50 and 100 mg/kg) to corn-soybean diets on lipid metabolism of laying hens for 7 weeks. The results showed that 600 mug/kg chromium or 100 mg/kg L-carnitine had significant effects on most indices of lipid metabolism (p < 0.05 or 0.01). There were significant interactions on the concentration of liver triglycerides, egg yolk cholesterol, abdominal fat percentage between chromium and L-carnitine (p = 0.0003-0.0500). Adding 400 mug/kg chromium and 100 mg/kg L-carnitine simultaneously was the best for reducing egg yolk cholesterol and adding 400 mug/kg chromium and 50 mg/kg L-carnitine at the same time was the best for reducing abdominal fat percentage. There was no side effect on production performance of laying hens while chromium or (and) L-carnitine reduced liver lipid, abdominal fat and egg yolk cholesterol.