Abstract: An experiment was conducted using a total of 288 three-week-old AA broiler chickens to investigate the effects of adding yeast chromium (0, 400, 600 μg·kg-1 respectively) and betaine (0, 800, 1 000 mg·kg-1 respectively) to corn soybean diets on carcass quality and lipid metabolism in broiler chickens and their interaction. Chickens were randomly divided into 9 treatments (32 for each treatment, 8 for each replicate). A 3×3 (chromium×betaine) experiment with replicates was designed. The basal diet was used as control group, and the experiment lasted for four weeks. The result showed:(1) There were significant effects of interaction between betaine and chromium on slaughter rate, abdomininal fat rate, the rate of the whole pure thorax, (P＜0.01) and no significant interactive effects on half pure thorax rate (P＞0.05).(2) Betaine and chromium on the content of cholesterol (TC) and triglycerides (TG) in liver and muscle of chest and leg had interactive effects (P＜0.01). Analysis showed that, it was better for the test group to add 1 000 mg·kg-1 betaine and 400μg·kg-1 chromium at the same time.(3) At the end of 7 weeks, betaine and chromium significantly increased the concentrations of serum total protein (TP), albumin (ALB), free fatty acid (FFA), high density lipid protein chloesterol(HDL-C) in serum compared with control group (P＜0.01) and significantly reduced the concentrations of cholesterol (TC), uric acid (UA), low density lipid protein chloesterol (LDL-C), triglycerides (TG), and glucose (Glu).

Key words: Betaine, Yeast chromium, Broiler chickens, Carcass quality, Lipid metabolism