Effect of dietary yeast chromium and L-carnitine on lipid metabolism of sheep

A 56-day feeding experiment was conducted to investigate the effects of yeast chromium (Cr, 300 μg/kg diet) and/or L-carnitine (100 mg/kg diet) on lipid metabolism and their interaction in sheep. After a 14-day adaptation period, 32 3-month-old sheep were randomly divided into four groups of eight. All sheep were fed with basal diets according to the American feeding standard of the National Research Council. At the end of the experiment, yeast Cr and/or L-carnitine supplementation significantly decreased abdominal fat mass and abdominal fat percentage, suggesting an improved mutton quality. Compared with the control group, the ratio of glucose to insulin was significantly increased, due to unchanged glucose levels and reduced insulin levels in yeast Cr and/or L-carnitine supplement groups, indicating high insulin sensitivity and well-controlled serum glucose levels. In addition, yeast chromium and/or L-carnitine induced significant decreases in serum triglyceride levels and serum total cholesterol levels, while increasing serum free fatty acid levels and high-density lipoproteincholesterol levels. The findings show that adding a yeast Cr and/or L-carnitine supplement may give better control of glucose and lipid variables.