Effects of dietary L-carnitine supplementation on growth performance and some biochemical parameters in Japanese quails (Coturnix coturnix japonica)

This experiment was carried out to determine the effects of different contents of L-carnitine added to quail diets on some growth characteristics and blood biochemical parameters. For that, 345 one week old Japanese quail chickens (Coturnix coturnix japonica) were divided into 5 equal groups according to the L carnitine contents added to the diet for 4 weeks (0 mg/kg of diet in the control group, 50, 100, 150 and 200 mg/kg in the treatment groups 1, 2, 3 and 4, respectively). Body weights, body weight gains, food intake and food efficiency were determined weekly. At the 4(th) week of treatment, carcass traits and blood biochemical parameters (serum total protein, cholesterol and triglyceride concentrations as well as serum ALP, AST and ALT activities) were analyzed from 12 randomly selected males in each group. With the highest L carnitine dosage, body weights significantly increased at the 2(nd) week of treatment and the cumulative body weight gains on the whole period were significantly higher than in the other groups. In parallel, the total food intake tended to slightly decrease whereas food efficiency and weights and yields of carcasses tended to be improved in the group treatment 4 but not significantly. By contrast, lower dosages of L carnitine failed to induce changes in weight gain, food consumption or in carcass traits. Furthermore, biochemical parameters were not affected by L carnitine supplementation whatever the dose used. These results suggest that higher dosages of L carnitine (above 200 mg/kg) would be necessary for improving lipid metabolism and growth in quails.