Abstract

This experiment was conducted to consider the effect of ractopamine and L-carnitine as lipolytic agent and growth promoter on broiler chicks. Nine experimental diets were fed to 675 broiler chicks at the growth periods (3 to 6 weeks of age). Three levels of ractopamine (0, 5 and 10 mg/kg) and L-carnitine (0, 60 and 120 mg/kg) were fed. A completely randomized design with a 3 × 3 factorial arrangement was used. Growth performance, blood biochemical parameters and carcass traits were measured. Results indicate that daily body weight gain (DBWG), feed intake (FI) and feed conversion ratio (FCR) were not affected significantly (p>0.05) by different levels of ractopamine and L-carnitine. Ractopamine (10 mg/kg) significantly (p<0.05) increased blood serum cholesterol and albumin levels. On the other hand, triglyceride, blood urea nitrogen and globulin were reduced (p<0.05) in 10 mg/kg of ractopamine. L-Carnitine (60 mg/kg) significantly (p<0.05) reduced triglyceride, blood urea nitrogen and albumin, but increased blood serum cholesterol and glucose levels. The lowest level of triglyceride was observed by diets 5 (5 and 60 mg/kg) and diet 8 (10 and 60 mg/kg), which contained with ractopamine and L-carnitine, respectively. Carcass traits, except thigh and liver fat percentage were not influenced by added ractopamine. A significant (p<0.05) reduction was observed in abdominal fat pad due to supplemental L-carnitine. Liver fat content was significantly (p<0.05) reduced by (10 mg/kg) ractopamine. Blood biochemical parameters and some carcass traits of broilers were responsive to supplemental ractopamine and L-carnitine.

Key words: Ractopamine, L-carnitine, performance, carcass traits, broiler chicks.