comparison of the effects of licorice extract (glycyrrhiza glabra) and lincomycine on abdominal fat biochemical blood parameter and immunity of broiler chickens.

a 42-d trial with 400 unsexed broiler chicks (cobb 500) was conducted to study the effects of licorice (glycyrrhizaglabra) extract and an antibiotic-lincomycin- on performance abdominal fat and weights of selected internal organs, blood metabolites immunity system response. the feeding program consisted of a starter diet (1-21) d of age and a grower diet (22-42) d of age. chicks were randomly assigned to 5 treatments (there were 4 replications per treatment with 20 chicks per pen): basal diet (control); 5 ppm of lincomycin; basal diet plus 0.1, 0.2, and 0.3 % licorice extract via drinking water. no differences in feed intake, body weight gain and feed conversion ratio were observed (p>0.05). birds receiving licorice extract had lower weights of gallbladder and abdominal fat compared to those fed control diet (respectively significant for 0.1 and 0.3% licorice extract( p<0.05). however no effects were detected for breast, thigh, liver, pancreas, bursa, thymus, and spleen weight.  licorice extract consumption significantly reduced the serum levels of ldl and total cholesterol in a dose-dependent manner (p<0.05), but no differences between treatments were observed regards to serum triglyceride and hdl concentrations. in 21 and 42 d of age, antibody responses to newcastle and influenza diseases vaccines as well as lymphocyte percentage and heterophil to lymphocyte ratio were unaffected by treatments. from these results it was concluded that licorice extract can reduce abdominal fat without any adverse effects on broilers performance and immune status.