Performance, carcass characteristics, and immunity in broiler chickens fed dietary neem (Azadirachta indica) as alternative for an antibiotic growth promoter

This experiment was conducted to examine the effect of neem (Azadirachta indica) as an antibiotic growth promoter substitute on growth performance, carcass traits, and humoral immune responses in broiler chickens. A total of 192 one-d-old mixed sex broiler chicks (Ross 308) were weighted and randomly allocated to four treatment groups, each with 4 replicate pens of 12 chicks. The dietary treatments consisted of the basal diet (control), control + 4.5 mg flavophospholipol/kg, or control + 7 or 12 g neem fruit powder/kg. Body weights of broilers were determined at d 1, 14, 28, and 42, feed intake was determined at the same periods, and feed conversion ratio was calculated accordingly. At d 42, two birds per replicate were slaughtered for determination of carcass and organ weights. Antibody titers against Newcastle, influenza viruses, and sheep red blood cells (SRBC) were determined. Dietary supplementation of flavophospholipol increased final body weight of broilers at 42 d of age compared with those fed diets supplemented with neem (P < 0.05). Birds fed 7 g neem/kg in the diet had the highest feed conversion ratio at 42 d, compared with other treatments. Daily feed intake, internal organ weights, and carcass traits were not influenced by the dietary treatments at d 42. Supplementation with 7 g neem/kg led to greater antibody titers against SRBC compared with 12 g neem/kg (P < 0.05) and influenza virus compared with the control diet and the diet supplemented with flavophospholipol (P < 0.05). In conclusion, the results indicate that supplementing broiler diet with 7 g neem/kg could induce favorable influences on immune responses of broilers without any adverse effect on growth performance.