Abstract

This study investigated the role of vitamin C and Citrus Sinensis peel (sweet orange peel (Sop)) on growth, carcass characteristics and health status in 160 one day old broiler chickens (Ross308) which were randomly divided into four equal groups consisting 4 pens. Each pen having 10 birds (5 male and 5 female) for 35 days. All chicks were exposed to heat stress (33⁰C) during all the experimental period (35 days). Group one considered as control, groups 2, 3, 4 were given feed containing vitamin C (500ppm/ feed), sweet orange peel (Sop) (1,2 % respectively). Sop 2% significantly increased average body weight gain and feed intake during the grower period (16-28) (P<0.05). The birds fed Sop 2% during the whole experimental period had higher FI and greater feed conversion ratio (P<0.05) compared to the other groups. The mortality rate tended to be the lowest in the birds fed the feed additives (P<0.05). The relative weight of internal organs, blood profiles pictures were not affected by Sop with two tested levels (P<0.05) or vitamin C compared with the control group. Broiler fed vitamin C or Sop levels had greater primary and secondary antibody responses to sheep red blood cells (SRBC) and against phytohemagglutinin (PHA-P) antigen compared with those in the control group (P<0.05). Sop and vitamin C increased antibodies titer against Newcastle disease during the secondary antibody response (P<0.05). Overall, Sop as feed additive improved immune responses in broiler chickens under heat stress. Also the result indicate that the Sop 2 % during the grower period had a positive effect on growth performance of broiler chickens under heat stress.