The objective of this study was to assess the effect of supplementation of
Nigella sativa oil (NSO) as a
growth promoter in broiler diets. A total of 300 unsexed one day old Arbor Acre broiler chicks were randomly
divided into five treatment groups (60 chicks/group). Each group was divided into five replicates with 12 chicks
per replicat e. G roup 1 was fed on the basal diet with no additives (control). Gr oup 2 was fed the basal diet
supplemented with oxytetracycline (OTC) at the level of 50 ppm. G roups 3, 4 and 5 were fed the basal diet
supplemented with 500, 1000 and 1500 ppm NSO, respectively. Birds fed on 1500 ppm NSO diet showed the
heaviest body weight at 14, 28 and 42 days of age. Feed conversion ratio was significantly improved at all ages
with the inclusion s of OTC and NSO generally superior to the control group. The relative weight of spleen was
increased significantly by the addition of NSO at various levels . relative weights of thymus and bursa
were not altered by the treatments. Total bacterial count, total yeast and moulds count, E. coli and salmonella
spp. counts were reduced significantly , whereas the total lactic acid bacteria count was increased in OTC and
NSO groups compared with control. Nigella sativa oil could be used in broiler chicken feeds as a natural
alternative to antibiotic growth promoters to improve gut health and consequently growth performance.