Effect of different levels of black seed (Nigella sativa L.) and dietary protein on performance, carcass composition and blood parameters of broiler chickens

An experiment was conducted to evaluate the effect of different levels of black seed and two dietary protein levels on performance and blood parameters of broiler chickens. A total number of 336 un-sexed day-old Ross 308 broiler chickens were used in a 2×3 factorial arrangement with a completely randomized design consisted of 6 treatments (three levels of black seed (0, 1, 2 percent) in two protein levels (NRC recommended and 87% NRC, 1994)) with 4 replicates and 14 chicks in each replicate. All diets were iso-caloric and had the minimum nutrient requirements recommended by NRC (1994) except for protein. The results showed that using diets with NRC protein level rather to low protein diets resulted in a higher live body weight (P<0.05). Reducing dietary protein level led to reduced protein consumption and increased protein efficiency ratio (P<0.05). Reducing dietary protein level resulted in a significant decrease in carcass and thigh percentage (P<0.05). Serum albumin concentration decrease significantly when dietary protein reduced (P<0.05) Supplemented low protein diet with 1 and 2% black seed significantly improve live body weight, feed conversion ratio and protein efficiency ratio (P<0.05), as these values were similar to those birds were fed diets with sufficient quantity of protein. Supplemented low protein diet with black seed significantly improve breast, heart and gizzard (P<0.05) since their values were close to diets containing NRC recommended protein. These results demonstrated that supplementing black seed to low protein diet improve broilers growth performance.