Growth performance, serum biochemistry and blood hematology of broiler chicks fed different levels of black seed (Nigellasativa) and peppermint (Mentha piperita)

This study was conducted to investigate the effect of dietary supplementation with black seed and peppermint on the performance, carcass traits, immune responses, serum biochemistry, hematological parameters and meat acceptability in broilers. A total number of 240 day-old male broilers (Ross 308) were randomly allocated to five treatments with four replicates. The dietary treatments consisted of the basal diet as control, 2 and 4 g/kg black seed, 4 and 8 g/kg peppermint added to the basal diet. Body weights of broilers were measured at 1, 14, 28 and 42 days, feed intake was measured for different periods and FCR was calculated accordingly. At 42 days two birds per replicate were slaughtered for determination of carcass and organ weights and also meat sensory evaluation. At 18 and 28 days blood samples (8 samples per treatment) were taken for measuring antibody titers and at 42 days for biochemical and hematological analysis. Supplementing 4 g/kg peppermint increased body weight of broilers at 28 days of age (P < 0.05), but final body weight at 42 days was not affected. Broilers fed 4 g/kg black seed significantly showed the most efficient FCR (0–42 days). Internal organ weights and carcass characteristics were not significantly influenced by treatments. Black seed supplementation also caused a marked (P < 0.05) increase in the weight of lymphoid organs at 42 days but other immune related parameters were not statistically different among treatments. Biochemical parameters including serum protein, albumin, triglyceride, LDL, HDL and total cholesterol, SGOT and SGPT enzymes concentrations were not statistically (P > 0.05) influenced. Black seed significantly increased RBC count, hemoglobin concentration and hematocrit percentage compared to control birds (P < 0.05). Sensory evaluation of thigh meat displayed no abnormal odor or flavor in meat induced by feed additives.