Effect of Black Seed (Nigella sativa) on Antioxidant Status, Inflammatory Response, Biochemical Indices and Growth Performance in Broilers Subjected to Heat Stress

Heat stress has adverse effects on the health and performance of broilers. This study was conducted to investigate the protective effects of black seed (BS) supplementation on broilers subjected to heat stress (HS). A total of 500 (day-old) Ross-308 male broiler chicks were randomly assigned into five groups with five replicated pens (20 broilers per pen): thermoneutral (TN), heat stress (HS), and HS with a diet supplemented with three different levels of black seed (Nigella sativa) powder (BSP (at rates of 5g/kg (BSP-5), 10 g/kg (BSP-10), and 15 g/kg (BSP-15. Exposure to HS reduced feed intake, and weight gain and elevated feed conversion ratio (FCR), mortality (P < 0.05). Also, low antioxidant enzyme activity (such as glutathione peroxidase, superoxide dismutase, and catalase) and high malondialdehyde levels in serum, liver, and spleen were observed in the birds of the heat stress group compared to the TN treatment (P < 0.05). Moreover, HS elevated interleukin-6 and tumor necrosis factor-α and lowered interleukin-10 levels in serum, liver, and spleen (P < 0.05). In addition, heat stress causes an increase in ALT, AST, ALP, triglycerides, and cholesterol levels compared to the TV group (P < 0.05). Compared with the HS group, broilers in the BSP-10 group had a higher body weight gain, a lower feed conversion ratio, and mortality (P < 0.05). Broilers in the BSP-10 and BSP-10 groups showed higher levels of antioxidant enzyme activities and lower malondialdehyde in serum, liver, and spleen compared to the HS group. BSP supplementation at 10 and 15 mg/kg reduced TNF-α and interleukin-6 levels and enhanced interleukin-10 in serum, liver, and spleen compared to the HS group. Additionally, BSP supplementation at 15 mg/kg reduced the effect of the heat stress on ALT, AST, ALP, triglycerides, and cholesterol compared to the HS group. Obtained results showed that BSP in diet during heat stress may have a role in the reduction of the changes exerted by heat stress in broiler chickens.