Effects of dietary-black cumin (Nigella sativa) oil on growth, antioxidant and biochemical indices and digestive enzyme activities in electric yellow cichlid (Labidochromis caeruleus)

The current study was performed to examine the efficacy of dietary- black cumin (Nigella sativa) oil on the growth rate, some antioxidant and biochemical parameters, as well as digestive enzyme activity in electric yellow cichlid. Fish (1.29 ±0.08 g) were divided into three groups and fed the diets containing 0, 1% and 1.5% black cumin oil for 50 days. Results showed that growth performance was enhanced in the treatment groups compared to the control group (p < /em> < 0.05). Among different antioxidant indices, higher total antioxidant activity was observed in the treatment group fed fed the diets containing 1.5% black cumin oil (p < /em> < 0.05), but lipid peroxidation product, indicated by MDA, was not altered compared to the control group. Meanwhile, activities of some antioxidant enzymes, including superoxide dismutase and catalase in both treatment groups and glutathione S-transferase in group fed fed the diets containing 1.5% black cumin oil were higher compared to the control group (p < /em> < 0.05). During this experiment, higher protein level was also recorded in the treatment groups (p < /em> < 0.05), but no significant changes were noted in alanine aminotransferase level in comparison with the control group. Feeding with black cumin oil also led to a significant increase in amylase and acid phosphatase activities (p < /em> < 0.05), whereas no significant changes were noted in lipase and protease activities. Therefore, the results show that the administration of black cumin oil, especially at 1.5%, had the potential to improve the growth rate, some antioxidant indices, as well as digestive enzyme activities in electric yellow cichlid.