Abstract
The role of Nigella sativa seed (NSS) and garlic as dietary additions for enhancing growth performance and detoxification of dietary lead acetate in New Zealand White rabbits were studied. Rabbits were classified into nearly 6 similar groups in their average body weights: first and second groups served as positive and negative controls, third and fourth groups received lead acetate plus either Nigella sativa seed or garlic, respectively. Fifth and sixth groups received only Nigella sativa seed or garlic, respectively. The obtained data revealed that final body weight, daily body weight gain, efficient of feed consumed and performance index of rabbits decreased significantly (p≤0.05) in the negative control group (G2), which received 0.5% lead acetate. All these traits were slight improved in group 3 and 4, and significantly improved (p≤0.05) in group 5 and 6 of rabbits when compared to the negative control group. Biochemical parameters showed significant (p≤ 0.05) increase in levels of cholesterol, triglycerides, aspertate amino transferase (AST), alanine aminotransferase (ALT), urea and creatinine, as well as, significant decrease (p≤ 0.05) in level of total protein and albumin in the negative control group. In groups 3, 4 , 5 and 6 of rabbits levels of cholesterol, triglycerides, AST, ALT, urea and creatinine decreased significantly (p≤0.05), as well as, levels of total protein and albumin increased significantly (p ≤ 0.05) when compared to the negative control group. Groups 5 and 6 of rabbits that received only Nigella sativa seed or garlic with the basal diet showed no significant differences in digestability coefficient, as well as in panel test. On the other hand the weight of kidneys, liver and heart as % of live body weight increased significantly by lead acetate. After eight weeks, liver samples were collected and analyzed for malondialdehyde (MDA), glutathione (GSH), glutathione S-transferase (GST) and glutathione peroxidase (GPx) contents. Lead acetate exposure significantly (p≤0.05) increased MDA (lipid peroxidation biomarker) and reduced the GSH levels and the GST and GPx activities. Concurrently supplemented NSS or dry garlic significantly (p≤0.05) decreased MDA levels and restored the GSH, GST, and GPx contents successfully. The residue of lead in liver, kidneys and muscles reduced significantly by additives. The % of mortality rate was not affected in all tested groups during the experimental period. In conclusion, the addition of 2 % Nigella sativa seeds or 0.8 % dry garlic to growing rabbit diet was safe and practical method to minimize the lead toxicity in rabbit diet.

Key words: Rabbits, detoxification, black seeds, garlic, lead acetate