The decline of
cadmium pollution in fish farms is needed by any adequate method. The present study was designed to explore the effect of dietary
cadmium contamination and its amelioration by using dietary
clay, probiotic (Bactocell®),
vitamin C, and
vitamin E supplementation in Nile tilapia fish diet on growth rate, feed efficiency, blood components, and
cadmium residues. Fish were separated into 15 groups, each group of fish was stocked into three aquaria and each contains 20 fishes. The fish of the first five groups were fed the basal diet, the second five groups were fed the basal diet contaminated with 25 mg
cadmium/kg, and the third five groups were fed the same diet contaminated with 50 mg
cadmium/kg. Within each dietary
cadmium level, the first group was fed the diet without any supplementation, the second was fed the diet supplemented with natural
clay (
bentonite) at level 3%, the third group was fed the diet supplemented with 1 g Bactocell®/kg, the fourth group was fed the diet supplemented 50 mg
vitamin E/kg, and the fifth group was fed the diet supplemented with 100 mg
vitamin C/kg. Live
body weight, daily
body weight gain, and feed intake of Nile tilapia decreased significantly (P < 0.001) with increasing dietary
cadmium level, while feed conversion was impaired. Fish group fed on diets contaminated with 50 mg
cadmium/kg recorded the lowest live
body weight and
weight gain. Serum total
protein and
albumin concentration significantly (P < 0.001) decreased, while serum
creatinine, AST, and ALT significantly (P < 0.001) increased with increasing
cadmium level in fish diets. Blood
hemoglobin and total erythrocyte (RBCs) significantly (P < 0.001 or 0.05) decreased with
cadmium contamination in fish diets, while leukocytes were insignificantly affected. Body
cadmium residues increased significantly (P < 0.001) by increasing
cadmium level in fish diets. Live
body weight, daily
body weight gain, and feed intake of Nile tilapia increased significantly (P < 0.001) with feed additive supplementation in diets, also while feed conversion improved. Fish group fed on diets supplemented with probiotic Bactocell® or natural
clay recorded higher
body weight and gain rate than the other experimental groups. Serum total
protein, blood hemoglobin, and total erythrocyte increased, while
urea-N,
creatinine, ALT, AST, and leukocytes decreased as affected with the feed additive supplementation. Feed additive supplementation in fish diets significantly (P < 0.001) decreased
cadmium residues in fish bodies. Irrespective of dietary
cadmium level, feed additive supplementation in fish diet improved the growth rate and decreased the concentrations of serum
creatinine and ALT. The obtained results indicated that feed additive supplementation could modify the function of the kidney and liver in fish exposed to the
cadmium toxicity.