Animal Production Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt.
Animal Production Department, Faculty of Agriculture, Tanta University, Tanta, Egypt.
Environ Sci Pollut Res Int. 2017 Oct;24(30):23636-23645. doi: 10.1007/s11356-017-9986-1. Epub 2017 Aug 30.
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.
需要采取任何适当的方法来减少鱼类养殖场的镉污染。本研究旨在探讨在尼罗罗非鱼饲料中添加膳食镉污染以及用膳食粘土、益生菌（Bactocell®）、维生素 C 和维生素 E 进行改良对生长率、饲料效率、血液成分和镉残留的影响。将鱼分为 15 组，每组鱼放养在三个水族箱中，每个水族箱包含 20 条鱼。第一组鱼喂食基础饲料，第二组鱼喂食含 25mg/kg 镉的基础饲料，第三组鱼喂食含 50mg/kg 镉的相同饲料。在每种膳食镉水平下，第一组喂食不含任何补充剂的饮食，第二组喂食含 3%天然粘土（膨润土）的饮食，第三组喂食含 1g Bactocell®/kg 的饮食，第四组喂食含 50mg/kg 维生素 E/kg 的饮食，第五组喂食含 100mg/kg 维生素 C/kg 的饮食。尼罗罗非鱼的活体体重、每日体重增加和饲料摄入量随着膳食镉水平的升高而显著降低（P<0.001），而饲料转化率受到损害。摄食 50mg/kg 镉的日粮的鱼组记录的活体体重和体重增加最低。血清总蛋白和白蛋白浓度显著降低（P<0.001），而血清肌酐、AST 和 ALT 随着鱼饲料中镉水平的升高而显著升高（P<0.001）。随着鱼饲料中镉的污染，血液血红蛋白和总红细胞（RBC）显著降低（P<0.001 或 0.05），而白细胞则不受影响。随着鱼饲料中镉水平的升高，鱼体中的镉残留量显著增加（P<0.001）。在饲料中添加饲料添加剂可显著提高尼罗罗非鱼的活体体重、每日体重增加和饲料摄入量（P<0.001），同时饲料转化率也得到改善。喂食添加益生菌 Bactocell®或天然粘土的饲料的鱼组比其他实验组获得更高的体重和增重率。血清总蛋白、血液血红蛋白和总红细胞增加，而尿素氮、肌酐、ALT、AST 和白细胞随着饲料添加剂的添加而减少。在鱼饲料中添加饲料添加剂可显著降低鱼体中的镉残留量（P<0.001）。无论膳食镉水平如何，在鱼饲料中添加饲料添加剂均可改善生长率并降低血清肌酐和 ALT 的浓度。研究结果表明，饲料添加剂的添加可以改善暴露于镉毒性的鱼的肾脏和肝脏功能。
