为研究不同水平饲料镉对罗非鱼生长性能和肠道消化酶活性的影响。将300尾罗非鱼随机分为5个处理,饲料镉添加水平分别为0、50、100、200、400mg/kg,试验期为8周。结果表明：与对照组相比,饲料镉添加组增重率和特定生长率均逐渐降低,200、400mg/kg添加水平组显著降低（P〈0.05）;各处理组之间摄食率、饲料系数和成活率均无显著差异（P〉0.05）。饲料镉添加水平组罗非鱼肠道淀粉酶活性和蛋白酶活性均显著低于对照组（P〈0.05）,当饲料中添加50mg/kg镉时,罗非鱼肠道淀粉酶活性和蛋白酶活性即可显著降低（P〈0.05）;罗非鱼脂肪酶活性仅在饲料镉添加水平400mg/kg时显著低于对照组（P〈0.05）,其余各处理组间差异不显著（P〉0.05）。表明罗非鱼对饲料镉耐受程度较高,饲料中镉达到200mg/kg时,才可显著影响罗非鱼增重率和特定生长率。饲料中不同水平镉对罗非鱼肠道消化酶活性具有不同程度的抑制作用,饲料中添加50mg/kg镉时即可显著降低肠道淀粉酶和蛋白酶的活性,肠道脂肪酶活性仅在400mg/kg时显著降低。%300 tilapias were used to investigate the effects of different level of dietary Cd on growth, digestive enzyme activities of tilapia intestinal tract, which were divided into 5 groups with four replicates in each group and exposed to dietary Cd at concentrations of 0, 50, 100, 200, 400 mg/kg for 8 weeks. Compared with the control group, the weight gain rate and specific growth rate were both decreased significantly in 200, 400 mg/kg Cd group (P〈0.05); No significant difference in the feed rate, feed conversion rate and survival rate were found among all groups(P〉0.05); The activities of amylase and protease in intestinal tract were decreased significantly when the level of dietary Cd was 50 mg/kg (P〈0.05), the activity of lipase in intestinal tract was decreased significantly only in 400 mg/kg Cd group (P〈0.05). It suggested that tilapia had strong tolerance to dietary Cd, the weight gain rate and specific growth rate could be restrained significantly in 200 mg/kg Cd group. And the activities of amylase and protease were decreased in 50 mg/kg group significantly, the activity of lipase decreased only in 400 mg/kg group.
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