日粮中铜胁迫对吉富罗非鱼幼鱼抗氧化、脂质过氧化及肝脏组织结构的影响

Effects of Dietary Copper Stress on Antioxidation,Lipid Peroxidation and Tissue Structure of Liver in Juvenile GIFT Tilapia( Oreochromis niloticus)

吉富罗非鱼是我国南方沿海地区水产养殖中的主要经济鱼类之一,但近年来,随着我国城镇化和工业化进程的推进,罗非鱼养殖面临着前所未有的铜富集的挑战。为探明日粮中铜胁迫对吉富罗非鱼幼鱼抗氧化系统和肝脏组织结构的影响,将1 080条罗非鱼幼鱼暴露于6个浓度梯度(0、3、30、300、1 000、3 000 mg·kg-1)的高铜日粮中,通过60 d的暴露试验,实时测定罗非鱼血清与肝脏抗氧化能力,监测肝脏病理变化。结果表明,在本试验条件下,罗非鱼幼鱼血清和肝脏中MDA的含量随日粮中铜含量的增加和胁迫时间的延长显著升高,而SOD、GSH-PX和Cu Zn-SOD的活性表现出先升高后降低的趋势;各组间肝脏表现出不同程度的病变,主要是浊肿变性和脂肪变性,且第Ⅲ、Ⅳ、Ⅴ组肝脏病变严重。综上,日粮中铜胁迫对吉富罗非鱼幼鱼的抗氧化机能有较明显的抑制作用,长时间的暴露能严重损伤其肝脏的组织结构,因此,建议吉富罗非鱼幼鱼日粮中铜的实际含量应控制在42.36 mg·kg-1以下。

GIFT tilapia is an important economic species in aquaculture production in coastal regions in south of China, where is now facing an increasing challenge from Cu contamination with accelerated urbanization and industrialization. In order to evaluate the effects of dietary Cu stress on antioxidant activity and liver structure of juvenile GIFT tilapia, a total of 1 080 fishes were fed with 6 different concentrations of Cu in diets （0, 3, 30,300, 1 000, 3 000 mg.kg-1） for 60 days. Antioxidation of serum and liver was measured, and the pathological changes of liver were observed. The results showed that the concentration of MDA in serum and liver increased significantly with exposure time and the increase of Cu accumulation in diets. Activities of SOD, CuZn-SOD and GSH-PX showed a down trend afler a rise. Meanwhile, cloudy swelling and fatty degeneration in ceils of liver was observed, especially pathological changes of liver aggravated when Cu concentration was increased to groupⅢ , Ⅳ and V. It could be concluded that dietary Cu stress depressed the antioxidant activity and damaged the liver oftilapia. Therefore, we suggest that Cu concentration in diets for juvenile tilapia should not be more than 4236 mg.kg-1.