盐度对褐菖鲉幼鱼生长、体成分、消化和抗氧化酶活力的影响

Effects of salinity on growth,body composition,digestive enzyme and antioxidant enzyme activities of juvenile Sebastisucus Marmoratus

以人工繁育的褐菖鲉幼鱼[(3. 65±0. 82) g]为研究对象,设置7. 5、10、15、20、25、30共6个盐度梯度,进行为期8周的养殖试验。通过测定其体成分、消化酶(胃蛋白酶,胰蛋白酶,淀粉酶,脂肪酶)活性及抗氧化酶(过氧化氢酶,总超氧化物歧化酶,谷胱甘肽过氧化物酶)活性,研究盐度对褐菖鲉幼鱼体成分、消化能力和非特异免疫能力的影响。结果显示,褐菖鲉幼鱼在盐度为10、15和20的水体中均生长良好,存活率均大于90%。幼鱼的粗脂肪和粗蛋白均随盐度增加呈先升高后降低的趋势,并在盐度为23. 05和19. 07时达到理论最大值,而随盐度增加,水分则呈下降趋势。各组间脂肪酶活力均无显著差异(P> 0. 05),盐度在15、20时淀粉酶活力较低,盐度为15时显著低于盐度为30时(P <0. 05)。胃蛋白酶和胰蛋白酶活力均随盐度变化呈先降后升的趋势,盐度在7. 5-20时,胰蛋白酶和胃蛋白酶活力较高,25时最低。幼鱼体内3种抗氧化酶活力呈先升高后降低再升高的变化趋势,各组间谷胱甘肽过氧化物酶活性均无显著差异(P> 0. 05)。总超氧化物歧化酶和过氧化氢酶活性在盐度20、25时较低,其他组间均无显著差异(P> 0. 05)。综上,褐菖鲉幼鱼最适宜盐度为20左右。

In this experiment,6 salinity gradients(7.5,10,15,20,25,30)were set up to carry out a 8-week culture test with artificially juvenile Sebastisucus marmoratus[(3.65±0.82)g],and the content of body composition,the activity of digestive enzymes(amylase,pepsin,trypsin,lipase)or antioxidant enzymes(total superoxide dismutase,glutathione peroxidase,catalase)were determined.The effects of salinity on the composition,digestion and non-specific immunity of juvenile Sebastisucus marmoratus were studied.The results showed that juvenile fish grew well in water bodies with salinity of 10,15 and 20,and the survival rate was greater than 90%.The moisture content of young fish decreased with the increase of salinity,while crude protein and crude fat increased first and then decreased with the increase of salinity,and reached the theoretical maximum value when the salinity was 23.05 and 19.07.There was no significant difference in lipase activity(P>0.05)in the visceral of young fish between groups,while amylase activity was lower in salinity 15 and 20 groups and significantly lower at 15 than 30(P<0.05).The changes of pepsin and trypsin activity decreased first and then increased with the change of salinity.In the range of salinity 7.5—20,pepsin and trypsin activity were higher,and decreased at 25.The activity of 3 kinds of antioxidant enzymes in young fish had the tendency of increasing first and then decreasing,and there was no significant difference in glutathione peroxidase activity between groups(P>0.05).The activity of superoxide dismutase and catalase was lower in salinity 20、25,and there was no significant difference between other salinity groups(P>0.05).Therefore,the most suitable salinity for juvenile Sebastisucus marmoratus is about 20.