盐度对刀鲚生长、抗氧化应激和渗透压调节能力的影响

Influence of salinity on the growth, digestive ability, antioxidant ability and osmoregulation of Coilia nasus

为研究不同养殖水体盐度对刀鲚(Coilia nasus)生长性能、抗氧化应激、渗透压调节能力的影响,选用初始体重为15.31±1.78g的刀鲚为研究对象,设置2个盐度实验组(5、10)和一个淡水对照组,每组3个重复,开展了为期135d的养殖试验。结果表明,在第50d和第135d时,刀鲚的增重率、特定生长率均未受到养殖盐度的显著影响(P>0.05);淡水组刀鲚肠道淀粉酶和脂肪酶在第50d和第135d时显著高于盐度组(P<0.05);而3个组的胃蛋白酶没有显著差异(P>0.05);淡水刀鲚肝脏过氧化氢酶(CAT)和超氧化物歧化酶(SOD)酶活性在第50d显著低于盐度组(P<0.05),在第135d显著高于盐度组(P<0.05),而盐度组之间差异不显著(P>0.05);淡水组肝脏丙二醛(MDA)含量一直显著低于盐度组(P<0.05),盐度组之间差异不显著(P>0.05);在养殖第50d刀鲚鳃Na^+K^+-ATP酶(NKA)酶含量10‰最高,而淡水组最低,且3个组之间都有显著差异(P<0.05),而养殖到第135d 3个组之间并无显著差异(P>0.05)。综上,基于对刀鲚的生长性能、抗氧化应激和渗透压调节能力的检测,人工繁育的刀鲚能够在低盐的环境中正常生长;本研究推荐根据刀鲚的洄游特性进行养殖盐度的调控,即养殖前期使用淡水,养殖后期使用低浓度盐水。

Coilia nasus is a migration fish species. It, spends its early life stage in freshwater and swimswims to the sea to grow up. This fish species is, and a highly potential aquaculture candidate in China. Because of overfishing and environmental impact, it has been endangering ed since 2007. Under the efforts of Freshwater Fisheries Research Center, its artificial breeding had broken through. For it ecological characteristics, salinity is a very important factor that influences their life cycle. However, there is not any report regarding its their culture in salt water. We designed an experiment to investigate the effect of different salinities on the growth, digestive ability, antioxidant ability and osmoregulation of C. nasus(body weight: 15.31 1.78 g). Fish individuals were randomly assigned to one of three salinities(0, 5 and 10 salinity). The results indicated that no significant differences wasere observed in final body weight, weight gain, and specific growth rate of fish growing fed at different salinities on days 50 and 135(P>0.05). Fish reared in freshwater had higher activities y on day 50 and 135 in amylase(AMS) and lipase(LPS)(P<0.05). But no significant differences wasere found in pPepsin(P>0.05). Fish reared in freshwater showed lower the activity in contents and catalase activities of catalase(CAT) and superoxide dismutase(SOD) on day 50, but higher activities y on day 135(P<0.05). Fish reared in freshwater showed a lower malondialdehyde(MDA) content than those of the salinity groups, but MAD was not significant different(P>0.05) between the 5 and 10 groups. Fish from 10 salinity group had the highest Na^+K^+-ATP enzyme activity, while those fish from freshwater group showed the lowest NKA enzyme activity(P<0.05) on day 50, but no significant difference was found on day 135. In conclusion, C.nasus can grow normally in salinity environment. In this study, we recommended that regulating the salinity in the cultivation of C.nasus should be regulated according to its migratory characteristics, i.e., using freshwater in the early stage of cultivation and lowering salinity atin the late stage of cultivation.