不同盐度对斜带石斑鱼幼鱼生长和生理的影响

Effects of Different Salinities on Growth and Physiology of Orange-Spotted Grouper, Epinephelus coioides

设置6、12、18、24、30等5个盐度梯度,在循环水养殖条件下饲养体质量56±7.2 g(平均值±标准差,下同)、的斜带石斑鱼幼鱼65 d,研究工厂化养殖条件下,盐度对斜带石斑鱼幼鱼生长、渗透压调节、消化酶活性等的影响。结果表明:盐度12和18组的特定生长率分别为(0.80±0.05)%/d(0.77±0.07)%/d,显著高于其他盐度组(P<0.05),且两者的特定生长率差异不显著(P>0.05);盐度12和18组饵料系数分别为1.20±0.08、1.16±0.03,显著低于其余盐度组(P<0.05),两者的饵料系数差异不显著(P>0.05);鳃丝Na+-K+-ATP酶活性在盐度12时最低;消化酶活性在盐度24时最高;血清中谷草转氨酶(GOT)活性在盐度6时活性最高,其余盐度组之间差异不显著(P>0.05);盐度12与18组血清超氧化物歧化酶(SOD)活性和溶菌酶(lysozyme)活性显著高于其他组(P<0.05)。综合各盐度条件下的生长、饵料转化、生理变化情况,适当降低盐度可提高斜带石斑鱼养殖效益。

Effects of different salinities on growth and physiology of orange-spotted grouper（Epinephelus coioides） reared in recirculating systems was studied.Juvenile orange-spotted groupers,with initial weight 56 ± 7.2 g（mean ± standard error,and the same below）at five different levels of salinity（6,12,18,24 and 30） for 65 days.The special growth rate（SGR） of the grouper at salinity of 12 and 18 was 0.80 ± 0.05 %/d and 0.77 ± 0.07 %/d,respectively,and were significantly higher compared to other groups（P 0.05）.The food conversion ratio of the grouper at salinity of 12 and 18 was 1.20 ± 0.08 and 1.16 ± 0.03,respectively,and were significantly lower compared to other groups（P 0.05）,but there was no significant difference between group of salinity 12 and 18 in special growth rate and food conversion ratio（P 0.05）.The Na＋-K＋-ATPase activity in gill of the grouper reared at salinity 12 was significantly lower than other groups（P 0.05）.The digestive enzyme activity of group of salinity 24 was significantly higher than other groups（P 0.05）.Glutamic-oxaloacetic transaminase（GOT） activity in blood was significantly higher at salinity 6,and there was no significant difference among the groups of salinity 12,18,24 and 30（P 0.05）.Superoxide dismutase（SOD） and lysozyme activity in blood at salinity 12 and 18 were significantly higher than other groups（P 0.05）.Farming economics could be improved by rearing orange-spotted grouper at lower salinities,with respect to growth rate,food conversion and physiology.