卤虫无节幼体的营养强化对半滑舌鳎稚鱼生长、消化酶及相关激素水平的影响

Effects of nutrition enriched Artemia nauplii on growth, digestive enzyme and associated hormones in tongue sole Cynoglossus semilaevis postlarvae

中文关键词: 蛋氨酸  半滑舌鳎  稚鱼  消化酶  胆囊收缩素

英文关键词: Methionine  Cynoglossus semilaevi  Postlarvae  Digestive enzyme  Cholecystokinin

中文摘要:

      通过投喂经蛋氨酸及裂壶藻强化的卤虫，研究其对半滑舌鳎稚鱼(初始体长1.67±0.14cm)生长性能、主要消化酶活性(淀粉酶、胃蛋白酶、类胰蛋白酶)、碱性磷酸酶活性及胆囊收缩素(CCK)、甲状腺素(T4)、三碘甲状腺原氨酸(T3)和皮质醇浓度的影响。试验设3个实验组(蛋氨酸组、裂壶藻组和蛋氨酸加裂壶藻组)，分别投喂经蛋氨酸、裂壶藻及蛋氨酸+裂壶藻强化的卤虫，对照组投喂未经强化的卤虫。试验进行16d，每4d取样1次。结果显示，裂壶藻组的体长和体重在试验结束时处于最高水平，体重显著高于对照组(P<0.05)，体长在12d时显著高于其他组(P<0.05)。裂壶藻组碱性磷酸酶活力在16d时显著高于蛋氨酸组和对照组，类胰蛋白酶活力在16d时显著高于其他组(P<0.05)，T3含量在12d时显著高于蛋氨酸组及对照组，T4水平在12d时显著高于对照组(P<0.05)。蛋氨酸加裂壶藻组淀粉酶活力在12d时显著高于蛋氨酸组(P<0.05)。对照组的CCK含量在4d时显著高于蛋氨酸组和蛋氨酸加裂壶藻组(P<0.05)，12d显著高于3个实验组，16d时显著高于裂壶藻组(P<0.05)。蛋氨酸组的皮质醇含量在4d时显著低于其他3个试验组(P<0.05)，8d和16d时显著低于对照组及蛋氨酸加裂壶藻组(P<0.05)。其碱性磷酸酶、淀粉酶活力及T4和T3水平在试验前期都较高，说明蛋氨酸强化的卤虫投喂对半滑舌鳎稚鱼的生长及激素水平有较微弱的促进作用，可能是由于卤虫无节幼体含有的蛋氨酸基本可以满足鱼体生长需要。

英文摘要:

      Effects of methionine enriched Artemia nauplii on growth performance, main digestive enzymes (amylase, acid protease, and alkali protease) activity, alkaline phosphatase activity and concentration of digestion related hormones (cholecystokinin, thyroxin, triiodothyronine, and cortisol) in Cynoglossus semilaevis Günter (initial length 167±014cm) were studied. Three groups of postlarvae, including methionine group, Schizochytrium group, and methionine+Schizochytrium group, were fed Artemia nauplii enriched with methionine, Schizochytrium, and methionine+Schizochytrium respectively.A control group was fed Artemia nauplii without enrichment. Larvae were cultured for 16 days， sampled and tested at 4 day intervals. Postlarvae in the Schizochytrium treatment showed the highest growth at the end of the experiment；their weight was significantly greater than the control(P<005), and their length was significantly greater than other treatments at 12d. Alkaline phosphatase activity in Schizochytrium treatment was significantly greater than the methionine treatment and the control at 16d (P<0.05), and their alkali protease activity was significantly greater than the other treatments at 16d (P<0.05). The concentration of triiodothyronine (T3) in Schizochytrium treatment was significantly higher than the methionine treatment and the control at 12d (P<0.05). Thyroxin (T4) content in Schizochytrium treatment was significantly greater than the control at 12d (P<0.05). Amylase activity in methionine+Schizochytrium treatment was significantly greater than the methionine treatment at 12d (P<0.05). CCK level of the control was significantly higher than methionine+Schizochytrium treatment and methionine treatment at 4d (P<0.05), and was significantly higher than the other treatments or Schizochytrium treatment at 12d and 16d. No significant differences were found in acid protease activity between four different treatments. Cortisol levels of methionine treatment was significantly lower than the other treatments at 4d, and significantly lower than the control and methionine+Schizochytrium treatment at 8d and 16d (P<0.05). However, alkaline phosphatase, amylase activity, T3 and T4 levels were higher at the earlier stages of the experiment. It is suggested that methionine enriched Artemia nauplii feeding can meet the growth requirement of C. semilaevis larvae.