温度和盐度对半滑舌鳎幼鱼消化酶活性的影响

Studies on the Specific Activities of Digestive Enzymes of Cynoglossus semilaevis Günther at Different Salinities and Temperatures

以半滑舌鳎(Cynoglossus semilaevis Günther)幼鱼为实验对象,分别设置3个盐度水平(22、26和30)和4个温度水平(18,21,24和27℃),采用酶活性分析的方法比较研究了在不同温度和盐度的养殖环境下,半滑舌鳎肝胰脏和肠道内不同部位蛋白酶、淀粉酶和脂肪酶3种消化酶活性的差异。结果表明,盐度和温度对半滑舌鳎消化酶活性影响均显著(P<0.05)。不同温度和盐度组合下,3种消化酶活性变化有所差异。总体比较,肝胰脏和肠道内3种消化酶比活力均以盐度26、温度21和24℃组合下活性较高。在相同温度和盐度下,肝胰脏和肠道的不同部位的3种消化酶活性有所差异,其中,蛋白酶比活力以肝胰脏和后肠最高,显著高于前肠和中肠(P<0.05);淀粉酶比活力以肝胰脏内最高,各肠段之间淀粉酶比活力差异不显著(P>0.05);淀粉酶比活力也以肝胰脏内最高,其次分别为前肠、后肠和中肠,各部位脂肪酶比活力差异显著(P>0.05)。本研究发现半滑舌鳎幼鱼体内淀粉酶比活力相对比较高,说明半滑舌鳎幼鱼对淀粉具有较强的消化能力,建议在配制半滑舌鳎幼鱼饲料时可适当提高淀粉比例,以降低饲料成本。

Variations of specific activities of protease, amylase and lipase in foregut, midgut, hindgut, liver and pancreas of juvenile tongue-sole Cynoglossus semilaevis Gunther were studied at different salinities（22, 26, 30） and temperatures（18, 21,24, 27 ℃ ）. The results showed that temperature and salinity had significant effects on specific activities of digestive enzymes（P 〈 0.05）. Generally, the specific activity was higher when the temperature was 21 ℃ and 24 12 and the salinity was 26. At the same temperature and salinity conditions, the specific activities of the digestive enzymes in intestines and pancreas were different. The highest protease specific activities occurred in liver and hindgut, and in foregut and midgut the specific activity was in lower level and the difference between them was not significant when analyzed by one way ANOVA（P 〉0.05）. The specific activity of amylase in liver was significantly higher than that in intestines（P 〈 0.05）; however, the difference in different intestines was not significant （P〉0.05）. The specific activity of lipase was different in the intestines and pancreas, and the rank from high to low was live, foregut, hindgut and midgut; the difference be- tween them was significant（P 〈 0.05）. The research indicated that juvenile tongue-sole had strong ability to digest the starch, while the specific activity of amylase was comparatively higher. It was suggested that in the feeding process, the proportion of starch can be appropriately increased to reduce the costs and improve aquiculture benefits.