温度对小黄鱼体内抗氧化酶及消化酶活性的影响

摘要

Small yellow croaker,Larimichthys polyactis ,is an important marine fish species and widely distributed throughout the Bohai Sea,the Yellow Sea,and the East China Sea of the Northwest Pacific Ocean.To investigate the effect of water temperature on L.polyactis,the survival,activities of antioxidant enzymes (i.e.Superoxide dismutase,SOD,and Catalase,CAT )and digestive enzymes (i.e.Lipase,LPS,and Amylase,AMS)of 4.5 month-old L.polyactis at different temperatures (27℃,29℃,31℃,32℃ and 33℃)were compared.The results showed that the mortality rate of L.polyactis was zero at the temperatures of 27℃,29℃,and 31℃,and the mortality was 16.67% at the temperature of 32℃.Nevertheless,the survival rate was 75.56% at the temperature of 33℃.This study indicated that the temperature of 32℃ may be the upper limit for L.polyactis.The water temperature significantly affected the activities of antioxidant and digestive enzymes of liver and intestine of L. polyactis(except the activities of intestine CAT ).The SOD,CAT ,LPS and AMS activities increased and then de-clined with increasing water temperature in the temperature range of 27-33℃.A quadratic regression was fit to describe the relationship between the SOD,CAT ,LPS,AMS activities and the water temperature,and only the R2 of regression models of liver and intestine LPS and temperature were higher than 0.85 (R2 was 0.89 and 0.93 respectively),which were meaningful.Moreover,SOD and CAT activities in liver were higher than those of intes-tine.Conversely,LPS and AMS activities in liver were lower than those of intestine.There were highly significant correlation between the body weight and LPS activities of liver.There were high activities of antioxidant and diges-tive enzymes and high survival rate of L.polyactis at the temperature of 29℃ and 31℃,which means those tem-peratures conductive to culture L.polyactis.Those results would be good references for healthy culture of L. polyactis.%为了深入了解不同温度条件下小黄鱼的应激反应，为小黄鱼的人工养殖提供参考。本次研究以人工繁殖的4．5月龄小黄鱼为研究对象，采用不同水温（27℃、29℃、31℃、32℃、33℃）进行养殖，以此确定小黄鱼的高温致死温度，并检测不同养殖水温条件下小黄鱼肝脏和肠道中抗氧化酶（超氧化物歧化酶 SOD、过氧化氢酶 CAT ）和消化酶（脂肪酶 LPS、淀粉酶 AMS）的活性，比较小黄鱼不同组织中4种酶活性的变化情况。结果显示，32℃的养殖水温为小黄鱼的初始致死温度；养殖温度对小黄鱼肝脏和肠道中几种酶的活性均存在显著影响（P ＜0．05）：抗氧化酶和消化酶活性均随着养殖水温的升高呈现先升高后下降的趋势（除了肠道中的 CAT ）。另外，肝脏中抗氧化酶活性强于消化酶，而肠道中则相反，表明肝脏侧重于机体免疫反应，而肠道更侧重于食物消化。通过二次项回归方程拟合了温度与酶活性的回归方程，只有肝脏和肠道中的 LPS 活性与温度的回归方程有意义，决定系数 r2分别为0．89和0．93（在0．85以上）。此外，肝脏中 LPS 活性与实验鱼体质量呈极显著正相关关系（P ＜0．01），研究结果为小黄鱼专用配合饲料的研发提供了重要参考。研究还得出，养殖水温29℃和31℃时，进行小黄鱼养殖可取得较好效果，研究结果可为小黄鱼快速养成提供指导。