盐度对长江刀鲚幼鱼非特异性免疫酶和消化酶活力的影响

以人工繁育的长江刀鲚Coilia nasus幼鱼(体质量为2.12 g±0.88 g)为对象,研究了盐度对其肝脏非特异性免疫酶和胃、肠、盲囊消化酶活力的影响。试验设6个盐度(3、6、9、12、15、18)处理组,每组设3个平行,每个平行放养50尾鱼,试验共进行55 d。结果表明:盐度为15时,长江刀鲚幼鱼肝脏酸性磷酸酶(ACP)和碱性磷酸酶(AKP)活力均处于最低值,分别为104.77、60.72 U/g,盐度为18时,肝脏ACP活力显著高于其他盐度组(P0.05);超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活力随盐度变化的趋势相同,与谷胱甘肽过氧化物酶(GSH-PX)活力变化趋势相反,盐度对肝脏CAT活力无显著性影响(P0.05);相同盐度下,肠淀粉酶(AMS)、脂肪酶(LPS)、蛋白酶(胃蛋白酶PPS、胰蛋白酶TPS)活力比胃和盲囊高,胃LPS活力明显低于盲囊和肠;盐度为9时盲囊LPS活力以及盐度为15时肠TPS活力出现最大值;相同盐度下,不同消化组织AMS活力总体上为肠盲囊胃,盐度为12时,各消化组织AMS活力处于较低水平,盐度为15时,各消化组织AMS活力整体处于相对较高水平。根据盐度对不同组织不同酶活力的影响规律,得出适宜长江刀鲚生存的盐度为12~15。

Effects of salinity on activities of non-specific immune and digestive enzymes in juvenile estuarine tapertail anchovy Coilia nasus

An experiment was conducted to investigate effects of various salinities on activities of non-specific im-mune and digestive enzymes in liver, stomach, intestine and caecum of juvenile estuarine tapertail anchovy Coilia nasus(body weight 2. 12 g±0. 88 g). Juvenile estuarine tapertail anchovy with body weight of (2. 12±0. 88) g was reared in a 1 t tank at a rate of 50 fish at a salinity of 3, 6, 9, 12,15 and 18 for 55 days with triplication. Results showed that there were the minimal activities of acid phosphatase (ACP) (104. 77 U/g) and alkaline phosphatase ( AKP) (60. 72 U/g) in liver of the fish at a salinity of 15, significantly higher ACP activity in liver at a salinity of 18 than at other salinities(P<0. 05). The same trend was observed in the changes in activities of superoxide dis-mutase ( SOD) and catalase ( CAT) as the salinity was elevated, while the opposite case was found in activity of glutathione peroxidase (GSH-PX),without significant difference in CAT activity. There were higher activities of amylase( AMS) , lipase( LPS) and trypsin( TPS) in intestine than in stomach and caecum, significantly lower LPS activity in stomach than in intestine and caecum, with the maximal activities of LPS in caecum and of TPS in intes-tine at a salinity of 9 (P<0. 05). At the same salinity, the order of amylase activity was ranged in descending order as intestine>caecum>stomach, and the relatively lower amylase activities in different digestive organs were observed at a salinity of 12 and higher at a salinity of 15 , indicating that 12-15 is of the optimal salinity for juvenile estuar-ine tapertail anchovy.