黄鳍金枪鱼体质量与消化酶和免疫相关酶活性的关系研究

Relationship between body mass and activities of digestive enzymes and immune-related enzymes of juvenile yellowfin tuna(Thunnus albacares)

为积累黄鳍金枪鱼(Thunnus albacares)幼鱼陆基循环水养殖基础数据,测定了不同体质量的黄鳍金枪鱼幼鱼血清、肌肉、肝脏、胃、肠道等组织的酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、淀粉酶、脂肪酶、蛋白酶等活性。结果显示,ACP活性在各组织中由高至低为肠道>肌肉>肝脏>血清,AKP活性则为肠道>肝脏>肌肉>血清。随着体质量的增加,ACP活性在肌肉、肠道和肝脏组织中差异较小,而AKP活性在肝脏中呈逐渐上升的趋势,且相邻两组间差异显著(P<0.05),其在肠道、肌肉中呈波动性变化;黄鳍金枪鱼幼鱼消化酶活性整体稳定,组间差异不显著(P>0.05),仅在体质量达1000 g时肠道胰蛋白酶活性显著下降(P<0.05),随后小范围浮动,组间差异不显著(P<0.05)。综上,ACP和AKP活性在黄鳍金枪鱼幼鱼组织中较高且稳定,这种稳定的高活性模式可保证机体对磷(P)高效分解、吸收、再利用,提供对外源物的持续免疫力;黄鳍金枪鱼在养殖期间营养需求稳定,且蛋白质需求旺盛。

In order to accumulate the land-based recirculating aquaculture basic data of juvenile yellowfin tuna(Thunnus albacares),we studied the activities of acid phosphatase(ACP),alkaline phosphatase(AKP),amylase,lipase and protease in the serum,muscle tissue,liver,stomach,intestine and other tissues of the juveniles of different body mass.The ACP activity showed a descending order of intestine>muscle>liver>serum,while the AKP activity showed a descending order of intestine>liver>muscle>serum.With the increase of body mass,there was little difference in the ACP activity in muscle,intestine and liver,while the AKP activity in liver increased gradually,and there was significant difference between the two adjacent groups(P<0.05).In general,the digestive enzyme activity of the larvae was stable,without significant difference between the groups(P>0.05).Only when the body mass reached 1000 g,the intestinal trypsin activity decreased significantly(P<0.05),and then floated in a small range,without significant difference between the groups(P<0.05).In conclusion,the ACP and AKP activities are high and sta-ble in the tissues of juvenile T.albacares,which ensures stable functions for the decomposition,absorption and reuse of phos-phorus(P)and immunity to external substances;during the breeding period of T.albacares,the nutritional demand is stable and the protein demand is strong.