养殖密度对循环水系统中大菱鲆生长和蛋白质代谢的影响

摘要

在工厂化循环水养殖系统中,将初始体质量为186 g±2.0 g的大菱鲆(Scophthalmus maximus)放养于低(9.4 kg/m2±0.2 kg/m2)、中(13.6 kg/m2±0.8 kg/m2)、高(19.1 kg/m2±1.3 kg/m2)3个养殖密度,以研究不同养殖密度对大菱鲆生长、消化酶和蛋白质代谢的影响.养殖120 d后,低、中、高试验组养殖密度分别增长至26.1 kg/m2±1.2 kg/m2、38.2 kg/m2±2.5 kg/m2、52.3 kg/m2±3.6 kg/m2.结果表明:低密度组和中密度组中大菱鲆增质量率、特定生长率、肥满度和蛋白质效率均显著(P<0.05)高于高密度组;而饲料系数显著低于高密度组(P<0.05).低密度组和中密度组大菱鲆总蛋白酶和淀粉酶活力显著低于高密度组(P<0.05);但脂肪酶活力在3个密度组之间无显著性差异.与低密度组相比,高密度组显著提高了谷氨酸脱氢酶活力,同时降低了谷草转氨酶和亮氨酸氨肽酶活力(P<0.05),而对谷丙转氨酶活力无任何影响.综上所述,在工厂化循环水系统中,增加养殖密度能提高养殖的产量,但过高的养殖密度会对大菱鲆生长、消化酶活力以及蛋白质代谢产生不利的影响.%The aim of this study was to evaluate the effect of stocking density on growth, digestive enzyme activity, and protein metabolism of turbot (Scophthalmus maximus L.) with an initial body weight of (186 ± 2.0) g in a re-circulating aquaculture system (RAS). In this experiment, turbot were reared at three different initial densities (low 9.4 kg/m2 ± 0.2 kg/m2, medium 13.6 kg/m2 ± 0.8 kg/m2, and high 19.1 kg/m2 ± 1.3 kg/m2) for 120 days. Final den-sities were 26.1 kg/m2 ± 1.2 kg/m2, 38.2 kg/m2 ± 2.5 kg/m2, and 52.3 kg/m2 ± 3.6 kg/m2, respectively. The result shows that fish held at the highest density showed a lower (P < 0.05) weight gain rate (WGR), specific growth rate (SGR), condition factor (CF), and protein efficiency ratio (PER) at the conclusion of the study than fish held at lower densities, but the highest density group had a higher (P < 0.05) feed coefficient rate (FCR) than fish held at lower densities. The total protease (TMP) and amylase (AMS) activities of the highest density group were signifi-cantly higher (P < 0.05) than those of the lower density groups, and the three groups did not differ significantly in lipase (LPS) activities. As stocking densities increased, the glutamate dehydrogenase (GDH) activities were sig-nificantly increased and the aspartate transaminase (AST) and leucine aminopeptidase (LAP) activities were sig-nificantly decreased, but the alanine transaminase (ALT) activities were not significantly affected by density. We conclude that increasing stocking density can improve production in a RAS, but high stocking density may impact growth, digestive enzyme activity, and protein metabolism.