密度胁迫对凡纳滨对虾稚虾免疫指标及生长的影响

Effects of stocking density on immune parameters and growth of juvenile Litopenaeus vannamei

将体长为(3.59±0.26)cm的凡纳滨对虾(Litopenaeus vannamei)按1 800尾.m-3、1 500尾.m-3和1 200尾.m-3的密度分别饲养在注水0.3 m3的圆形玻璃纤维桶(容量为0.5 m3)中30 d,检测了基本水质因子、对虾肝胰腺和肌肉组织中的酚氧化酶(PO)活力、超氧化物歧化酶(SOD)活力、抗菌活力(Ua)、碱性磷酸酶(AKP)活力、体质量增长和成活率,研究了不同放养密度对凡纳滨对虾稚虾免疫指标及生长的影响。统计分析发现,试验过程中水体理化因子均在适宜范围,各处理间水质因子的差异不显著;对虾的PO活力、Ua和AKP活力均随着密度的增加而降低,SOD活力则反之;对虾的体质量增长、体质量特定增长率和成活率随着密度的增加而降低,成活率差异显著(P<0.05)。结果表明,凡纳滨对虾(体长<4.8 cm或体质量<1.2 g)在密度为1 200～1 800尾.m-3时,密度胁迫可明显影响其免疫指标和生长。

In order to investigate the effects of different stocking density on the immune parameters and growth of juvenile Litopenaeus vannamei,we cultured the shrimps [body length（3.59±0.26） cm] in 0.3 m3 fiberglass tanks（water volume 0.5 m3） at 1 800 ind · m-3,1 500 ind · m-3 and 1 200 ind · m-3,respectively,for 30 d to determine the phenoloxidase（PO） activity,superoxide dismutase（SOD） activity,antibacterial activity（Ua）,alkaline phosphatase（AKP） activity in hepatopancreas and muscle,as well as weight gain,survival and basic water quality factors.It is showed that the physical and chemical factors vary within suitable range with no significant difference.The PO activity,Ua and AKP activity in the muscle of shrimp reduce while SOD activity increases with the increase of stocking density.The weight gain,special weight growth rate（SGRw） and survival reduce with the increasing stocking density with significant difference in survival（P〈0.05）.The results indicate that stocking density may obivously affect the growth and immune parameters of juvenile L.vannamei（body length〈4.8 cm or body weight〈1.2 g） when stocking density is within 1 200~1 800 ind · m-3.