白斑综合征病毒卵黄抗体对凡纳滨对虾免疫相关酶活力和抗病毒能力的影响

Effects of lg-Guard(shrimp) on immunity-related enzyme activities and WSSV resistance of Litopenaeus vannamei

免疫活性物质可以调动或激活虾类自身的免疫系统,提高动物的免疫机能,增强动物的抗病毒能力。实验通过连续投喂的方法,用3个水平(1%、0.5%、0.1%)的Ig-Guard(shrimp)制成的试验饲料,同时以基础饲料为空白对照饲喂凡纳滨对虾(Litopenaeus vannamei)20 d,分别测定了第5,10,15,20天血淋巴的酚氧化酶(PO)、溶菌酶(UL)、酸性磷酸酶(ACP)及肌肉匀浆液的超氧化物歧化酶(SOD)等非特异性免疫因子活性,并对血清及肌肉匀浆液中蛋白进行定量。结果表明,免疫组的PO、UL、ACP、SOD活力均显著高于对照组(P<0.05)。免疫20d后,用白斑综合征病毒(WSSV)投喂感染。攻毒后第7天各免疫组的相对免疫保护率分别为17.95%、23.08%、35.90%。实验结果说明,Ig-Guard(shrimp)能有效提高对虾免疫因子的活性,对于提高抗WSSV感染能力也有一定作用。将对虾免疫因子活性和累计死亡率协同分析,摄食低浓度Ig-Guard(shrimp)组较之高浓度组的酶活力高,其累计死亡率低,建议适当地投喂低浓度Ig-Guard(shrimp)更为合理。

Immunoreactive substances can stimulate the immune system of shrimps, and enhance the immunocompetence of animal. The influence of egg yolk immunoglobulin on the immunity-related enzyme activities and WSSV resistance of shrimps has not been reported. In this research, we fed basic diets containing three levels （ 1% , 0. 5% , 0. 1% ） （ M/M ） of Ig-Guard （ shrimp ） to Litopenaeus vannamei continuously for 20 days, and the basic diets as blank control. Then phenoloxidase （ PO）, acid phosphatase （ACP） and lysozyme（UL） activities of the serum and superoxide dismutase（SOD） activity of the muscle, and protein concentration of the serum and the muscle were detected on days 5, 10, 15 and 20. All the immune parameters of the test groups measured were higher （ P 〈 0.05 ） than the control group. After 20 days, we fed white spot syndrome virus （WSSV） to shrimps, and recorded the mortalities of challenging test in seven days. The relative percent survival（RPS） value of the test groups was 17.95%, 23.08% , 35.90%. This experiment indicates that Ig-Guard （shrimp） can effectively enhance the shrimps＇ immunity-related enzyme activities, and it can also promote shrimps＇ WSSV resistance. Based on the results of immunityrelated enzyme activities and cumulative mortality, the enzyme activities of the lower concentration group was higher than those of the higher concentration group, and its cumulative mortality was lower, so this paper suggests that to feed the lower concentration Ig-Guard（shrimp） properly is reasonable.