低溶解氧对凡纳滨对虾酚氧化酶原激活系统和相关免疫因子的影响

EFFECTS OF HYPOXIC ON THE PROPHENOLOXIDASE SYSTEM AND RELATED DEFENCE PARAMETERS IN LITOPENAEUS VANNAMEI

本文研究了凡纳滨对虾在低溶解氧条件下酚氧化酶原系统的激活机制。结果表明:低溶氧(1.5mg/L,3.0mg/L)胁迫对凡纳滨对虾血淋巴中多巴胺含量、血细胞数量、酚氧化酶原激活系统相关酶活力、血淋巴中类α2-巨球蛋白活力影响显著(P<0.05),且各指标表现出明显的时间效应性。在实验时间内,DO为3.0mg/L处理组,总血细胞、小颗粒细胞和透明细胞数量均在12h内降低而后趋于稳定,大颗粒细胞数量在24h内降低后保持稳定,DO为1.5mg/L处理组,总血细胞数量和三类血细胞数量均在24h内降低而后趋于稳定;DO为3.0mg/L和1.5mg/L处理组凡纳滨对虾血淋巴中多巴胺含量分别在24h、12h内呈峰值变化,至12h、6h时达到最大值,在24h、12h后恢复至对照组水平并趋于稳定;血细胞中酚氧化酶原活力分别在12h、6h时显著降低,且均在24h时趋于稳定;丝氨酸蛋白酶活力在6h时均显著降低,在24h时达到最低值,而后趋于稳定,蛋白酶抑制剂活力显著降低,但类α2-巨球蛋白活力48h内呈峰值变化,与对照组比较均显著升高,48h后趋于稳定。实验期内对照组DO为5.5mg/L各指标变化不显著。

Hypoxic conditions （1.5mg/L, 3.0mg/L） were shown to have a significant effect on dopamine （DA） concentration, haemocyte count, the proPO system, and α2-M activity in the white shrimp Litopenaeus vannamei （P〈0.05）. Total haemocyte count （THC）, hyaline cells count, and semi-granular cells count were lowest at 12h; granular cells count was low- est at 24h in the experimental group 3.0mg/L. In the experimental group 1.5rag/L, total haemocyte count （THC）, and differential haemocyte count （DHC） were lowest at 24h. In the group 3.0 mg/L, and 1.5 mg/L DA concentration in haemolymph showed peak-value changes before 24h and 12h, and reached the maximum at 12h and 6h, then recovered to the control level at 24h, 12h; the phenoloxidase activity of haemocyte exhibited a decrease tend- ency before 12h, 6h, and recovered to the control level at 24h; serine proteases （SP） activity showed significant decrease before 6h and reached the minimum at 24h, then recovered to the control level, proteinase inhibitor（PI） decreased significantly, but α2-M activity peaked be- fore 48h, and all showed remarkable decrease compare with the control group, and then sta- bilized after 48h.