Cheng Winton, Wang Ching-Hsien, Chen Jiann-Chu
Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung, Taiwan 912, ROC.
Dis Aquat Organ. 2003 Dec 3;57(1-2):151-5. doi: 10.3354/dao057151.
This work is part of a continuing series of investigations on the effect of commonly used aquaculture chemicals on the immune resistance and susceptibility of the giant freshwater prawn Macrobrachium rosenbergii to Lactococcus garvieae. The methodology has been described in earlier publications of the series. Potassium permanganate at 1.0 mg l(-1) in tryptic soy broth (TSB) had no effect on the growth rate of L. garvieae. The mortality of M. rosenbergii challenged with 4 x 10(6) colony-forming units (cfu) prawn(-1) of TSB-grown L. garvieae was significantly greater than that of challenged controls. Addition of potassium permanganate at 1.0 mg l(-1) in TSB significantly increased the virulence of L. garvieae to M. rosenbergii. Exposure of M. rosenbergii to potassium permanganate prior to challenge with TSB-grown L. garvieae at 4 x 10(6) and 3 x 10(6) cfu prawn(-1) revealed that 96 h mortality was significantly lower for prawns held in water containing 0.3 mg l(-1) of the chemical than for prawns in water containing 1.0 mg l(-1) or no chemical. Potassium permanganate caused no significant changes in total hemocyte counts and differential hemocyte counts, compared to the control treatments. However, a concentration of 1.0 mg l(-1) or more for 96 h resulted in decreased phenoloxidase activity, phagocytic activity and clearance efficiency. Respiratory burst increased with exposure to 0.3 mg l(-1). In conclusion, treatment with potassium permanganate at 0.3 mg 1(-1) was effective in reducing M. rosenbergii mortality from L. garvieae infection, but higher concentrations had a negative effect, probably due to reduced prawn defenses.
本研究是关于常用水产养殖化学品对罗氏沼虾免疫抗性及对加氏乳球菌易感性影响的一系列持续调查的一部分。该系列早期出版物中已描述了研究方法。胰蛋白胨大豆肉汤（TSB）中1.0 mg l(-1)的高锰酸钾对加氏乳球菌的生长速率没有影响。用TSB培养的加氏乳球菌4×10(6) 菌落形成单位（cfu）/虾对罗氏沼虾进行攻毒，其死亡率显著高于攻毒对照组。在TSB中添加1.0 mg l(-1)的高锰酸钾显著增加了加氏乳球菌对罗氏沼虾的毒力。在用TSB培养的加氏乳球菌4×10(6) 和3×10(6) cfu/虾攻毒前，将罗氏沼虾暴露于高锰酸钾中，结果显示，与含有1.0 mg l(-1)或不含该化学品的水中的虾相比，含有0.3 mg l(-1)该化学品的水中的虾96小时死亡率显著更低。与对照处理相比，高锰酸钾对总血细胞计数和不同类型血细胞计数没有显著影响。然而，1.0 mg l(-1)及以上浓度处理96小时会导致酚氧化酶活性、吞噬活性和清除效率降低。暴露于0.3 mg l(-1)时呼吸爆发增加。总之，0.3 mg 1(-1)的高锰酸钾处理可有效降低罗氏沼虾因加氏乳球菌感染导致的死亡率，但较高浓度有负面影响，可能是由于虾的防御能力下降。
