Regional Research Centre of CIFA, Hesarghatta, Bangalore 560 089, India.
Vet Parasitol. 2012 Nov 23;190(1-2):297-304. doi: 10.1016/j.vetpar.2012.05.010. Epub 2012 May 19.
The efficacy of two avermectins, doramectin and ivermectin via oral and parenteral routes and their prophylactic effects against Argulus siamensis infestation in Indian major carp, Labeo rohita was studied. Doramectin and ivermectin were fed once to L. rohita sub-adults naturally infested with A. siamensis parasites at graded levels of 1000, 750 and 500 μg/kg body weight and 500, 300 and 200 μg/kg body weight, respectively. The mean time of clearance of parasites was 24 ± 0.149 h for 1000 and 24 ± 0.210 h for 750 μg of doramectin/kg body weight fish, however, the dose of 1,000 μg resulted in adverse reactions and mortality in fish. A single dose of 500μg/kg body weight of ivermectin also cleared the infestation in 24 ± 0.258 h. In second experiment, L. rohita naturally infested with A. siamensis were administered with doramectin and ivermectin intramuscularly as single dose of 200, 150 and 100 μg/kg body weight. Both doramectin and ivermectin at 200 μg/kg body weight cleared the infestation in 4 ± 0.149 and 4 ± 0.258 h respectively, however, those resulted in adverse reactions viz., black pigmentation, lethargy and poor appetite in fish. The mean time of clearance of parasites from fish was 6 ± 0.210 and 12 ± 0.314 h for doramectin and ivermectin, respectively, when given at a lower dose of 150 μg/kg body weight. The prophylactic effects of both drugs were also evaluated by challenging naïve rohu with metanaupliar larvae of A. siamensis after feeding the fish single dose of the doramectin and ivermectin at 750 and 500 μg/kg body weight, respectively. The effects of both the drugs were found to last for 17-18 days. The effects of bath treatment with doramectin and ivermectin at different concentrations on adult A. siamensis and metanaupliar larvae of A. siamensis were also evaluated. The results suggested that ivermectin could act more rapidly compared to doramectin. However, detailed studies on the toxicity and pharmacokinetics of doramectin and ivermectin upon their administration to aquatic organisms and the environmental impacts of their usage are required to be undertaken before finally recommending the safe use of these drugs for control of parasitic infections.
本研究评估了两种阿维菌素类药物——多拉菌素和伊维菌素经口服和注射途径给药的疗效及其对印度鲤（Labeo rohita）三叶虫感染的预防作用。多拉菌素和伊维菌素分别以 1000、750 和 500μg/kg 体重以及 500、300 和 200μg/kg 体重的剂量喂食自然感染三叶虫寄生虫的成年印度鲤亚成体。1000μg/kg 体重的多拉菌素和 750μg/kg 体重的多拉菌素分别在 24±0.149h 和 24±0.210h 时清除寄生虫，然而，该剂量会导致鱼类出现不良反应和死亡。伊维菌素的单次剂量为 500μg/kg 体重，也能在 24±0.258h 内清除寄生虫。在第二个实验中，自然感染三叶虫的印度鲤被肌肉注射多拉菌素和伊维菌素，剂量分别为 200、150 和 100μg/kg 体重。多拉菌素和伊维菌素的单剂量为 200μg/kg 体重时，寄生虫在 4±0.149h 和 4±0.258h 内被清除，但这两种药物都会导致鱼类出现不良反应，如黑色素沉着、嗜睡和食欲不振。当剂量降低至 150μg/kg 体重时，多拉菌素和伊维菌素清除寄生虫的平均时间分别为 6±0.210h 和 12±0.314h。在给鱼喂食多拉菌素和伊维菌素的单剂量 750μg/kg 体重和 500μg/kg 体重后，用三叶虫的幼体桡足类幼虫感染未感染的罗非鱼，评估了这两种药物的预防效果。结果表明，与多拉菌素相比，伊维菌素的效果更快。然而，在最终推荐这些药物安全用于控制寄生虫感染之前，还需要对其在水生生物中的毒性和药代动力学以及使用它们对环境的影响进行详细研究。
