Skilbrei Ove Tommy, Espedal Per Gunnar, Nilsen Frank, Garcia Enrique Perez, Glover Kevin A
Institute of Marine Research, PO Box 1870 Nordnes, Bergen 5817, Norway.
Dis Aquat Organ. 2015 Apr 8;113(3):187-94. doi: 10.3354/dao02832.
Experimental releases of Atlantic salmon smolts treated with emamectin benzoate (EB) against salmon lice have previously been used to estimate the significance of salmon lice on the survival of migrating smolts. In recent years, the salmon louse has developed reduced sensitivity to EB, which may influence the results of such release experiments. We therefore tested the use of 2 anti-lice drugs: EB was administered to salmon smolts in high doses by intra-peritoneal injection and the prophylactic substance EX (SubEX) was administered by bathing. A third, untreated control group was also established. Salmon were challenged with copepodids of 2 strains of salmon lice (1 EB-sensitive strain and 1 with reduced EB-sensitivity) in mixed-group experimental tanks. At 31 d post-challenge, the numbers of pre-adult lice on treated fish were around 20% compared with the control fish, with minor or no differences between the 2 treatments and lice strains. Both treatments therefore appeared to give the smolts a high degree of protection against infestation of copepodids of salmon lice. However, significantly lower growth of the EB-treatment group indicates that bathing the fish in SubEX is less stressful for smolts than intra-peritoneal injection of EB.
先前曾通过实验性放流用苯甲酸盐阿维菌素（EB）处理过的大西洋鲑幼鱼来对抗鲑虱，以此评估鲑虱对洄游幼鱼生存的影响。近年来，鲑虱对EB的敏感性降低，这可能会影响此类放流实验的结果。因此，我们测试了两种抗虱药物的使用：通过腹腔注射给鲑幼鱼高剂量的EB，并通过浸浴使用预防性物质EX（SubEX）。还设立了第三个未处理的对照组。在混合组实验水箱中，让鲑鱼接触两种鲑虱菌株的桡足幼体（1种对EB敏感的菌株和1种对EB敏感性降低的菌株）。在攻毒后31天，处理组鱼体上的未成熟虱数量约为对照组鱼的20%，两种处理方法和虱菌株之间差异很小或没有差异。因此，两种处理方法似乎都能为幼鱼提供高度保护，防止其受到鲑虱桡足幼体的侵扰。然而，EB处理组的生长显著较低，这表明用SubEX浸浴鱼对幼鱼造成的压力小于腹腔注射EB。
