The salmon louse Lepeophtheirus salmonis, a type of sea lice (family Caligidae), is enzootic in marine waters of British Columbia and poses a health risk to both farmed Atlantic Salmon Salmo salar and wild Pacific salmon Oncorhynchus spp. At the adult stage, sea lice infections can often result in severe cutaneous lesions in their salmonid hosts. To evaluate and compare the physiological consequences of adult L. salmonis infections, smolts of Atlantic Salmon and Sockeye Salmon O. nerka were exposed to 2 (low), 6 (medium), or 10 (high) adult female lice/fish. Mean lice abundance decreased over time in all groups. Skin disruption due to parasite infection was observed in both species. Plasma samples were collected from infected fish and uninfected controls at 1, 3, 5, and 7 d postinfection and measured for indicators of osmoregulatory function and stress. Sockeye Salmon, regardless of L. salmonis exposure level, showed a rapid onset of elevated osmolality and sodium and chloride ion concentrations which were sustained until 7 d postinfection when values returned to levels comparable with the unexposed controls. Conversely, these effects were not measured in Atlantic Salmon. Additionally, differential host effects in blood glucose levels were observed, with Sockeye Salmon displaying immediate elevation in glucose. Relative to Atlantic Salmon, infection with L. salmonis caused a profound physiological impact to Sockeye Salmon characterized by loss of osmoregulatory integrity and a stress response. This work provides the first comprehensive report of the physiological consequences of infections with adult L. salmonis in Sockeye Salmon smolts and helps to further define the mechanisms of susceptibility in this species.

中文翻译：

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成年鲑鱼虱对红鲑鱼和大西洋鲑鱼生理反应的差异影响

鲑鱼虱 Lepeophtheirus palmis 是一种海虱（Caligidae 科），在不列颠哥伦比亚省的海水中流行，对养殖的大西洋鲑鱼和野生太平洋鲑鱼 Oncorhynchus spp 构成健康风险。在成年阶段，海虱感染通常会导致鲑鱼宿主的严重皮肤损伤。为了评估和比较成年鲑鱼感染的生理后果，大西洋鲑鱼和红鲑鱼的小鲑鱼暴露于 2（低）、6（中）或 10（高）成年雌性虱子/鱼。所有组的平均虱子丰度都随着时间的推移而下降。在两个物种中都观察到寄生虫感染导致的皮肤破裂。在第 1、3、5、3 天从受感染的鱼和未受感染的对照中收集血浆样本。和感染后 7 天，并测量渗透调节功能和压力的指标。红鲑鱼，无论 L.salmonis 暴露水平如何，都显示出渗透压和钠离子和氯离子浓度升高的快速开始，这种情况一直持续到感染后 7 天，当值恢复到与未暴露的对照组相当的水平时。相反，在大西洋鲑鱼中没有测量到这些影响。此外，观察到不同宿主对血糖水平的影响，红鲑鱼显示葡萄糖立即升高。相对于大西洋鲑鱼，鲑鱼感染对红鲑鱼造成了深远的生理影响，其特征是渗透压调节完整性丧失和应激反应。这项工作提供了第一个关于成年 L. 感染的生理后果的综合报告。