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Chronic stress of rainbow trout Oncorhynchus mykiss at high altitude: a field study
Author(s) -
Hunt von Herbing I.,
Pan T.C. F.,
MéndezSánchez F.,
GarduñoPaz M.,
HernándezGallegos O.,
RuizGómez M. L.,
RodríguezVargas G.
Publication year - 2015
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/jfb.12710
Subject(s) - rainbow trout , biology , zoology , effects of high altitude on humans , antioxidant , antioxidant capacity , altitude (triangle) , hypoxia (environmental) , trout , oxidative stress , endocrinology , fishery , oxygen , fish <actinopterygii> , chemistry , biochemistry , anatomy , geometry , mathematics , organic chemistry
The stress response of Oncorhynchus mykiss in high‐altitude farms in central Mexico was investigated over two seasons: the cool (9·1–13·7° C) dry winter season, and the warmer (14·7–15·9° C), wetter summer season. Fish were subjected to an acute stress test followed by sampling of six physiological variables: blood cortisol, glucose, lactate, total antioxidant capacity, haemoglobin concentration and per cent packed cell volume ( V PC %). Multivariate analyses revealed that lactate and total antioxidant capacity were significantly higher in the summer, when water temperatures were warmer and moderate hypoxia (4·9–5·3 mg l −1 ) prevailed. In contrast, plasma cortisol was significantly higher in the winter (mean ± s.e .: 76·7 ± 4·0 ng ml −1 ) when temperatures were cooler and dissolved oxygen levels higher (6·05–7·9 mg l −1 ), than in the summer (22·7 ± 3·8 ng ml −1 ). Haemoglobin concentrations (mg dl −1 ) were not significantly different between seasons, but V PC % was significantly higher in the summer (50%) than in the winter (35%). These results suggest that in summer, effects of high altitude on farmed fish are exacerbated by stresses of high temperatures and hypoxia, resulting in higher blood lactate, increased total antioxidant capacity and elevated V PC % levels.