Artículo
Chronic stress of rainbow trout Oncorhynchus mykiss at high altitude: a field study
Autor
Hunt von Herbing, Ione;#0000-0003-4335-6878
Pan, Francis;#0000-0002-1550-4581
GARDUÑO PAZ, MONICA VANESSA; 220811
Hernández Gallegos, Oswaldo; 36845
MENDEZ SANCHEZ, JOSE FERNANDO; 80843
Ruiz Gómez, María de Lourdes; 220569
Rodríguez Vargas, Georgina;x1345674
Hunt von Herbing, Ione
Pan, Francis
GARDUÑO PAZ, MONICA VANESSA
Hernández Gallegos, Oswaldo
MENDEZ SANCHEZ, JOSE FERNANDO
Ruiz Gómez, María de Lourdes
Rodríguez Vargas, Georgina
Institución
Resumen
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 (VPC%). 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 mgl−1) prevailed. In contrast, plasma cortisol was significantly higher in the winter (mean±s.e.: 76⋅7±4⋅0 ngml−1) when temperatures were cooler and dissolved oxygen levels higher (6⋅05–7⋅9 mgl−1), than in the summer (22⋅7±3⋅8 ngml−1 ). Haemoglobin concentrations (mg dl−1) were not significantly different between seasons, but VPC% 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 VPC% levels.