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Effects of growth hormone transgenesis on metabolic rate, exercise performance and hypoxia tolerance in tilapia hybrids
Author(s) -
McKenzie D. J.,
Martínez R.,
Morales A.,
Acosta J.,
Morales R.,
Taylor E. W.,
Steffensen J. F.,
Estrada M. P.
Publication year - 2003
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 - 10.1046/j.1095-8649.2003.00162.x
Subject(s) - tilapia , biology , respirometry , anaerobic exercise , hypoxia (environmental) , oreochromis , metabolic rate , aquaculture , zoology , oxygen , endocrinology , fishery , fish <actinopterygii> , biochemistry , physiology , chemistry , organic chemistry
Swimming respirometry was employed to compare inactive metabolic rate ( R r ), maximum metabolic rate ( R max ), resultant aerobic scope and maximum sustainable (critical) swimming speed ( U crit ), in growth hormone transgenic (GHT) and wild‐type (W) tilapia Oreochromis sp. hybrids. Although the R r of GHT tilapia was significantly (58%) higher than their W conspecifics, there were no significant differences in their net aerobic scope because GHT tilapia exhibited a compensatory increase in R max that was equal to their net increase in R r . As a consequence, the two groups had the same U crit . The GHT and W tilapia also exhibited the same capacity to regulate oxygen uptake during progressive hypoxia, despite the fact that the GHT fish were defending a higher demand for O 2 . The results indicate that ectopic expression of GH raises metabolic rate in tilapia, but the fish compensate for this metabolic load and preserve such physiological determinants of fitness as aerobic scope, swimming performance and tolerance of hypoxia.