TY - JOUR
T1 - Effects of growth hormone transgenesis on metabolic rate, exercise performance and hypoxia tolerance in tilapia hybrids
AU - McKenzie, DJ
AU - Martinez, R
AU - Morales, A
AU - Acosta, J
AU - Morales, R
AU - Taylor, Edwin
AU - Steffensen, JF
AU - Estrada, MP
PY - 2003/8/1
Y1 - 2003/8/1
N2 - 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. (C) 2003 The Fisheries Society of the British Isles.
AB - 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. (C) 2003 The Fisheries Society of the British Isles.
KW - lactate
KW - oxygen uptake
KW - citrate synthase
KW - maximum metabolic rate
KW - critical swimming speed
KW - aerobic scope
U2 - 10.1046/j.1095-8649.2003.00162.x
DO - 10.1046/j.1095-8649.2003.00162.x
M3 - Article
SN - 0022-1112
VL - 63
SP - 398
EP - 409
JO - Journal of Fish Biology
JF - Journal of Fish Biology
IS - 2
ER -