TY - JOUR
T1 - Bioenergetics and RNA/DNA ratios in the common carp (Cyprinus carpio) under hypoxia
AU - Zhou, B. S.
AU - Wu, R. S.S.
AU - Randall, D. J.
AU - Lam, P. K.S.
N1 - Funding Information:
Acknowledgements We would like to thank the Agriculture and Fisheries Department, Hong Kong, for supplying the experimental fish. This research was supported by the Research Grants Council of Hong Kong. (No. 9040387). Experiments in this study comply with the current law of Hong Kong, SAR, China.
PY - 2001
Y1 - 2001
N2 - Hypoxia caused by eutrophication occurs over large areas in aquatic systems worldwide. Common carp (Cyprinus carpio) exposed to hypoxia (1 mg · O2 · 1-1 and 2 mg · O2 · 1-1) for 1 week showed a significant reduction in feeding rate, respiration rate, faecal production and nitrogenous excretion compared to those maintained at normoxia (7 mg · O2 · 1-1). Fish exposed to hypoxia showed negative scope for growth (SfG), but no significant difference in the specific growth rate was revealed after 1 week in both hypoxic groups. A significant reduction in RNA/DNA ratio was, however, clearly evident in the white muscle of the 1 mg · O2 · 1-1 treatment group, but not in the 2 mg · O2 · 1-1 treatment group. Both specific growth rate and RNA/DNA ratio were significantly reduced when fish were exposed to severe hypoxia (0.5 mg · O2 · 1-1) for 4 weeks. At all levels of hypoxia, growth reduction was accompanied by a significant decrease in RNA/DNA ratio in white muscle. Covariance analysis showed no significant difference between the slope of RNA/DNA ratio and growth rate under normoxic conditions and 0.5 mg · O2 · 1-1 for 4 weeks (F = 1.036, P > 0.326), as well as 1.0 mg · O2 · 1-1 and 2.0 mg · O2 · 1-1 for 1 week (F = 0.457, P > 0.5), indicating that the RNA/DNA ratio serves as a biomarker of growth under all oxygen levels, at least under controlled experimental conditions. SfG also appears to be more sensitive than the RNA/DNA ratio in responding to hypoxia in fish.
AB - Hypoxia caused by eutrophication occurs over large areas in aquatic systems worldwide. Common carp (Cyprinus carpio) exposed to hypoxia (1 mg · O2 · 1-1 and 2 mg · O2 · 1-1) for 1 week showed a significant reduction in feeding rate, respiration rate, faecal production and nitrogenous excretion compared to those maintained at normoxia (7 mg · O2 · 1-1). Fish exposed to hypoxia showed negative scope for growth (SfG), but no significant difference in the specific growth rate was revealed after 1 week in both hypoxic groups. A significant reduction in RNA/DNA ratio was, however, clearly evident in the white muscle of the 1 mg · O2 · 1-1 treatment group, but not in the 2 mg · O2 · 1-1 treatment group. Both specific growth rate and RNA/DNA ratio were significantly reduced when fish were exposed to severe hypoxia (0.5 mg · O2 · 1-1) for 4 weeks. At all levels of hypoxia, growth reduction was accompanied by a significant decrease in RNA/DNA ratio in white muscle. Covariance analysis showed no significant difference between the slope of RNA/DNA ratio and growth rate under normoxic conditions and 0.5 mg · O2 · 1-1 for 4 weeks (F = 1.036, P > 0.326), as well as 1.0 mg · O2 · 1-1 and 2.0 mg · O2 · 1-1 for 1 week (F = 0.457, P > 0.5), indicating that the RNA/DNA ratio serves as a biomarker of growth under all oxygen levels, at least under controlled experimental conditions. SfG also appears to be more sensitive than the RNA/DNA ratio in responding to hypoxia in fish.
KW - Bioenergetics
KW - Biomarker
KW - Hypoxia
KW - RNA/DNA ratio
KW - Scope for growth
UR - http://www.scopus.com/inward/record.url?scp=0035135035&partnerID=8YFLogxK
U2 - 10.1007/s003600000149
DO - 10.1007/s003600000149
M3 - Article
C2 - 11263726
AN - SCOPUS:0035135035
SN - 0174-1578
VL - 171
SP - 49
EP - 57
JO - Journal of Comparative Physiology - B Biochemical, Systemic, and Environmental Physiology
JF - Journal of Comparative Physiology - B Biochemical, Systemic, and Environmental Physiology
IS - 1
ER -