TY - JOUR
T1 - Effects of premature seawater transfer and fasting on plasma growth hormone levels of yearling coho salmon (Oncorhynchus kisutch) parr
AU - Varnavsky, Vladimir S.
AU - Sakamoto, Tatsuya
AU - Hirano, Tetsuya
N1 - Funding Information:
Oleg N. Saravanskya nd SanaeH asegawaa ided in conductingt he experiment.F inancial assistancef or this study was provided in part by a fellowship from the Japan Society for the Promotion of Science, and also by grants-in-aidf or scientific researchf rom the Ministry of Education, Science and Culture, and also from the Fisheries Agency, Japan.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1995/10/1
Y1 - 1995/10/1
N2 - The influence of starvation and premature seawater transfer on plasma growth hormone (GH) concentration in yearling coho salmon parr, was studied. Juveniles were separated into four groups: (1) unfed fish in fresh water (FW), (2) fed fish in FW, (3) unfed fish in sea water (SW) (24%.), (4) fed fish in SW. Plasma sodium concentration, GH and cortisol levels were analyzed after 0, 1, 3, 4, 5 weeks of exposure. Hypoosmoregulatory ability seemed to be impaired after long-term exposure of the juveniles to SW: after 5 weeks, plasma sodium concentrations in SW groups were significantly higher than those in FW groups. The cortisol levels increased slightly in response to transfer from FW to SW as well as to starvation. Plasma GH levels were elevated in unfed FW fish but not in unfed SW fish after 3, 4, and 5 weeks of starvation. In fed SW groups, the increase of plasma GH levels was greater than that of the unfed FW groups. Analysis of variances of plasma GH levels showed the influence of salinity to be greater than that of fasting. It is suggested that the main reason for the high GH levels in 'stunted' salmon may arise from premature transfer to SW rather than from starvation.
AB - The influence of starvation and premature seawater transfer on plasma growth hormone (GH) concentration in yearling coho salmon parr, was studied. Juveniles were separated into four groups: (1) unfed fish in fresh water (FW), (2) fed fish in FW, (3) unfed fish in sea water (SW) (24%.), (4) fed fish in SW. Plasma sodium concentration, GH and cortisol levels were analyzed after 0, 1, 3, 4, 5 weeks of exposure. Hypoosmoregulatory ability seemed to be impaired after long-term exposure of the juveniles to SW: after 5 weeks, plasma sodium concentrations in SW groups were significantly higher than those in FW groups. The cortisol levels increased slightly in response to transfer from FW to SW as well as to starvation. Plasma GH levels were elevated in unfed FW fish but not in unfed SW fish after 3, 4, and 5 weeks of starvation. In fed SW groups, the increase of plasma GH levels was greater than that of the unfed FW groups. Analysis of variances of plasma GH levels showed the influence of salinity to be greater than that of fasting. It is suggested that the main reason for the high GH levels in 'stunted' salmon may arise from premature transfer to SW rather than from starvation.
KW - Oncorhynchus kisutch
KW - Plasma growth hormone
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U2 - 10.1016/0044-8486(95)01001-7
DO - 10.1016/0044-8486(95)01001-7
M3 - Article
AN - SCOPUS:0001223915
SN - 0044-8486
VL - 135
SP - 141
EP - 145
JO - Aquaculture
JF - Aquaculture
IS - 1-3
ER -