Repeated acute stress reduces growth rate of Atlantic salmon parr and alters plasma levels of growth hormone, insulin-like growth factor I and cortisol
Sd. Mccormick et al., Repeated acute stress reduces growth rate of Atlantic salmon parr and alters plasma levels of growth hormone, insulin-like growth factor I and cortisol, AQUACULTURE, 168(1-4), 1998, pp. 221-235
Atlantic salmon (Salmo salar) parr were subjected to acute handling stresse
s and growth-monitored for at least 30 days. In fish stressed twice daily,
growth rate in weight was 61% lower than controls after 11 days (1.00 vs. 2
.57% day(-1)) and over a 30 day period it was 50% lower than controls (1.53
vs. 3.07% day(-1)). In fish stressed once daily, growth rate was 18% lower
than controls after 10 days (2.17 vs. 2.63% day(-1)) and over a 30-day per
iod it was 34% lower than controls (1.71 vs. 2.59% day(-1)). In fish stress
ed once daily, food consumption was reduced by 62% and 37% after 17 and 37
days, respectively. At the end of 40 days of acute stress once daily, contr
ol and stressed fish were sampled 1 h prior to, 3 and 7 h after a stress ev
ent. Plasma growth hormone levels were significantly higher in the stressed
group than in the controls prior to and 7 h after stress. Plasma insulin-l
ike growth factor I (IGF-I) levels were higher in the stressed group only 3
and 7 h after stress. Plasma cortisol levels were lower in the stressed gr
oup prior to and 3 h after stress. The results indicate that acute stressor
s decrease growth of Atlantic salmon parr, with increasing frequency of str
ess having a more rapid and greater effect. (C) 1998 Elsevier Science B.V.
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