Aquat. Living Resour.
Volume 13, Number 3, May 2000
|Page(s)||139 - 144|
|Published online||15 May 2000|
Effect of long-term pinealectomy on growth and precocious maturationin Atlantic salmon, Salmo salar parr
Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden
Accepted: 15 May 2000
While the pineal organ in poikilothermic vertebrates consistently influences a number of physiological processes, its precise role, and what controlling signal (hormonal and/or neural) is abolished by its removal, is still uncertain. For this reason, the effect of long-term pinealectomy (PINX) on seasonal growth and reproductive development was investigated in Atlantic salmon, Salmo salar, parr. Mean daytime plasma melatonin level in the control, sham-operated and PINX fish was 35 pg·mL–1 in all groups, while mean night-time levels were 296, 255 and 25 pg·mL–1, respectively, indicating that PINX abolished the natural nocturnal rise in melatonin. Pinealectomy did not influence the incidence or timing of early sexual maturation in the male parr. However, pinealectomy significantly affected growth, its effect being boldly seasonally dependent. Compared to sham-operated and control fish, pinealectomized fish showed significantly lower specific growth rates (SGRs) during the period of lengthening photoperiod up until the summer solstice. Thereafter, corresponding to the season of decreasing photoperiods, the pinealectomized fish exhibited higher SGRs. These results suggest a functional relationship between the pineal organ and somatic growth in the Atlantic salmon, although what controlling signal from the pineal (melatonin or neural) is involved has yet to be determined.
Key words: pineal organ / pinealectomy / melatonin / growth / reproduction / Salmo salar
© Elsevier, Inra, Ifremer, Cemagref, Ird, Cnrs, 2000
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.