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Exposure to continuous light disrupts retinal innervation of the preoptic nucleus during parr-smolt transformation in Atlantic salmon

Ebbesson, Lars O. E.; Ebbesson, Sven O. E.; Nilsen, Tom O.; Stefansson, Sigurd O. and Holmqvist, Bo LU (2007) 7th International Workshop on Salmonid Smoltification In Aquaculture 273(2-3). p.345-349
Abstract
High quality salmon smolts are essential for aquaculture, enhancement programs and wild populations. However, intensification of aquaculture smolt production and changes in natural habitats can cause sub-optimal environmental conditions, which may result in poor smolt quality. The salmon brain, as the integrator of environmental information, plays a focal role in relaying this information through the light-brain-pituitary axis, which includes retinal and pineal innervation of the hypothalamus. Here we investigated the effect of rearing juvenile Atlantic salmon, Salmo salar, under constant light (LL) on optic nerve fiber growth into the hypothalamus. This was compared with the normal increased fiber growth in fish reared under a... (More)
High quality salmon smolts are essential for aquaculture, enhancement programs and wild populations. However, intensification of aquaculture smolt production and changes in natural habitats can cause sub-optimal environmental conditions, which may result in poor smolt quality. The salmon brain, as the integrator of environmental information, plays a focal role in relaying this information through the light-brain-pituitary axis, which includes retinal and pineal innervation of the hypothalamus. Here we investigated the effect of rearing juvenile Atlantic salmon, Salmo salar, under constant light (LL) on optic nerve fiber growth into the hypothalamus. This was compared with the normal increased fiber growth in fish reared under a simulated-natural photoperiod (LDN). Parr were sampled from the LDN group in February and from the LDN and LL groups in May (peak smolt status for the LDN group). Retinohypothalamic projections to the preoptic area were traced using 1, 1'-dioctadecyl-3,3, 3,3-tetramethylindocarbocyanine perchlorate (DiI) and confocal laser scanning microscopy. Data showed that parr exposed to LL did not develop the same extensive retinal innervation to the preoptic nucleus (NPO) observed in control salmon smolts raised under LDN. Since the cells in NPO are central pituitary regulatory neurones, the increased retinohypothalamic innervation during normal smoltification may be responsible for the increased endocrine response to photoperiod information. The deprivation of photoperiod information, during continuous light exposure, may inhibit the natural developmental program to proceed during the parr-smolt transformation. (C) 2007 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
in
Aquaculture
volume
273
issue
2-3
pages
345 - 349
publisher
Elsevier
conference name
7th International Workshop on Salmonid Smoltification
external identifiers
  • wos:000252346700020
  • scopus:36549006412
ISSN
1873-5622
0044-8486
DOI
10.1016/j.aquaculture.2007.10.016
language
English
LU publication?
yes
id
f6dbc10c-84ac-4716-946f-8d14d66cf996 (old id 1407721)
date added to LUP
2009-05-29 13:25:48
date last changed
2017-01-01 04:42:51
@inproceedings{f6dbc10c-84ac-4716-946f-8d14d66cf996,
  abstract     = {High quality salmon smolts are essential for aquaculture, enhancement programs and wild populations. However, intensification of aquaculture smolt production and changes in natural habitats can cause sub-optimal environmental conditions, which may result in poor smolt quality. The salmon brain, as the integrator of environmental information, plays a focal role in relaying this information through the light-brain-pituitary axis, which includes retinal and pineal innervation of the hypothalamus. Here we investigated the effect of rearing juvenile Atlantic salmon, Salmo salar, under constant light (LL) on optic nerve fiber growth into the hypothalamus. This was compared with the normal increased fiber growth in fish reared under a simulated-natural photoperiod (LDN). Parr were sampled from the LDN group in February and from the LDN and LL groups in May (peak smolt status for the LDN group). Retinohypothalamic projections to the preoptic area were traced using 1, 1'-dioctadecyl-3,3, 3,3-tetramethylindocarbocyanine perchlorate (DiI) and confocal laser scanning microscopy. Data showed that parr exposed to LL did not develop the same extensive retinal innervation to the preoptic nucleus (NPO) observed in control salmon smolts raised under LDN. Since the cells in NPO are central pituitary regulatory neurones, the increased retinohypothalamic innervation during normal smoltification may be responsible for the increased endocrine response to photoperiod information. The deprivation of photoperiod information, during continuous light exposure, may inhibit the natural developmental program to proceed during the parr-smolt transformation. (C) 2007 Elsevier B.V. All rights reserved.},
  author       = {Ebbesson, Lars O. E. and Ebbesson, Sven O. E. and Nilsen, Tom O. and Stefansson, Sigurd O. and Holmqvist, Bo},
  booktitle    = {Aquaculture},
  issn         = {1873-5622},
  language     = {eng},
  number       = {2-3},
  pages        = {345--349},
  publisher    = {Elsevier},
  title        = {Exposure to continuous light disrupts retinal innervation of the preoptic nucleus during parr-smolt transformation in Atlantic salmon},
  url          = {http://dx.doi.org/10.1016/j.aquaculture.2007.10.016},
  volume       = {273},
  year         = {2007},
}