|Appears in Collections:||Aquaculture Journal Articles|
|Peer Review Status:||Refereed|
|Title:||Relationships between environmental changes, maturity, growth rate and plasma insulin-like growth factor-I (IGF-I) in female rainbow trout|
Porter, Mark J R
Bromage, Niall R
|Citation:||Taylor J, Porter MJR, Bromage NR & Migaud H (2008) Relationships between environmental changes, maturity, growth rate and plasma insulin-like growth factor-I (IGF-I) in female rainbow trout, General and Comparative Endocrinology, 155 (2), pp. 257-270.|
|Abstract:||Size reflecting growth rate, energy balance or nutritional status is regarded as an important determinant of the ability of trout to undergo puberty. The relationship of a change in photoperiod, either natural (SNP) or advancing (ADV), with growth, IGF-I and reproduction was investigated in virgin female rainbow trout. Under SNP 63% of the population attained maturity while only 29% spawned 6 months in advance in the ADV regime. Under SNP both size and growth rate in late spring-early summer appeared to determine whether an individual may initiate reproduction while condition factor appeared to be a better predictor in the ADV regime. A complete seasonal relationship between plasma IGF-I, daylength and temperature was demonstrated under natural conditions, and provides direct evidence for the relationship between reproduction and IGF-I. Conversely, trout maintained under ADV exhibited a significantly different plasma IGF-I profile relative to those under a natural photoperiod. Furthermore, IGF-I levels accurately reflected growth rate prior to elevations in sex steroids, suggesting that IGF-I may provide an endocrine signal between the somatotropic and reproductive axes that growth rate and/or size is sufficient to initiate gonad development. In addition, maturing individuals under SNP typically expressed higher circulating IGF-I levels than those that remained immature and may reflect a greater opportunity for IGF-I to act on the pituitary to stimulate gonadotropin production. We observed elevated levels in maturing fish for 3 months under SNP compared to only I month under ADV were observed. This may reflect a reduction in the window of opportunity to initiate reproduction under advancing photoperiods and hence explain the reduction in fish successfully recruited.|
|Rights:||The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study.|
|General and Comparative Endocrinology 2008.pdf||321.95 kB||Adobe PDF||Under Permanent Embargo Request a copy|
Note: If any of the files in this item are currently embargoed, you can request a copy directly from the author by clicking the padlock icon above. However, this facility is dependent on the depositor still being contactable at their original email address.
This item is protected by original copyright
Items in the Repository are protected by copyright, with all rights reserved, unless otherwise indicated.
If you believe that any material held in STORRE infringes copyright, please contact email@example.com providing details and we will remove the Work from public display in STORRE and investigate your claim.