Physiological and endocrine changes in Atlantic salmon smolts during hatchery rearing, downstream migration, and ocean entry

2013 ◽  
Vol 70 (1) ◽  
pp. 105-118 ◽  
Author(s):  
Stephen D. McCormick ◽  
Timothy F. Sheehan ◽  
Björn Thrandur Björnsson ◽  
Christine Lipsky ◽  
John F. Kocik ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Condition Factor ◽  
Anthropogenic Impacts ◽  
Downstream Migration ◽  
Endocrine Function ◽  
Plasma Growth Hormone ◽  
Data Set ◽  
Hatchery Fish ◽  
Igf I ◽  
Freshwater Habitats

Billions of hatchery salmon smolts are released annually in an attempt to mitigate anthropogenic impacts on freshwater habitats, often with limited success. Mortality of wild and hatchery fish is high during downstream and early ocean migration. To understand changes that occur during migration, we examined physiological and endocrine changes in Atlantic salmon (Salmo salar) smolts during hatchery rearing, downstream migration, and early ocean entry in two successive years. Gill Na+/K+-ATPase activity increased in the hatchery during spring, increased further after river release, and was slightly lower after recapture in the ocean. Plasma growth hormone levels increased in the hatchery, were higher in the river, and increased further in the ocean. Plasma IGF-I remained relatively constant in the hatchery, increased in the river, then decreased in the ocean. Plasma thyroid hormones were variable in the hatchery, but increased in both river- and ocean-captured smolts. Naturally reared fish had lower condition factor, gill NKA activity, and plasma thyroxine than hatchery fish in the river but were similar in the ocean. This novel data set provides a vital first step in understanding the role and norms of endocrine function in smolts and the metrics of successful marine entry.

Parr-smolt transformation in Atlantic salmon: thyroid hormone deiodination in liver and brain and endocrine correlates of change in rheotactic behavior

2000 ◽  
Vol 78 (5) ◽  
pp. 696-705 ◽  
Author(s):  
Jennifer L Specker ◽  
J Geoffrey Eales ◽  
Masatomo Tagawa ◽  
William A Tyler, III
Keyword(s):  
Atlantic Salmon ◽  
Activity Ratio ◽  
Condition Factor ◽  
Major Change ◽  
Downstream Migration ◽  
High Ratio ◽  
Natural Photoperiod ◽  
The Brain ◽  
Behavior Condition ◽  
Turbidity Increase

We tested the hypothesis that metabolism of thyroid hormones by the brain of Atlantic salmon (Salmo salar) changes when rheotactic behavior reverses during parr-smolt transformation (PST). We measured brain and liver thyroxine (T4) and 3,5,3'-triiodo-L-thyronine (T3) outer-ring deiodination (ORD) and inner-ring deiodination (IRD) activities and plasma T4 and T3 levels in Atlantic salmon held under natural photoperiod in fresh water at 10°C in the spring of 1993 and 1994. We also measured changes in T4, T3, and cortisol levels during the change in rheotactic behavior. Condition factor decreased while salinity tolerance improved from mid-March to late April. The turbidity-induced transition from upstream to downstream swimming occurred in mid to late April. The main changes in brain deiodination were reduced T3IRD (1993 study) and elevated T4ORD (1994 study). In both years, a high ratio of T4ORD/T3IRD activities in the brain indicated an increased potential for T3 production in the brain during advanced PST. Liver deiodination profiles differed between years, but during advanced PST the low T4ORD activity and low T4ORD/T3IRD activity ratio suggested a low potential for hepatic, and hence systemic, T3 production. However, plasma T4 was increased in downstream swimmers at 1 d (1993) and 4 h (1994) after the turbidity increase. Since at this time brain deiodination pathways were poised towards T3 production, the surge in plasma T4 would likely increase local T3 formation in brain. We conclude that during PST there is no major change in hepatic deiodination and hence probably no major change in systemic T3 availability. But deiodination properties in brain during late PST indicate the potential for local T3 formation. This may be significant when plasma T4 increases at the time of downstream migration.

scholarly journals Effects of an advanced temperature cycle on smolt development and endocrinology indicate that temperature is not a zeitgeber for smolting in Atlantic salmon

2002 ◽  
Vol 205 (22) ◽  
pp. 3553-3560 ◽  
Author(s):  
Stephen D. McCormick ◽  
J. Mark Shrimpton ◽  
Shunsuke Moriyama ◽  
Björn Thrandur Björnsson
Keyword(s):  
Atlantic Salmon ◽  
Atpase Activity ◽  
Effect Of Temperature ◽  
Temperature Cycle ◽  
Plasma Growth Hormone ◽  
Factor I ◽  
Rate Of Increase ◽  
Igf I ◽  
Short Days

SUMMARY Atlantic salmon (Salmo salar) juveniles were reared under simulated conditions of normal photoperiod (LDN) or short days (LD 9:15) and ambient temperature (AMB: normal temperature increases in April) or an advanced temperature cycle (ADV: temperature increases in February). Under both photoperiod conditions, the timing of increased and peak levels of gill Na+,K+-ATPase activity were not altered by temperature,although the rate of increase was initially greater under ADV. ADV/LD 9:15 resulted in peak gill Na+,K+-ATPase activity that was half of that seen under normal photoperiod and temperature conditions. Plasma growth hormone (GH) levels increased threefold in late March under ADV/LDN,but not under ADV/LD 9:15, indicating that there is a photoperiod-dependent effect of temperature on levels of this hormone. Plasma insulin-like growth factor I (IGF-I) increased in spring in all groups, with increases occurring significantly earlier in the ADV/LDN group. In each photoperiod condition, the advanced temperature cycle resulted in large decreases in plasma thyroxine(T4) levels in March, which subsequently recovered, whereas plasma 3,5,3′-triiodo-L-thyronine (T3) levels were not substantially affected by either photoperiod or temperature. There was no consistent pattern of change in plasma cortisol levels. The results do not provide support for the role of temperature as a zeitgeber, but do indicate that temperature has a role in the timing of smolting by affecting the rate of development and interacting with the photoperiod.

Pituitary and plasma growth hormone dynamics during sexual maturation of female Atlantic salmon

2010 ◽  
Vol 167 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Susana Benedet ◽  
Eva Andersson ◽  
Christian Mittelholzer ◽  
Geir Lasse Taranger ◽  
Björn Thrandur Björnsson
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Sexual Maturation ◽  
Plasma Growth Hormone

Expression of IGF-I and -II mRNA in the brain and craniofacial region of the rat fetus

Development ◽  
1991 ◽  
Vol 111 (1) ◽  
pp. 105-115 ◽  
Author(s):  
C. Ayer-le Lievre ◽  
P.A. Stahlbom ◽  
V.R. Sara
Keyword(s):  
Nervous System ◽  
Olfactory Bulb ◽  
Endocrine Function ◽  
Target Cells ◽  
Pars Intermedia ◽  
Sensory Ganglia ◽  
Rat Fetus ◽  
Amino Terminal ◽  
Igf I ◽  
The Brain

Insulin-like growth factors (IGF-I and -II) are present in the brain during development, with high levels of both being also found in the periphery particularly in the embryo. IGFs in the brain are believed to stimulate the proliferation of neuronal and glial precursors and their phenotypic differentiation. Using in situ hybridization, we have investigated the distribution of cells producing IGF-I and -II in the rat fetus during the second half of prenatal development with special emphasis on the peripheral and central nervous system. High levels of IGF-I mRNA were found in the olfactory bulb and in discrete neurons of the cranial sensory ganglia, notably in the trigeminal ganglion, as early as 13 days of gestation, in the pineal primordium of 18 day old fetuses, and in discrete groups of cells in the cochlear epithelium located laterally outside the forming spiral organ, in day 13 to 21 fetuses. High levels of IGF-II mRNA in the brain, besides the choroid plexus and the leptomeninges, were detected in hypothalamus, in the floor of the 3rd ventricle at all stages studied, in the pineal primordium at 18 days and in the pars intermedia of the pituitary or in the Rathke's pouch epithelium from which it is derived, with progressive fading towards the end of the gestation. In the peripheral nervous system the IGF-II mRNA was only found in association with the vascular endothelia of the ganglia. IGF-II mRNA in the nervous system was found in highly vascularized areas, meninges, blood vessels and choroid plexuses. It is thus associated with structures involved in the production of extracellular fluids and/or substrate transport and supply in the nervous tissues. A more specific role in the differentiation or fetal endocrine function should be considered for IGF-II in cells producing melatonin and melanocyte stimulating hormone (MSH) in the pineal and pituitary glands, respectively. The presence of IGF-I mRNA in the nervous system could be associated with fiber outgrowth and synaptogenesis in the cases of olfactory bulb and developing iris. The role of IGF-I in restricted populations of cells of the cochlear epithelium and in the pineal gland is unclear and requires further investigations including a search for IGF-I receptors in possible target cells. In the sensory ganglia, the presence of high levels of IGF-I mRNA eventually corresponds to the production, by post-translational processing, of the amino-terminal tripeptide of IGF-I, which might represent a neurotransmitter for these sensory neurons.

A peak in gh-receptor expression is associated with growth activation in Atlantic salmon vertebrae, while upregulation of igf-I receptor expression is related to increased bone density

2005 ◽  
Vol 142 (1-2) ◽  
pp. 163-168 ◽  
Author(s):  
Anna Wargelius ◽  
Per-Gunnar Fjelldal ◽  
Susana Benedet ◽  
Tom Hansen ◽  
Björn Thrandur Björnsson ◽  
...  
Keyword(s):  
Bone Density ◽  
Atlantic Salmon ◽  
Receptor Expression ◽  
Gh Receptor ◽  
Igf I ◽  
Growth Activation

scholarly journals Impairments to the GH-IGF-I Axis in hSOD1G93A Mice Give Insight into Possible Mechanisms of GH Dysregulation in Patients with Amyotrophic Lateral Sclerosis

Endocrinology ◽  
2012 ◽  
Vol 153 (8) ◽  
pp. 3735-3746 ◽  
Author(s):  
F. J. Steyn ◽  
S. T. Ngo ◽  
J. D. Lee ◽  
J. W. Leong ◽  
A. J. Buckley ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Mouse Model ◽  
Transgenic Mouse ◽  
Gh Deficiency ◽  
Transgenic Mouse Model ◽  
Endocrine Function ◽  
Α Subunit ◽  
Gh Secretion ◽  
Igf I ◽  
Lateral Sclerosis

GH deficiency has been found in subjects with amyotrophic lateral sclerosis (ALS). Disrupted endocrine function could contribute to the progressive muscle loss and hypermetabolism seen in ALS. It is not possible to study all the elements of the GH-IGF-I axis in ALS patients. Consequently, it remains unclear whether dysfunctional GH secretion contributes to disease pathogenesis and why GH and IGF-I directed treatment strategies are ineffective in human ALS. The hSOD1G93A transgenic mouse model is useful for the detailed investigation of the pathogenesis of ALS. We report that symptomatic male hSOD1G93A transgenic mice exhibit a deficiency in GH secretion similar to that seen in human ALS. Further characterization of the GH-IGF-I axis in hSOD1G93A mice reveals central and peripheral abnormalities that are not found in wild-type age-matched controls. Specifically, we observe aberrant endogenous pulsatile GH secretion, reduced pituitary GH content, and decreased circulating levels of IGF-I, indicating global GH deficiency in hSOD1G93A mice. Furthermore, a reduction in the expression of the IGF-I receptor α-subunit in skeletal muscle and lumbar spinal cords of hSOD1G93A mice suggests impaired IGF-I signaling within these tissues. This is the first account of disrupted GH secretion in a transgenic mouse model of ALS. These observations are essential for the development of effective GH and IGF-I targeted therapies in ALS.

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