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Effectiveness of the Air Stripping in Two Salmonid Fish, Rainbow Trout (Oncorhynchus Mykiss) and Brown Trout (Salmo Trutta Morpha fario)
Published on: September 16, 2018
Salinity acclimation affects the somatotropic axis in rainbow trout
Brian S Shepherd1, Katherine Drennon, Jaime Johnson
1National Center for Cool and Coldwater Aquaculture, ARS/USDA, 11861 Leetown Rd., Kearneysville, WV 25430, USA. bshepherd@ncccwa.ars.usda.gov
Summary
This study shows that gradual salinity exposure increases insulin-like growth factor-binding proteins (IGFBPs) in rainbow trout plasma, suggesting their crucial role in regulating IGF-I during salinity acclimation.
Area of Science:
- Comparative Physiology
- Endocrinology
- Aquaculture
Background:
- The somatotropic axis plays a role in fish physiology.
- Understanding ion-regulation mechanisms is vital for aquaculture and fish health.
Purpose of the Study:
- To investigate the role of the somatotropic axis in ion regulation in rainbow trout.
- To determine if plasma insulin-like growth factor-binding proteins (IGFBPs) change with gradual salinity exposure.
Main Methods:
- Freshwater-adapted rainbow trout were gradually exposed to 66% seawater over 5 days.
- Plasma ion levels (Ca2+, Cl-, Na+), cortisol, growth hormone (GH), IGF-I, and gill Na+-K+-ATPase activity were measured.
- Plasma IGFBPs (21, 32, 42, and 50 kDa) were identified and quantified.
Main Results:
- Salinity exposure led to increased plasma GH, IGF-I, and gill Na+-K+-ATPase activity.
- Plasma levels of all identified IGFBPs (21, 32, 42, 50 kDa) were elevated in salinity-acclimated fish.
- Transient changes in specific IGFBP levels were observed during the 5-day acclimation period.
Conclusions:
- Elevated plasma IGFBPs suggest a significant role in IGF-I regulation during salinity acclimation in salmonids.
- The somatotropic axis, particularly IGFBPs, is involved in the physiological response to changing salinity environments in rainbow trout.
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