title: Effects of aquaculture related stressors and nutritional restriction on circulating growth factors (GH, IGF-I and IGF-II) in Atlantic salmon and rainbow trout.
abstract: The effects of aquaculture related stressors on circulating levels of GH, IGF-I and for the first time, IGF-II in Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) were investigated. Specifically, circulating growth factor levels were measured in four different experiments. Two 24 h confinement stressor procedures, (one with Atlantic salmon, the other with rainbow trout); following a hypo-osmotic stressor (freshwater bath) in salt water acclimated, adult, Atlantic salmon; and during a 22 day starvation and re-feeding protocol with juvenile Atlantic salmon. Handling and confinement resulted in significant decreases in circulating levels of all three growth factors in Atlantic salmon, and IGF-I and IGF-II (but not GH) in rainbow trout. A 2-3 h freshwater bath to remove gill parasites on a commercial Atlantic salmon aquaculture operation caused a significant decrease in circulating GH and IGF-I concentrations, but no significant change in IGF-II concentration, 2 days post bathing. Starvation for a period of 15 days in Atlantic salmon resulted in a significant increase in circulating GH levels and a significant decrease in circulating IGF-I and IGF-II. Re-feeding of starved fish for 7 days resulted in a significant decrease in GH to the concentration measured in continually fed fish, however re-feeding did not change plasma levels of IGF-I and IGF-II relative to continually starved fish. The results presented here confirm previously observed handling and confinement stressor induced effects on GH and IGF-I and, for the first time, on IGF-II in salmonids. Furthermore this study confirms the nutritional regulation of GH, IGF-I and IGF-II in juvenile Atlantic salmon.
authors.affiliation: School of Biological Sciences, Flinders University of South Australia, G.P.O. Box 2100, Adelaide, S.A. 5001, Australia. Ryan.Wilkinson@utas.edu.au
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Wilkinson
authors.forename: Mark
authors.initials: M
authors.lastname: Porter
authors.forename: Hannah
authors.initials: H
authors.lastname: Woolcott
authors.forename: Ryan
authors.initials: R
authors.lastname: Longland
authors.forename: John F
authors.initials: JF
authors.lastname: Carragher
mesh_terms: D000818:Animals; D017756:Aquaculture; D005260:Female; D005502:Food; D013006:Growth Hormone / Q000097:blood*; D006234:Handling, Psychological; D006854:Hydrocortisone / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D008297:Male; D017686:Oncorhynchus mykiss / Q000502:physiology*; D009997:Osmotic Pressure; D012149:Restraint, Physical; D020317:Salmo salar / Q000502:physiology*; D013217:Starvation / Q000503:physiopathology*
chemical_list: D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone; D006854:Hydrocortisone