title: Growth and endocrine effects of recombinant bovine growth hormone treatment in non-transgenic and growth hormone transgenic coho salmon.
abstract: To examine the relative growth, endocrine, and gene expression effects of growth hormone (GH) transgenesis vs. GH protein treatment, wild-type non-transgenic and GH transgenic coho salmon were treated with a sustained-release formulation of recombinant bovine GH (bGH; Posilac). Fish size, specific growth rate (SGR), and condition factor (CF) were monitored for 14 weeks, after which endocrine parameters were measured. Transgenic fish had much higher growth, SGR and CF than non-transgenic fish, and bGH injection significantly increased weight and SGR in non-transgenic but not transgenic fish. Plasma salmon GH concentrations decreased with bGH treatment in non-transgenic but not in transgenic fish where levels were similar to controls. Higher GH mRNA levels were detected in transgenic muscle and liver but no differences were observed in GH receptor (GHR) mRNA levels. In non-transgenic pituitary, GH and GHR mRNA levels per mg pituitary decreased with bGH dose to levels seen in transgenic salmon. Plasma IGF-I was elevated with bGH dose only in non-transgenic fish, while transgenic fish maintained an elevated level of IGF-I with or without bGH treatment. A similar trend was seen for liver IGF-I mRNA levels. Thus, bGH treatment increased fish growth and influenced feedback on endocrine parameters in non-transgenic but not in transgenic fish. A lack of further growth stimulation of GH transgenic fish suggests that these fish are experiencing maximal growth stimulation via GH pathways.
authors.affiliation: Department of Fisheries & Oceans, Centre for Aquaculture & Environmental Research, West Vancouver, BC, Canada V7V 1N6.
authors.forename: P A
authors.initials: PA
authors.lastname: Raven
authors.forename: D
authors.initials: D
authors.lastname: Sakhrani
authors.forename: B
authors.initials: B
authors.lastname: Beckman
authors.forename: L
authors.initials: L
authors.lastname: Neregård
authors.forename: L F
authors.initials: LF
authors.lastname: Sundström
authors.forename: B Th
authors.initials: BT
authors.lastname: Björnsson
authors.forename: R H
authors.initials: RH
authors.lastname: Devlin
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002417:Cattle; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000235:genetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D017684:Oncorhynchus kisutch; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism
chemical_list: C073294:growth hormone, bovine; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone