Physiological and biochemical factors affecting carotenoid utilization in salmonid fish. Gregory Ian Page Carotenoid utilization in rainbow trout (Oncorhynchus mykiss Walbaum) and Atlantic salmon (Salmo sa/ar L.) has been investigated with respect to tissue distribution of carotenoids and the role of the liver on the bioavailability of the lipid soluble carotenoids, astaxanthin and canthaxanthi...

Estrogen hormones interact with cellular ERs to exert their biological effects in vertebrate animals. Similar to other animals, fishes have two distinct ER subtypes, ERα (NR3A1) and ERβ (NR3A2). The ERβ subtype is found as two different isoforms in several fish species because of a gene duplication event. Although predicted, two different isoforms of ERα have not been demonstrated in any fish s...

Rainbow trout are carnivorous fish and poor metabolizers of carbohydrates, which established this species as a model organism to study the comparative physiology of insulin. Following the recent characterisation of key roles of several miRNAs in the insulin action on hepatic intermediary metabolism in mammalian models, we investigated the hypothesis that hepatic miRNA expression is postprandial...

Gut-associated lymphocytes were described in fish, but their involvement in immune responses is still unknown. In rainbow trout, intraepithelial lymphocytes (IELs) are scattered between gut epithelial cells, but neither Peyer's patches nor mesenteric lymph nodes were identified. Rainbow trout IELs contain mainly T cells, because they expressed transcripts of T cell marker homologs of CD8, CD4, ...

When nonnative species become established within new communities, competition may play a role in determining the persistence of ecologically similar native species. In western North America, many native cutthroat trout (Oncorhynchus clarkii) populations have been replaced by nonnative rainbow trout (Oncorhynchus mykiss). Superior competitive ability of rainbow trout and cutthroat–rainbow trout ...

Myxobolus cerebralis caused severe declines in rainbow trout populations across Colorado following its introduction in the 1980s. One promising approach for the recovery of Colorado's rainbow trout populations has been the production of rainbow trout that are genetically resistant to the parasite. We introduced one of these resistant crosses, known as the GR×CRR (cross between the German Rainbo...

Polymorphism. A variable number of tandem repeat (VNTR; Nakamura et al., 1987) polymorphism was detected in rainbow trout (Oncorhynchus rnykiss Walbaum) using BgZII. The probe, RW9401, was isolated from a genomic DNA cosmid library developed from the RTG-2 cell line (Wolf and Quimby, 1962). Method of Detection. Nylon filters containing rainbow trout genomic DNA digested with BgZII were prehy...

Olfactory epithelial structure and olfactory bulb neurophysiological responses were measured in chinook salmon and rainbow trout in response to 25 to 300 mg copper (Cu)/L. Using confocal laser scanning microscopy, the number of olfactory receptors was significantly reduced in chinook salmon exposed to $50 mg Cu/L and in rainbow trout exposed to $200 mg Cu/L for 1 h. The number of receptors was ...

As there are few data on primary structures of fish apolipoproteins (apo), we determined the N-terminal sequence of a 28 kDa major serum protein of rainbow trout, a possible homologue of apoAI protein in higher vertebrates. Rainbow trout serum was separated by two-dimensional electrophoresis. A spot of the 28 kDa protein (pl 5.45) was cut out and directly applied to a protein sequencer. We succ...

The Pacific salmonid species Oncorhynchus mykiss is separated into a migratory form (steelhead trout) and a non-migratory form (rainbow trout). A decrease in water temperature is likely a cue triggering downstream behavior in the migratory form, and testosterone inhibits onset of this behavior. To elucidate differences in sensitivity to water temperature decreases between the migratory and non-...