title: Determination of relative protein degradation activity at different life stages in rainbow trout (Oncorhynchus mykiss).
abstract: Rainbow trout were reared from 5 g to approximately 400 g on a diet formulated to supply the required protein from either fishmeal or plant proteins. The fish were sampled at every weight doubling and liver and muscle samples were obtained. From these tissue samples RNA and protein were isolated and analyzed for the expression of a number of muscle regulatory and protein degradation genes and enzymatic activity for proteins involved in the caspase, calpain, and ubiquitin-proteasome pathways for protein proteolysis. Only MyoD2 showed significant differences in expression between the two diets, while no significant changes over the course of the experiment were determined for MyoD2 or the other muscle factors. For the degradation genes significant changes in expression were determined for calpain1 and calpastatin. Calpastatin also showed a significant increase in expression over the course of the experiment in the muscle of fish fed a fishmeal diet and significant decrease in expression in the liver of fish fed the fishmeal based diet. Differences in proteasome enzyme activity were found between diets in the liver and muscle of fish and for caspase-3 activity in muscle. Significant changes in activity over the course of the experiment were noted for proteasome and calpain activity in the liver and muscle. These findings suggest that diets replacing fishmeal with plant material can have some effects on protein turnover in muscle and that some degradation pathways are differentially regulated during the growth of rainbow trout.
authors.affiliation: USDA-ARS, Hagerman Fish Culture Experiment Station, Hagerman, ID 83332, USA. Ken.Overturf@ars.usda.gov
authors.forename: Ken
authors.initials: K
authors.lastname: Overturf
authors.forename: T Gibson
authors.initials: TG
authors.lastname: Gaylord
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004032:Diet; D005247:Feeding Behavior / Q000187:drug effects; D029941:Fish Proteins / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D008018:Life Cycle Stages / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D009132:Muscles / Q000187:drug effects / Q000201:enzymology; D017686:Oncorhynchus mykiss / Q000254:growth & development* / Q000378:metabolism*; D010940:Plant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000235:genetics
chemical_list: D029941:Fish Proteins; D009124:Muscle Proteins; D010940:Plant Proteins