9300914 Hershberger Silverstein Japan STA Program: Biochemical Correlates of Metabolic Enzymes in Juvenile Salmon This award will provide supplementary support to enable Dr. Jeffrey Silverstein of the University of Washington to conduct collaborative research with Dr. Hiroshi Ogata for 24 months at the National Research Institute of Aquaculture in Mie, Japan. They will apply Dr. Silverstein's theories on the genetic parameters defining growth and reproductive traits of the male coho salmon to the stock of masu salmon at Dr. Ogata's laboratory. The breeding of fast growing, late maturing fish is a central goal of salmonid culture. The relationship between growth and sexual maturation is of great importance especially since there is a marked reduction in growth rate and loss of economic value in salmon when they begin to sexually mature. Previous research on condition factors and fat levels of fast growing, early maturing males has led to a hypothesis that an energy or growth threshold must be surpassed in order for sexual maturation to ensue. The goal of Silverstein and Ogata is to examine salmonids with known differences in sexual maturation phenotype for differences in nutrient partitioning into fat and lean growth. Utilizing Dr. Ogata's expertise in masu salmon genetics, the team will examine 10 full-sibling families of salmon which have high and low probabilities for early maturation and develop assays for metabolic enzymes such as ornithine decarboxylase (ODC), fatty acid synthetase, ATP citrate lyase, and several NADPH generating enzymes. The experimental results will not only clarify the association between metabolic and sexual maturation phenotypes, it will provide evidence of biochemical differences between fast and slow growing phenotypes. By gaining an understanding of lean and fat growth in these species of salmon, the salmonid industry will be able to more quickly modify its selection criteria and approach its goal of fast growth and delayed ma turation in cultured fish.
