ARS | Publication request: MYOSIN EXPRESSION LEVELS IN TROUT MUSCLE: A NEW WAY FOR MONITORING SPECIFICGROWTH RATES FOR RAINBOW TROUT ONCORHYNCHUS MYKISS (WALBAUM) ON VARIED PLANES OF NUTRITION.

Submitted to: Aquaculture Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2001
Publication Date: April 1, 2001

Interpretive Summary: Efficient and accurate monitoring of growth in fish is imperative in order to formulate diets that maximize the production of commercially valuable animals while limiting the cost. Research was initiated to determine if the level of myosin gene expression in trout muscle is related to growth. The experiment design consisted of separating a number of matched age and size trout into different tanks and to feed the fish in one tank to satiation while feeding the other tanks increasingly smaller amounts. The growth of fish is determinate upon the deposition of muscle, which makes up greater than 60% of the animal. Myosin is a major component of animal muscle and the development of a test that measures the relative production of myosin would be a valuable assay in evaluating different formulated fish diets and in monitoring the growth of fish in hatcheries. This research demonstrated that not only was the monitoring of myosin levels a rapid and efficient method for monitoring growth of fish on varying diets, but this method could also be utilized for other applications such as the effects of diet formulation, fish health status, effects of photoperiod, and slight genetic differences between strains or families

Technical Abstract: Fish growth is manifested by a number of measurable physical changes. We have developed a sensitive method for monitoring the growth rate of fish fed at four different planes of nutrition. This technique consists of measuring expression levels of myosin RNA isolated from the muscle of experimental animals. Using PCR (polymerase chain reaction) primers, and a afluorescent-labeled single-stranded DNA probe that hybridizes specifically to a region within the myosin mRNA of rainbow trout Oncorhynchus mykiss (Walbaum), we were able to detect differences the relative level of myosin expression between groups of fish. This method also allows for the determination of absolute expression levels when reactions are performed with standards comprised of known levels of in vitro transcribed myosin RNA. With the proper equipment this novel procedure can be performed rapidly on large numbers of individuals and with the procurement of noninvasive muscle biopsies, the same experimental animal could theoretically be sampled multiple of times throughout the course of the study. This new method could be used to measure differences in muscle synthesis in fish associated with various nutrient intake levels, environmental parameters, life history stages, and health status.