REGULATION OF MUSCLE GROWTH IN SABLEFISH Anoplopoma fimbria DURING GROW OUT

Lisa C. Armbruster*, J. Adam Luckenbach, William T. Fairgrieve, Madison S. Powell, Ronald B. Johnson, Walton W. Dickhoff, and Gordon K. Murdoch
 
Dept. of Animal and Veterinary Science
University of Idaho
875 Perimeter Drive
Moscow, ID 83844-2330
chan6984@vandals.uidaho.edu
 

Skeletal muscle accounts for the bulk of body mass in finfish species selected for aquaculture. This fact highlights the importance of understanding muscle tissue development to enhance overall growth. Sablefish (Anoplopoma fimbria) is a Northeast Pacific species with stable wild-capture fisheries and an emerging U.S. aquaculture industry, the latter thanks to high market value and fast growth in culture. Hatchery and grow-out protocols are being developed for sablefish, and producers stand to benefit from knowledge of how the 'growth environment' impacts muscle tissue development, growth potential, and product quality (e.g., temperature, nutrition, genetic strain). The research presented here is part of a larger study investigating development of red and white muscle using 11 molecular markers of muscle growth and metabolism. This work begins to decipher the transcriptional regulation of muscle development in sablefish and serves as a baseline to which future comparisons can be made to expedite decisions for optimal production by industry.

Species-specific qRT-PCR assays were developed using the TaqMan MGB primer-probe system for highly-conserved genes with known critical functions in vertebrate muscle development. These molecular tools were employed to measure mRNA levels in muscle from a cohort of cultured sablefish at four time points, spanning 16 months of grow out (Fig 1). Evaluation of red muscle specific growth is important as it represents a localized microniche (e.g., maturity, metabolism) where satellite cell recruitment and myogenesis are not assumed to equal that of white muscle.

Differential regulation of the target genes (e.g., MyoD1, MyoD2) at advancing stages of the growth cycle suggest important and conserved roles in sablefish muscle development (Fig 2). These tools will be further validated and used to determine what growth environment maximizes sablefish growth performance.