Studies on carcass quality traits in two populations of coho salmon (Oncorhynchus kisutch): phenotypic and genetic parameters.

摘要

Two populations of coho salmon (Oncorhynchus kisutch; n = 3444; 21 months old) taken from a specialized breeding programme were used to obtain phenotypic and genetic parameter estimates of carcass quality traits. The sample included 1642 female and 1802 male fish. In each population, sex was found to affect total body, total visceral and gonad wt., abdominal fat percentage, fillet percentage, steak width and cutlet area markedly. Cutlet height, ventral thickness, dorsal fat thickness, dressing percentage, and carcass wt. were also affected by sex, but less consistently. Total fillet and abdominal fat wt. were not markedly affected by sex, and flesh texture and fat content were similarly unaffected. Heritability was estimated to be of low to medium magnitude for body, carcass and fillet wt., fillet percentage, dorsal fat and ventral thickness, steak width, cutlet height and area, and flesh texture and fat content. Heritabilities for total visceral, gonad and abdominal fat wt., abdominal fat percentage and dressing percentage were of medium magnitude. Phenotypic and genetic correlations between various biometrical traits were in the ranges 0.33-0.90 and 0.48-0.96, respectively. Selection for growth was found to affect carcass wt., fillet percentage and texture favourably; however, the effects of this type of selection upon dressing percentage and flesh fat content were unfavourable. A moderate, positive genetic correlation was identified between abdominal fat percentage and flesh fat content in salmon, but abdominal fat percentage and carcass wt., and abdominal fat percentage and dressing percentage were negatively correlated.