Ploidy and family effects on Atlantic salmon (Salmo salar) growth, deformity and harvest quality during a full commercial production cycle

This study examined performance traits between diploid and triploid siblings within 44 full-sib families (produced by 15 sires and 44 dams) under commercial rearing conditions from first feeding to harvest. Survival did not differ between ploidy levels throughout the production cycle. Triploids grew faster (+ 30%) in freshwater, but slower during the seawater phase (- 7.5%), although overall growth was comparable between ploidy levels (SGR 1.17 vs. 1.18% day- 1). Triploids showed no visual deformity in freshwater but a significantly increased prevalence in seawater, mainly evident as jaw malformations and radiological deformed vertebrae. However, severity of deformities was considerably lower than in previous studies, as was the occurrence of cataracts. Using fixed effect linear models the combined effect of deformity and cataract only explained 50% of reduced growth performance, suggesting that other factors were also contributing to reduced performance in triploids. These differences could be due to different nutritional requirements and environmental tolerances in triploids. Family differences were obtained for growth traits (weight and length). Family ranking for production traits was also consistent between diploid and triploid siblings. Harvest quality grading was high (> 99% superior) and flesh quality was comparable between ploidy levels, although triploids did have significantly higher PUFA levels at harvest. The study indicates the potential for superior triploid growth, and in conjunction with development of triploid specific diets may be sufficient in order to establish viable triploid salmon aquaculture