Optimized feed to improve growth and welfare of triploid growth hormone transgenic Atlantic salmon (Salmo salar)

Previous reports have shown that juveniles triploid (3N) growth hormone transgenic (TG) Atlantic salmon (Salmo salar) grow rapidly and consume less feed than their diploid (2N) non-transgenic (NTG) siblings. Furthermore, recent studies have also demonstrated the ability of TG salmon to tolerate high plant protein feed without affecting growth performance. The aim of the present study was to optimize two feed formulations to provide the nutrient requirements in different life stages of 3N TG to ensure improved growth performance and feed utilization efficiency. Thus, triplicate groups of full sibling, size-matched 3N TG and 2N NTG Atlantic salmon reared in fresh water at 12-14 °C and 12L:12D photoperiod were fed to satiation daily until achieving 1 kg body weight. Two feed formulations (F1 and F2) were optimized, using practical feed ingredients, and fed to 3N TG in different life stages. F1 (55/18: CP/CL) and F2 (45/23: CP/CL) were fed from 10 g to 300 g and from 300 g to 1 kg, respectively. Micronutrient levels were adjusted to fulfil the predicted 3N TG salmon requirements. In parallel, a commercial diet was fed to other groups of both 3N TG and 2N NTG as controls. In addition, a feed conversion study was performed from 30 to 120 g and from 300-900 g for F1 and F2, respectively. Samples of whole fish and fillets were collected at the beginning and the end of each feeding trial for each feed formulation. The results of this comparative study will be presented including assessment of growth, feed conversion and body composition.