The effect of broodstock ration size on the composition of rainbow trout eggs ( Salmo gairdneri)

Abstract

Female rainbow trout were given half- (0.35%) or full-ration (0.7% body weight per day) of a commercial trout pellet for a period of 1 year prior to spawning. During development of the eggs produced by each group of trout, samples of the eyed eggs, yolk-sac and swim-up fry were analysed for proximate, elemental, amino acid, fatty acid and enzyme composition. The eggs produced by the half-ration fish were significantly smaller than those of the full-ration trout. A number of small differences were also found between the composition of both groups of eggs. However, the data obtained suggested that ample supplies of the materials essential for successful embryo production were present in eggs from both half- and full-ration fed rainbow trout.