Growth and vitality in yellow forms of rainbow trout

The colour genes controlling the palomino and albino phenotype in the sprin g spawning rainbow trout [Oncorhynchus mykiss (Walbaum 1792)] strain reared at the Department of Salmonid Research Rutki, Poland were found to have st rong detrimental pleiotropic effects on growth and vitality. After 5 and 9 months of rearing, the differences in mean body weights in albino, palomino and wild-coloured trout were statistically highly significant, with albino showing the poorest, palomino as the intermediate and wild-coloured trout having the highest growth. An identical ranking of colour phenotypes was ob served for survival. The influence of colour phenotypes on both traits show ed a diminishing tendency with increasing age of fish. It is concluded that alleles controlling palomino and albino colouration cannot be recommended as genetic markers. If reference groups are needed, instead of albino trout , palomino trout should be used since their pleiotropic effects are less pr onounced.