Protein digestion, growth and food conversion in Atlantic salmon and Arctic charr with different trypsin-like isozyme patterns

Protein digestibility and food conversion were determined in groups of Atlantic salmon ( Salmo salar L.) and Arctic charr ( Salvelinus alpinus L.) with or without the trypsin-like isozyme TRP-2*92 . Determinations were made at two salinities, 0 and 27 ppt; at two temperatures, 6 and 10° C and on large (200 g) and small (30–90 g) fish. The overall digestibility of protein was found to be 81.4±0.2% and was unaffected by the presence of the isozyme or the other variables. The feed conversion ratio of Atlantic salmon possessing TRP-2*92 was observed to be significantly lower with significantly higher specific growth rate than in fish without this isozyme.