INFLUENCE OF THE TYPE OF DIETARY STARCH O N THE USE OF 2 PROTEIN-SOURCES BY RAINBOW-TROUT REARED AT 8-DEGREES-C OR 18-DEGREES-C

The effect of the type of dietary starch (gelatinized vs native) on th e biological value of fish meal (FP) and fish soluble protein concentr ate (CPSP) was studied through the nitrogen balance in rainbow trout ( Oncorhynchus mykiss) reared for 3 weeks at 2 water temperatures: 8 or 18 degrees C. The protein sources were included in diets at a level of 60% and gelatinized or raw starch at a level of 30%. Gelatinized star ch improved the biological value of FP and CPSP by reducing the metabo lic nitrogen losses. Trout fed the diet with CPSP had a higher nitroge n excretion than those fed the diet with FP. The biological value of b oth protein sources was unaffected by wafer temperature.