Protein and energy nutrition of brook trout (Salvelinus fontinalis) at optimal and elevated temperatures

Abstract

The digestible protein (DP) and digestible energy (DE) requirements for maintenance and growth of brook trout (Salvelinus fontinalis) were determined using a factorial model at either optimum (15 °C) or elevated temperature (19 °C). Several key parameters of the factorial model were measured using a series of inter-related studies. The maintenance requirements for DP and DE were 0.10 gDP kg−0.69 day−1 (15 °C) and 0.31 gDP kg−0.78 day−1 (19 °C), and 34.86 kJDE kg−0.84 day−1 (15 °C) and 46.14 kJDE kg−0.86 day−1 (19 °C). The total requirements for DP were 0.10 gDP kg−0.69 day−1 + 2.14PG (protein gain) (15 °C) and 0.31 gDP kg−0.78 day−1 + 1.98PG (19 °C). The total requirements for DE were 36.86 kJDE kg−0.84 day−1 + 1.58EG (energy gain) (15 °C) and 46.14 kJDE kg−0.86 day−1 + 1.64EG (19 °C). The partial efficiencies for growth were 0.47 (15 °C) and 0.51 (19 °C) for protein, and 0.63 (15 °C) and 0.61 (19 °C) for energy. Nutrient gain was lower at the elevated temperature; however, feed formulation for brook trout should be adjusted to match changes in nutrient requirements at different culture temperatures. The protein and energy requirements model will be useful for developing commercial feeds and feeding charts for brook trout.