The calculated energy cost for protein gain (1/kP) ranged from 1.79 to 1.90 kJ per kJ protein energy deposited. Energy cost (1/kL) for lipid gain was lower than the energy cost for protein gain and ranged from 1.10 to 1.31 kJ per kJ lipid deposited.
Therefore, we conclude that utilization of energy and protein for growth does not appear to be very different across the species examined. Differences were found, however, in the magnitude and the composition of the weight gain, which ultimately determines the amount of energy and protein required.