EXPERIMENTS ON THE PROTEIN REQUIREMENTS OF GRASS CARP(CTENOPHARYNGODON IDELLUS (C.&V.))JUVENILES
Lin Ding;Mao Yongqing;Cai Fasheng Ichthyology Laboratory, Zhongshan (Sun Yatsen) University
Three experiments were carried out, each dealing with six aliquots of 60-100 grass carp fingerlings which weighed 2.4-8.0 g, Each aliquot was assigned to one of six dif- ferent dietary protein levels ranging 0.44-50.46%, with the daily feed allowance ap- proximated 5-9% the body weight of the fish, and kept in a 2.4M~3 concrete tank at 26-30.5℃ for 21-27 days. These experiments were aimed at determining the optimal level of dietary protein for the optimum growth of juvenile grass carp. The sources of protein used were casein and dried meal of silver carp muscle. The optimal protein level of the diet, determined by both methods of polynominal regression and parabolic curve, was found to be 22.77-27.66%. The protein efficiency ratio decreased with the increase in protein content of the diet according to the formula Y=29.2786-0.5296 X. At the optimal protein level, the protein efficiency ratio was defined as 14.72-17.11 %.