Agar-Microparticulated technique was used to study the protein requirements of shrimp, Penaeus japoncus, during weaning stage. Four experimental diets containing different dietary crude protein (CP) levels (25, 35, 45 and 55% CP) were prepared as Agar micro-binding diets (Agar- MBD) with size of 500-800 μm. All Agar-MBD were isocaloric and
contained gross energy of 456-490.2 Kcal GE /100g diet, however they varied in protein to energy ratio (56.5-1 19.3 mg protein per Kcal metabolizable energy). Eight circular conical bottomed fiberglass tanks with capacity of 300 L were used to rear 2000 PL20 (postlarvae) each. Initial weight of PL was 23 mg. Feeding period continued for six weeks until the
final weight of PL reached to one gram. Each tank was provided with fine aeration, seawater inlet, seawater outlet and light source. All tanks were filled with filtered seawater. Water exchange rate was about 30% daily of the total volume of rearing water. Results showed that survival rate of P. japonicus increased as protein level increased until 41% CP, then it decreased. The same trend was found for final weight, gain and specific growth rate. The best feed conversion ratio was obtained when shrimps were fed on 41 % CP. Maximum growth of P. japonicus was obtained as the postlarvac consumed
10.7 mg. Day-1 of the dietary protein. However, protein efficiency ratio decreased as the protein level increases. Therefore, the optimum protein level for weaning shrimp was 41 % CP with P/E ratio of 92.92 mg protein per Kcal ME.