Dietary protein and energy requirements of Penaeus vannamei and the optimal protein to energy ratio

Abstract

The dietary protein requirement of penaeid shrimp has been investigated under different experimental conditions. The recommended protein levels reported for each species have not been based on energy density of the diet because no interaction between protein and energy has been shown. This study was designed to determine the dietary protein and energy requirements of juvenile Penaeus vaimamei and the optimal protein:energy ratio. Acid-washed diatomaceous earth was chosen as an alternative non-nutritive filler to cellulose to vary protein:energy ratio of test diets. The results of this feeding trial showed that acid-washed diatomaceous earth was not digested by P. vannamei and did not affect apparent protein and energy digestibilities of P. vannamei. Addition of a potent feed attractant (2-. freeze-dry Artemia meal) to purified test diets increased ingestion rate of P. varmamei by three fold. The data from this feeding trial indicated that with increased ingestion rate, juvenile P. vannamei required less protein in the diet. Feeding frequency and daily ration also had significant effects on growth of shrimp. Juvenile P. vannamei grew faster under the feeding regime of 15 times per day in excess of consumption compared to eight times per day at a restricted ration. when fed 15 times per day in excess of consumption with semi-purified diets containing casein, gelatin and freeze-dried Artemia meal at a ratio of 4:1:4, the minimum dietary protein for maximum growth was requirement of juvenile P. vannamei for maximum growth was 150-o of diet with 3839 kcal gross energy/kg. The optimal protein:energy ratio was 39 mg protein/kcal based on optimal growth. one reason that the dietary protein requirement of juvenile P. vannamei determined in this study is extremely low compared to previously reported levels regardless of shrimp species, age, and dietary protein source, is the much higher feeding frequency (15 times per day) since all the previous studies were conducted with only one or two f.eedings per day.