Studies on the nutrition of marine shrimp of genus Penaeus

Several pelletized feeds containing 30 to 35% total protein were tested on two species of marine shrimp, Penaeus setiferus and Penaeus stylirpstris. Diets were based on an experimental standard diet having 31.5% shrimp meal, 8.0% fish meal, 44.0% rice bran, 5.0% squid meal, 3.0% soy and bound with 2.5% sodium alginate. Based on this ration, several series of diets were prepared in order to evaluate: a) the nutritional response of the shrimp to the replacement of squid meal with different proportions of [alpha]-soy; b) the possibility of replacing some expensive ingredients, such as [alpha]-soy protein, sodium alginate and shrimp meal, with cheaper or more readily available ingredients to make the diet useful from the commercial point of view. The nutritional responses of the two species to the different diets were correlated to dietary fatty acid profiles. Attempts were made to show a relation between growth and the assimilation of proteins and carbohydrates from the pelletized diet. The two species of shrimp showed different responses to the same diets. For P. stylirostris, growth depended upon the size of the animals. Small shrimp (0.7 g) showed a linear relation between growth and the level of squid meal in the diets, while larger animals had larger increases in biomass with rations containing 3.2 or 6.4% squid meal. For P. setiferus (0.7 g), greatest growth was obtained by using 5 to 6% of [alpha]-soy with squid meal. For small animals of both species, brewer's yeast may replace [alpha]-soy. Corn meal can be incorporated into the formulated feeds at 15 to 20%, which suggests that expensive sodium alginate would not have to be used as a binder. This, with the fact that 50% of the shrimp meal from the standard diet can be replaced by the same percent of brewer's yeast results in a significant reduction in the cost of diets for shrimp farming. In most cases, the experimental diets gave better nutritional performances than the best commercial ration available. [...]