Incorporation de protéines végétales dans un aliment composé pour crevettes Macrobrachium rosenbergii

In order to know more about nutritional acceptance of a freshwater prawn Macrobrachium rosenbergii and to obtain additional information on the feedstuffs which can be used in a prawn diet, several growth tests were carried out. Three sets of experimental tanks were used. Diets were combined so as to introduce either copra meal or acacia meal, plus troca meaI. The major ingredients are tropical products, and were easy to col1ect in large quantites. The protein Ievel was maintained at about 30%. In the first experiment, it was found that a 40% copra meal diet resulted in a fair rate of growth. A higher level of copra meal brought about similar growth levels and a survival rate which was not significantly lower (analysis of variance). This result was checked and confirmed in a 400-m2 pond. In a second experiment, a diet composed of 40% acacia meal was tested on M. rosenbergii to find oul whether the level of mimosine was toxic or not to the metabolism of this prawn, and lo investigate the potentialities of this source of protein for the growth of M. rosenbergii. Two other typical herbivorous diets were used for comparison. No pathogenic signs were noticed. The survival rate was equivalent and an analysis of variance showed significant differences between the three diets: the 43.1.1.0. was the more efficient diet. The introduction of acacia meal into a Macrobrachium diet seemed quite beneficial from several points of view (Ca/P ratio, protein quality and pigmentation of the animal). (1) Regarding the minerai requirements of this species, it is pointed out that among the six diets tested the best growth rate was obtained with a Ca/P ratio above 1 in the diet. This underlines the importance of the mineraI mixture. (2) Amino acid composition of the diet has to be as similar as possible to the shrimp muscle; the level f methionine is particularly important to the animal, and more essential than lysine which could be a limiting factor in the formulae without affecting the growth. (3) Leucaena meal con tains a level of mimosine which is fairly normal and non-toxic for the freshwater prawn. In addition, the growth is very acceptable though a supplementation with troca meal seems quite suitable. Leaf protein contains a large quantity of B-carotene, which seems to bear sorne relation to the good pigmentation of the prawns after the feeding trial. [NOT CONTROLLED OCR]