PARTIAL AND TOTAL REPLACEMENT OF FISH-MEAL WITH SOYBEAN-MEAL AND DISTILLERS BY-PRODUCTS IN DIETS FOR POND CULTURE OF THE FRESH-WATER PRAWN (MACROBRACHIUM-ROSENBERGII)

This study was conducted to evaluate the effect of partially or completely replacing fish meal with soybean meal and distillers' dried grains with solubles (DDGS) in diets for pond-raised freshwater prawns. Juvenile prawns averaging 0.51+/-0.27 g were stocked into nine 0.02-ha earthen ponds at 39,520/ha. Three isonitrogenous diets (32% crude protein) containing 15, 7.5 or 0% fish meal were fed to prawns in triplicate ponds. A variable percentage of soybean meal and a fixed percentage (40%) of DDGS replaced fish meal. Average yield, survival, individual weight, and feed conversion did not differ significantly (P<0.05) among shrimp fed the three diets. When averaged over the three diets, results were: yield, 1268 kg/ha; survival 78.1%; individual weight 42 g; and feed conversion 2.9. Replacement of fish meal caused increases in dietary levels of glutamine, proline, alanine, leucine, and phenylalanine, and decreases in aspartic acid, glycine, arginine, and lysine levels in the diets. Changes in fatty acid profiles of the diets were: increased concentrations of 16:0, 18:2n-6, and 20:1n-9, and decreased concentrations of 14:0, 16:1n-7, 18:1n-9, 18:3n-3, 20:4n-6, 20:5n-3, 22:5n-3 and 22:6n-3. Results indicate that fish meal can be partially or totally replaced with soybean meal and distillers' by-products in diets for pond production of freshwater prawns in temperate areas.