Protein sources, hydrolyzed fish protein concentrate and plasmolyzed lactic yeast, were used to partially replace fish meal and soybean meal, respectively, in a basal diet (diet 1) at these levels; 5% fish protein concentrate + 5% lactic yeast (diet 2), 5% fish protein concentrate (diet 3), and 5% lactic yeast (diet 4). A commercial diet was used as control. Diets were fed to Penaeus monodon postlarvae in an eight-week feeding trial in tanks. Parameters measured to determine diet efficiency were weight gain, survival, mass weight and feed conversion efficiency. Growth rates of shrimp postlarvae fed diets 2 and 4 were similar to those of the basal and commercial diets but significantly higher (P0.05) from diets 1, 2, and 4. Performance in terms of mass weights gave no significant differences among treatments. Field-testing of the diets showed that both fish protein concentrate and lactic yeast can support shrimp production in brackishwater ponds
