Specific Amino Acid-Free Semi-Purified Diets for Penaeus monodon Juveniles

To determine the effects of deficiency of individual amino acids believed to beessential to Penaeus monodon juveniles, a 28-day feeding experiment was carried outwith P.monodon postlarvae.P.monodon postlarvae weighing around 120 mg each were randomly distributed inindividual perforated one liter jars, 10 jars in 60-liter, fiberglass tanks, in a flow through seawater system, which passed through a 0.35 micron filter before use. Animals were reared in these jars for 28 days on semi-purified moist diets. Salinity and temperature ranged from 27 to 32 ppt and 26 to 28.9°C, respectively.Percentage weight gains and survival rates were not significantly different amongtest diets. However, some amino acids seemed to be more critical than others in thediets. Animals given phenylalanine-free, leucine-free, and methionine-free diets gained more than 300% compared to those fed the complete amino acid diets. A low weightgain of 228.6% was observed in animals fed arginine-free diet. Animals fed the histidine-free, lysine-free, threonine-free and valine-free diets also gained less than 200%.Survival rates were 60% for those given threonine-free and isoleucine-free diets, 70%for histidine-free and complete amino acid diets, whereas those fed the phenylalanine-free, leucine-free and methionine-free diets had survival of 80 to 85%. These results suggest the possibility that some amino acids were taken from sources outside thediets and could have come from whatever bacterial growth there was in the rearing jars