Threonine requirement of juvenile marine shrimp Penaeus monodon

Abstract

The threonine requirement was determined for juvenile marine shrimp. Penaeus monodon postlarvae, PL20, were stocked in 30-1 fiberglass tanks at ten shrimp per tank arranged in a completely randomized design with six replicates per treatment. They were fed amino acid test diets (40% protein) with casein-gelatin as natural protein sources and supplemented with crystalline L-amino acids to simulate the amino acid profile of shrimp muscle except for threonine. Graded levels of threonine were incorporated to obtain 0.72, 1.0, 1.28, 1.56, 1.84, and 2.12 g per 100 g diet or 1.8, 2.5, 3.2, 3.9, 4.6, and 5.3% of dietary protein. Relationship of weight gain with dietary threonine level was analyzed by the quadratic regression method to derive the threonine requirement. Results showed that the quantitative threonine requirement for growth is 1.4% of the diet or 3.5% of dietary protein. This requirement for growth conforms with the threonine level in the shrimp muscle.