UTILIZATION OF CRYSTALLINE AMINO ACIDS BY PACIFIC WHITE SHRIMP Litopenaeus vannamei

Anneleen Swanepoel*, G.A. Harsha S. Chaturanga, Xuan Qiu, Melanie Rhodes,
 Romi Novriadi, João Reis, Carter Ullman and D. Allen Davis
 
 School of Fisheries, Aquaculture and Aquatic Sciences
 Auburn University, AL, USA 36849-5419
 azs0162@tigermail.auburn.edu
 

In view of the variability in recommendations for essential amino acid (EAA) and the use of amino acids supplements in shrimp diets, this study was designed to determine the efficacy of crystalline amino acids (CAA) in a practical shrimp feed formulation. The basal diet was designed to contain 30% protein and 6% lipid. The primary protein source of the basal diet included: 5% fishmeal, 37% soybean, and 5% gelatine. Intact protein was incrementally reduced to produce diets with 28, 26, 24, and 22% protein. In a second series of diets, CAA were supplemented to the reduced protein diets to return the diets to 30% protein. Thus, producing a series of diets containing 30% protein with 2, 4, 6, and 8% crystalline amino acids. The trial was conducted twice to confirm results.  In the first trial, the shrimp (mean initial weight 0.25 ± 0.02) were stocked at 10 shrimp per tank and there were four replicates per diet run over a seven week period. The second trial was stocked at 15 shrimp per tank (mean initial weight 0.30 ± 0.01) run over a six week period. Data within treatments for both trials were variable, resulting in limited statistical differences. From a biological standpoint, percentage weight gain (PWG) appeared to decrease with protein level of the diet (R2-value, trial 1: 0.30, trial 2: 0.34). The addition of CAA resulted in a similar trend but did not appear to improve performance. Mean final weight (MFW) also appeared to have a decrease with protein level of the diet (R2-value, trial 1: 0.44, trial 2: 0.38). None of the diets with supplemented CAA appeared to have reached the same mean final weight or PWG as the basal diet. It also appeared that the higher the percentage of CAA that were supplemented a decrease in the mean final weight and PWG was observed. There was a high variation observed in the growth performance of the shrimp. The FCR for the treatments was also very poor. Another trial is being run comparing a fishmeal based diet to a soybean meal based diet with and without amino acid supplementation at two different protein levels and will be reported.