Daily digestible protein and energy requirements for growth and maintenance of sub-adult Pacific white shrimp (Litopenaeus vannamei)

This study utilized two diets (25 and 35% crude protein) fed at 10 different rates to produce differences in shrimp specific growth rate which were regressed against daily digestible protein (DP) and digestible energy (DE) intake to estimate daily DP and DE requirements for sub-adult L. vannamei. Apparent DP and DE requirement for maximum growth decreased throughout the 7-week trial as shrimp size increased. Mean apparent daily DP requirement for 7.69 to 13.08-g L. vannamei fed the 25% protein diet was 6.31 g DP kg-1 BW d-1 while the 35% protein diet produced a mean apparent daily DP requirement of 8.00 g DP kg-1 BW d-1 for 8.11- to 13.79-g L. vannamei. Maintenance requirements were estimated by regressing DP feed allowances back to zero weight-gain and were 1.03 g DP kg-1 BW d-1 for shrimp fed the 25% protein diet and 1.87 g DP kg-1 BW d-1 for shrimp fed the 35% protein diet. Mean apparent daily DE requirement for shrimp fed the 25% protein diet was 402.62 kJ DE kg-1 BW d-1 while the 35% protein diet produced an apparent daily DE requirement of 334.72 kJ DE kg-1 BW d-1. Mean apparent daily DE maintenance requirements for shrimp fed the 25% protein diet was 66.23 kJ DE kg-1 BW d-1 while the requirement was 78.82 kJ DE kg-1 BW d-1 for shrimp fed the 35% protein diet. Daily DP and DE requirements were also determined by regressing whole-body protein or energy change against daily DP and DE intake and were similar to those values obtained by regressing change in body weight against daily DP and DE intake. Another component of this project involved evaluating 32 different feedstuffs for dry matter, protein and energy digestibility coefficients. Fish meal apparent crude protein digestibility coefficients as a group were higher than all other ingredient classifications except purified ingredients. Protein in 48% soybean meal and 90% isolated soybean protein were significantly more digestible than protein found in fish, animal and marine meals tested. This data will improve the quality and reduce the cost of commercial shrimp feeds.