Supplementation of coated and uncoated crystalline amino acid mix in formulating a low-fishmeal diet for Penaeus monodon (Fabricius, 1798): Effect on growth, digestibility, body composition, haemolymph indices and nitrogen metabolism

Abstract

A sixty-day feeding trial was conducted to elucidate the effect of coated and uncoated crystalline amino acid mix (CAA) in Penaeus monodon. The control diet (CNT) was formulated with 250 g/kg fishmeal, and three more test diets were prepared by replacing 50% (125 g/kg) of fishmeal (w/w) using a blend of plant proteins with no supplementation of CAA (AA-NL), supplementation of uncoated (AA-NC) and coated (AA-CT) CAA. The AA-CT diet showed (p < .05) lower leaching of amino acids (1.13%) than other diets (2.78%–3.04%). DGC was high (p < .05) in shrimp fed on CNT and AA-CT (1.48%–1.49%/day) than other groups (1.32%–1.37%/day). Of all the treatments, FCR was poor (p < .05) in AA-NL (2.25). The dietary treatments did not influence survival (p = .841) and whole-body composition. The peak of free amino acid was synchronized (60 min) between AA-CT and CNT groups. The control group showed a higher nitrogen intake, oxygen consumption and O:N ratio and lower ammonia-N excretion. Haemolymph indices varied (p < .05) among the dietary groups. As a result of the N-metabolism study, the experimental diets were ranked as CNT>AA-CT> AA-NC. In conclusion, a blend of CAA could be effective in formulating low-fishmeal diets and could replace 50% (125 g/kg) of dietary fishmeal using a plant protein mix in P. monodon.