Effect of dietary protein level on apparent heat increment and post-prandial nitrogen excretion of Penaeus setiferus, P-schmitti, P-duorarum, and P-notialis postlarvae

Abstract

The calorigenic effect of feeding (apparent heat increment, AHI) and post-prandial nitrogen excretion (PPNE) were measured in postlarval (PL 25-30) Penaeus setiferus, P. schmitti, P. duorarum and P. notialis fed a fixed ration of 3 mg/animal using purified diets with 40, 50, 60, or 65% protein, Both AHI and PPNE increased with increasing dietary protein, The contribution of PPNE to AHI varied from 6.1 to 94%, with lesser values for P. setiferus and greater ones for P. duorarum, Also, the AHI coefficient (percentage of ingested energy) increased with increasing dietary protein. The AHI and PPNE coefficients for the four shrimp species ranged from 0.3 to 6.5% and 0.02 to 5.04% of ingested energy, respectively, These results suggest close relationships among protein requirements, the capacity to use dietary proteins as a source of energy, and adaptation by different species to different types of food, The amount of energy used for production of ammonia is proposed as an adequate measure of the part played by dietary proteins in food cost.