Assessment of the ideal ratios of digestible essential amino acids for pacu,Piaractus mesopotamicus, juveniles by the amino acid deletion method

Abstract

The present study aimed to determine the ideal ratios of digestible essential amino acids (EAAs) for pacu (Piaractus mesopotamicus) juveniles by the amino acid (AA) deletion method. A completely randomized design which consisted of 11 treatments and three replicates each was used. The treatments included a control diet (CD) containing 55% of nonpurified natural ingredients and 45% of purified synthetic amino acids and ingredients, and other ten isonitrogenous and isoenergetic EAA limiting diets (LDs), each being deficient in 44.4 ± 0.02% of the respective EAA. Pacu juveniles with initial average body weight of 6.22 ± 0.09 g were distributed among 33 fiber glass tanks. Fish were fed with semipurified and extruded diets for 113 days two times a day until apparent satiation. The ideal ratio of each dietary EAA was calculated on the basis of the relationship between body N retention and amount of EAA deleted from the respective EAA LD. Based on the AA deletion method, the ideal ratios of digestible EAAs for pacu juveniles, relative to lysine requirement of 100% were estimated as: methionine 14.6%, threonine 35.0%, tryptophan 6.6%, arginine 62.8%, histidine 13.6%, isoleucine 26.3%, leucine 43.7%, phenylalanine 27.2%, and valine 35.8%.

Effect of protein reduction with indispensable amino acid supplementation at different levels in practical diets of Nile tilapia (Oreochromis niloticus) fish.

“…Therefore, it has become essential to minimize the reliance on FM by using less expensive protein ingredients and/or reducing dietary protein levels in fish diets, but in both cases, the deficiency in some essential amino acids, which are known as "limiting amino acids" is the most prominent concern. Therefore, the strategy of crystalline amino acid (CAA) supplementation has been widely used in tilapia diet formulation based on the ideal concept to ensure a well-balanced amino acid profile for optimum growth performance [6][7][8] .…”