Crude protein reduction with amino acid supplementation in tambaqui fingerling diets

Abstract

The aim of this study was to evaluate the effect that reduced crude protein (CP) diets with amino acid supplementation, based on the ideal protein concept, have on the performance of tambaqui fingerlings. In total, 750 fingerlings with an initial weight of 0.44 ± 0.14 g, were used in a completely randomized design, with six treatments, five replications, and 25 fish per experimental unit. Treatments consisted of six isocaloric, isocalcic, isophosphoric, and isolysinic diets containing 32.0, 30.5, 29.0, 27.5, 26.0, and 24.5% CP. Performance parameters, carcass yield, body composition (body humidity, protein, and fat content), and nitrogen retention efficiency (NRE) of the fish were evaluated. When the CP content was reduced to 27.5%, there was an improvement in weight gain, specific growth rate, feed conversion, and protein efficiency rate. Feed intake was higher in fish fed diets containing 26% CP, followed by those fed diets containing 29 and 27.5% CP; diets containing other levels of CP did not differ among themselves. CP intake was reduced by the use of diets containing 24% CP, and the carcass yield was not influenced by the treatments. Reduced CP had no influence on body composition. NRE was higher in response to diets containing 26.0 and 24.5% CP. Reducing dietary CP content, from 32.0 to 24.5%, based on the ideal protein concept, is possible for tambaqui fingerlings, and a decrease of up to 24.5% enhances the fish performance. Key words: Amino acids, Colossoma macropomum, performance, protein nutrition ResumoAvaliou-se os efeitos da redução da proteína bruta (PB) com suplementação de aminoácidos, com base no conceito de proteína ideal, em rações no desempenho de alevinos de tambaqui. Utilizou-se 750 alevinos com peso inicial de 0,44 ± 0,14 g, em delineamento inteiramente casualizado, com 6 tratamentos, 5 repetições e 25 peixes por unidade experimental. Os tratamentos consistiram em 6 rações isoenergéticas, isocálcicas, isofosfóricas e isolisínicas com 32,0; 30,5; 29,0; 27,5; 26,0; 24,5% de PB. Avaliaram-se as variáveis de desempenho, composição corporal (umidade, proteína e gordura corporais) e eficiência de retenção de nitrogênio (ERN). Com a redução da PB a partir de 27,5%, observou-se melhora no ganho de peso, na taxa de crescimento específico, na conversão alimentar e na taxa de eficiência proteica. O consumo de ração foi superior nos peixes alimentados com dietas contendo 26% de PB, seguidos de 29,0 e 27,5% de PB, os demais níveis não variaram entre si. O consumo de proteina bruta reduziu com a utilização da dieta com 24% de PB e o rendimento de carcaça não foi influenciado pelos tratamentos. A redução da PB não influenciou a composição corporal dos peixes. A ERN foi superior nos níveis de 26,0 a 24,5% de PB. É possível reduzir de 32,0 para 24,5% o teor de PB em rações, com base no conceito de proteina ideal, para alevinos de tambaqui, e a redução do teor de PB até o nível de 24,5% potencializa o desempenho dos peixes.

The farming and husbandry ofColossoma macropomum: From Amazonian waters to sustainable production

“…Considering that fish do not have specific dietary protein requirements, but rather need a balanced pool of dietary essential amino acids, 254,255 experimental trials based upon the concept of ideal protein 273 or, as currently redefined, the essential nitrogen concept are fundamental for the advancement of knowledge on the nutrition and feeding of tambaqui. In this regard, Lima et al 274 reported that it is possible to reduce dietary protein contents from 32 to 24.5% if the diet of postlarvae tambaqui (0.44 g) is supplemented with a balanced pool of essential amino acids. In the same line of research, Marchão et al 275 reported that juvenile tambaqui (22.9 g) require 1.58% dietary lysine, that is diets containing 5.7% lysine within the crude protein.…”