EXIGÊNCIA DE METIONINA MAIS CISTINA DIGESTIVEL PARA MANTENÇA E EFICIÊNCIA DE UTILIZAÇÃO PARA TAMBAQUI COM DIFERENTES PESOS CORPORAIS.

Abstract

Tambaqui (Colossoma macropomum) is an endemic species of the Amazon river, which is prominent in Brazilian psiculture, due to its characteristics such as the taste of its meat, its omnivorous food habit, which allows the use of industrial feed in its creation and adapts well to the system intensive cultivation. However, there are few studies in the literature that report the effect of body weight on amino acid requirements for maintenance and utilization efficiency of for tambaqui. The objective was to determine the requirement of methionine plus digestible cystine for maintenance and utilization efficiency of use for tambaqui with different body weights. Two experiments were carried out, in the first experiment 125 tambaquis were used with initial mean weights of 100 ± 8.41 g and in the second experiment 75 tambaquis were used with weight of 300 ± 42.52 g. Both experiments were distributed in a completely randomized design, with four treatments and five replications, with five and three fish for animals with body weights of 100 and 300 g, respectively, per experimental unit. The treatments consisted of diets containing 0.264; 0.396; 0.528 and 0.660% methionine plus cystine digestible, formulated using the diet dilution technique. To determine the requirement of methionine plus digestible cystine for maintenance, a was performed regression analysis between the consumption of methionine plus digestible cystine and the retention of body protein; and maintenance was determined when consumption of methionine plus digestible cystine provided protein retention equal to zero. To determine the efficiency of using methionine plus cystine for growth, the value of the slope coefficient of the line was used, obtained through the regression analysis between the consumption of methionine plus ingested digestible cystine and its retention. The protein and methionine retention data plus cystine were compared by the parallelism test and no difference was observed between the parameters, being needed one equation for to describe the responses from tambaquis with body weights of 100 and 300 g. The requirement for methionine plus digestible cystine for maintenance tambaqui with body weights of 100 and 300 g is 60.47 mg kg-0.7 day-1 and the utilization efficiency is 42%, with no influence of body weight for the weight ranges 100 to 300 g.