Threonine : lysine relation for tambatinga fingerlings (Colossoma macropomum x Piaractus brachipomum)

Abstract

The research was carried out with the objective to define the lower threonine:lysine relation which does not interfere on performance of tambatinga fingerlings. A total of 300 fingerlings with mean initial weight of 5.31 ± 0.24 g were reared into 20 interconnected tanks with water recirculation system for 35 days. Fish were fed with isonutritive diets varying the threonine:lysine relation in 67.43, 62.81, 58.19, 53.57, and 48.97%. Fish were fed four times daily until apparent satiation. The parameters of growth performance and carcass composition were submitted to regression analysis. There were no significant differences in the parameters studied, with the reduction of threonine:lysine. It was considered that the relation of 48.97% threonine:lysine digestible, which corresponds to levels of 1.11 and 1.00% of total and digestible threonine, respectively, can be used in diets formulation for tambatinga fingerlings, without impairment for productive performance.