| Resumo: |
Energy is a nutritional component obtained through the oxidation of organic nutrients that make up the diet, being used for maintenance and production of new body tissues. The objective of this study was to determine the level of digestible energy in the diet of tambatinga (♀Colossoma macropomum x ♂Piaractus brachypomus) in the phase between 20 and 100 grams. Five diets with different levels of digestible energy were formulated (2,900, 3,000, 3,100, 3,200, 3,300 Kcal of DE/kg). A total of 192 tambatinga juveniles with two initial weight ranges were used: 23.70 ± 0.34 g and 35.93 ± 0.51 g, distributed in a randomized block design. Increasing the digestible energy level of the diet did not influence (p > 0.05) weight gain, specific growth rate, feed conversion, energy efficiency for weight gain, body protein content, body moisture and protein depositions, and nitrogen retention efficiency of the fish. However, a linear increase (p < 0.05) was observed in digestible energy intake and body fat content. Body moisture content decreased linearly (p < 0.05) and body ash content decreased quadratically (p < 0.05) to an estimated level of 3,134 Kcal of DE/kg in the diet. A quadratic effect (p < 0.05) was observed on body fat and ash deposition, with lowest values at 3,038 and 3,108 Kcal of DE/kg, respectively. The recommended dietary level of digestible energy is 2,900 Kcal/kg, corresponding to an energy:protein ratio of 92.95 Kcal of DE/g, to optimize the performance and body deposition of tambatingas in the phase between 20 and 100 grams. |
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