Níveis de energia líquida com e sem ajuste nutricional para suínos machos castrados em recria

Abstract

The use of the liquid energy system to formulate diets for pigs meets the energy requirement more accurately, as it equalizes the energy needs of the animals and the energy content of the feeds. However, in the scientific literature, studies that evaluated net energy levels did not investigate the effects of energy levels comparing their nutritional adjustments. In this context, this study was carried out with the objective of evaluating levels of net energy (NE) with and without nutritional adjustment for castrated male pigs, in rearing. Sixty male castrated pigs, from 30 to 50 kg and from 50 to 70 kg, were distributed in a randomized block design, in five diets with 2.35, 2.45, 2.55, 2.65 Mcal of EL maintaining calorie ratio: nutrient and 2.65 Mcal of EL changing the calorie: nutrient ratio, with two animals per pen and six repetitions per treatment. EL levels were obtained through the inclusion of soybean oil in place of kaolin. Performance variables such as final weight, weight gain, feed intake, net energy, digestible lysine and crude protein were evaluated, and carcass variables such as loin eye area, muscle depth, backfat thickness and lean meat. The increase in EL levels in the diets reduced (P<0.05) feed intake and digestible lysine, and improved (P<0.05) feed conversion in the two evaluated phases. In the first phase, NE consumption had an increase over energy concentration, and in the second phase, net energy consumption showed a linear reduction (P<0.05). There was no effect on carcass traits with increasing levels of EL in the diets. The level of 2.65 Mcal/kg without adjustment provides the best performance for barrows from 30 to 70 kg, without changing the carcass characteristics.