Óleo de palmiste em dietas para tourinhos em confinamento

Abstract

In order to study the effect of palm kernel oil on metabolism and animal production, two experiments were carried out to determine the best level (0.0; 11.5; 23.0 and 34.6 g/kg DM) of inclusion of palm kernel oil (PO) in the diet of bulls in a feedlot. The first experiment was carried out in a completely randomized design, with thirty-two Nellores bulls, with an average age of 24 months and an average body weight of 413 ± 29.0 kg, to assess nutrient intake, performance, ingestive behavior and carcass characteristics. The second experiment was carried out in a 4 x 4 double Latin square experimental design, with eight crossbred steers with ruminal cannula with an average body weight of 435 ± 70 kg, in which the digestibility coefficients, nitrogen balance, microbial protein synthesis , short-chain fatty acids and the rumen protozoan population count were estimated. The inclusion of palm kernel oil resulted in a negative linear effect on intake of kg/day of DM (P < 0.001), CP (P < 0.001), apNDF (P < 0.001), NFC (P < 0.001) and TDN (P < 0.001). However, intake of EE (P < 0.001) showed a positive quadratic effect with maximum predicted intake at 15.36 g/kg DM level. There was no effect of palm kernel oil on the time spent (min/day) on feeding (P = 0.921), but a positive quadratic effect (P < 0.001) was observed for the time spent on rumination and a quadratic reduction (P < 0.001) in idle time. Digestibility of DM (P < 0.001), apNDF (P < 0.001) and TDN (P = 0.004) decreased linearly. On the other hand, EE digestibility (P = 0.053) had a trend of increase with the level of PO in the diet. The digestibility coefficient of CP (P = 0.475) and NFC (P = 0.114) did not change significantly. The consumption of nitrogen (P < 0.001), nitrogen retained (P < 0.001) and the production of microbial protein (g/day) (P < 0.001) decreased linearly with the increase of palm kernel oil. However, for the efficiency of microbial protein production in g/kg TDN ingested there was no influence (P = 0.807). A linear reduction was observed for the final weight (P < 0.001), average daily gain (P < 0.001), hot carcass weight (P < 0.001), cold carcass weight (P < 0.001), hot carcass yield (P < 0.001), cold carcass yield (P < 0.001), rib eye area (P = 0.015) and thickness of subcutaneous fat (P = 0.002). The inclusion of palm kernel oil in up to 34.6 g / kg DM in diets of confined bulls is not9 recommended, as it reduces the consumption of DM and nutrients, in addition to negatively affecting digestibility and performance.