Óleo de palmiste na suplementação de ovinos a pastos.

Abstract

The inclusion of palm kernel oil in the supplement of grazing sheep and its effects on intake, ingestive behavior, digestibility, physiological and ruminal parameters and zootechnical performance were evaluated. Thirty-two crossbred, male, non-castrated sheep with an average initial weight of 23 kg were used for 74 days. The animals were kept in aruana grass paddocks and daily at 8:00 am, they received supplements in individual troughs. The supplements were composed of ground corn, soybean meal, mineral nucleus for sheep and levels of 0%, 2%, 4% and 6% of palm kernel oil and provided at 1.4% of body weight. For the evaluation of intake, digestibility, ingestive behavior and physiological parameters and performance, a completely randomized design was used. For the evaluation of short-chain fatty acids, ammoniacal nitrogen, pH and quantification of protozoa in the rumen, four male sheep with rumen fistula were used, which were distributed in a 4 x 4 Latin square, for a total period of 60 days. The data were submitted to polynomial regression analysis, using orthogonal contrasts to test the linear and quadratic effects of the inclusion of palm kernel oil in the sheep supplement on all evaluated variables. There was a linear reduction in the consumption of dry matter and nutrients with the inclusion of palm kernel oil in the supplement, except for the consumption of ether extract, which increased linearly (p=0.0002). The inclusion of palm kernel oil in the supplement reduced feeding time (p<0.0001) and increased resting time (p<0.0001). Rumination time was not affected. DM and cpNDF feeding efficiencies were not affected by the inclusion of palm kernel oil, however there was a reduction in DM (p=0.0172) and cpNDF (p=0.0273) rumination efficiencies. The digestibility of the ether extract increased as larger amounts of oil were added to the supplement (p<0.0001). The presence of palm kernel oil in the supplement reduced the rectal temperature of the animals (p=0.0477), but did not influence the respiratory rate. Ruminal pH, ammonia, acetate, butyrate and propionate values were not affected by the inclusion of oil. There was a reduction in final body weight (p=0.0273), total weight gain (p=0.0207) and average daily gain (p=0.0207) with the inclusion of palm kernel oil in the sheep supplement, however, efficiency or feed conversion was affected. The inclusion of up to 296% of palm kernel oil in sheep grazing supplement reduces consumption, alters feeding behavior, but does not affect ruminal fermentation parameters despite decreasing the population of ruminal protozoa. In addition, the inclusion of oil impaired the performance of the animals. It also reduced rectal temperature, which can be a benefit for animals raised in warmer regions, as it helps maintain thermal comfort.