Óleos funcionais como aditivo em dietas de alto grão para bovinos de corte em confinamento– produção de gases in vitro

Abstract

The objective of this study was to evaluate the in vitro production of rumen gases in high-grain diets with the inclusion of virginiamycin additives, Essential® functional oil composed of castor and cashew nut liquid functional oils and the consortium of Essential® functional oil with monensin for feedlot finished cattle. Three Girolando cows with average weight of 650 ± 100 kg were used as inoculum donors, the additional inoculum was obtained by mixing three inoculums. A randomized block design (RBD) was used, where the 4 diets were tested in 4 blocks (3 inoculum donor animals plus an additional block – mixture of three inoculums). Diets without additive and diets with the inclusion of the additives virginiamycin, functional oil (Essential®) and the association of functional oil (Essential®) with monensin in high-grain diets for feedlot finishing cattle and their effects on ruminal gases production were evaluated in vitro. Pressure measurements were performed at times 2, 4, 6, 9, 12, 16, 20, 24, 30, 36, 48, 72 and 96 hours. By the parallelism test, the diets with additives were parallel (p<0.05), only the diets with virginiamycin and functional oil with monensin were identical (p<0.05). The inclusion of virginiamycin and functional oil with monensin reduced the total production of gases in relation to the control and functional oil treatments, however the diet with functional oil obtained similar total production of gases to the other treatments with additives in relation to the control. Colonization time was shorter for diets without additives and with functional oil. The fractional degradation rate (µ) increased with the inclusion of the additives virginiamycin, functional oil and functional oil with monensin in relation to the diet without additive. The control diet showed effective degradability with a passage rate 8% h-1 higher than the diets with additives, followed by the diet with functional oil, virginiamycin and essential oil + monensin, which had lower values of effective degradability compared to the control diet. The diet without additives had dry matter degradation in relation to diets with virginiamycin additives, functional oil with monensin (p<0.05), however, when the essential oil treatment was compared with the other treatments, they had similar dry matter degradation. Organic matter degradability was similar for all treatments (p>0.05). The use of the functional oil additive associated or not with monensin in an exclusively concentrated diet for feedlot-finished cattle promotes degradation of dry and organic matter similar to the diet with virginiamycin additive. The use of the functional oil additive in a high-grain diet for feedlot-finished cattle reduces the cumulative production of gases in vitro in relation to the diet without additive, however, the association with monensin potentiates the reduction in the total production of gases, being similar to the diet with virginiamycin. The degradation of matter and organic in vitro is similar for diets with the inclusion of the additives virginiamycin and functional oil associated or not with monensina.