Impactos fermentativos e nutricionais na produção de TMRS ensiladas com adição de monensina e óleos essenciais

Abstract

The use of additives in silage is a common practice to improve its conservation and nutritional quality in total mixed ration (TMR) silages. Thus, the objective of this research was to evaluate the influence of the addition of sodium monensin (MON) and limonene essential oil (OEL) on the fermentative and nutritional quality of TMR silages. Two different trials were evaluated, the first to evaluate TMR silage for growing lambs (trial 1 ) with 65% dry matter (DM) and the other for lactating cows (trial 2) with two moisture conditions (30% and 40% DM). For both trials, the following treatments were used: control (no additive), MON35 (35 mg of monensin/kg DM), MON45 (45 mg of monensin/kg DM ), OEL300 (300 mg of essential oil/kg DM) and OEL600 (600 mg of essential oil/kg DM). Among the parameters evaluated, fermentation losses, short chain fatty acid profile, aerobic stability, chemical bromatological composition and in vitro DM digestibility (IVDMD) of the silages were analyzed. In trial 1, the treatments with OEL presented the lowest pH values and the highest lactic acid concentrations, with the OEL600 treatment leading to the greatest aerobic stability (297.88 h). Regarding the nutritional composition, the additives MON and OEL reduced the DM and non fibrous carbohydrate contents and only the starch contents of the treatments with OEL were lower than the others. In trial 2, the wetter silages (30% DM) and with OEL600 and MON35 were those th at presented the greatest gas losses (2.72and 2.13% DM respectively). Silages with higher moisture contents (30% DM) and with OEL600 showed the lowest DM recovery values(92.66% DM), lactic acid (5.59% DM) and higher pH (4.17) when compared to silages with lower moisture contents (40% DM). The highest lactic acid:acid ratios were observed in silages with higher moisture added with MON45 and MON35 (8.94 and 8.4 respectively). The acetic acid content was higher in the wetter silage and with OEL600 (1.54% DM). The use of MON and OEL increased aerobic stability, with the highest values observed for OEL600 (92.35 hours) and MON35 (91.56 hours). Treatments with MON and OEL resulted in silages with lower neutral detergent fiber and acid detergent fiber conten ts and higher ether extract and starch contents when compared to the control. The additives MON and OEL provided better IVDMD, with the treatment with MON35 having the best digestibility (77.56% DM). It is concluded that sodium monensin and limonene essent ial oil can improve the fermentation quality of TMR silage without major changes in the nutritional composition. However, OEL should be used in lower doses in wetter silages to avoid undesirable fermentations.