Composição química de silagens pré-secadas de tifton 85 com a adição de inoculantes microbianos e glicerina bruta

Abstract

Tropical grasses, among them Tifton 85, are characterized by having low levels of dry matter and soluble carbohydrates, which associated with the high values of buffer power, harm the ensilage process resulting in a product that is not very attractive to animals. As a result, the objective was to evaluate the changes in the chemical composition of the pre-dried silages of Tifton 85 grass with the addition of different doses of crude glycerin and microbial additives. The experiment was implemented in a completely randomized design in a 3x3 factorial scheme, three doses of crude glycerin (0, 60 and 120 g / kg natural matter), and three types of inoculation [control (distilled water), SIL (Lactobacillus plantarum 2, 6x1010UFC / g and Pediococcus pentosaceus 2,6x1010UFC / g) and INC (Bacillus subtilis 2.0x109 UFC / g, Lactobacillus plantarum 8.0x109 UFC / g and Pediococcu sacidilactici 1.0x1010UFC / g)] with five repetitions per treatment (mini experimental silos) . A negative linear effect (P <0.05) was observed in the contents of mineral matter and fibrous fractions of silages due to the addition of crude glycerin. The reductions in the contents of NDF and ADF of the silages were 28.25 and 31.11%, when compared to the silage with a higher dose of crude glycerin with the control silage, respectively. The reductions in the levels of hemicellulose and cellulose were 29.28 and 39.54% in the comparison between the silage with the highest dose of crude glycerin and the control silage, respectively. No significant differences were observed between the doses of crude glycerin and the levels of CP of the silages, however an interaction (P <0.05) was observed between the doses and the inoculants. The mean values of CP levels were very close between treatments, ranging from 95.5 to 98.9 g / kg DM. The same behavior (P> 0.05) was observed in the lignin contents, whose results varied between 58.8 to 78.6 g / kg DM. The values of the in vitro digestibility coefficients of dry matter followed a positive linear behavior due to the addition of crude glycerin, varying from 510.9 to 699.1 g / kg DM which represents an increase of 36.83% in digestibility coefficient “in vitro” of dry matter. The use of inoculants also provided silages with higher digestibility coefficients 635.1 and 646.8 g / kg DM in silages inoculated with INC and SIL, respectively. It is concluded that crude glycerin increases the nutritional value of pre-dried Tifton 85 grass, and that microbial inoculants only collaborated with the improvement of digestibility.