Influência da adição de glicerina bruta na composição química de silagens pré-secadas de coast cross

Abstract

Tropical grasses, including Coast Cross, are characterized by having low dry matter and soluble carbohydrate contents, which, associated with the buffer power values, affect the ensiling 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 pre-dried Coast Cross grass silages as a function of the inclusion of different doses of crude glycerin and microbial inoculants. The experiment was implemented in a randomized block design, where four levels of inclusion of crude glycerin (0, 3.5, 7.0 and 10.5% ensiled natural matter) were tested, with 5 replications per treatment, totaling 20 experimental plots. To enhance the fermentation process, a commercial inoculant (INC) was added, consisting of Bacillus subtilis 2.0x109 CFU/g, Lactobacillus plantarum 8.0x109 CFU/g and Pediococcus acidilactici 1.0x1010 CFU/g. The results were subjected to analysis of variance, considering the inclusion doses of glycerol as sources of variation, evaluated using the Scott Knott test at 5% probability. An increase in the final weight of the bales was observed, both in Dry Matter (DM) and in Natural Matter (MN), where the highest doses of Crude Glycerin (GB) were applied. Regarding the fibrous fractions, an increase of 1.89% and a reduction of 3.93% and 12.71% for NDF was observed, for the ADF values, a reduction of 0.41%, 10.86% and 15 was observed. .50% for the treatments 3.5%, 7.0% and 10.5% MN respectively. A 34.44% reduction in the crude protein (CP) content was observed in the silages that were treated with doses of crude glycerin, compared to the control treatment. For the values referring to In Vitro Dry Matter Digestibility (DIVMS) positive quadratic effects were observed, a decrease of 4.15% was observed, and an increase of 1.82% and 12.84% for the 3.5% treatments, 7.0% and 10.5% respectively. It was concluded that despite the diluting effect of crude glycerin on CP, there was an increase in the nutritional value of pre-dried Coast Cross grass silages, this result being aided by the inclusion of the microbial additive, thus providing a better fermentation of the ensiled material.