Valor nutricional da silagem da parte aérea da mandioca colhida em diferentes idades e aditivadas com grãos de milho moído

Abstract

Cassava (Manihot esculenta Crantz) has become a good alternative for silage production in semiarid regions. However, it presents high-moisture content at harvest, which requires the use of additives (e.g., ground grain corn). The objective of this study was to evaluate the effect of ground grain corn as additive to silage of aerial part of cassava (APC) harvested at diferente maturities on the fermentation, chemical, and microbiological characteristics. The treatments were: SM-90 (APC harvested at 90 d, without corn); SM-120 (APC harvested at 120 d, without corn); SM-150 (APC harvested at 150 d, without corn); CM-90 (APC harvested at 90 d, with corn); CM-120 (APC harvested at 120 d, with corn); CM-150 (APC harvested at 150 d, with corn). A total of 15% ground grain corn was added based on the total silage weight. Each treatment consisted of four replicates, totaling 24 experimental units. Plastic buckets (12 L) were used as experimental silos. On average, 8.718 ± 0.248 kg of silage was compacted (density of 726.46 ± 20.70 kg m-3). The silos were opened after 60 d of storage. The means were compared using Tukey's test at 5% significance. There was an effect of maturity (P < 0.001) on the lactic acid bacteria count, with higher counts in silages harvested at 120 and 150 d. There was an effect of the additive (P = 0.006) on the yeast and aerobic spore-forming bacteria count, where higher counts were observed in silages without additive. There was an effect (P=0.011) of the additive on aerobic stability, with silages with additive having lower stability. There was an effect (P=0.025) of maturity on dry matter losses (DML), which was lower in silages harvested at 90 and 120 d. There was an effect of maturity (P=0.001) and additive (P<0.001) on DM concentration, which was higher in silages harvested at 150 d. Higher dry matter (DM) was observed in silage with additive. There was an effect (P<0,05) of maturity, additive, and maturity × additive interaction on crude protein (CP) and neutral detergent fiber (NDF) concentration. The additive in silages harvested at 90, 120, and 150 resulted in lower CP and lower NDF than silages harvested at the same maturity, without additive. The inclusion of ground corn grain favored the fermentation process, reducing fungal and yeast counts and PMS, improving the nutritional profile, but reducing the aerobic stability of the feed.