Fermentative profile and nutritional value of sugarcane silages inoculated with a mixture of fibrolytic enzymes

Abstract

Sugarcane has a high yield potential; however, ensiling has been a challenge, and its fibre has low quality for ruminant feed. This study aimed to evaluate increasing levels of a fibrolytic enzymatic blend (300 U xylanase + 300 U cellulase/g) during sugarcane ensiling on fermentative profile, losses, chemical composition, in vitro degradation, and aerobic stability. Forty silos were assigned to four treatments: 0, 200, 400 and 600 mg enzymatic blend/kg sugarcane fresh matter. The trial was performed in a randomised blocked design, in which five sugarcane cultivars were defined as blocks. Silos were performed in 15-L PVC tubes and stored at room temperature for 45 days. Enzyme level did not affect silage pH, ammonia-N, soluble carbohydrates, ethanol, or organic acid concentration. Although increasing enzyme levels linearly increased effluent losses, there was no effect on gas losses or dry matter recovery. Treatment had no effect on silage chemical composition, in vitro degradation, or silage pH after aerobic exposure. However, enzyme treatment quadratically affected silage temperature after aerobic exposure and aerobic stability period. Intermediate levels of enzymes increased silage temperature after aerobic exposure and reduced the aerobic stability period. Therefore, addition of enzymes during sugarcane ensiling shows no effect on silage fermentation, nutritional value or dry matter recovery, but linearly increases effluent losses. Although an intermediate level of enzymes decreases aerobic stability, it has no effect on silage pH after aerobic exposure.