Silage Making of Napier Grass and Sugarcane Top at Different Proportions: Evolution of Natural Fermentation Characteristics, Chemical Composition, and Microbiological Profile

The co-ensiling technique is widely used to improve silage quality; however, it remains unclear as to what high-quality silages can be made by co-ensiling Napier grass (NG) with Sugarcane top (ST). The aim of this study was to evaluate the fermentation characteristics, chemical composition, and microbiological profile of silage produced from mixtures of NG and ST in varying ratios. Silage was prepared using a small-scale fermentation system, and treatments were designed as control silage (NG ensiled alone) or with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%ST on a fresh matter basis with six replicates, respectively. Increasing ST in the silage reduced the contents of crude protein, ash, acetic acid, butyric acid, ammonia-N, as well as pH, but increased the contents of dry matter, ether extract, neutral detergent fiber, acid detergent fiber, water-soluble carbohydrate, lactic acid, and lactic acid bacteria. Lactobacillales and Enterobacterales were the dominant orders, with Lactiplantibacillus and Weissella as the dominant genera. Co-ensiling NG with ST enhanced microbial diversity and richness. ST, as a local by-product, is a viable additive to improve NG silage quality and nutrition. This study suggests that good-quality silages can be produced with NG: ST ratios of 40:60 to 20:80 and that these silages offer an opportunity to optimize the nutrient supply for ruminants.