Conservation, fermentation, and nutritional quality of apple pomace silage with moisture-absorbing additives

The objective of this study was to evaluate the use of moisture-absorbing additives for the conservation of apple pomace silage, and the effects on its fermentation and nutritional quality. The dry matter content (DMC) of apple pomace was determined using a microwave oven method, which was tested and compared to the standard oven method to facilitate calculation of the apple pomace quantities required to achieve 350 g kg-1 DMC in the ensiled mass. Five treatments were evaluated in experimental silos: fresh apple pomace (FAP); FAP with ground maize grain; FAP with soybean meal; FAP with wheat bran; and FAP with soybean hulls. A randomized block experimental design was used. Data were analyzed using the R statistical program, adopting a significance level of 0.05. The DMC obtained using the microwave oven method was similar to that obtained with the standard oven method (164.4 and 156.1 g kg-1, respectively). The nutritional composition of the silages varied with additives; soybean meal increased crude protein content, while soybean hulls increased the fiber fraction (p < 0.001). The pH values were below 4.20. The addition of wheat bran resulted in 176.42 g kg-1 of ammoniacal nitrogen, indicating increased proteolysis. The incorporation of moisture-absorbing additives into apple pomace silage reduced gas losses by 20.1% and effluent losses by 65.9% (p < 0.001). Overall, the additives improved fermentation profile and reduced losses, enhancing the silage's nutritional composition.