Evaluating the Combined Effect of Lactococcus lactis, Bacillus subtilis and Saccharomyces cerevisiae in the Mixed Silage of Navel Orange Pomace and Rice Straw

A three-factor completely randomized design was used to evaluate the effects of Lactococcus lactis, Bacillus subtilis, and Saccharomyces cerevisiae on the fermentation quality and nutritional composition of mixed silage prepared from navel orange pomace and rice straw. The addition of L. lactis increased lactic acid content and Flieg’s score of the mixed silage. The addition of B. subtilis decreased the pH value and increased the lactic acid content of the mixed silage. The addition of S. cerevisiae decreased the lactic acid content and Flieg’s score of the mixed silage. However, the interaction between the three strains significantly affected many parameters of the mixed silage. With respect to fermentation quality (Flieg’s score), adding 0.3 g kg−1 L. lactis and not adding S. cerevisiae achieved the best performance of the mixed silage. Under these conditions, increasing the level of B. subtilis resulted in a higher crude protein content of the mixed silage, whereas neutral detergent fiber and acid detergent fiber contents first decreased and then increased, and water-soluble carbohydrate content first increased and then decreased. Therefore, within the selected combination of adding 0.3 g kg−1 L. lactis and not adding S. cerevisiae, the addition of 0.8 g kg−1 B. subtilis gave the best nutritional quality.