Effects of Lactobacillus plantarum and Cellulase on Mixed Silages of Amaranthus hypochondriacus and Cornmeal: Fermentation Characteristics, Nutritional Value, and Aerobic Stability

Abstract

In order to develop new feed resources, the aim of this study was to investigate the effects of moisture content, additives, and their interactions on the fermentation quality, aerobic stability, and in vitro digestibility of mixed silage of amaranth and cornmeal. The mass ratios of amaranth and cornmeal were 69:31, 76:24, and 84:16 for adjusting the moisture content of silage to 60% (W1), 65% (W2), and 70% (W3), respectively. The silage treatments included no additives (U), the addition of Lactobacillus plantarum (L), the addition of cellulase (E), and the addition of Lactobacillus plantarum + cellulase (M) mixed reagents. The results revealed that the pH and ammonia nitrogen (NH3-N/TN) ratios were significantly lower in W1 than in W2 and W3 (3.66,19.3 g kg−1 TN vs. 3.70, 3.70, 20.0 kg−1 TN, 25.1 kg−1 TN, p < 0.05). Moreover, dry matter (DM), organic matter (OM), in vitro dry matter digestibility (ivDMD), in vitro organic matter digestibility (ivOMD), and in vitro crude protein digestibility (ivCPD) significantly increased (p < 0.05). Meanwhile, the aerobic stability of mixed silage containing amaranth and cornmeal decreased with increasing water content. The aerobic stability of the L, E, and M treatment groups was improved by 15, 105, and 111 h, respectively, compared with that of the control group at W1. The pH and NH3-N/TN ratios were lower with the addition of E (E and M) than with the absence of E (U and L) (3.73, 20.1 g kg−1 DM vs. 3.64, 22.9 g kg−1 DM, p < 0.05). NDF and ADF were significantly lower with the addition of E than without the addition of E (598 g kg−1 DM, 145 g kg−1 DM vs. 632 g kg−1 DM, 160 g kg−1 DM, p < 0.05). However, CP, ivDMD, ivOMD, and ivCPD were significantly higher (p < 0.05). AA and NH3-N/TN were significantly lower (p < 0.05) with the addition of L (L and M) than without the addition of L (U and E). In conclusion, the best fermentation quality, in vitro digestibility, and aerobic stability of amaranth and cornmeal mixed silage treated with Lactobacillus plantarum + cellulase (M) were achieved at 60% water content. The present study confirmed the potential of amaranth as silage and its potential application for improving feed quality and animal performance.