Effects of different moisture content and additives on the quality and nutritional value of pepper straw silage

This experiment used the fresh straw after the last harvest of pepper (Capsicum annuum) as raw material. The moisture content was adjusted to 73% (H), 65% (M), or 55% (L) by pre-drying, and the additives used were 1.0 × 10⁶ cfu·g⁻¹ Lactobacillus plantarum (W₁), 1.0 × 10⁶ cfu·g⁻¹ L. plantarum + 0.15 g·kg⁻¹ cellulase (W₂), 0.5 × 10⁶ cfu·g⁻¹ L. plantarum + 0.5 × 10⁶ cfu·g⁻¹ Bacillus subtilis (W₃), 1.0 × 10⁶ cfu·g⁻¹ L. plantarum + 4% molasses (W₄), 0.15 g·kg⁻¹ cellulase (W₅), or with no additives (W₀) as the control group. After 60 d of silage at room temperature, the effects of different water content and additives on the quality and nutritional value of pepper straw silage were studied, and the optimal moisture content and additive treatment were determined. The results revealed that moisture content, additives, and their interaction had significant (P < 0.05) or extremely significant (P < 0.01) effects on the quality of pepper straw silage. When the moisture content was M, the contents of crude protein (CP), ether extraction, water-soluble carbohydrates (WSC), lactic acid (LA), and relative feed value (RFV) were the highest, pH and NH₃-N/TN were the lowest, and the silage quality was the best. The second-best water content was L. When W₃ and W₄ were used as additives, the dry matter, CP, WSC, LA, and RFV contents of the silage were higher than those of the other additives, while the pH and NH₃-N/TN were lower. Combined with sensory evaluation, comprehensive value evaluation, Cornell Net carbohydrate protein system and in vitro tests, the MW₃ combination revealed the best comprehensive effect, followed by MW₄. In summary, the most suitable water content of pepper straw silage is M, and the use of additives W₃ or W₄ had the best effect on silage quality; hence, these can be recommended for actual silage production.