Dried soybean curd residue: A promising absorbent for cleaner production of high-quality silage

Abstract

In humid and rainy regions, such as tropical and subtropical areas, forage crops have a high moisture content and are difficult to wilt after harvest, which can easily cause poor fermentation and effluent production of silage. In the present study, the best product, with a high moisture-absorbing capacity (MAC) and stable structure, was selected from 12 types of agricultural and sideline products and the effects of its addition to high-moisture Napier grass (Pennisetum purpureum) silage at 0%, 3%, 6%, or 9% of fresh grass weight were studied. The results showed that dried soybean curd residue (SR) not only had the strongest MAC but also had the most stable structure at different pH levels. Adding SR even at 3% significantly improved fermentation quality and reduced protein degradation and effluent production (38.3 vs. 107.5 ml kg−1 FM) during ensiling compared with those in the control (P < 0.01). The effluent production of control silage significantly increased in the first 30 days of ensiling (P < 0.01) and, thereafter, did not increase (P > 0.05). The dry matter and crude protein losses from the effluent in the control silage significantly increased (P < 0.01) during early ensiling (3–15 d), and there were no significant changes (30–60 d, P > 0.05). The addition of 6% SR completely prevented the production of effluent from the silage. These results demonstrate that SR is a promising and efficient moisture absorbent for cleaner production of high-quality silages without effluent.