Improving the quality and reducing harmful microbes of total mixed ration silage with dried soybean curd residue

Abstract

The production of safe and high-quality silage has always been the main concern. This experiment aimed to investigate the impact of waste dried soybean curd residue (SR) and Lactobacillus plantarum CCZZ1 on the fermentation quality and microbial community of total mixed ration (TMR) silage based on Napier grass (Pennisetum purpureum). Napier grass was made into TMR, and SR at 3%, 6% or 9% on dry material basis was included, which replaced the equivalent amount of corn meal, then they were inoculated without or with Lactobacillus plantarum CCZZ1 (10⁵ cfu g⁻¹; LP). The research results showed that incorporating SR even at 3% resulted in significant reduction in ammonia nitrogen content (87.3 g kg⁻¹ total nitrogen vs. 109.7 g kg⁻¹ total nitrogen), increased lactic acid content (34.4 g kg⁻¹ DM vs. 25.5 g kg⁻¹ DM), and higher relative abundance of Lactobacillus (94.5% vs. 32.2%). Additionally, it led to decreased relative abundances of pathogenic microorganisms such as Escherichia coli (< 0.1% vs. 9.68%), Staphylococcus epidermidis (< 0.1% vs. 9.46%), and Streptococcus pneumoniae (< 0.1% vs. 8.53%) during the ensiling process. When SR was used together with LP inoculation, they were further improved. These findings suggest that the inclusion of SR, even at a 3% level without LP inoculation, can effectively improve the fermentation quality and microbial profile of TMR silage based on fresh Napier grass. This offers a promising technical approach to utilizing SR and producing safe and high-quality TMR silage based on fresh grass.

Graphical Abstract