Effect of fungal inoculants from sheep gut in rehydrated corn grain silage

This study evaluated the effects of Trichoderma longibrachiatum and Paecilomyces lilacinus, fungal strains isolated from the gastrointestinal tract of sheep, on the fermentation profile, chemical composition, and in vitro dry matter digestibility (IVDMD) of rehydrated corn grain silage (RCGS). Importantly, the primary aim of using these fungal inoculants was not to enhance energy availability or fiber degradation in corn grain, an ingredient naturally low in fiber and high in energy, but to assess the feasibility of using RCGS as a practical matrix for delivering direct-fed microbials (DFM) to ruminants, particularly those consuming low-quality forages typical of tropical livestock systems. Treatments included a control (CTL), a commercial lactic acid bacteria inoculant (ICO), and three fungal inoculants: P. lilacinus (IPA), T. longibrachiatum (ITR), and a combination of both fungi (IPT). Silages were stored for 45 or 90 days in a completely randomized 5 × 2 factorial design (5 microbial inoculants × 2 storage lengths). Overall, fungal inoculation had limited effects on fiber fractions and pH but influenced lactic and acetic acid concentrations. IPT and ITR treatments yielded the highest lactic acid levels, with IPT reaching 21.0 g/kg DM at 45 days, while CTL and ICO showed 12.2 and 11.1 g/kg DM, respectively. Inoculated treatments showed reduced enterobacterial counts and improved aerobic stability. The IPT treatment showed lower silage temperature compared to CTL and ICO treatments for about 80 h post-opening, followed closely by the ITR and IPA treatments. DMIVD was highest in ICO treatment (969 vs. 958 g/kg DM) at 45 days of storage, but became similar across treatments at 90 days (>957 g/kg DM). At 45 days of storage, CTL and IPT treatments exhibited 30.6 % lower gas losses and 29.8 % lower total losses compared to IPA and ITR. By 90 days, losses declined across all treatments, with CTL maintaining the lowest values and IPA the highest for both measures. These results suggest that combining P. lilacinus and T. longibrachiatum is an effective inoculation strategy for RCGS, promoting silage preservation through reduced fermentation losses and temperature rise, maintaining digestibility, stabilizing microbial populations, and enhancing fermentation end-products. The findings support the potential use of fungal-inoculated RCGS as a microbial delivery system for ruminants in tropical production settings.