Inoculant effects on limpograss silage nutritive value, fermentation characteristics, microbiology, and in vitro gas...

The objective of this study was to evaluate the effects of a microbial inoculant on nutritive value, fermentation parameters, microbiology, and gas production of 'Gibtuck' limpograss (Hemarthria altissima [Poir.] Stapf & C.E. Hubbard) silage. Treatments were silage treated or not with an inoculant containing a mixture of Lactococcus lactis and Lentilactobacillus buchneri (SiloSolve FC; Novonesis, Lyngby, Denmark) at 0.5 g/Mg of as-fed forage. Treatments were distributed in a randomized complete block design with 10 replicates (blocks), where each block consisted of one control and one inoculated mini silo. The experiment was conducted in Ona, FL, from March to July 2023. Twenty 9 m² plots of established Gibtuck limpograss were harvested at 15-cm stubble height with 58 days of regrowth interval. Samples were chopped, treated, placed into mini-silos (capacity of 1.2 kg of fresh forage), and silos were sealed immediately. The silos were opened after 60 days for analysis. There was no difference (P ≥ 0.42) between the inoculant and control treatments on dry matter concentration, dry matter recovery, neutral detergent fiber (NDF), non-fiber carbohydrates, and total digestible nutrients concentrations. However, silage treated with inoculant had greater (P ≤ 0.04) crude protein, in vitro true dry matter digestibility, and NDF digestibility, and lesser acid detergent fiber concentrations than the control. The inoculant did not affect (P ≥ 0.28) silage pH and lactic acid concentrations but resulted in greater (P ≤ 0.02) acetic and propionic acids, and decreased butyric acid, isobutyric acid, and ammonia-N concentrations. Aerobic stability, and mold and yeast counts were not affected (P ≥ 0.28) by the inoculant treatment. At the genus level, there was no difference (P ≥ 0.54) in relative abundance of Lentilactobacillus, Enterobacter, Enterococcus, and Weissella among treatments, but silage inoculation tended to reduce Clostridium and Pediococcus (P ≤ 0.09), while increasing the relative abundance of Lactococcus and Bacillus (P ≤ 0.01). Limpograss silage treated with inoculant tended to reduce in vitro gas (P = 0.07) and methane production (P = 0.06) compared with the control. These results indicate that SiloSolve FC is an effective microbial inoculant for limpograss silage and suggest that it may potentially improve the quality of other warm-season perennial grass silages under subtropical and tropical conditions.