Efficacy of six lactic acid bacteria strains as silage inoculants in forages with different dry matter and water-soluble carbohydrate content

The dry matter (DM), water-soluble carbohydrate (WSC) content, and epiphytic microbiota of forage during ensiling are critical for the production of high-quality preserved forage. This study tested the efficacy of six additive treatments (10⁶ CFU/g FM Lacticaseibacillus rhamnosus IMI 507023, Lactiplantibacillus plantarum [IMI 507026, IMI 507027, and IMI 507028] or Pediococcus pentosaceus [IMI 507024 and IMI 507025]) as ensiling agents for grass-clover preservation. Treated and untreated forages were ensiled in 1.75 L glass jars and stored for 90 days at 20 ± 2°C. The effects of treatments on silage fermentation and aerobic stability were tested using grass-clover forage at low and high levels of DM (24.0%–40.1%) and WSC (1.78%–5.27%). Data analysis using a mixed-effects model and principal component analysis revealed improved silage fermentation in treated forages compared to that in the control. The fermentation-related analytes in the treated silages (low pH, ethanol, acetic acid, and high lactic acid) represented a typical homofermentative metabolic pathway. The silage inoculants significantly lowered DM losses and ammonia-N, % of total nitrogen content, ranging between 30.4%–52.5% and 30.5%–63.1% respectively, compared to the control. Additionally, forage type interacted with treatment, indicating that forage management is vital for ensiling and should be considered alongside inoculant use. The improvement in aerobic stability by lactic acid bacteria (LAB) was inconsistent. The principal component analysis of all analytes showed that aerobic stability was most closely correlated with acetic acid and butyric acid concentrations. In conclusion, all LAB strains successfully improved the preservation of forage materials.