Enhancing fermentation quality and fiber decomposition of <i>Phragmites australis</i> silage by introducing <i>Bacillus subtilis</i> and lactic acid bacteria consortia.

Abstract

<h4>Introduction</h4>As a low-cost, high-fibre biomass resource, <i>Phragmites australis</i> (reed) has significant potential for feed applications, particularly as a partial replacement for conventional roughage in ruminant diets.<h4>Methods</h4>This study investigated the effects of integrating <i>Bacillus subtilis</i> (<i>B. subtilis</i> BNCC109047) with homofermentative/ heterofermentative lactic acid bacteria (LAB) consortia on the fermentation and nutritional quality of <i>Phragmites australis</i> (reed) silage. Five treatments were evaluated: a Control (CK, without inoculum) and four inoculants-LAB (1.5 × 108 CFU/kg LAB, 1:4 homofermentative (<i>Lentilactobacillus plantarum</i> BNCC 336421 and <i>Pediococcus pentosaceus</i> BNCC 135034 in a ratio of 1:1): heterofermentative (<i>L. buchneri</i> BNCC 187961) ratio), LAB-BS2.5 (LAB plus 2.5 × 10⁷ CFU/kg <i>B. subtilis</i>), LAB-BS5.0 (LAB plus 5.0 × 10⁷ CFU/kg <i>B. subtilis</i>), and LAB-BS10.0 (LAB plus 1.0 × 10⁸ CFU/kg <i>B. subtilis</i>)-with triplicate samples per group. Silage fermentation was conducted for 90 days.<h4>Results</h4>LAB-BS10.0 demonstrated superior fermentation outcomes, achieving the highest lactic acid-to-total acid ratio (62.3%, <i>p</i> < 0.05) and the lowest ammonia nitrogen (NH₃-N) content (0.60 ± 0.09 g/kg, <i>p</i> < 0.05). Acetic and butyric acid concentrations were significantly reduced (<i>p</i> < 0.05), while neutral detergent fiber (NDF) decreased by 5.9% compared to the Control. Ether extract (EE) increased to 4.76% (<i>p</i> < 0.01), highlighting enhanced lipid preservation.<h4>Conclusion</h4>These results emphasize the synergistic potential of <i>B. subtilis</i> and LAB to optimize <i>P. australis</i> silage, providing a sustainable strategy to enhance forage quality and tackle global feed shortages.