Assessing the impact of phyllosphere microbiota on dynamics of in-silo fermentation of Italian ryegrass harvested at heading and blooming stages.

Abstract

The present study aimed to investigate the relationship between the phyllosphere microbiota of Italian ryegrass (Lolium multiflorum Lam.) harvested at heading (H) [> 50% earing rate or 216 g kg-1 fresh weight (FW)] and blooming (B) (> 50% bloom or 254 g kg-1 FW) stages and in-silo fermentation products, and the composition, abundance, diversity and activity of bacterial community. In total, 72 (4 treatments × 6 ensiling durations × 3 replicates) laboratory scale (400 g) silages of Italian ryegrass were prepared: (i) irradiated heading stage silages (IRH) (n=36) were inoculated with phyllosphere microbiota inoculum (2mL) eluted from fresh Italian ryegrass at either heading (IH) (n=18) or blooming (IB) (n=18) stages; (ii) irradiated blooming stage silages (IRB) (n=36) were inoculated with either IH (n=18) or IB (n=18). Triplicate silos of each treatment were analyzed after 1, 3, 7, 15, 30 and 60 days of ensiling. In fresh forage, Enterobacter, Exiguobacterium and Pantoea were the three major genera at heading stage, and Rhizobium, Weissella and Lactococcus were the most abundant genera at blooming stage. Higher metabolic activity was found in IB. After 3 days of ensiling, the large amounts of lactic acid in IRH-IB and IRB-IB can be attributed to the higher abundances of Pediococcus and Lactobacillus, 1-phosphofructokinase, fructokinase, l-lactate dehydrogenase and glycolysis I, II and III. The composition, abundance, diversity and functionality of the phyllosphere microbiota of Italian ryegrass at different growth stages could remarkably affect silage fermentation characteristics. © 2023 Society of Chemical Industry.