Effect of Applying Lactobacillus plantarum and Pediococcus acidilactici Isolated on Fermentation Dynamics, Microbial Community and Aerobic Stability of Napier Grass (Pennisetum purpureum) Silage

The aim of this study was to determine the effect of applying three of lactic acid bacteria isolates AZZ1, AZZ4, AZZ7 and one commercial (CB) on the fermentation dynamics, microbial community and aerobic stability of Napier grass silage. The grass was ensiled with or without the addition of a lactic acid bacteria inoculant at 1.0x10(6) CFU/g of fresh material to Napier grass silage. Napier grass was ensiled in laboratory silos and treated as follows: no additives (control), Pediococcus acidilactici (AZZ1), Lactobacillus plantarum subsp. plantarum (AZZ4), Lactobacillus plantarum subsp. argentoratensis (AZZ7) and Lactobacillus plantarum, Ecosyl MTD/1 (CB). To follow the fermentation dynamics during ensiling samples were taken on days 7, 14, 30, 60 and 90 of ensiling for chemical and microbiological analysis. Aerobic stability was determined on day 90 of ensiling. The experimental design was a completely randomized design, with a 5 x 5 x 3. The inoculant resulted in a more decreased (P<0.0001) in pH, water soluble carbohydrate, ammonia nitrogen, organic acid, aerobic bacteria and yeast, while a higher (P<0.0001) level of lactic acid content and lactic acid bacteria compared with control group. Treatment with AZZ4 had the better (P<0.0001) fermentation results. The aerobic stability of Napier silage was reduced with strains treatment compared with the control. In conclusion, the addition of bacteria inoculant resulted in better preservation and reduced the aerobic stability of silage.