Effects of microbial inoculants Enterococcus faecium EF2/3s and EF26/42 on microbial, chemical, and fermentation parameters in grass silage

Survival of inoculants in grass silages may enable them to improve the quality of silages through enrichment with polyunsaturated fatty acids (PUFAs). The effects of 2 inoculants, Enterococcus faecium 2/3s (EF2/3s) and E. faecium 26/42 (EF26/42), on nutrient composition, fermentation parameters, and fatty acid content in grass silages during ensiling (111 days) of fresh grass (G) were examined under laboratory conditions. The G [285 g of dry matter (DM) kg^–1] was ensiled in 36 polyethylene jars (1 L) divided into 3 × 12 sets per treatment and ensiled at 21 °C for 111 days. The 3 silage treatments used were: 1) grass without inoculant (GS, control), 2) grass inoculated by the strain EF2/3s (GS+EF2/3s), and 3) grass inoculated by the strain EF26/42 (GS+EF26/42).The inoculant strains were sufficiently established during ensiling and reached 4.62 log10 cfu g–1 for EF2/3s and 3.76 log10 cfu g^–1 for EF26/42 on day 111 of ensiling. Crude protein contents were G GS+EF2/3s GS+EF26/42 GS (129, 110, 109, and 100 g kg^–1 of DM, respectively). The lactate-to-acetate ratios were GS GS+EF26/42 GS+EF2/3s (2.82, 4.20, and 4.70, respectively). Concentrations of α-linolenic acid and γ-linolenic acid were highest in grass before ensiling (P 0.001). Higher isomer C18:2 (9,11) content (P 0.01) was detected in GS+EF2/3s and GS+EF26/42 than in GS. Nutritional manipulation associated with Enterococcus faecium EF2/3s and EF26/42 inoculation of GS resulted in better quality of silages based on lower lactate (GS+EF26/42) and a greater lactic-to-acetic acid ratio (GS+EF2/3s and GS+EF26/42). This might positively affect PUFAs and their isomers.