Preliminary evaluation on the suitability of lactic acid bacteria for their use as inoculants in forage silages

Abstract

Silage inoculants are widely used in the cattle industry; those with fibrolytic activity constitute a recent innovation. The aim of this work consisted in the evaluation of two fibrolytic Lactobacillus ability to beneficially transform both chemical and microbiological profiles of inoculated maize silages. Materials and Methods: hybrid maize was chopped and hand sprayed according to the corresponding experimental group with L. sp. ETQ27 (homolactic, 1x106 CFU/g forrage), L. sp. CRL1669 (heterolactic, 1x106 CFU/g forrage), or with an equal amount of sterile suspension medium. Mini silos of 3kg were prepared in bags (duplicates for each opening day) and were opened for analysis at 5, 30, 60 and 90 days. Results and Discussion: ETQ27 reduced silage pH faster and produced more lactic acid than control and CRL1669 groups. On the other hand, CRL1669 produced higher concentrations of acetic acid, which could be the cause of the significantly lower amount of yeasts and consequently, of ethanol. Lactic acid bacteria and total culturable bacteria counts followed similar patterns. Conclusions: Both strains induced changes in the fermentation patterns of maize silages. ETQ27 showed a better inoculant ability, as the most important factor for preservation is lactic acid production. CRL1669 might be beneficial to improve silage aerobic stability. These assays are considered the first steps in the development of third generation inoculants.