New trends and opportunities in the development and use of inoculants for silage

Abstract

Inoculants are used as silage additives to improve preservation efficiency and to enhance animal performance. In most commercially available inoculants, homofermentative lactic acid bacteria (LAB) have been used because they are fast and efficient producers of lactic acid, improving natural silage fermentation. Specific LAB inuculants may also have beneficial effects on animal performance even if there is no effect on fermentation. However, these types of inoculants are not always advantageous. They do not necessarily prevent sermentation by clostridia in moist silages, and they sometimes impair the aerobic stability of grass and small grain silages. Therefore, new criteria for silage inoculants should be established which consider the specific needs of the crop being ensiled. New approaches which are being taken to develop improved inoculants for silage include the following: (1) using LAB isolates which are more specific to the target crops; (2) inclusion of heterofermentative LAB to produce volatile fatty acids to inhibit yeasts and moulds upon aerobic exposure; (3) inclusion of organisms other than LAB in inoculants to inhibit detrimental microorganisms; (4) selection or engineering of LAB strains to inhibit specific microorganisms; and (5) cloning and expression of genes which would enable selected LAB strains to utilize polysaccharides in crops which are low in soluble carbohydrates. Many of these new strategies for formulating inoculants are being tested, but further research is needed to determine the most successful approaches.

Effect of an inoculant and enzymes on fermentation quality and nutritive value of erect milkvetch (<i>Astragalus adsurgens</i> Pall.) silages

“…reduced pH, increased lactate to acetate ratio, or both) by inoculants, whereas DM digestibility (in vitro or in vivo) was increased in only 30% of the trials. Weinberg and Muck (1996), in their review, also reported instances in which fermentation was affected by a LAB inoculant, whereas digestibility was not.…”

A new probiotic and bacteriocin-producing strain of Enterococcus faecium EF9296 and its use in grass ensiling

“…In our experiment, a significant increase in DM content in the inoculated silage was detected during the whole ensiling period (P < 0.001). Similarly, Henderson (1993) and Weinberg and Muck (1996) reported that the treatment of silages with LAB inoculants could improve DM recovery by 1-3%. Furthermore, in barley silage treated with a mixture of bacterial inoculants (Pediococcus, Lactobacillus and Enterococcus spp.)…”

“…events during silage fermentation (Weinberg and Muck, 1996). Although the effects of inoculants on the preservation and nutritive value of silage have often been inconsistent, positive outcomes such as higher lactate:acetate ratios, lower ammonia N, decreased DM losses, increased digestibility, improved aerobic stability and enhanced growth performance have been reported (Henderson, 1993;McAllister et al, 1995McAllister et al, , 1998Zahiroddini et al, 2004).…”

“…Most available inoculants consist of selected strains of homofermentative LAB, such as Lactobacillus plantarum, Pediococcus sp. and Enterococcus faecium, which are of different origin (Weinberg and Muck, 1996;Přikryl, 2006). The inoculation rates of these products are usually 10 5 -10 6 viable cells/g, which is often sufficient for the inoculant LAB to outgrow the epiphytic LAB and become the predominant population in silage.…”

Ingestão e digestibilidade aparente em ovinos alimentados com silagens de capim-elefante inoculadas com Streptococcus bovis

“…Segundo Muck (1996) (Oliveira et al, 2007;Zanine et al, 2008;Zanine et al, 2009). No entanto, a verificação da silagem inoculada com S. bovis ainda não foi alvo de ensaio de consumo e digestibilidade, com a finalidade de avaliar seu efeito no animal.…”