New epiphytic strains of lactic acid bacteria improve the conservation of corn silage harvested at late maturity

Abstract

We evaluated fifty-three strains of lactic acid bacteria (LAB) isolated from corn silages from different farms for use as inoculants in corn silages. Bacteria were characterized for growth and pH reduction in corn extract, growth at different temperatures and the ability to inhibit the growth of silage-spoilage microorganisms. The strains CCMA1362, 1363 and 1364 (Lactobacillus farraginis), CCMA1365 (L. plantarum), CCMA1366 (L. buchneri), and CCMA1367 (Pediococcus acidilactici) isolated from corn silage and CCMA170 strain (L. hilgardii) isolated from sugarcane showed good results in laboratory evaluation (good growth and reduction of pH in corn extract; good growth at different temperature and ability to inhibit silage-spoilage microorganisms). These strains were selected and evaluated in corn silages harvested at an advanced stage of physiological maturity (454 g/kg DM). Experimental silos were opened after 10, 32 and 100 days of storage. Crude protein, ash and starch contents were not affected by the inoculation or storage time. Inoculation with the obligate homofermentative strain CCMA 1367 (P. acidilactici) resulted in silages with the greatest DM loss and the lowest aerobic stability. Silages treated with the obligate heterofermentative strains (L. buchneri, L. hilgardii and L. farraginis) had the lowest DM loss, highest aerobic stability, good acid production and pH value, and lowest numbers of yeasts. The species L. farraginis is reported for the first time in studies with corn silage and in particular the CCMA1362 (L. farraginis) strain was effective in lowering DM loss and reducing the numbers of yeasts throughout the ensiling period. Our results are important because they show that silage conservation can be improved even in late maturity corn silage when treated with select lactic acid bacteria L. farraginis CCMA1362. More studies are needed to evaluate the efficiency of these strains under field conditions.