Effects of lactic acid bacteria with bacteriocinogenic potential on the chemical composition and fermentation profile of forage peanut (Arachis pintoi) silage

Abstract

The objectives of this study were to evaluate the effect of lactic acid bacteria (LAB) with bacteriocinogenic activity isolated from stylo silages on the microbial population, chemical composition and fermentation profile of forage peanut silage (FPS) and to identify LAB species in forage peanut and its silages based on the 16 S rRNA sequence analysis. The experiment was conducted in a completely randomized design with a 5 × 6 factorial arrangement (five inoculants (I) × six fermentation periods (P)) and three replicates. The following inoculants were evaluated: without inoculant (CTRL); a commercial inoculant at a dose of 107 colony forming units (cfu) g-1 fresh matter (CI1); a commercial inoculant at a dose of 105 cfu g-1 fresh matter (CI2); Pediococcus acidilactici strain 10.6 (S1); and Pool of bacteriocinogenic strains (POOL), including S1, P. pentosaceus strain 6.16 and P. acidilactici strain 10.4. The fermentation periods were 1, 3, 7, 14, 28 and 56 days. The largest LAB populations were observed in silages treated with S1 (8.66 log cfu g-1) and POOL (8.69 log cfu g-1). At the end of the fermentation period, a higher content of dry matter (222.53 g kg-1) and lactic acid (66.30 g kg-1) and lower values of pH (4.76) and acid detergent insoluble nitrogen (9.50% of total nitrogen) were observed for silage treated with S1. The screening of LAB from forage peanut silage revealed that P. pentosaceus was the predominant species. In addition, the wild strain of P. acidilactici 10.6 established a desirable microbial population during the fermentation process reflecting a highest lactic acid concentration and lowest pH values after 56 days of fermentation.