Analysis of an outbreak of Klebsiella pneumoniae by the DiversiLab system and pulsed-field gel electrophoresis

Alkaline agents reduce the fiber content, but results in a buffering of the silage that can benefit the growth of undesirable micro-organisms. The association of alkaline agents and additives capable of inducing a decrease in the initial pH may be interesting. Our aim was to evaluate the effects of a wild strain of Lactobacillus plantarum (UFLA SIL 1) and the addition of propionic acid on the fermentation and aerobic stability of sugarcane silages treated with and without calcium oxide. Propionic acid reduced the pH value, the number of yeasts, filamentous fungi and clostridia. The L. plantarum reduced DM losses in silages without calcium oxide, without changing other microbiological and fermentative parameters. The addition of calcium oxide reduced the neutral detergent fiber (NDF), the concentration of ethanol and acetic acid and increased the populations of clostridia,filamentous fungi and yeasts. Calcium oxide lengthened aerobic stability and reduced the temperature during aerobic exposition. Addition of propionic acid or the strain of L.plantarum was not able to improve the microbiological quality of the silage treated withcalcium oxide. The addition of calcium oxide improved aerobic stability; however, thisaddition resulted in lower silage quality observed by higher counts of undesirable micro-organisms.   Key words: Aerobic stability, anaerobic fermentation, silage additives, lactic acid bacteria, yeasts.