THE EFFECT OF A PROPIONIC-ACID BACTERIAL INOCULANT APPLIED AT ENSILING ON THE AEROBIC STABILITY OF WHEAT AND SORGHUM SILAGES

The effect of a new strain of Propionibacterium shermanii(PAB), applie d at ensiling, on the aerobic stability of wheat and sorghum silages w as studied in several experiments under laboratory conditions, In the one experiment with wheat and in those with sorghum a lactic acid bact eria (LAB) inoculant (Lactobacillus plantarum and Pediococcus cerevisi ae) was also included, After treatment, the chopped forages were ensil ed in 1,5-L anaerobic jars which were sampled in triplicate on predete rmined dates to follow fermentation dynamics. At the end of the experi ments, the silages were subjected to an aerobic stability test, The PA B inoculant improved the aerobic stability only in one experiment with wheat, in which the decrease in pH was very slow; the final pH remain ed relatively high (4.5). The PAB-treated silages contained 19.5 +/- 2 .0 g of propionic acid per kg of dry matter, In the experiments with s orghum, the control and PAB-inoculated silages were stable, whereas LA B-inoculated silages deteriorated, The results suggest that PAB can su rvive in and improve the aerobic stability of only slow-fermenting sil ages which are prone to aerobic deterioration.