In vitro assessment of probiotic potential of selected bacteria isolated from pig faeces with potential application of odour reduction

To evaluate the odour reduction potential of four different bacterial species such as Enterococcus faecium, Enterococcus faecalis, Acetobacter tropicalis, and Bacillus subtilis subsp. subtilis that were isolated from fresh faeces of pigs and identified based on16S rDNA gene sequence analyses. Faecal slurry in anaerobic salt medium with 1% soluble starch (which was served as control group) and the addition of four different isolated bacterial cultures (1.0 × 10(7)CFU/mL), designated as M1, M2, M3, and M4, respectively, were incubated anaerobically for 12 and 24 h. Total gas production was increased with the incubation period (p < 0.05). M1 and M4 had decreased pattern (p < 0.05) of ammonia and hydrogen sulphide gas from 12 to 24 h. The lowest total volatile fatty acids (p < 0.05), highest lactate, and moderate butyrate concentration was observed in the M1 group at 24 h of incubation. Likewise, M1 group had the lowest total biogenic amine, histamine, ethylamine, putrescine, methylamine, and cadaverine compared to the other groups (p < 0.05) at 24 h of incubation. Overall results suggest that E. faecium can be used as a potent odour reducer in pigs production.