There is a significant range of bacterial inoculants for forage ensiling, but there is still a need for formulations to improve
the safety of feed. The objective of the study was to evaluate the usefulness of three lactobacilli strains in alfalfa (
Medicago sativa
L.) The following bacterial inoculants were used:
Lactocacillus plantarum
K KKP 593p (LPK),
L. plantarum C
KKP 788p (LPC),
L. buchneri
KKP 907p (LB), and mix of all three strains (LPK+LPC+LB). The application of bacterial
inoculants in alfalfa ensiling resulted in a reduction of the total number of molds,
Clostridium perfringens
and
Listeria
sp.
(up to 5, 7, and 5 times respectively for LB inoculant in comparison to untreated silage). Total inhibition of
Salmonella
sp. and
Escherichia coli
growth was achieved in silages treated with all inoculants except for LPC. Aerobic stability in the
control silage was the lowest (77 h) and doubled under the influence of bacterial inoculants. The most stable according
to aerobic stability was silage treated with LB inoculant (175 h), where the highest concentrations of acetic acid (4.8 g
kg
-1), propionic acid (0.7 g kg
-1) and 1,2-propanediol (526 mg kg
-1) were reported. The study discussed that it is important
to evaluate not only the effect of bacterial inoculants on physicochemical and microbiological silage properties, as the
presence and expression of antibiotic resistance genes in lactic acid bacteria have been reported. The results of antimicrobial
susceptibility testing of the strains showed that almost all minimum inhibitory concentrations values for eight antibiotics
were equal to or below the corresponding breakpoints proposed by the European Food Safety Authority, Additives and
Products or Substances used in Animal Feed Panel.
