Monensin from three different manufacturing companies (Eli Lilly Co., Indianapolis, USA; Pharmachim, Bulgaria; Spofa Prague, Czech Republic) were added to pure cultures of rumen strain Enterococcus faecium CCM 4231 at final concentrations 25 micrograms per ml and 50 microgram per ml. Enterococci represent a strong bacterial group colonizing the rumen regarding to lactic acid production. Ent. faecium CCM 4231 is own, lactic acid-producing isolate from the rumen content of calf with a broad antimicrobial activity (bacteriocin production). This strain was obtained in the microbial preparation Inhicol to protect enteritis in young ruminants, especially. The growth of CCm 4231 strain was inhibited at both concentrations (25 microgram/ml; 50 micrograms/ml) using all three monensins in comparison with controls (Figs. 1 and 2). The beginning of the growth inhibition was detected within 2 hours after ionophore addition. Monensin made in Bulgaria was the most effective of all when the three monensins were compared. No significant differences are found in the effect of monensins made in different production companies. Our results extend the knowledge about inhibition effect of monensin on Gram-positive bacteria, enterococci including. Moreover, the quality of monensins made by different companies is attested synchronous. In general, regarding the practical point of view, it is also contribution for the selection and application of the most suitable additives.

Institute of Animal Physiology Slovak Academy of Sciences Kosice Slovak Republic

Comparison of nisin and monensin effects on ciliate and selected bacterial populations in artificial rumen