SUSCEPTIBILITY OF CHICKEN INTESTINAL LACTOBACILLI TO COCCIDIOSTATS

Two strains of lactobacilli (26R and 51R) were tested for growth characteristics in MRS broth and in moistened chicken feed mixture BR-1-IT with and without coccidiostat supplements (monensin, maduramicin and robenidin). Minimal inhibition concentrations (MIC) for all three coccidiostats were measured in MRS broth. The strains were most susceptible to monensin (MIC 2 mg.1(-1) for both strains) and most resistant to robenidin (MIC 90 mg.1(-1) for strain 26R and 110 mg.1(-1) for strain 51R). The onset of growth in moistened feed was delayed by monensin from 0.14 h to 7.07 h for strain 26R and from 0.87 h to 3.59 h for strain 51R. The other coccidiostat did not affect the growth of either strain to any significant extent. The results suggested that probiotics containing lactobacilli can only be combined with specific coccidiostats.