Enterococcus faecium AL 41: Its Enterocin M and Their Beneficial Use in Rabbits Husbandry

Enterococci are ubiquitous microbiota constituting a large proportion of autochthonous microflora in animals. Some produce bacteriocins mostly enterocins; some of bacteriocin-producing strains also possess probiotic properties. Enterococcus faecium AL 41, Ent M-producing strain was tested for beneficial effect in rabbits. Five-week-old animals (72, Hycole) were divided into experimental groups (E1, E2) and control (C); 24 animals in each. Rabbits in E1 were administered AL 41 (500 μl per animal/day, 10(9) cfu/ml) in water for 21 days; rabbits in E2 were administered Ent M (50 μl/animal/day, activity 12,800 AU/ml) in water for 21 days. Rabbits in C fed a commercial diet. The experiment lasted 42 days. Sampling of faeces and blood was provided on day 0-1 and 21, 42; 3 animals per group were slaughtered. Caecum and appendix were separated. AL 41 colonized rabbits intestines <1.0 (log10) cfu/g, but stimulation of immunity was noted (P < 0.01; P < 0.001). Antimicrobial activity of both was noticed in faeces and/or caecum against pseudomonads. Significant decrease of coliform bacteria in faeces of E1 was noted on day 42 comparing with E2 (P < 0.05). On day 21, S. aureus cells were not detected in E1, E2. On day 42, S. aureus was not found in E2; in E1 their counts were <1.0 cfu/g, while in C it was in the count more than 1.0 cfu/g. In appendix, on day 21, significant decrease of not specified bacteria was found in E1, E2 comparing with C (P < 0.01). Administration of additives has not evoked oxidative stress. Biochemical parameters were not influenced. Higher average daily weight gains were detected by both, AL 41 and Ent M.