The use of Enterococcus faecium as feed additive in livestock nutrition is common practice. In contrast to the performance enhancing effects in livestock, probiotics are used mainly to stimulate the health by potential positive influence on gut flora and immune system in the case of companion animals. The present study was conducted to investigate the influence of Enterococcus faecium DSM 7134 on the digestive tract and microbiological and immunological parameters in adult dogs.
Ten beagle dogs were used for the trial. The study was divided in five successive periods. The trial started with the first control period.
Probiotic periods and control periods followed alternatively. During the whole trial the dogs obtained a complete dry diet adjusted to their feed demand. The probiotic supplement was given as ¿top dressing¿ to the complete dry diet during the probiotic periods. The concentration of the strain was 9,7x105 CFU/g feed in period probiotic A and 4,7x107 CFU/g feed in period probiotic B respectively. Beside the rating of health condition of the dogs (differential blood count, haematology and body condition) digestive parameters (consistency of feces, frequency of defecation, apparent digestibility of crude nutrients, dry matter and water of the feces, pH-value, lactate and ammonia concentration of feces) were investigated. Cultural and molecular biological (RAPD-PCR) methods were used to determine the bacterial composition of the fecal flora (Enterococcus spp., Clostridium perfringens, E. coli). The concentration of immunoglobulins and acute phase proteines in serum, as well as the concentration of IgA in feces by an ELISA test were determined to assess modulating effect of Enterococcus faecium DSM 7134 on the immune system. Additional parameters such as lymphocyte proliferation activity and the determination of the percentage and absolute composition of lymphocyte populations (flow cytometery) have been analysed.
The results of the study showed that Enterococcus faecium DSM 7134 changed the bacterial composition of the gut flora and influenced the immune system.
The concentration of Enterococcus spp. during probiotic periods increased. The strain could not be detected in feces by RAPD-PCR method.
But the supplementation caused a change of the composition of Enterococcus spp.. The number of Clostridium perfringens was successively decreasing during the whole trial period. The influence of the supplementation on concentration of E. coli seems to be unclear and needs further investigations.
The percentage ratio of CD21+ lymphocytes increased during period probiotic B. The lymphocytes showed a higher activity of proliferation.
No influences on immunoglobulins neither in serum and in feces, nor on acute phase proteines in serum were detected. Effects on digestive processes were not found, although apparent digestibility of crude fat was lower.
The strain Enterococcus faecium DSM 7134 increased the concentration of Enterococcus spp. in feces and affects their RAPD-pattern. The probiotic strain seems to influence the cellular immune response. It is not obvious from this study whether these properties cause an increase of resistence and an improvement of health. Further investigations on stressed, ill or immune suppressed dogs are necessary to answer these questions.
probiotic / dog / gut flora / immune system / RAPD-PCR