| Popis: |
High numbers of a diverse array of micro-organisms inhabit the equine gastro-intestinal tract (GIT), guaranteeing functionality and stability in the face of stresses and environmental fluctuations. The first part of this review reports on the number, diversity and identification of the autochthonous microbial communities present in the different anatomic segments. Although bacteria are present in great concentrations along the length of the GIT, viruses, protozoa and fungi have so far been reported only in the hindgut. There is a special focus on the microbiota of equine faeces. Despite recent advances on the microbial diversity in the different segments of the GI tract, there still is a profound lack of knowledge about these microorganisms. The adult optimal microbiota depends on the establishment in the young animal. The second part of this review is dedicated to the colonization by viral, fungal and bacterial communities of the foal GIT. Despite a rapid colonization following birth, the digestive population in its whole complexity is probably not fully established until weaning. There is a need to better understand the colonization of the bacterial communities in foals, measure correlations with the establishment of immunity and the impact on to the future adult digestion. The final part of this review firstly presents the potential role of the GI microbiota for the host in terms of gut health. Whereas little is known in horses, it could be accepted like in other mammals, that commensal gut bacteria play an essential role in angiogenesis, postnatal intestinal maturation, mucosal barrier fortification, and nutrient absorption. Secondly, the complex GIT microorganism interactions organized in trophic chains to degrade fibre, hydrolyze rapidly digestible carbohydrates, fat, and utilize protein are described. The nutritional role of the microbial communities is probably even more essential than previously thought and from the stomach to the colon the contribution of feed hydrolysis and fermentation has to be precisely evaluated for better comprehension. |
