Profiling of Reindeer’s Rumen Microbial Communities: Characteristics and Age-Related Analysis

Reindeer are animals adapted to live in a poor diet and low temperatures in the Arctic regions. The aim of this research was to study the biodiversity of ruminal microorganisms of Rangifer tarandus inhabiting the Murmansk region, Russian Federation. Samples of the ruminal contents from 11 individuals, incl. young (YA, n = 3), mature (MA, n = 4) and old (OA, n = 4) animals were used for the research. The ruminal bacterial community of reindeer was studied using the T-RFLP (Terminal restriction fragment length polymorphism) method. A significant number of DNA sequences in the rumen of Rangifer tarandus were classified as uncultured bacteria (up to 69.88%), the largest share of which was found in groups YA and OA. The representation of several taxa had age differences: in individuals of the MA group, the share of Lachnospiraceae, Eubacteriaceae, Thermoanaerobacteriaceae, Ruminococcaceae increased and in the AO group the share of Clostridiaceae increased. It was important to note in the rumen of reindeer the presence of various diseases pathogens and their association with a certain age of animals: Campylobacteraceae was noted in the YA group; Enterobacteriaceae, Pseudomonadaceae, and Pasteurellaceae in the MA group; Staphylococcus sp., Tenericutes, Fusobacteria, Actinobacteria in the OA group. In general, according to the alpha-diversity index values of ruminal microorganisms (taxonomic units, Shannon's index), a tendency toward a decrease in biodiversity and an increase in its homogeneity was revealed increasing age in reindeer.