The structure and functional profile of ruminal microbiota in young and adult reindeers ( Rangifer tarandus) consuming natural winter-spring and summer-autumn seasonal diets

• Published in: PeerJ
• Main Authors: Yildirim, Elena, Ilina, Larisa, Laptev, Georgy, Filippova, Valentina, Brazhnik, Evgeni, Dunyashev, Timur, Dubrovin, Andrey, Novikova, Natalia, Tiurina, Daria, Tarlavin, Nikolay, Laishev, Kasim
• Other Authors: Russian Science Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: PeerJ 2021
• Subjects: Arctic; nenets; Rangifer tarandus
• Online Access: http://dx.doi.org/10.7717/peerj.12389; https://peerj.com/articles/12389.pdf; https://peerj.com/articles/12389.xml; https://peerj.com/articles/12389.html

Background The key natural area of Russian reindeer ( Rangifer tarandus , Nenets breed) is arctic zones, with severe climatic conditions and scarce feed resources, especially in the cold winter season. The adaptation of reindeer to these conditions is associated not only with the genetic potential of the animal itself. The rumen microbiome provides significant assistance in adapting animals to difficult conditions by participating in the fiber digestion. The aim of our study is to investigate the taxonomy and predicted metabolic pathways of the ruminal microbiota (RM) during the winter–spring (WS) and summer–autumn (SA) seasons, in calves and adult reindeer inhabiting the natural pastures of the Yamalo-Nenetsky Autonomous District of the Russian Federation. Methods The RM in reindeer was studied using the Next Generation Sequencing method with the MiSeq (Illumina, San Diego, CA, USA) platform. Reconstruction and prediction of functional profiles of the metagenome, gene families, and enzymes were performed using the software package PICRUSt2 (v.2.3.0). Results The nutritional value of WS and SA diets significantly differed. Crude fiber content in the WS diet was higher by 22.4% ( p < 0.05), compared to SA, indicating possibly poorer digestibility and necessity of the adaptation of the RM to this seasonal change. A total of 22 bacterial superphyla and phyla were found in the rumen, superphylum Bacteroidota and phylum Firmicutes being the dominating taxa (up to 48.1% ± 4.30% and 46.1% ± 4.80%, respectively); while only two archaeal phyla presented as minor communities (no more then 0.54% ± 0.14% totally). The percentages of the dominating taxa were not affected by age or season. However, significant changes in certain minor communities were found, with seasonal changes being more significant than age-related ones. The percentage of phylum Actinobacteriota significantly increased (19.3-fold) in SA, compared to WS ( p = 0.02) in adults, and the percentage of phylum Cyanobacteria increased up to seven-fold ( p = ...