Species diversity of bovine rumen ciliates and the effectiveness of probiotic transplantation

This study conducted a comparative analysis of the species composition, morphometric characteristics, and abundance of rumen ciliate protozoa in three cattle breeds: Yakutian aboriginal, Simmental, and crossbred. Rumen samples were collected via esophageal probe, fixed in 4% or 10% formalin, and analyzed within 6 hours. Ciliate abundance ranged from 535 to 26,500 individuals/mL, influenced by season and feeding type (roughage for Yakutian cattle, mixed rations for Simmental and crossbred). Bacterial concentrations ranged from 100 million to 10 billion/mL. The highest species diversity (36 species, 12 genera) was observed in Yakutian cattle, including 13 breed -specific species, such as the rare Charonina ventriculi and a previously undescribed Metadinium sp., likely due to adaptation to coarse feed and the cow-calf housing system. Simmental cattle exhibited two specific species, while crossbred cattle lacked specific species. Morphometric analysis revealed significant differences in cell sizes among breeds (p<0.001), with Metadinium medium being the largest ciliate (up to 224.2 µm in length) and Entodinium exiguum the smallest (28.3–36.4 µm). Faunal comparisons using the Jaccard-Malyshev coefficient (Kj– m = 0.67) and the Chekanovsky-Sørensen index (Ics = 40%) indicated the greatest differences between Yakutian and Simmental cattle. Probiotic transplantation (biomass with > < 0.001), with Metadinium medium being the largest ciliate (up to 224.2 µm in length) and Entodinium exiguum the smallest (28.3–36.4 µm). Faunal comparisons using the Jaccard-Malyshev coefficient (Kj– m = 0.67) and the Chekanovsky-Sørensen index (Ics = 40%) indicated the greatest differences between Yakutian and Simmental cattle. Probiotic transplantation (biomass with >5,000 ciliates/mL) from healthy Yakutian donors to three Holstein heifers confirmed the method’s efficacy in normalizing digestion, restoring microbiota postantibiotic therapy, preventing gastrointestinal disorders, enhancing feed digestibility, and improving productivity. The method reduced diarrheal episodes and improved nitrogen balance, highlighting its potential in cattle farming.

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