Characterizing the Alteration in Rumen Microbiome and Carbohydrate-Active Enzymes Profile with Forage of Muskoxen Rumen through Comparative Metatranscriptomics

Abstract

Muskox (Ovibos moschatus), as the biggest herbivore in the High Arctic, has been enduring the austere arctic nutritional conditions and has evolved to ingest and digest scarce and high lignified forages to support the growth and reproduce, implying probably harbor a distinct microbial reservoir for the deconstruction of plant biomass. Therefore, metagenomics approach was applied to characterize the rumen microbial community and understand the alteration in rumen microbiome of muskoxen fed either triticale straw or brome hay. The difference in the structure of microbial communities including bacteria, archaea, fungi, and protozoa between the two forages was observed at the taxonomic level of genus. Further, although the highly abundant phylotypes in muskoxen rumen fed either triticale straw or brome hay were almost the same, the selective enrichment different phylotypes for fiber degrading, soluble substrates fermenting, electron and hydrogen scavenging through methanogenesis, acetogenesis, propionogenesis, and sulfur-reducing was also noticed. Specifically, triticale straw with higher content of fiber, cellulose selectively enriched more lignocellulolytic taxa and electron transferring taxa, while brome hay with higher nitrogen content selectively enriched more families and genera for degradable substrates-digesting. Intriguingly, the carbohydrate-active enzyme profile suggested an over representation and diversity of putative glycoside hydrolases (GHs) in the animals fed on triticale straw. The majority of the cellulases belonged to fiver GH families (i.e., GH5, GH6, GH9, GH45, and GH48) and were primarily synthesized by Ruminococcus, Piromyces, Neocallimastix, and Fibrobacter. Abundance of major genes coding for hemicellulose digestion was higher than cellulose mainly including GH8, GH10, GH16, GH26, and GH30, and these enzymes were produced by members of the genera Fibrobacter, Ruminococcus, and Clostridium. Oligosaccharides were mainly of the GH1, GH2, GH3, and GH31 types and were associated with the genera Prevotella and Piromyces. Our results strengthen metatranscriptomic evidence in support of the understanding of the microbial community and plant polysaccharide response to changes in the feed type and host animal. The study also establishes these specific microbial consortia procured from triticale straw group can be used further for efficient plant biomass hydrolysis.

Exploring winter diet, gut microbiota and parasitism in caribou using multi-marker metabarcoding of fecal DNA

“…As previously described in reindeer 31,92,93 , the gut microbiota of caribou was mainly composed of Firmicutes and Bacteroidota in our study, and several of the most abundant taxa detected were also found as dominant in other ruminants worldwide 94 , further supporting that a core microbiota exists in ruminants. Interesting correlations between the gut microbiota and the diet have been detected, con rming trends observed in other ruminants 19,94,95 . First, the beta diversity of the bacterial community was correlated with the diversity of the lichen diet and, to a lesser extent, to the herbaceous plant diversity.…”

Review: Effect of Experimental Diets on the Microbiome of Productive Animals

“…On the other hand, its colonization has been shown to decrease the relative abundance of Firmicutes such as the Ruminococcaceae family known for their fibrolytic activity [ 162 , 163 ]. Although Prevotella is present in many animals, its abundance has been increased in diets containing carbohydrates with a high level of dietary fiber as in studies in ruminants [ 164 ]. such as Holstein dairy cows and Hu lambs, as proposed by Wang et al (2020) and Du et al (2022), respectively.…”

Influence of Feeding Corn Impurities on Rumen Bacteria and Fermentation Characteristics of Sheep

“…We found an increase in total bacteria count, especially with corn impurities, which is appropriate to moderate pH values and the rise of ammonia and volatile fatty acids productions, there were different kinds of cellulolytic bacteria, Zhang et al (30) observed high rumen pH values when feeding straw and increasing of Oscillibacter cellulolytic bacteria. The importance of adaptation period is to create microbial population suitable for fermentation and utilization from the feed, Wu et al (29) noticed change of rumen microbial populations with different feeds and environmental influences, like increasing dilution and flow rate of rumen liquor when feeding hydroponic fodder (26). Sha et al (23) found similar rumen microbial community with no differ between two aged cattle 2 and 3 years when examined the functional characteristics and species composition of rumen microorganisms.…”