Factors influencing Euryarchaeal gut methanogens distribution in dairy cattle in smallholding farms

Abstract

Guts of ruminants contain symbiotic domains (Eubacteria, Archaea and Eukarya) that aid in the breakdown of consumed carbohydrates from plants to simple molecules that can be absorbed into the ruminant’s bloodstream. Methanogenesis occurs during the gut fermentation and methane gas is released in the final step of biomass degradation from the fermentation chambers. The Archaea that play a major role critical for methane emissions are methanogens and are found freely in the ruminants’ gut. Methane production from ruminants has attracted global attention due to their input on the Green House Gases effect, contribution to global warming and negative effects on farmers’ productivity. The objective of this study was to determine the factors contributing to the methanogens’ gut distribution in dairy cows from smallholder farms using next generation sequencing techniques. A total of 48 samples from smallholding dairy farms were used during this study and were collected from Kenya (Kiambu county) and Tanzania (Lushoto and Rungwe). The collected data samples from the experimental animals were from both the rumen fluid (6) and fecal (42). Samples were analyzed using metagenomic approaches and statistical analysis was undertaken using IBM SPSS statistics software version 28.0.0.0. Results showed that the gut site along the gastrointestinal tract and the feeding regime significantly contributed to the distribution and presence of various methanogenic species (P<0.1). The herd and the genotype had no statistical effect. A total of 12 families were identified. The family Methanobacteriaceae was identified with the leading number (8) of the methanogenic species. A third of the identified families showed presence for at least two methanogenic species with Methanobrevibacter ruminantium being abundant. For proper curbing mechanisms, efforts to reduce methane release should be channeled to the whole gastrointestinal tract and advanced studies carried out on any potential interspecies presence facilitation and/or elimination.