In Pursuit of Understanding the Rumen Microbiome

Abstract

The rumen plays an indispensable role in ruminants to utilize ligno-cellulosic material and convert non-protein nitrogen into nutrients otherwise unavailable for human consumption. Recent advancements in the sequencing technology and omics approach have provided profound insights into the rumen world, wherein a consortium of archaea, bacteria, protozoa, fungi, and viruses exist and interact. These ruminal microbes alter the ruminal environment and execute several interlinked metabolic cascades that produce substrates for the host’s energy and body requirements. Methane is emitted as a by-product during this complex fermentation process in ruminants leading to a loss in productivity while negatively impacting the environment. As ruminants play an ever-increasing role in our food supply chain, manipulating the rumen is the critical step towards maximizing the ruminant product’s nutritional value while reducing its carbon footprint. Diet is the most straightforward way to alter the rumen microbiome, possibly in conjunction with phytobiotics and probiotics as feed supplements. Early life interventions allow the manipulation of microbial population structure and function that could persist later on in adult life. It has also been proven that the host exerts influence on the rumen microbiome as a heritable trait. The goal of this review is to provide a better understanding of the rumen, its key organisms, and its development to better identify, characterize, and engineer the rumen microbiome for efficient feed conversion and methane reduction.

Life at the borderlands: microbiomes of interfaces critical to One Health

“…Other factors that can be detrimental to microbial population due to changes in ruminal pH or decrease in feed intake include environmental stressors, such as heat stress (Kim et al 2022 ), animal transportation (Li et al. 2019 ), or changes in management practices (Sanjorjo et al 2023 ) which can, for example, favour the growth of lactate-producing bacteria such as Streptococcus, Enterobacteriaceae , and Lactobacillus . In addition, feed ingredients or plants containing natural toxins can have unintended consequences on ruminal microbial development, leading to imbalances in the rumen microbiota (Loh et al 2020 ).…”

Integrating Omics Technologies for a Comprehensive Understanding of the Microbiome and Its Impact on Cattle Production

“…These fungi exclusively belong to the Neocallimastigomycota phylum [ 45 ]. The rumen virome, mainly composed of Caudovirales [ 47 ], is influenced by a multitude of factors, prominently including ruminant species, diet, age, gender, environment, and geographical location [ 9 , 48 ]. This microbial community showcases a significant degree of functional redundancy.…”

“…The composition of these microbial communities within the rumen is contingent on a multitude of factors. These include breed, age, external environment, diet, and nutritional factors (as outlined in Table 1 ) [ 9 , 42 ]. Moreover, other variables, such as the process of weaning, energy requirements, and the presence of potentially toxic metabolic byproducts, can also exert an impact on the microbial composition and abundance within the rumen.…”

“…Recent strides in advanced technologies, such as next-generation sequencing and mass spectrometry, have catalyzed remarkable progress in the investigation of the rumen microbiome. These innovations have facilitated the complete genome sequencing and comprehensive profiling of the rumen microbial community [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ].…”

“…Within the gastrointestinal tract (GIT) of ruminants like cattle, the rumen and the lower GIT accommodate a range of symbiotic, commensal, and parasitic microorganisms. These microorganisms exert significant effects on the physiology and performance of the animals, thereby contributing to the overall metabolic capacity of the rumen [ 8 , 9 , 10 ].…”