Characteristics of ruminal microbial community: Evolutionary and ecological perspectives

Abstract

Ruminants perhaps appeared about 50 million years ago (Ma). Five ruminant families had been extinct and about 200 species in 6 ruminant families are living today. The first ruminant family probably was small omnivore without functional ruminal microbiota to digest fiber. Subsequently, other ruminant families evolved around 18-23 Ma along with woodlands and grasslands. Probably, ruminants started to consume selective and highly nutritious plant leaves and grasses similar to concentrates. By 5-11 Ma, grasslands expanded and some ruminants used more grass in their diets with comparatively low nutritive values and high fibers. Historically, humans have domesticated 9 ruminant species that are mostly utilizer of low quality forages for human benefits. Thus, the non-functional rumen microbiota to predominantly concentrate fermenting microbiota, followed by predominantly fiber digesting microbiota had evolved for mutual complementary benefits of holobiont over the million years. The core microbiome of ruminant species seems the resultant of hologenome interaction in an evolutionary unit. The inertia and resilience properties of ruminal ecosystem seem to be due to this core microbiota, which makes the ecosystem most stable in response to perturbations because this core microbiota has evolutionary advantages with logically more generalists (i.e., wide metabolic versatile and redundancy). Also, a part of the ruminal microbiome shows highly plasticity, which is likely useful for evolutionary adaptability of holobiont. This review discusses ecological characteristics of ruminal microbial community in evolutionary perspectives. Th e updated understanding of ecological traits of ruminal microbiome would be helpful to better modulate the ruminal fermentation favorably for human benefits.

Effect of oral dosing of live and autoclaved culture of Ruminococcus flavefaciens FD-1 on rumen bacterial and fungal populations in Murrah buffaloes

“…isolated from bison and pigs when administered to fibre-rich hay diets in bovines. Hence, it was suggested that autochthonous (native) microbes seem advantageous over allochthonous (outside the native habitats) species for quick adaptation and establishment (Patra, 2020), as also demonstrated recently in tropical buffaloes (Singh et al 2021).…”

“…Ruminococcus are the predominant cellulose-digesting bacteria in rumen (Wanapat and Cherdthong, 2009;Israeli-Ruimy et al 2017;Patra, 2020;Wang et al 2020). A shift in microbial population was noted previously when Ruminococcus spp.…”

“…are supplemented (Krause et al 2001). However, it is also established that successful results are more likely to be obtained when bacterial culture originating from the host species (autochthonous) are supplemented (Patra, 2020;Singh et al 2021). While the multitude of research explorations on various bacterial cultures is available, there seems limited published information on isolating fibrolytic bacteria from buffalo rumen and its subsequent evaluation on microbial population dynamics in vivo.…”

Peningkatan Populasi Ternak Ruminansia di Kabupaten Penajam Paser Utara Berdasarkan Potensi Hijauan Pakan

“…Keistimewaan ternak ruminansia dibandingkan jenis ternak non-ruminansia (unggas dan babi) adalah kemampuannya dalam mengubah pakan berserat menjadi daging, susu, dan wool. Kondisi ini terjadi akibat adanya enzim yang berasal dari mikroorganisme, seperti bakteri, protozoa, dan fungi yang hidup didalam sistem pencernaan ruminansia (Patra, 2020). Oleh kemampuannya tersebut, maka ternak ruminansia berperan penting didalam system pertanian yang berkelanjutan (Oltjen & Beckett, 1996;Guyader et al, 2016).…”

Ruminal Microbiome Manipulation to Improve Fermentation Efficiency in Ruminants

“…Rumen inhabits several microbial populations, that is, bacteria, protozoa, fungi, bacteriophages, yeasts, and methanogens symbiotically, which are very dynamic, plastic, and redundant in function with the changes in diets though core microbiota persists, which has probably evolved by host-microbiota interaction in the evolutionary pressure over thousands of years [1]. A symbiotic relationship exists between rumen microbes and host animals in which both provide desirable substrates to each other mainly through these ways-1) physical breakdown of feed particles by mastication and rumination expands their surface area for microbial attachment and degradation, and consequently, microbes secrete various enzymes for dietary substrate degradation, 2) ruminal movements bring microbes in contact with the dietary substrate by mixing of digesta and consequently produce fermentation products (e.g., H 2 , CO 2 , ammonia, short-chain fatty acids (SCFAs), and 3) utilization (absorption and consumption) of the fermentation products for keeping optimal ruminal conditions (e.g., pH) to maintain microbial growth and microbial protein synthesis [2].…”