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INTRODUCTION
The rumen microbial ecosystem is one of the most complicated, diverse, and well-studied microbiological environments. Robert E. Hungate, the father of rumen microbiology, start searching this system in the 1940's and half a decade later, many of his detection still hold true(2).The bacteria in the rumen have co-evolved with the host and produce the enzymes vital to digest plant cell, give the host to get, energy from an another indigestible feed source (Cell wall)(25). The health and productivity of the ruminant is highly dependent on the rumen ecosystem (13,18,23). One of the main issues in the current ruminant animal industry is how the most successful use the employ of feed resources to maximize efficiency of feed digestibility,(27) because feed efficiency ultimately affects profitability and sustainability of the industry. In fact, it has been considered that feed costs account for nearly 75% of the total input costs (17). Moreover, an improvement in feed efficiency has been proposed to bring reductions in nutrient excretion (12) and in methane emissions (11).Forages provide energy and nutrients that are essential for the growth and productivity of ruminant and therefore represent an important feed resource for ruminant production. However, the comparatively high lignin and fiber concentrations in forages limit the extent to which they are digested by ruminant. Therefore, various methods of improving the...