The dramatic increase in the human population - estimated to reach 9.7 billion people by the year 2050 - will require an approximately 25% increase in gross agricultural output between 2020 and 2050 to meet the global food demand of humanity. A high-concentrate diet also has the capacity to change the rumen environment through shifts in ruminal pH, which in turn affects the diversity and composition of rumen microbiota. Belanche et al. proposed that Ascophyllum nodosum possessed anti-protozoal activity and showed that it decreased CH4 emissions from rumen fluid in vitro. In the rumen, archaea are one of the four main microbial groups. The domain archaea are divided into two different kingdoms: Euryarchaeota, consisting of methanogens and extreme halophytes, and Crenarchaeota, consisting of hyperthermophiles and nonthermophiles. Methanogens share a commensal relationship with rumen ciliates, and these protozoa-methanogen consortia account for approximately 30-40% of the enteric CH4 produced in ruminants.