CONTROL OF RUMEN METHANOGENESIS

During the last decades, considerable research on methane production i n the rumen and its inhibition has been carried out. Initially, as met hane production represents a significant loss of gross energy in the f eed (2-15%), the ultimate goal of such intervention in rumen fermentat ion was an increase in feed efficiency. A second reason favouring rese arch on methane inhibition is its role in the global warming phenomeno n and in the destruction of the ozone layer. In this review, the autho rs describe briefly several interventions for reducing methane emissio n by ruminants. The objective can be reached by intervention at the di etary level by ration manipulation (composition, feeding level) or by the use of additives or supplements. Examples of additives are polyhal ogenated compounds, ionophores and other antibiotics. Supplementation of the ration with lipids also lowered methanogenesis. More biotechnol ogical interventions, e.g., defaunation, probiotics and introduction o f reductive acetogenesis in the rumen, are also mentioned. It can be c oncluded that drastic inhibition of methane production is not unequivo cally successful as a result of several factors, such as: instantaneou s inhibition often followed by restoration of methanogenesis due to ad aptation of the microbes or degradation of the additive, toxicity for the host animal, negative effects on overall digestion and productive performance. Therefore, methanogenesis and its inhibition cannot be co nsidered as a separate part of rumen fermentation and its consequences on the animal should be taken into account.