Influences of diet and rumen fermentation on methane production by ruminants

Abstract

This work is based on the study of several databases to extract predictive models of CH4 production based on diets and ruminal fermentations.Methanogenesis is described with the main principles of the stoichiometry and thermodynamics of ruminal fermentation.It appears a particularly positive relationship between CH4 production and the ratio of acetic / propionic in rumen liquor (Ac / Pr).Changes in the profile of the volatile fatty acids (VFA) and of CH4 production reflect phenomena of adaptation of the rumen microbesto the amount of available energy. Among the various criteria for predicting the food production of CH4, the digestible organic matter(DOM) is an interesting parameter to be considered: it is closely linked to the rumen fermentable OM, therefore CH4, and theenergy value of food. However, the ratio CH4/DOM also varies depending on dietary factors that also affect the ratio Ac / Pr in therumen: the feeding level, forage quality, the dietary concentrate and fat. A final section is devoted to the study of mechanistic modelsthat are based on the principles of stoichiometry of VFA, these models constitute a step towards integrated modeling of all phenomenaand digestive fermentation in the rumen..