Effect of different concentrate diet levels on rumen fluid inoculum used for determination of in vitro rumen fermentation, methane concentration, and methanogen abundance and diversity

Abstract

This study investigated the effects of different diet concentrate levels in animal diets as a source of rumen fluid inoculum for in vitro ruminal fermentation, CH4 concentration, and methanogen abundance and diversity. Three non-lactating mature cows assigned to a 3 × 3 Latin square design were fed with Italian rye grass and concentrate feed at 2 (low), 5 (medium), and 8 (high) kg per animal per day were used as rumen fluid donors. The experiment consisted of three 21-d periods that each consisted of 14 d adaptation followed by 7 d of continuous feeding prior to rumen fluid collection for in vitro fermentation evaluation. High concentrate proportion produced the highest total gas in all incubation periods (p