الكاتب: Multiple References

The effects of disodium fumarate on microbial growth, CH4 production and fermentation of three diets differing in their forage content (800, 500 and 200 g/kg DM) by rumen micro-organisms in vitro were studied using batch cultures. Rumen contents were collected from four Merino sheep. Disodium fumarate was added to the incubation bottles to achieve final concentrations of 0, 4 and 8 mM-fumarate, and 15N was used as a microbial marker. Gas production was measured at regular intervals from 0 to 120 h of incubation. Fumarate did not affect (P.0·05) any of the measured gas production parameters. In 17 h incubations, the final pH and the production of acetate and propionate were increased linearly (P,0·001) by the addition of fumarate. Fumarate tended to increase (P¼0·076) the organic matter disappearance of the diets and to decrease (P¼0·079) the amount of NH3-N in the cultures. Adding fumarate to batch cultures tended (P¼0·099) to decrease CH4 production, the mean values of the decrease being 5·4 %, 2·9 % and 3·8 % for the high-, medium- and low-forage diet, respectively. Fumarate tended to increase (P¼0·082) rumen microbial growth for the high-forage diet, but no differences (P.0·05) were observed for the other two diets. These results indicate that the effects of fumarate on rumen fermentation depend on the nature of the incubated substrate, the high-forage diet showing the greatest response.