Effect of disodium fumarate on in vitro fermentation of mixed rumeinal micro-organisms

The influence of disodium fumarate with final concentrations at 0,4,7 and 10 mmol·L~(-1) on in vitro fermentation of high concentrate(m(corn powder)∶m(soybean meal)∶m(Chinese ryegrass)=5∶2∶3)was investigated using mixed rumen micro-organisms of goats as inoculum.Results showed that as compared with the control,total volatile fatty acids(TVFA),the percentage of propionate and total gas production for the disodium fumarate treatment increased significantly(P0.05),while the ratio of acetate to propionate and lactate production decreased significantly.A time course study was also conducted to investigate the effect of disodium fumarate at 7 mmol·L~(-1) on the fermentation kinetics of rumen micro-organisms.The results showed that the cumulative gas production was higher than that of the control during the incubation.From 12 h to 24 h of incubation,the pH value for the treatment was higher than that of the control(P0.01).No significant difference was observed between the disodium fumarate treatment and the control in lactate production at most sampling time,except for the 8 h samples.As compared with the control,the TVFA and propionate production were higher(P0.05)from the 8 h to 24 h of incubation.The CMCase activity at 12 h was higher than that of the control(P0.05),while the amylase activity at 8 h was lower compared with the control(P0.05).The results suggested that the addition of disodium fumarate to ruminant feed could stimulate the in vitro fermentation of rumen microorganisms,while reduce lactic acid production.