EFFECT OF DIRECT-FED MICROBIALS AND MONENSIN ON IN VITRO RUMEN FERMENTATION

• Main Author: Wingard, Sheryl
• Format: Others
• Published: UKnowledge 2014
• Subjects: Direct-fed microbial; monensin; rumen fermentation; forage-based diet; concentrate-based diet; Other Animal Sciences
• Online Access: http://uknowledge.uky.edu/animalsci_etds/42; http://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1042&context=animalsci_etds

The impact of supplying a mixed culture of lactate producing bacteria on in-vitro rumen fermentation of forage- (Experiment 1) and concentrate- (Experiment 2) based diets in the presence and absence of monensin was explored. In experiment 1, interactions between DFM and MON were absent (P>0.10) for gas production and fermentative end products. Gas production and fermentative end products were unaffected by DFM alone (P>0.10). Monensin decreased (P<0.001) CH4 and NH3 production, rate and total gas production, as well as total VFA concentration and molar proportions of acetate and butyrate. However, MON increased (P<0.001) proportions of propionate, valerate, isobutyrate and isovalerate. Independently, DFM and MON increased (P<0.001) end point pH. In experiment 2, DFM x MON interactions or tendencies (P=0.07, P<0.01, P<0.01) were present, DFM effects were abated by MON, for rate, total gas production and total VFA concentrations. Acetate:propionate ratio was decreased (P<0.01) with MON and was unaffected by DFM. Ammonia-N concentration was increased (P<0.01) by DFM and unaffected (P=0.75) by MON. Both DFM and MON treatment increased (P<0.01) ruminal pH levels. These studies suggest the effects of DFM and MON of in-vitro fermentation are dependent on the substrate being fermented and the observed interactions provide means for further research.