EFFECT OF ADDITION OF PROPIONIC ACID ON IN VITRO DRY MATTER DIGESTIBILITY, METHANE PRODUCTION AND RUMEN FERMENTATION IN MIXED DIETS CONTAINING WHEAT STRAW WITH SORGHUM OR BERSEEM AS ROUGHAGE SOURCE

An in vitro gas production technique was used to evaluate the effect of propionic acid (10 mM) on six diets i.e. high(80R:20C), medium (50R:50C) and low(20R:80C) fiber sorghum diet (HFSD,MFSD and LFSD) and berseem diets(HFBD, MFBD and LFBD). The results indicate that Dry Matter Digestibility(DMD) either not affected due to propionic acid supplementation or increased slightly in some of diets (3.3%,1.6%, 1.7% and 3.9% increases in MFSD,HFBD, MFBD and LFBD respectively).Methane production (mM/gDM) was not significantly different due to 10 mM propionic acid supplementation, however,it was decreased by 12.4% and 5.4% in HFBD and LFBD, respectively, when expressed in ml/gm DDM. Partition factor value was unaffected by propionic acid supplementation in almos all type of dietsexcept MFSD, in which, it was increased by 11.2%. Microbial biomass (MBM)yield was increased up to 23.5% in MFSD,4.0% in HFBD and 5.3% in LFBD. TotalVolatile Fatty Acids;TVFAs (mM/100ml)were increased significantly in all type of diets. A significant increase in propionic acid concentration (mM/100ml) was also seen in all the six type of diets. It was concluded from the results that thepropionic acid supplementation in sorghum and berseem containing diets decreased the methane production from 5.4 to 12.4% and propionate production was significantly increased without affecting the fiber digestibility.