Effect of a Blend of Essential Oils on Buffalo Rumen Microbial and Enzyme Profiles and In Vitro Feed Fermentation

Abstract

Three rumen-fistulated adult Murrah buffaloes (BW 426±45 kg) were arranged in a 3×3 LSD. The treatments involved supplementation of a blend (BEO-CL) of clove bud oleoresin and lemongrass oil (in 1:1 ratio) at the rate of 0, 0.75 and 1.5% of BW. After 20d of feeding, the rumen liquor and rumen contents were sampled before (0h) and 4h after feeding and analyzed for various parameters. There was neither any effect of feed additive nor sampling time on the concentration of VFAs, NH3-N, lactic acid and activities of select enzymes (carboxymethylcellulase, avicelase, xylanase, amylase, β-glucosidase, α-glucosidase and acetyl esterase). The population of rumen bacteria, fungi, ciliate protozoa, Fibrobacter succinogenes, Ruminococcus flavefaciens, Ruminococcus albus and methanogens were not affected by BEO-CL supplementation. In vitro gas production test to evaluate various feedstuffs namely hays (berseem, oat and maize); dry roughages (wheat straw, paddy straw and sugarcane bagasse) complete feeds with 20:80, 35:65 and 50:50 concentrate: roughage ratio) as substrates was conducted using rumen liquor of these buffaloes as inocula. There was an increase in gas production with rumen liquor of BEO-CL supplemented buffaloes irrespective of substrate. Methane production was decreased with 0.75% BEO-CL supplemented inoculum but not with paddy straw and sugarcane bagasse. The in vitro true digestibility (IVTD) of feed was increased with BEO-CL inoculum only with complete diet having 20:80 concentrate:roughage ratio as substrate. It is concluded that BEO-CL at the level of 0.75% of BW did not affect rumen characteristics and major microbial populations but inhibited in vitro methane production; hence, it can be further explored for its use as a feed additive to mitigate methane emission in buffaloes.