Effect of Vegetable Oils on Ciliate Protozoa, Methane Yield, Enzyme Profile and Rumen Fermentation In vitro

An experiment was conducted to assess the effect of locally available vegetable oils on rumen fermentation characteristics, methanogenesis, enzyme profile and rumen protozoal population in in vitro studies. Four locally available vegetable oils viz., mustard oil, sunflower oil, sesame oil and rice bran oil were incubated at 39±0.5°C for 24 h at four levels viz., 0, 50, 100 and 200 μl in 100 ml glass syringes having 200±5 mg of substrate (paddy straw and concentrate mixture in 1:1 ratio) and 30 ml of incubation medium (mixed rumen microbial culture). Total rumen protozoa as well as isotrichidae and entodiniomorphid population and methane production decreased (P<0.01) due to sunflower oil in the medium. Although, all the vegetable oils did not have any effect on total volatile fatty acid production, propionic acid and microbial biomass production increased (P<0.01) and ammonia nitrogen concentration decreased (P<0.01) due to inclusion of sunflower oil. Inclusion of sunflower oil also improved the activity of carboxymethyl cellulase. However, sunflower oil had no effect on dry matter degradability. Inclusion of sesame oil in the medium at higher dose (200 μl/30 ml incubation medium) decreased (P<0.01) total protozoal number and methanogenesis. Mustard and rice bran oils did not have any effect on ciliate protozoal population, ruminal methanogensis, activity of polysaccharide degrading enzymes, microbial biomass production, ammonia nitrogen concentration and dry matter degradibility in vitro. It can be concluded that sunflower oil in mixed microbial culture reduced ciliate protozoal population, ruminal methanogenesis, ammonia nitrogen concentration and improved microbial biomass and propionic acid production.