Effect of dietary sunflower oil on rumen protozoal population and fermentation characteristics in growing crossbred calves

A study was undertaken to investigate the effect of dietary sunflower oil supplementation on rumen protozoal population, fermentation charaterestics and enzyme profile in growing calves. Fifteen growing Jersey male crossbred calves were divided in to three equal groups (G1, G2 and G3) of five each. These calves were fed individually under stall feeding on a mixed ration containing green maize fodder and concentrate mixture in 50:50 ratio for 110 days. Sunflower oil was supplemented along with concentrate mixture at 0, 2 and 4% of the daily DM intake for two consecutive days at seven days intervals to the calves of G1, G2 and G3 group, respectively. Daily DM intake and apparent nutrient digestibility were similar among the three groups. Lowest (P<0.01) rumen protozoal number (both holotrich and spirotrich) was observed in the calves of G3 group followed by G2 and G1 group. Rumen pH and ammonia nitrogen concentration became lower (P<0.01) while TVFA and propionate production were higher in G2 and G3 calves. Further, the pH and ammonia nitrogen level were lower (P<0.01) whereas TVFA and propionate concentration were higher (P<0.01) in the rumen liquor of calves fed 4% (G3) than 2% (G2) sunflower oil. Activity of carboxymethyl cellulase, xylanase and ?-glucosidase was not influenced by the dietary supplementation. The results of the study indicated that dietary sunflower oil supplementation drastically reduced the rumen protozoal population and increased ruminal propionate production.