Diversity of anaerobic fungi and rumen fermentation characteristic in swamp buffalo and beef cattle fed on different diets

A comparative study was conducted on swamp buffalo and beef cattle to investigate rumen anaerobic fungi, cellulolytic bacteria and their relationships with the fermentation characteristics. Four, rumen-fistulated crossbred beef cattle and four rumen-fistulated swamp buffalo were randomly assigned to a duplicated 4 × 4 Latin square design with 21-day periods. The dietary treatments consisted of four treatments; rice straw + 0% urea in concentrate (RS + 0U), rice straw + 4% urea in concentrate (RS + 4U), urea–lime treated rice straw + 0% urea in concentrate (ULTS + 0U), urea–lime treated rice straw + 4% urea in concentrate (ULTS + 4U). The results revealed that intake, ruminal NH3–N and BUN were significantly different among treatments and were found to be higher in swamp buffalo fed with 4% urea concentrate and 2% ULTS (P < 0.05). Total VFAs were slightly increased by ULTS and were greater in buffalo than in cattle. Molar proportions of individual VFAs in both cattle and swamp buffalo were not affected by either roughage source or level of urea. Feeding with ULTS increased cellulolytic bacterial population, particularly, the distribution of predominant cellulolytic bacteria of swamp buffalo with 8.75 × 109 copies/ml for Fibrobacter succinogenes, 3.57 × 107 copies/ml for Ruminococcus flavefaciens, and 5.68 × 106 copies/ml for Ruminococcus albus, respectively. The denaturing gradient gel electrophoresis (DGGE) analysis demonstrated that bacterial diversity tended to be slightly different between cattle and buffalo (P = 0.07). When samples were grouped according to similar band pattern, feeding with rice straw were more diverting than ULRS with respect to sampling time and species rather than sampling method. Diversity of anaerobic fungi was shown in 7 clusters in the phylogenetic relationship. The results from this study suggest that swamp buffaloes utilize feeds more efficiently with a higher rumen fermentation efficiency and higher microorganism population when fed with ULTS as a roughage source and supplemented with 4% of urea in concentrate mixture.