The objective of this work was to evaluate the effects of soluble carbohydrate and protein supplementation on feed digestibility and rumen characteristics of swamp buffaloes fed total mixed fiber (TMF) silage by using an in vitro technique. A completely randomized design with 3 treatments (soluble carbohydrate (SCH) and protein ratio) and 6 replicates was used. Treatments consisted of total mixed fiber silage rations with SCH: protein ratio of 300 g : 300 g (1 : 1) (A1), SCH : protein ratio of 600 g : 300 g (2 : 1) (A2), and SCH : protein ratio of 900 g : 300 g (3 : 1) (A3). Measurements were taken on nutrient digestibility rates (dry matter, organic matter, crude protein, and crude fiber), fiber digestibility rates (NDF, ADF, cellulose, and hemicellulose), and rumen fermentation condition (concentrations of RAN, total VFA, acetate, propionate, butyrate, and methane and pH). Results showed that significant effects (P LT 0.05) of treatments were found on nutrient digestibility rates (dry matter, organic matter, crude protein, crude fiber, ADF, cellulose, and hemicellulose), rumen fermentation conditions (concentrations of RAN, total VFA, acetate, propionate, butyrate, and CH4). Meanwhile, no effects (P GT 0.05) of treatments were found on NDF digestibility and pH levels. It was concluded that TMF silage ration supplemented with SCH and protein ratio of 3 : 1 (900 g : 300 g) gave the best results in terms of nutrient digestibility rates and rumen fermentation condition of swamp buffaloes.

The ability to utilize low-quality roughage of swamp buffalo has been reported, thus, rumen of swamp buffalo might be a suitable source for isolation of potent fibrolytic bacteria. A total of 165 gram-negative cocci fibrolytic bacteria were screened from rumen contents of 4 swamp buffalo. Six isolates were identified as Ruminococcus flavefaciens and phylogenetically grouped with type strain. Strain OS14 showed the highest fiber digestion alone or combination with non-fibrolytic bacteria and higher than type strain. DM digestibility of cellulose powder in co-culture of OS14 with all strains non-fibrolytic was increased. Moreover, co-culture of OS14 with S137 showed the highest fiber digestion and notably increased of acetate and propionate. These results indicated that possible cross-feeding between R. flavefaciens with non-fibrolytic bacteria could improve fiber digestion but the amount of improvement might be based on the combination of bacteria strains. The in vitro fermentation products and abundance in co-culture need to be quantified in further study.