RESUMEN
Probiotics of Lactobacillus acidophilus, Saccharomyces cerevisiae, and Aspergillus niger and three commercial exogenous fibrolytic enzymes (EFE) were tested in vitro to select best source and optimum dose followed by in vivo studies on male buffalo calves. Bacterial (P < 0.001) and protozoal population were increased significantly (P < 0.001) with probiotics and EFE. In vitro dry matter digestibility was more (P < 0.001) on L. acidophilus and then on S. cerevisiae. Dose required for L. acidophilus and S. cerevisiae probiotics was 1 x 10(9) and 3 x 10(9) cfu/flask, respectively. Cellulase and xylanase were effective at 4,000 and 12,500 IU/kg DM. In vitro cell wall digestibility was increased (P < 0.001) when probiotics and EFE were used together. Best source and optimum dose of probiotics and EFE were fed to 18 male buffalo calves with concentrate supplement (CS). Calves were randomly divided into three groups either without probiotics and EFE (CG) or with probiotics (EG(1)) or probiotics combined with EFE (EG(2)) on wheat straw diet. Organic matter, neutral detergent fiber, and acid detergent fiber digestibility was improved significantly. Average daily weight gain (ADG) and feed efficiency were significantly higher (P < 0.001) in EG(2) than EG(1) or CG. Final body weight was 4% and 12% and feed efficiency was 2.6% or 1.6% more (P < 0.001) in EG(2) compared to CG or EG(1), respectively. Fortification of CS with probiotics and EFE together had more impact on FE and ADG in buffalo calves.