In Vitro DM and Cell Wall Degradability of Total Mixed Rations Influenced by Exogenous Fibrolytic Enzymes Supplementation

Two in vitro experiments were conducted to identify promising exogenous fibrolytic enzymes (EFE), cellulase and xylanase combinations and their optimum level of supplementation for improving the degradability of TMRs’. In experiment, 3 mixtures of EFE were prepared containing cellulase (4000 IU/g) and xylanase (7990 IU/g) in 75:25(E,), 60:40(E₂) and 50:50(E₃) w/w proportions and added at 1.5,3.0 and 6.0 g/kg DM of substrates. Three substrates were having concentrate: wheat straw: green fodder (sorghum) in 25:60:15(S₂), 40:45:15 (S₂) and 60:25:15 (S₃) proportions on DM basis. IVDMD and IVNDFD of all substrates at 48h were improved (P<0.05) on addition of EFE in E₁, E₂ and E₃ proportions at 1.5 and 3.0 g/kg DM of TMR, while both IVDMD and IVNDFD declined (P<0.05) on addition of 6.0g EFE/kg DM of TMR. In experiment II, to find out the best method of addition of EFE to the diet of the animals, 1.5 and 3.0g cellulase and xylanase mixed in 50:50 (w/w) proportion per kg DM as selected from the experiment I, were added in either concentrate or roughage portion separately or in the mixed in substrates containing concentrate, wheat straw and green fodder in 25:60:15(S₁), 40:45:15 (S₂) and 60:25:15 (S₃) proportions on DM basis. The best method of addition of EFE to the diet of the animals on the basis of IVDMD and IVNDFD was observed to be through concentrate and TMR as compared to roughage. Thus it could be concluded that the optimum level of cellulase(4000 I.U/g) and xylanase (7990 I.U./g) supplementation in 50:50 (w/w) ratio to substrates containing up to 60% wheat straw was 1.5 and 3.0 g/kg DM, added either through concentrate portion or in the TMR.