Microbial synthesis efficiency and enzyme activity in cattle supplemented with fibrolytic enzymes

It was investigated the effects of fibrolytic enzymes (cellulase and xylanase) on the microbial protein synthesis efficiency and enzymatic activity of beta-1,4-endoglucanase (cellulase) in animals receiving diets with corn silage and Tifton 85 hay (Cynodon spp.). Eight bovines fitted with rumen and duodenum cannulas were randomly assigned to two replicated 4 x 4 Latin squares with a 2 x 2 factorial arrangement of treatments (two forage sources with or without fibrolytic enzymes). The commercial enzymatic complex used in this trial was extracted from Aspergillus niger and Trichoderma longibrachiatum fungi. Each animal received 12 g/day of the enzymatic complex by mixing it in the ration. Inclusion of fibrolytic enzymes in the diet increased the beta-1,4-endoglucanase activity in the ruminal fluid of animals fed both forages. However, there was no effect of enzymes on efficiency of microbial protein synthesis that averaged 31.8 and 33.9 g of N/kg of OMDR and 0.40 and 0.41 g of N/Mcal of EDR, respectively, for corn silage and Tifton hay diets. Similarly, duodenal flows of microbial nitrogen (mic-N) and non ammonia nitrogen (NAN) did not differ and averaged 78.2 and 52.5 g/day and 89.6 and 76.3 g/day for corn silage and Tifton hay, respectively. Supplementation with fibrolytic enzymes had no effect on the ruminal parameters of cattle fed hay or corn silage.