Effect of Vitamin E on Ruminal Fermentation and Nutrient Digestion in Steers Supplemented with Microencapsulated Conjugated Linoleic Acid

The aim of this study was to evaluate the effect of vitamin E on ruminal fermentation and nutrient digestion in steers supplemented with microencapsulated conjugated linoleic acid (CLA). Four male rumen- and duodenum-cannulated Holstein steers (450±93 kg) were used in a 4×4 Latin square design, randomly assigned to four treatments: control (basal diet with 50g of microencapsulated CLA) and the same supplemented with three levels of vitamin E at 4000, 8000, or 12000 IU/d. The supplements (CLA and vitamin E) were placed intra-ruminally. The basal diet consisted of 68% of concentrate and 32% of forage. DM intake was restricted to 2.1% of the initial LW. Chromium oxide was administrated as inert digesta marker via ruminal cannula. There were no significant differences in ruminal pH and production of VFAs due to vitamin E; but butyrate and total VFAs concentration tended to decrease. Also, vitamin E treatments tended to increase acetate:propionate ratio. Ruminal digestion of CP tended to decrease and flow to duodenum of CP tended to increase. Faecal excretion of DM and OM decreased significantly (P<0.05), while total-tract digestion of DM and OM increased significantly (P<0.05) with vitamin E. In conclusion, vitamin E improves total-tract digestibility of DM and OM in steers supplemented with microencapsulated CLA. This suggests that vitamin E could improve the gastrointestinal conditions, impacting positively the productive performance of animals.