Abstract: The objectives of this study were to examine the changes of composition and content of fatty acid in ruminal fluid and the changes of volatile fatty acid in ruminal fluid when EPA/DHA was added in diet. The experiment using the RUSITEC(rumensimulation technique) apparatus. Treatments of the experimental diet were as follows: basal diet (CK, 40∶60 forage to concentrate),or a basal diet plus 0.65% EPA/DHA(Trt1) ,or basal diet plus 1.30%EPA/DHA(Trt2). Experimental period was consisted of 6 d for adaptation and 1 day for sampling. Culture fluid was collected every 2 h over a 12 h period on the last day of the experimental period. Compared with CK, C18∶0 decreased by 76.93% and 80.35% in Trt1 and Trt2, respectively; while the concentration of trans11C18∶1 increased by 185% and 127% in Trt1 and Trt2, respectively; and c9t11CLA increased by 147% and 222% in Trt1 and Trt2, respectively compared with CK. The concentration of VFA, transC18∶1 and c-9,t-11CLA in different sampling time were different. EPA/DHA supplementation could markedly affect VFA and fatty acids profile in rumen fluid.

Key words: EPA/DHA; artificial rumen; ruminal ferment; trans11C18∶1; cis-9; trans-11 CLA