Acta Veterinaria Hungarica 54 (3), pp. 333–342 (2006) DOI: 10.1556/AVet.54.2006.3.4 0236-6290/$ 20.00 © 2006 Akadémiai Kiadó, Budapest RUMEN FERMENTATION RESPONSE TO A DIRECT-FED XYLANASE ENZYME PREPARATION FROM THERMOMYCES LANUGINOSUS IN SHEEP V. JURKOVICH 1* , J. KUTASI 2 , Hedvig FÉBEL 3 , J. REICZIGEL 4 , E. BRYDL 1 , L. KÖNYVES 1 and P. RAFAI 1 1 Department of Animal Hygiene, Herd Health and Veterinary Ethology and 4 Department of Biomathematics and Informatics, Faculty of Veterinary Science, Szent István University, H-1400 Budapest, P.O. Box 2, Hungary; 2 Department of Plant Anatomy, Eötvös Lóránd University, Budapest, Hungary; 3 Research Institute for Animal Breeding and Nutrition, Herceghalom, Hungary (Received 16 June 2005; accepted 13 February 2006) A study was conducted to obtain data on the effects of a fungal fibrolytic enzyme preparation (Rumino-zyme, with 250 FXU/g xylanase activities) from Thermomyces lanuginosus on some rumen fermentation parameters in sheep. Ruminal fluid samples were taken just before the morning feeding and then 2 h and 4 h after feeding. Xylanase activity, pH, concentration of ammonia and vola- tile fatty acids were measured. The enzyme supplementation did not affect the pH but increased the xylanase activity and the total VFA concentration of the rumen fluid. The molar proportion of acetate increased, propionate was not affected and butyrate decreased after enzyme administration. The concentration of ammonia also decreased after supplementation with the enzyme product. It can be con- cluded that the xylanase enzyme preparation from T. lanuginosus induced favour- able changes in the major rumen fermentation parameters in sheep. Key words: Xylanase, ruminal fermentation, Thermomyces lanuginosus, sheep Early studies on the use of exogenous proteolytic or fibrolytic enzymes in ruminant diets have been conducted from the 1960s, but the number of publica- tions concerning their possible application in the feeding of ruminants has in- creased in the last 15 years. Although the results obtained with exogenous fibro- lytic enzymes (EFE) or microbes producing EFE are far from being unequivocal, an increasing use of such enzymes might be predicted. Important production in- dices of both the beef and the dairy industry have shown improvement as a result * Corresponding author; Fax: 0036 (1) 478-4243; E-mail: Jurkovich.Viktor@aotk.szie.hu