INFLUENCE OF DIET AND YEAST SUPPLEMENT OF IN-VITRO RUMINAL CHARACTERISTICS

The effect of Yea-Sacc supplement on the level of rumen fermentation p roducts in dependence on the diet has been investigated in the Rusitec fermentation apparatus. The solid and liquid components of the rumen contents of sheep fed a diet consisting of 80% meadow hay and 20% grou nd barley were used as an inoculum. Three experiments were carried out in which four fermentation vessels were each fed Diet 1 (80% meadow h ay and 20% barley), Diet 2 (50% hay and 50% barley) and Diet 3 (65% ha y, 20% barley and 15% treated beech sawdust). The yeast culture Yea-Sa cc 1026 contained 10(8) live cells of Saccharomyces cerevisiae per gra m and was added to two fermentation vessels every day at an amount of 0.5 g l-1. Results showed that the Yea-Sacc supplement increased the d igestibility of hemicellulose with Diets 1 and 2. The digestibilities of other parameters were not affected. With Diet 3 digestibility of dr y matter, neutral detergent fibre, hemicellulose and cellulose were si gnificantly lowered. Microbial proteosynthesis increased with Diets 1 and 3. No significant differences were found in the pH, ammonia N and gas production values. The volatile fatty acid production was variable . From the results it followed that the Yea-Sacc additive significantl y influenced some aspects of rumen fermentation in vitro, which appear ed to be dependent on the nature of the diet used.