Population of protozoa and carbohydrate-digesting enzymes in the rumen of sheep fed a diet supplemented with yeast Saccharomyces cerevisiae

Abstract

The aim of the study was to compare the effect of two yeast (Saccharomyces cerevisiae) preparations in the diet on the number of protozoa and carbohydrate-digesting enzymes in the rumen of sheep. The experiment was conducted in six sheep with a cannula in the rumen. The animals were divided into three groups of two sheep. Each group received a different sequence of three treatments (control−CON, live yeast–LY or yeast culture–YC), resulting in three study periods. Sheep were fed meadow hay and concentrate alone or the same ration supplemented with LY or YC at a dose of 5 or 30g/day, respectively. The rumen fluid and digesta were collected before (0h) and 2 and 4h after feeding. The lowest pH was recorded for sampling at 2 and 4h after feeding, and the highest at 0h. The number of Diplodinium spp. and Dasytricha sp. was lower when sheep were fed YC and LY, respectively, than when they were fed CON. Fibrolytic and amylolytic activities were lower 2 and 4 after feeding for all groups and YC, respectively, compared to the results at 0h. Our data suggested that the addition of LY and YC to the sheep diet modified the abundance of the protozoan genera Diplodinium and Dasytricha and could affect fibrolytic and amylolytic activities in the rumen.