Influence of a Probiotic Yeast ( Saccharomyces cerevisiae CNCM I-1077) on Microbial Colonization and Fermentations in the Rumen of Newborn Lambs

Six lactating Holstein cows fitted with rumen and T-type duodenal cannulas were used in a crossover design to examine effects of yeast culture supplement on production parameters, rumen fermentation, and flow of N to the duodenum. Treatments were control and control plus 10 g/d of yeast culture. Dry matter intake was greater, and milk production tended to be higher, for cows supplemented with yeast culture, but milk composition was not affected. Rumen pH was not affected by yeast culture, but peak lactic acid concentration decreased from 1.93 to 1.73 mM. Rumen fluid acetate:propionate ratio, dilution rate (percentage per hour), and ammonia N concentration (milligrams per deciliter) were 2.28, .12, and 10.7 and 2.04, .13, and 9.6 for control cows and for cows supplemented with yeast culture, respectively. Although numbers of fiber-digesting bacteria were not affected by yeast culture, DM disappearance of wheat straw tended to be higher at 12 and 24 h, and CP and ADF digestibilities were greater. Duodenal NAN flow tended to be higher in cows supplemented with yeast culture because of higher bacterial N flow. Duodenal AA profile and flow of Met were significantly affected by yeast culture supplementation. The results suggest that yeast culture may alter the AA profile of bacterial protein.

The establishment of ciliate protozoa in the rumen was studied in conventional lambs reared under different conditions of management. The role of the microflora in the kinetics of this establishment was also investigated in conventionalized lambs. In lambs reared under farm conditions ciliate protozoa appeared in the following order: Entodinium (15-20 days), Polyplastron, Eudiplodinium, and Epidinium (20-25 days), and Isotricha (50 days). Entodinium was the most abundant (10(5)-10(6) ciliates mL-1). During the 3rd month, ciliates disappeared spontaneously in about 60% of the lambs during a period that varied from 1 to 4 weeks. In lambs fed only cow's milk Entodinium spp. and Polyplastron multivesiculatum became established at low levels. The results obtained with the conventionalized lambs demonstrate that the establishment of the ciliates in the rumen requires that the bacterial flora be well established beforehand.