Effects of Saccharomyces Cerevisiae Fermentation Products on the Microbial Community throughout the Gastrointestinal Tract of Calves

SIMPLE SUMMARY: Saccharomyces cerevisiae fermentation products (SCFP) are widely used for dairy cows and have been suggested to improve calf performance and health. However, the changes in microbial community along the gut in calves supplemented with SCFP have not been investigated extensively. This manuscript exhibited that calves supplemented with Saccharomyces cerevisiae fermentation products changed the microbial community of GIT and stimulated fibrolytic bacteria (Lachnospiraceae and Ruminococcaceae) colonization in early rumen and large intestine, respectively. Those alternations of microbiota in GIT might explain how SCFP works in calves. ABSTRACT: The effect of Saccharomyces cerevisiae fermentation products (SCFP) on improving growth and health of calves could be attributed to the ability of SCFP to modulate the microbiota in the gastrointestinal tract (GIT). However, the changes in microbial community along the gut in calves supplemented with SCFP have not been investigated extensively. The aims of this study were to investigate the effect of SCFP on microbial communities in each sites of GIT using high-throughput sequencing technique. Fifteen Holstein male calves were used and randomly assigned to 1 of the 3 treatments including a calf starter containing 0 (Control, CON), 0.5 (SCFP1) or 1% SCFP (SCFP2, Original XPC, Diamond V, Cedar Rapids, IA, USA) of dry matter from day 4 to 56. The supplemented calves were fed with an additional 1 g/d SCFP (SmartCare, Diamond V, Cedar Rapids, IA, USA) in milk from day 2 to 30. Rumen fluid was sampled at day 28 of age via esophageal tube. All calves were slaughtered and gastrointestinal samples collected on day 56. Inclusion of SCFP increased the microbial species richness in the large intestine. The SCFP also affected the bacterial community at an early age in the rumen and later in rectum microbiota. Supplementation of SCFP stimulated colonization by fibrolytic bacteria (Lachnospiraceae and Ruminococcaceae) in rumen and large intestine, respectively. No differences were found between SCFP1 and SCFP2. This is the first study to analyze the effect of SCFP on bacterial community of the GIT microbiota in calves. The results provide the basic bacterial community information, which helps us understand the mechanism of action of SCFP for improving the health and performance of pre-weaning calf.