Effect of Saccharomyces cerevisiae strain CNCM I-1077 on the ruminal degradability of forages from South America

Abstract

ABSTRACT: The effect of live yeast Saccharomyces cerevisiae strain CNCM I-1077 (SC) on the ruminal degradability of forages commonly found in dairy diets in South America was evaluated. Four non-lactating rumen-cannulated Holstein cows were housed in a tie-stall barn and randomly assigned to two treatment sequences: Control-SC-Control or SC-Control-SC, in a switchback design, with three 30-d periods. Cows in the SC treatment were supplied with 1 × 10 10 cfu of yeast daily via rumen cannula. The in situ degradability of DM and NDF was measured in 16 forage samples collected in Brazil, Argentina, Colombia and Peru, and included corn silage (n = 5), tropical grass silage (n = 2), sugarcane silage (n = 2), oat silage (n = 2), ryegrass silage (n = 2), alfalfa silage (n = 1), alfalfa hay (n = 1) and kikuyu (n = 1). Each forage was incubated in the rumen for 0, 12, 24, 36 and 120 h after feeding. Rumen fluid was collected from the ventral sac for measuring yeast count, pH, ammonia and VFA. Cows supplemented with SC had higher counts of live yeasts in rumen fluid, showed a trend of higher ruminal pH and lower ruminal ammonia concentration. Acetate to propionate ratio was higher in the rumen fluid of animals receiving SC. Live yeast supplementation decreased the pool size of fraction C (undegradable) and increased fraction B (potentially degradable) of DM and NDF. Furthermore, SC accelerated the DM and NDF degradation, as noticed by higher disappearance of DM and NDF at 12 and 24 h of incubation. Live yeast supplementation is a strategy to improve rumen function and increase the nutritive value of forages grown in tropical and subtropical areas.