Supplementation of Saccharomyces cerevisiae modulates the metabolic response to a lipopolysaccharide challenge in feedlot steers

Abstract Text:

Live yeast has the potential to serve as an alternative to the use of low-dose supplementation of antibiotics in cattle due to the ability to alter ruminant metabolism; which in turn may influence the immune response.  Therefore, the objective of this study was to determine the metabolic response to a lipopolysaccharide (LPS) challenge in feedlot steers supplemented with Saccharomyces cerevisiae CNCM I-1079 (SC).  Steers (n=18; 266±4 kg BW) were processed and separated into three treatment groups (n = 6/treatment): 1) steers were fed a standard receiving diet and served as the control (Cont); 2) steers were fed the receiving diet supplemented with SC (Lallemand, Inc.) at 0.5 g/hd/d (SC-0.5); and 3) steers were fed the control diet supplemented with SC at 5.0 g/hd/d (SC-5.0) for 29 d.  On d 27 steers were fitted with indwelling jugular cannulas and rectal temperature (RT) probes, and were placed in individual stalls.  On d 28, steers were challenged i.v. with LPS (0.5 µg/kg BW at 0 h) and blood samples were collected at 30-min intervals from -2 to 8 h and at 24 h post-challenge.  Serum was isolated and stored at -80^oC until analyzed for glucose, non-esterified fatty acids (NEFA), and blood urea nitrogen (BUN) concentrations.  There was a treatment (P=0.02) and time effect (P<0.001) for glucose; SC-0.5 steers had greater glucose concentrations (77.8±1.6 mg/dL) than Cont (71.5±1.3 mg/dL) and SC-5.0 steers (71.6±1.4 mg/dL).  Glucose concentrations also increased (P<0.001) over time in response to LPS challenge. Concentrations of NEFA were also affected by time (P<0.001) but were not affected by treatment (P=0.42).  For all treatments, NEFA concentrations increased in response to LPS challenge.  There was a treatment (P<0.001) and a time (P<0.001) effect for BUN concentrations; BUN concentrations were greater (P<0.001) in SC-0.5 steers (14.5±0.2 mg/dL) than Cont (12.8±0.2 mg/dL) and SC-5.0 (12.8±0.2 mg/dL) steers. For all three groups, BUN concentrations increased (P<0.001) in response to LPS challenge. These data demonstrate that Saccharomyces cerevisiae supplementation may alter the metabolic response to LPS challenge.  Repartitioning of nutrients may help explain the variations in the acute phase response observed in cattle supplemented with Saccharomyces cerevisiae.  Data from this study suggest that Saccharomyces cerevisiae products may be useful as alternatives to antibiotic use in feed in order to enhance cattle health.

Keywords: cattle, live yeast, metabolism