Modulation of the acute phase response in feedlot steers supplemented with Saccharomyces cerevisiae

Abstract Text:

This study was designed to determine the effect of supplementing feedlot steers with Saccharomyces cerevisiae CNCM I-1079 (SC) on the acute phase response to a lipopolysaccharide (LPS) challenge.  Steers (n = 18; 266 ± 4 kg BW) were separated into three treatment groups (n = 6/treatment): one group was fed a standard receiving diet (Control, Cont); one group was fed the standard receiving diet supplemented with SC (Lallemand, Inc.) at 0.5 g/hd/d (SC-0.5), and the final group was fed the standard receiving 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 that measured RT continuously at 5-min intervals 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 24 h post-challenge.  Serum was isolated and stored at -80^oC until analyzed for cortisol and cytokine concentrations. Prior to the challenge there was an effect of treatment (P < 0.001) on RT; SC-0.5 steers (39.50± 0.03^oC) had greater RT than Cont (39.06 ± 0.04^oC) and SC-5.0 (39.27 ± 0.04^oC) steers. Also, Cont steers had greater (P < 0.001) RT than SC-5.0 steers.  Therefore, RT was further analyzed as the change from baseline.  In response to LPS challenge, the change in RT was affected by treatment (P < 0.001); Cont steers had the greatest change in RT (0.434 ± 0.0510^oC) compared to SC-0.5 (-0.059 ± 0.039^oC) and SC-5.0 (-0.007 ± 0.045^oC) steers.  There was a tendency (P = 0.06) for baseline cortisol concentrations to be affected by treatment; SC-5.0 steers having greater (7.8 ± 0.8 ng/mL) cortisol than Cont (4.9 ± 0.8 ng/mL) steers.  Post-LPS challenge, there was a treatment x time interaction (P = 0.005); SC-5.0 steers had decreased (P < 0.02) cortisol concentrations than Cont steers from 4.5 to 7 h post-challenge.  There was a treatment effect (P ≤ 0.05) for all cytokines (tumor necrosis factor-α, interleukin-6, and interferon-γ).  Cytokines were decreased in SC-0.5 and SC-5.0 steers compared to Cont steers following LPS challenge.  While these data demonstrate that Saccharomyces cerevisiae supplementation can reduce the inflammatory response to a LPS challenge, further research is needed to determine whether or not Saccharomyces cerevisiae supplementation is beneficial when animals are exposed to a live pathogen.

Keywords: immune response, cattle, live yeast