Effects of live yeast supplementation on lipopolysaccharide-induced inflammatory responses in broilers

The effects of supplemental live yeast (LY) on inflammatory responses in broilers challenged with lipopolysaccharide (LPS) were investigated. One-day-old broilers were randomly divided into two treatment groups with two subgroups of each (8 replicate pens; 10 birds/pen) and were fed a basal diet without or with 0.5 g/kg of LY (Saccharomyces cerevisiae NCYC 47Hr+, 1.0 × 10¹⁰ CFU/g). Birds from each subgroup of the two treatment groups were intra-abdominally injected with LPS (1.5 mg/kg of BW) or saline at 21, 23, 25, and 27 d of age. Samples were obtained after 8 h of the first injection (d 21) and the last injection (d 27), respectively. Results showed that no treatment differences (P > 0.05) were detected in the relative spleen and bursa weights, as well as serum lysozyme activity and ceruloplasmin content regardless of the immunological status. LY addition tended to alleviate (P = 0.097) LPS-induced increase in serum α-acid glycoprotein content on d 27. LPS induced increased (P < 0.05) serum nitric oxide content and myeloperoxidase activity on d 21 and 27, however, there was a tendency towards reduced (P < 0.10) serum nitric oxide content and myeloperoxidase activity on d 21 in response to LY inclusion. Besides, LY-fed birds had lower (P < 0.05) serum nitric oxide content on d 27 relative to the control counterparts. LPS resulted in increased (P < 0.05) relative mRNA expression of splenic interleukin-1β on d 21 and 27, but which was lower (P < 0.05) in LY-treated birds compared with that in control. In conclusion, dietary supplementation of LY had potential to alleviate LPS-induced inflammation in broilers.