Effects of liquid yeast cell wall on growth performance, intestinal development, immunity, and cecal Salmonella population of broilers.

An experiment was conducted to evaluate the effect of liquid yeast cell wall (YCW) supplementation in water on growth performance, intestinal development, immunity, and cecal microbiota in broilers. A total of 360 Cobb 500 male broilers were randomly allocated to three treatments with 6 replicates of 20 birds each. Experimental water treatments consisted of 1) a control (CON) group supplied with municipal water; 2) a liquid yeast cell wall (YCW1) supplemented group during d 0-14 and d 39-42 at 2.5 mL/L; 3) a liquid yeast cell wall (YCW2) supplemented group during d 0-14 and d 39-42 at 5 mL/L. All data were subjected to the one-way ANOVA using the GLM procedure of SAS. Means were further separated using Tukey's HSD test. A significant difference was considered at P ≤ 0.05. Liquid YCW supplementation linearly improved FCR during the d7-14 of age. A quadratic effect on BWG peaks at 2.5 mL/L inclusion rate was found during the d14-21 period. Growth performance was not affected by liquid YCW during 42 d grow-out period. Liquid YCW supplementation linearly increased duodenal villus height (P = 0.014) at d14. Meanwhile, broilers of YCW2 group had a lower villus height: crypt depth ratio (P = 0.037). Supplementation of liquid YCW linearly upregulated the proinflammatory cytokine interferon gamma (IFN-γ) and nuclear factor kappa B (NF-κB) and downregulated anti-inflammatory cytokine interleukin-10 (IL-10) in ceca tonsil compared to the control (P < 0.05). At d 42, YCW2 had a lower Salmonella population in ceca compared to the other treatments (P = 0.021). Additionally, supplementation of liquid YCW increased Lactobacillus population in the ceca compared to the control group (P < 0.01). In conclusion, liquid YCW supplementation positively affected early age growth performance by improving intestinal development. Late-phase supplementation of YCW reduced Salmonella population in the ceca, suggesting YCW as a potential intervention to reduce pre-harvest Salmonella load.