Effects of Yeast Product on Modulating the Adaptive Immune Function in Broilers
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In this study, Saccharomyces cerevisiae fermentation yeast product was fed to broilers to investigate the effect of yeast products on the broiler immune function. The broilers were vaccinated for Newcastle Disease Virus on day 1 (B1 strain) and day 21 (LaSota strain) via eye drop. Body weights, feed consumption, feed conversion ratio, and mortality were recorded to monitor growth performance. There was no significant difference in Body weights (Probability < 0.05) between the control and treated groups. Since there was only one pen per group, no statistical analysis was conducted for feed consumption or feed conversion. At day 14, 21, 28, 35(blood only), and 42 blood and immune organ samples (thymus, bursa of Fabricius, and spleen) were collected to evaluate immune system development. All data were considered significantly different at Probability < 0.05. The control group had greater thymus indices at day 28, and 42. The control group had greater bursa of Fabricius indices on day 14 and 42. The control group had greater spleen index on day 21. The result of Newcastle Disease Virus antibody titer measurement showed that the population of treated group Immunoglobulin G was higher than control group after 1st vaccination at day 14 and increased faster than the control group after boost at day 21. Cell proliferation results from blood showed similar trend with Newcastle Disease Virus antibody titer results. The control group of simulation index of thymus was higher than the treated group at day 14. Through histology observation, there was no significant difference (Probability > 0.05) in the thymus medulla and cortex ratio between the control and treated groups. In the spleen, the control group contained more nodules at day 14. All these results demonstrated that feeding the yeast product does influence broiler live immune system development.
Park, Jung-Woo (2014). Effects of Yeast Product on Modulating the Adaptive Immune Function in Broilers. Master's thesis, Texas A & M University. Available electronically from