The current study was conducted to investigate the effects of yeast cell wall (YCW) powder
processed to different particle sizes on the growth performance, serum metabolites,
immunity and antioxidant status of broilers. A total of 144 one-day-old Arbor Acres broiler
chicks were allocated into 3 dietary treatments consisting of 6 replicates with 8 chicks
per replicate, and received a basal diet and basal diet supplemented with either 1 g/kg
coarse or fine grinding YCW powder until 42 days of age, respectively. Treatments did not
affect growth performance of broilers. Compared with the control group, total cholesterol
content in serum (P = 0.032) and bursa weight (P = 0.019) was increased by the inclusion
of YCW at 42 day. Fine rather than coarse grinding YCW powder increased ileal secretory
immunoglobulin A (SIgA, P = 0.040) and immunoglobulin G (IgG, P = 0.019) content
at 21 day. Additionally, birds fed diets containing fine grinding YCW showed increased ileal
total superoxide dismutase (T-SOD) activity (P = 0.049) at 21 day whereas decreased malondialdehyde
(MDA) accumulation at 42 day (P = 0.021), respectively. In conclusion, the
ability to improve immune function and intestinal oxidative status of broilers was more
pronounced in fine grinding YCW powder