Effects Of Yeast Cell Wall On Growth Performance, Immune Function And Antioxidant Capacity Of Yellow-feathered Broilers

Single factor design was used in this experiment. 1260 one-day old yellow-feathered male broilers were randomly divided into 3 groups with 6 replicates of 70 each. The three groups were group A, B, C respectively. Group A was control group, feeding with the basal diet. Group B and C were fed the diets supplemented with 0.1% yeast cell wall from two different companies. The feeding experiment was divided into 3 stages, namely the age of 1-21, 22-42, 43-63 day. Through feeding experiment, growth performance, carcass traits, immune organ indexes, intestinal p H, antioxidant ability and immune function were determined.Growth performance: The yeast cell wall didn’t affect the growth performance of broilers in three stages(P>0.05), but presented an improving trend. In day 22-42, the ADG of group B and C were increased with 1.3% and 0.29% respectively compared with the control group. At the same time, the ADG of group B was increased by 0.59%, and the ADFI of group C was decreased with 0.81%. In day 43-63, the ADG of group B and C were increased by 0.32% and 0.84%. The whole period, different yeast cell wall improved the values of ADG, ADFI and G/F.Slaughter Index: In the day 42, there was no significant difference in slaughter index among the three groups. However, there was an increasing trend of dressing percentage for group B(P=0.056). The values of semi-eviscerated weight and eviscerated weight were increased by different degree(P>0.05).Intestinal p H: In the day 21, 42 and 63, there was no significant difference in intestinal p H among the three groups(P>0.05). The yeast cell wall decreased the values of p H in ileum and cecum, and the cecum p H of group B and C at the age of 63 were decreased by 1.22% and 0.91%, respectively.Antioxidant ability: At the age of 42, there was no significant difference in GSH-Px and SOD among the three groups. However, the values of two antioxidants in group A and B were higher than the control group. Compared with the control group, the T-AOC showed significant difference among the three groups(P<0.05). The T-AOC in the group B and C were increased by 15.41% and 14.47% compared with the control group.Immune function: At the age of 21, the spleen index of group B was significant higher than the control group(P<0.05). In the day 42, there was no significant difference in immune organ index among the three groups. The values of thymus indexes in group B and C increased by 0.87% and 4.64% respectively, compared with the control group. In the day 63, there was still no significant difference, too. At the age of 42, the result of blood T lymphocyte subsets reveal that CD3+ of group B and C were significant higher than the control group(P<0.05). However, the CD4+、CD8+ and CD4+/ CD8+ were no significant difference among the three groups(P>0.05).In summary: 0.1% yeast cell wall from two companies supplemented in diet didn’t affect the performance of yellow-feather broilers. But the yeast cell wall Ⅰ presented an improving trend in dressing percentage of birds. And, there was positive effect in improving the immune function and antioxidant ability of broilers.