Yeast Cell Wall Affects The Growth Performance By Intervening In Immunity And Antioxidant Ability Of Yellow-Feathered Broilers

The experiments were conducted to investigate the effects of yeast cell wall on growth performance, immune function and antioxidant ability of yellow-feathered broilers. A total of 1680 one-day-old yellow-feathered broilers were randomly assigned to 4 groups, and each group was allotted to 6 replicates with 70 chickens in each replicate.The control group was fed a corn-soybean meal basal diet,and the trial group was fed the basal diet supplemented with 0.05%,0.1% and 0.15% of yeast cell wall, respectively. The experiment divided three stages which was lasted for 63 d.The results revealed that as follows:1.In day 1~21, the diet supplemented with 0.1% yeast cell wall can improve ADFI(P<0.05)and 0.05% group can improve F/G(P<0.05), while there was no significant difference on ADG compared with the control group(P>0.05).In day 22~42 and 43~63,the groups with different level yeast cell wall had no significant difference on broiler growth performance(P>0.05).2. At the age of 21, the BF indices of group 0.1% was significant higher than that of group B(P<0.05). While at the age of 42, there was no significant difference on immune organs indices(P>0.05).In day 63, the diet supplemented with 0.15% yeast cell wall significantly increased the thymus indices compared with the control group(P<0.05).3. In the three stages, there was no significant difference in p H of ileum and cecum among the three treatment groups. While the result revealed that the diet supplemented with yeast cell wall by 0.15% decreased the p H of the cecum in broilers at the age of day 21.4. The diet supplemented with 0.15% yeast cell wall significantly improved the serum T-SOD activity and the ability of T-AOC compared with the control group(P<0.05).There was no significantly difference on serum GSH-Px activity and MDA content(P>0.05).5. At the age of day 63, the group 0.1% had higher percent of CD3+ T lymphocyte and CD4+/ CD8+ than control group(P<0.05). The treatment groups significantly improved CD4+ T lymphocyte compared with control group. The groups with yeast cell reduced the percent of CD8+ T lymphocyte by 32.28%, 17.81%, 14.01% compared with control group, but there was no significantly differenceamong four groups(P>0.05).6. The diet supplemented with 0.1% yeast cell wall significantly improved the ileum TLR-2MUC2, ZO-1, Occludin m RNA expression compared with the control group(P<0.05). There were no significance in ileum NF-ΚB, IL-2, IL-6, TNF-α m RNA expression(P>0.05). While the expressions of IL-2, IL-6 and TNF-α climbed with the increase of the yeast cell wall dose.7. The diet supplemented with 0.15% yeast cell wall significantly decreased the numbers of Escherichia and Salmonella in the ileum digest(P<0.05). Compared the control group, the treatment group can significantly increase the total bacteria count in the ilem mucosa(P<0.05). Meanwhile, the 0.1% and 0.15% group significantly decreased the count of Salmonella in the ilem mucosa(P<0.05).