Effects Of Yeast On Lipopolysaccharide-induced Acute Inflammatory Response In Yellow Broilers

The study was conducted to investigate the effects of yeast on production performance,immune function and intestinal function of yellow broilers induced immune stress by lipopolysaccharide(LPS).480 one-day old yellow broilers with average body weight of 38.5�1.01 g were randomly divided into 6 groups with 8 replicates per group and 10 broilers in each replicate. The experiment was designed in a 2�2 factorial design. The factors included dietary type(antibiotics,0.05% yeast or 0.5% yeast) and immunological challenge (LPS or physiological saline injection).2 groups in 6 treatment groups were fed diets containing 0.025%o dietary colistin,2 groups were fed diets containing 0.05% yeast, and 2 groups were fed diets containing 0.5% yeast. The experiment lasted for 56 days. On d 21,23, 25 and 27, broilers were injected with either lmg/kg BW of LPS or an equivalent amount of sterile saline. Rectal temperature of one bird selected randomly from per replicate was determined at 2h after injection on days 21 and 27,7 mL blood of one bird selected randomly from per replicate was collected from the wing vein at 3h and 12h after injection, the detection indices were the content of IL-1?,IL-2, IL-4,IL-6, IL-10, TGF-?, TNF?a, IFN-?, HSP70?TLR-2?TLR-4??-defensin1?IgG?IgA?IgM?lysozyme and acute phase protein including ?-AGP(a-acidoglycoprotein),SAA(serum amyloid A protein), CRP (C-reactiveprotein), HP(haptoglobin),AAT(al-antitrypsin),HP in serum. At 3h and 12h after injection on day 27, liver and spleen of one bird randomly selected from per replicate were removed and weighed 10g after slaughtered and the frozen in liquid nitrogen rapidly and stored at-80? for mRNA determination of IL-1??IL-2?IL-4?IL-6?IL-10?TGF-??TNF-??IFN-??HSP70?TLR-2? TLR-4??-defensinl.2cm intestinal segments of duodenum and jejunum and ileum of one bird randomly selected from per replicate were sniped on day 27,35 and 56, to determine intestinal morphology and immunostaining of proliferating/apoptotic cells. In addition, the chyme of ileum and cecum were obtained to quantify the live yeast cells and other microbiotas counts such as colibacillus, bifidobacterium, lactobacillus. Birds were weighed and feed intake will be recorded on days 1,21,28,35. The results showed as follows:(1) Compared with the control group injected with normal saline, LPS stimulation decreased the production performance and elevated body temperature of yellow broilers (P> 0.05). LPS stimulation decreased spleen index(P<0.05),but had no significant effect on liver index. Compared with the control group injected with antibiotic, the feed intake and body weight gain were significantly increased in the early stage (0-3 weeks) of yellow broilers by adding 0.05% or 0.5% yeast(P<0.05). Adding 0.5% yeast in late (5-8 weeks) diets achieved the same production performance with control group injected with antibiotics. The effect of yeast on production performance, rectal temperature, liver index and spleen index had no significant interaction with LPS stimulation (P>0.05).(2) Compared with the control group injected with normal saline, the rectal temperature of broilers increased significantly 2h after LPS injection on day 21 (P<0.05), the content of IL-1, IL-2, IL-4, IL-6, IL-10, TGF in serum increased significantly 3h after first injection(P< 0.05), the content of IL-1, IL-2, IL-4, IL-6, TNF-?, IFN and TGF increased significantly 12h later(P<0.05), the content of IL-1,IL-4, IL-6 increased significantly 3h after repeated injections (P<0.05). At the same time, the mRNA expression of inflammation factors related to liver and spleen in yellow broiler significantly changed. The mRNA expression of IL-1?? IL-2?IL-4?TGF-??TNF-??IFN-??TLR-2?TLR-4 in spleen and the IL-1??IL-6?IL-10? TNF-??IFN-??TGF-??TNF-??IFN-??HSP70?TLR-2?TLR-4??-defensinl increased significantly 3h after repeated LPS injection on d 27 (P<0.05).The expression of gene yeast on related factors yellow broilers serum cytokines and liver and spleen effect and LPS injection had no interactive relationship.(3) Compared with saline injected control group,3h and 12h after first injection of LPS increased the a-AGP content in serum of yellow broilers significantly (P< 0.05),3h after repeated LPS injection on day 27 significantly increased the HP content in serum(P<0.05). Adding yeast 3h and 12h after LPS injection on day 21 and 27 had no significant effect on the content of a-AGP?SAA?CRP?AAT?P in serum of yellow broilers (P>0.05). The effect of Yeast on the content of a-AGP?SAA?CRP?AAT?HP in serum had no significant interaction with LPS stimulation (P>0.05).(4) Compared with the control group, the IgG and IgM content in serum of yellow broilers were reduced significantly(P<0.05), the lysozyme content in serum were significantly increased(P<0.05), and the content of IgA in serum had no significant effect 3h after first LPS injection on d 21 (P>0.05).12h afer first LPS injection on day 27 significantly reduced IgG content in serum of yellow broilers(P<0.05).3h and 12h after repeated LPS injection on day 27, the IgQ IgA, IgM and lysozyme content had no significant effect (P>0.05). Adding yeast in diets had no significant effect on the IgG, IgA, IgM and lysozyme content on d 21 and d 27(P>0.05), the effect of yeast on the IgG, IgA, IgM and lysozyme content in serum on d 21 and d 27 had no significant interaction with LPS stimulation (P>0.05).(5) Compared with the control group injected with normal saline, the apoptotic index of duodenum was increased significantly after repeated LPS injection, and the apoptotic index of duodenum,jejunum and ileum on d 56 had no significant effect. Adding yeast in diets did not affect the the apoptotic index of duodenum, jejunum and ileum on d 27 and d 56(P> 0.05), the effect of yeast on the apoptotic index of duodenum, jejunum and ileum on d 27 and d 56 had no significant interaction with LPS stimulation (P>0.05). Compared with the control group injected with normal saline, the amount of yeast, lactic acid bacteria, bacillus and Escherichia coli in jejunum and ileum on d 27,d 35 and d 56 had no significant effect, adding yeast(0.05% and 0.5%) in diets increased the amount of yeast in ileum on d 27,d 35 and d 56, the effect of yeast on the amount of yeast, lactic acid bacteria, bacillus and Escherichia coli in jejunum and ileum on d 27,d 35 and d 56 had no significant interaction with LPS stimulation (P> 0.05).Compared with the control group injected with normal saline, the effect of LPS injection on the Vh?Cd?Vh/Cd in duodenum, jejunum and ileum of yellow broilers was not significant(P>0.05).Compared to the control group injected with antibiotics, adding 0.5% yeast in diets increased the Vh in jejunum of yellow broilers on d 35 (P<0.05),adding yeast had no significant effect on Vh,Cd and Vh/Cd of duodenum, jejunum and ileum(P>0.05). The effect of yeast on the Vh,Cd and Vh/Cd of duodenum, jejunum and ileum on d 27, d 35 and d 56 had no significant interaction with LPS stimulation (P>0.05).