| Ninety-six chickens twenty-day-old, SanHuang, were divided into four experiment groups randomly, In order to search for the injury mechanism in poultry, Group One of chicken were orally given physiological brine as control (D), the other three groups of chicken were orally given lipopolysaccharide, group two 100mg/kg (A),group three 200mg/kg (B), group four 300mg/kg (C) respectively. Methods of pathology, biochemistry and molecule biology were used to examine the injury in liver, small intestine and TLR4 mRNA expression of the liver in different phase in chicken. Hope to provide adequate grounds for injury evoked by LPS on the infection of G- bacteria and bacterial translocation in intestine of poultry.1. Effect of LPS on morphologic change of liver and intestine in chicken Injury of liver: Liver cell degeneration, hyperemia and macrophase illilization,etc. Injury of intestine: small intestine wall was thinner than group D, swelling of small intestine villus, leukocytosis of small intestine,etc.Experiment indicated lower dose of LPS had light injury on chicken,and higer dose of LPS had heavy injury on chicken.2. Influence of the blood biochemical paramerer of chicken treated with LPS In order to observe the hepatic functions of experiment chickens treated with LPS, Activies of AST, ALT, levels of DBIL, IBIL and ratio of ALB/GLO were detected. This study showed that different doses of LPS had different degrees damnification to experiment chickens.Results as following:Changes of AST in serum,it increased early time, decreased latterly. The activies of 4 h,12 h, 48 h in group A , 4 h, 48 h in group B and 4 h,12 h, and 48 h were significant compared with group D.(P<0.01)It was significant that in 12 h and 24 h in group B comared with group D.(P<0.01)Changes of ALT in serum, it increased early time, decreased latterly, the difference between 4 h and 12 h in group A was significant (P<0.05), and returned 12 h later, the differences between group B, C and D was significant (P<0.01).Changes of DBIL in serum,the tedency in group A, B is increased in early time and decreased lately, and group C went on. The difference between group A of 4 h,12 h and group D was significant (P<0.01), the diffeces beteen group B, C and group D both were significant. (P<0.01)Changes of IBIL in serum,the tendency was increased in early time and decreased laterly in group A and B,group A could return normal among them, but group B went on at high level after reaching top. The difference beteen group A, C and D was significant (P<0.01), the difference between group B and group D was significant only at 24 h. (P<0.05)3. Influence on anti-oxygenation enzyme for the chicken treated with LPSThere was no difference in control group on SOD, after given LPS, the tedency decreased in early time and increased laterly in experiment group A,B,C. In group A the activities of SOD decreased to the lowest at 12 h,the increased near to the normal level. In experiment group B,the lowest level was reached at 24 h,, then returned. It showed that after given different dose of LPS to the chickens, LPS could reduce the activities in 24 h, large amount of LPS can damnify chicken.LPS could increase the content of MDA in blood plasama. The tendency was increased at early time and returned lately after given LPS, and it increased with the dose of LPS at a certern time.Top level was reached at 24 h in group A and B, but group C was at 48 h.4. TLR4 mRNA Expression for liver treated with LPSIn order to observe the inlluence of LPS on TLR4 mRNA Expression for liver, RT-PCR technology was used to detect the TLR4 mRNA expression at indicated timepoints. Group A was higher than group D a little, group B, C decreased to the lowest at 12 h, but group C had the lowest number compared with group A, B. This study showed that TLR4 mRNA Expression changed with time and TLR4 had important role in LPS mideated liver injury.Study showed that different damnification can be made in chicken liver by LPS, and it got deeper with the dose of LPS.
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