| Avian colibacillosis is an avian local or systemic disease caused by Escherichia coli（E.coli） or some of its pathogenic serotype, which characterized by depression, anorexia,diarrhea, growth retardation and higher mortality rate. It has brought tremendous economiclosses. Immunization and medication are the two main methods of prevention and treatmentof the disease. Due to multi-serotypes of E. coli, low cross protection among bacterial strainsand irrational uses of antibacterial drugs, drug resistance problem is becoming increasinglyserious and further affecting food safety and export trade directly. There are many reports oncurative effects of traditional Chinese medicines in the prevention and treatment of aviancolibacillosis for the past few years, but reports on clarifying the mechanism from the point ofmodern pharmacology are rare. For this reason Jinzhucao Granules were applied in the studyfor the prevention and treatment experiment and further investigation in action mechanism ofartificial infected avian colibacillosis.（1）Modelling of avian colibacillosis:16512-day old HY Line Brown Chickens wererandomly divided into eleven groups and15chickens in each group. Bacterial liquid of1.6×109cfu/mL was modified into10concentration groups, respectively, including0.16×109cfu/mL，0.32×109cfu/mL，0.48×109cfu/mL and1.6×109cfu/mL and then injected intopectoral muscle with0.5mL bacterial liquid. Healthy control group (N) was injected inpectoral muscle with0.5mL physiological saline. The results showed that the chickensappeared following symptoms after challenged: produceing yellow-white liquid stools andparalysis of legs and wings, or even death. Typical histopathological changes caused by E.coli including necrosis of chicken pectoral muscle, pericarditis, perihepatitis, congestion andswelling of kidney, turbid air sac, congestion of intestinal mucosa and bleeding, which wereobserved via dissecting and fit completely with the properties of E. coli through separationculture of pathogenicbacteria and biochemical test. The incidence rate of the group treatedwith0.64×109cfu/mL bacterial liquid reached100%and the mortality rate was78%after72hours. These findings indicate that chicken challenged with0.5mL bacterial liquid of0.64×109cfu/mL successfully copied cases of avian colibacillosis.（2）The trial eperiment of treatment of Jinzhucao Granules:13512-day old HY Line Brown Chickens were randomly divided into nine groups and15chickens in each group.Treatment groups were treated with Jinzhucao Granules of0.0375g/kg,0.075g/kg,0.15g/kg,0.3g/kg,0.6g/kg,1.2g/kg and2.4g/kg respectively, as well as model group and healthy controlgroup. Chickens in healthy control group were injected with0.5mL physiological saline inpectoral muscle, and in Jinzhucao Granules treatment groups and model group werechallenged with0.5mL O78bacterial liquid of0.64×109cfu/mL. Jinzhucao Granulesdissolved into warm water were intragastrically administrated to chickens in JinzhucaoGranules treatment groups after the outbreak of the disease and physiological saline were alsointragastrically administrated to chicken in model group and healthy control group（isolatedrearing）. The results showed that the effective rate of Jinzhucao Granules against aviancolibacillosis gradually increased when the dose was between0.0375g/kg and0.3g/kg andwhen the dose was larger than0.3g/kg the effective rate tended to be stable. Therefore therecommended dose of Jinzhucao Granules is0.3g/kg which is equal to the drinkingadministration of1.5g-2.5g Jinzhucao Granules.（3）The therapeutic and preventive effect of Jinzhucao Granules on aviancolibacillosis in artificially infected chicken:40012-day old HY Line Brown Chickenswere divided into8groups randomly, including prevention group treated with JinzhucaoGranules (0.15g/kg), treatment groups treated with low-dose (0.15g/kg), mid-dose (0.3g/kg)and high-dose (0.6g/kg） of Jinzhucao Granules, respectively, drug control groups treatedwith Sihuang Anti-diarrheal Granules (0.2g/kg) and10%Ofloxacin (200mg/kg) respectively,healthy control group and model group with0.5mL physiological saline. Chickens in othergroups were challenged with E. colli O78besides the healthy control group. The preventiongroup was treated with Jinzhucao Granules3days before being challenged with E. colli O78,and Jinzhucao Granules were intragastrically administrated to chicken in each drug treatedgroup6hours after being challenged with E. colli for5successive days (one time per day).On3,7and11d, the concentration of cytokines (TNF-α and IL-1β) and biochemicalindicators of serum was evaluated. Besides, the chickens in each group were randomlydissected at the end of experiment for observation of the pathological change in each organ.The results showed that the protection rate in prevention group was extremely higher than thatof model group (P<0.01), and could be used for prevention and protection the attack of E.Colli O78. The effective rate and the cure rate at low-dose, mid-dose and high-dose wereextremely higher than those of model group (P<0.01), but there were no significantdifferences between drug control group and western medicine group (P>0.05), and superior tothe traditional Chinese medicine group. The levels of ALT, AST and TBIL in serum frommid-dose and high-dose group were extremely lower than those from model group on3,7and 11d (P<0.01), the levels of TB and GLB were extremely higher and showed no significantdifference when compared with healthy control group(P>0.05), and there was significantdifference in the levels of TB and TBIL when compared with medicine control groups(P<0.01).The levels of IL-1β in serum at mid-dose and high-dose were extremely lower thanthose of model group on7d, but no significant difference compared with healthy controlgroup（P>0.05）.The levels of TNF-α in serum at low-dose and mid-dose were significantlylower than those of model group on11d（P<0.05）. Necrosis of chicken pectoral muscle inJinzhucao Granules treated groups were disappearing observed via dissecting, inflammationof heart and liver turned better and swelling and bleeding of kidney was alleviated. Chaos andswelling of liver cell were alleviated via HE stained slice observation, cellulose attached onthe surface of liver disappeared, protein particles in endochylema decreased and congestionand stasis of liver was eased. It is suggested that Jinzhucao Granules effectively prevent aviancolibacillosis by reducing the levels of transaminase, total bilirubin and indirect bilirubin,increasing protein level, inhibiting production of proinflammatory cytokines and repairingdamaging and maintaining functions of liver and kidney.（4）The therapeutic effect of Jinzhucao Granules on avian colibacillosis innaturally infected chicken：The chickens naturally infected by coccidiosis were selected forthe test. The Jinzhucao Granule (2.5g/L) dissolved into drinking water was used for5successive days. The therapeutic effect was determined by analyzing the clinical symptoms，mortality，food intake and egg laying rate. The results showed that Jinzhucao Granule at2.5g/L could validly remit the chicken mortality, rapidly recover food intake, and increase egglaying rate. |
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