Establishment Of Clinical Mastitis Model For Milk Goat In Guanzhong ＆developmentof Its Vaccine

Mastitis is an inflammation of the mammary gland that often develops in response to intramammary bacterial infection,which is common in milk goat and cattle.In this study, clinical mastitis model was established by using Staphylococcus aureus and Escherichia coli isolated from clinical mastitis in milk goat by our laboratory ,five species of cytokines were detected by usings ELISA method,moreover,inactivated vaccine for mastitis caused by Staphylococcus aureus and Escherichia coli were developed .The main contents and results are as follows:1.To establish mastitis model in Guanzhong milk goats,the experiment was conducted by using Escherichia coli and Staphylococcus aureus which were isolated from milk goat with clinical mastitis by our laboratory.One group of milk goats were perfuse in ductus papillaris with Escherichia coli in dose of 3×103cfu/ml,and another group with Staphylococcus aureus in dose of 3×102cfu/ml. The index include milk yield,spirit condition, appetite, milk appearance,udder quale,body Temperature,somatic number were observed and detected continous in certain time , moreover the pathogenic bacteria were isolated and identified.The results shows that,the experimental goats were downcast and lower appetite as well as fever and milk yield decrease, the udder manifest acute inflammation symptom as red swelling, febrile,obvious haphalgesia,the milk sample turned ropiness and the color changed.Somatic cells number increase, mammary glands histopathologic slide indicated that a large quantity of inflammatory cells infiltrated in acinar lumina and interstitial tissue. Clinical and pathological changes induced by Staphylococcus aureus were more severe than Escherichia coli. Homologous pathogen were isolated from the milk sample of experimental goat.As a result,clinical mastitis model of dariy goat induced by Escherichia coli and Staphylococcus aureus were successfully established.2.To demonstrate the level changes of proinflammatory cytokines and its mechanism of action in pathogenesis of mastitis caused by staphylococci and Escherichia coli. Cytokines include interleukin-1β(IL-1β), interleukin-4, interleukin-6, interleukin-8 and gamma-interferon in milk and serum were detected respectively before and after infection by ELISA method,meanwhile, relationships between characteristic of mastitis induced by these two pathogen and cytokines were demonstrated. The results showed that infection with either bacterium resulted in increased levels of interleukin-1β(IL-1β), interleukin-4, interleukin-6, interleukin-8 and gamma-interferon in milk . Initial increases in cytokines'levels in the milk from E. coli-infected quarters were evident within 24 h and then decrease,but staphylococci quarters increased persistently within 72 h .Cytokines in serum were Generally decreased even lower than the level before. Together, these data demonstrate the variability of the host innate immune response to E. coli and S. aureus .3.To evaluate antibody titer of self-made vaccine for mastitis of milk goat. The Escherichia coli and staphylococci isolates were inactivated at 37℃using formaldehyde to prepare propolis and transfer factor inactivated vaccine, and non-adjuvant vaccine. Each vaccine was immunized to Milk goat at lactation period, then the serum and milk were harvested at different times, which were used to determine antibody titer of E. coli and staphylococci. The E. coli and staphylococci could be inactivated completely by formaldehyde. The specific antibody titers for E. coli and staphylococci were significantly increased compared with preimmune. Compared with non-adjuvant vaccine, both the propolis and transfer factor could significantly increase specific antibody titers in serum and milk, and the effect of transfer factor to promote the antibody secretion was the best. The SIgA was also significantly increased. The high-level specific antibody could be produced in blood and milk of milk goat after immunization of E. coli and staphylococci, and the effect of transfer factor to promote these antibody titers was optimal to propolis.