Yak Escherichia Coli Disease Propolis Vaccine

The research of the vaccines of Escherichia coli in yak have been only inactivated Al(OH)3 vaccine of Escherichia coli in yak at present. But inactivated Al(OH)3 vaccine is easily freezing and failure, there is good freeze-proof in propolis vaccine, and the problems that vaccine is transported and stored at low temperature in the Tibet plateau can be resolved effectually. The research on propolis vaccine can effectively prevent the disease of Escherichia coli in yak in Tibet plateau.This experiment is done with two kinds of propolis that come from Shandong and Sichuan in the study at the beginning. Two kinds of propolis are made extracting respectively according to the proportions of propolis to ethanol, by 1∶2, 1∶4, 1∶5, 1∶6 and 1∶8. The antifreezing experiment of ethanol extract of propolis shows that ethanol extracts of propolis extracted by the proportions of propolis to ethanol, by 1∶4, 1∶5, 1∶6 and 1∶8, were antifreezing at -28～-30℃on 72h; The proportion experiment of ethanol extract of propolis shows that the proportions of propolis to ethanol by 1∶5 is the best, and the effect on ethanol extract of propolis of Shandong is superior to Sichuan. Therefore, author selecte propolis of Shandong, and prepare 3 batchs propolis adjuvant by the way that he proportions of propolis to ethanol is 1∶5, and emulsifier and deionized water are added in the ethanol extract of propolis (propolis contents were 20mg/mL, 30mg/mL and 40mg/mL, respectively).Selected yak's Escherichia coli (Tibet-9903), the bacterial culture, the proof-test purely, the proof-test of live bacteria, the proof-test of inactivation and sterile are prepared. 3 batchs propolis vaccines are prepared by the way that 1 portion inactivate bacterial liquid added in 1 portion propolis adjuvant, mixed fully, this is propolis vaccine at 4℃standing overnight. 3 batchs propolis vaccines number as 200801, 200802 and 200803, respectively, (propolis contents were 10mg/mL, 15mg/mL and 20mg/mL, respectively). The back-check of the mixture of propolis adjuvant and vaccine, the back-check of finished products are prepared. The results showe that 3 batches of propolis vaccine of Escherichia coli in yak the sterility test are the negative; the physical character the examination is that after the settlement the upper formation was the tan liquid, the lower layer is khaki precipitates, and after oscillated are uniform opacity liquid; the safety tests in rabbits and yaks are all safety by primo vaccination and revaccination with increasing does; the potency test in rabbits and yaks are effective, and antibody titer are from 2.70927 log2 to 3.61236 log2 after immune, rabbits and yaks are protected. The rabbits are still protected after 6 months later, according to the eating and flowing laws of immune efficacy. The result of antifreezing test showe that the higher is propolis content, the better is antifreezing effect. No. 200801 propolis vaccine is easily iced at -18℃, but No. 200802 propolis vaccine is no iced at -18℃after 24h, and No. 200802 propolis vaccine is no iced at -18℃after 15d. The analysis results of efficacy experimental tests and antifreezing test showe that immune effects of 3 batchs propolis vaccines are no obvious difference; the ethanol content of No. 200802 propolis vaccine is lower than that of No. 200803 propolis vaccine, and it can satisfy the cold transportation on the conditions of Tibet plateau, so it is first choice.The result of comparative test on No. 200802 propolis vaccine, inactivated Al(OH)3 vaccine and oil vaccine showe that the immune effect of inactivated Al(OH)3 vaccine is slightly lower than those of propolis vaccine and oil vaccine, and inactivated Al(OH)3 vaccine is easily freezing; the immune effect of oil vaccine is slightly higher than those of propolis vaccine and inactivated Al(OH)3 vaccine, but it is unease injection and difficult to absorption; however, the immune effect of propolis vaccine is between inactivated Al(OH)3 vaccine and oil vaccine, it is antifreezing, easy injection and absorption. So propolis vaccine is first choice for prevention of the disease of Escherichia coli in yak. Therefore, successfully develope propolis vaccine provides a clinical basis for prevention of the disease of Escherichia coli in yak, and it provides an experimental basis for popularization and application of vaccine in Tibetan low temperature condition.