Studying On Fermental Cultivation Of Toxigenic Pasteurella Multocida (T～+Pm) And Biological Characterization Of The Fermental T～+Pm

Atrophic rhinitis (AR) is a chronic infection involved in upper respiratory tract of pigs characterized by degeneration of the bony and cartilaginous structures of the nasal cavity, which in severe cases can result in twisting and shortening of the pig's snout and growth retardation. AR, an important porcine infectious disease endangering the pig industry, has been found all over the world. At present it is widely accepted that the damages of the nasal turbinate bones and mucus caused by Bordetella bronchiseptica laid the foundation for the invasion toxigenic Pasteurella multocida. The mixture of Bordetella bronchiseptica and toxigenic Pasteurella multocida, together with some other factors, is the main cause of natural AR. A vaccine against AR, developed in Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, showed a well protection rate after many years' application in china. But traditional culture of the vaccinestrains could not satisfy the modern market need with high cost and low density.The study is to improve the producing efficacy of AR vaccine. Toxigenic Pasteurella multocida. (Pm 13-1) was cultured in the 15L BIOSTAT.C fermentor with experimental parameters (Time, Air Flow, Speed of stir, and pH). The optimum parameter condition of fermental culturing Toxigenic Pasteurella multocida (Pm 13-1) is determined by examining the concentration of Toxigenic Pasteurella multocida (Pm 13-1) in the fermentor. With the defined the parameters, the concentration of Toxigenic Pasteurella multocida (Pm 13-1) in the fermentor could reach 45~56 billion/ml, over 6-7 times higher than that of the traditional culture. The characterization of the fermental Toxigenic Pasteurella multocida (Pm 13-1) is studied according to the vaccine standard. The experiment results showed the characteristics of the fermental Toxigenic Pasteurella multocida could meet the standard of producing AR vaccine in the colony morphology, toxin pathogenesis, and other aspects. The serotype of fermental Toxigenic Pasteurella multocida did not change.