Combined vaccine for bacterial septicemia and red skin disease of grass carps, and preparation method of combined vaccine

The invention discloses a combined vaccine for bacterial septicemia and red skin disease of grass carps, and a preparation method of the combined vaccine. The safe and efficient two-tier white oil inactivated vaccine against aeromonas hydrophila septicaemia and pseudomonas aeruginosa red skin disease is developed by using beta-propiolactone as an inactivator, and can effectively control the occurrence of the bacterial septicemia and red skin disease of the grass carps. After the grass carps are immunized with the vaccine, the vaccine can stimulate the expression of IgM, IL-1beta, IFN, Mx, C3 and TLR3 immune-related genes in fish spleen and head kidney tissues. The vaccine can produce up to 80-90% relative immune protection rate for the grass carps; the relative protection rate can still bemaintained at 50% after immunization is performed for one year. The combined vaccine is simple to operate, is safe and effective, can prevent two diseases after being used for immunizing at a time, and not only reduces the u