Evaluation of growth conditions for an improved biomass of Pasteurella multocida vaccine production and immunogenicity

The haemorrhagic septicaemia is a world wide disease of ruminants and a significant problem in Asia and Africa, caused by specific stereotype of Pasteurella multocida B-6. Vaccination is internationally acknowledged as a best way of controlling haemorrhagic septicaemia. Quality vaccine therefore, occupies most important place in management of HS. An important problem associated with the production of quality vaccine against HS is its high cost of production. This is due to low yield of biomass of P multocida when grown in ordinary or routine media . To increase the biomass of P. multocida per unit volume of the primary vaccine culture, P. multocida B-6 was grown in different minimal and enriched media. The composition of media and influence on yield of biomass were monitored under differed it growth conditions and results were obtained through UV/VIS spectrophotometry and also on dry weight basis. pasteurella multocida when grown in various media yielded moderate to dense growth. Good growth was observed in BHI and CYS and poor growth was observed in RCM and in NB. This study investigated a relatively cheaper but effective formulation of casein yeast extract and saccharose (CYS medium). Maximum growth of P. multocida was supported by 1 Percent casein hydrolysate, 1 % yeast extract, 0.5 sodium chloride and in 1 percent saccharose in the medium When saccharose was replaced with home vise white sugar, maximum growth was observed at 0.4 percent concentration which slightly it increased growth than saccharose. Gurr is another form of cheaper sugar available in this study 0 7 percent concentration of yellowish brown gurr gave a very good growth in CYS medium inure increased aeration resulted with proportional increase in biomass of P multocida Maximum growth was seen at an aeration rate of 1 L/min 1 liter culture volume fermentor Maximum growth of P multocida was observed at pH. When the agitation was increased at an increment of 100 rpm upto 700 rpm, a steady and slow increase ease of growth were recorded with the increase in agitation. Maximum growth occurred at 18 hours of incubation and dropped later. Slow growth was observed at temperatures from 24 to 34 degree centigrade. Exponential growth was seen at temperatures from 34 to 37 degree centigrade. A total of 42 commonly available antibiotics were tested for sensitivity. When results were analyzed it was found that at least 33 % of the antibiotics tested were resistant, 19 percent showed moderate sensitivity and 48 % showed higher sensitivity. Biomass of P. multocida prepared in modified growth medium was converted into vaccine/bacterin proved having 90 % protection level. Cost comparison of various media employed in the study revealed that the modified media had a cheapest cost per unit dose of raw vaccine. It is concluded from the present investigation that providing defined medium, growth conditions and purity of vaccine through antibiotic marker could result in an increase biomass and decrease cost of production of HS vaccine.