Comparative efficacy of various toxoids against salmonellosis in poultry

An attempt was made to develop a vaccine against salmonellosis in poultry b y formalizing the Salmonella toxins (enterotoxin plus cytotoxins) that have been found to be the main virulent products of the organisms. Formalized ( FT) and carbonated (CT) toxoids were prepared from partially purified toxin s of Salmonella enterica subspecies enterica ser. Weltevreden (BM-1643) and S. enterica ser. Gallinarum (L-19/a). There was no mortality in birds vacc inated with formalized toxoid of serovar Weltevreden plus Freund's complete adjuvant (FCA) following homologous or heterologous (S. enterica ser. Gall inarum and S. enterica ser. Typhimurium) challenges. Protection ranged from 50% to 83.3% in the groups immunized with other preparations of S. enteric a ser. Weltevreden, i.e. with FT without FCA or with CT with or without FCA . Formalized toxoid prepared from S. enterica ser. Gallinarum (FTSG) toxins given with FCA afforded 100% protection against homologous challenge, but not against heterologous serovars. In the control group, only 16.7% of the birds survived in a subgroup challenged with S. enterica ser. Gallinarum, a nd none withstood challenge with S. enterica ser. Weltevreden or S. enteric a ser. Typhimurium. No untoward reactions were observed in any of the immun ized groups. Thus, the vaccine was considered to be potent and safe.