Evaluation of Clostridium septicum hemolytic activity, administration route, and dosage volume of a clostridial dermatitis (cellulitis) bacterin-toxoid on humoral immune response in commercial turkeys

Clostridial cellulitis or dermatitis affects commercial turkey flocks, primarily as they approach mar-ket age. In the field, this disease has been effectively con-trolled with antibiotics, but alternatives to antibiotics are needed. Bacterin-toxoid vaccination programs have been shown to prevent clostridial diseases in other species, including humans. Results from previous field studies indi-cate that vaccination with an experimental whole-cell Clostridium septicum (CS) bacterin-toxoid oil emulsion vaccine reduced clostridial dermatitis-associated mortality and antibiotic usage for some commercial turkey flocks, but vaccination was not always efficacious. To improve vaccine efficacy, studies were conducted to optimize the antigenic component of the experimental vaccine and to determine the appropriate antigen to adjuvant ratio, route, and volume for vaccine administration. It was deter-mined that the phase of culture at time of formalin inacti-vation played a key role in serum antibody titer and larger volume vaccine doses produced higher serum antibody immune response regardless of antigen:adjuvant formula-tion ratio or route of injection. No significant differences (P > 0.05) were found between formulation ratios or between the subcutaneous and tail head injection sites. Based on these results, we propose to look further into the relationship between culture phase and antigenic compo-nents produced by CS under different culture conditions.

Automated summary

Clostridial cellulitis or dermatitis affects commercial turkey flocks and has been controlled with antibiotics, but alternatives are needed. Bacterin-toxoid vaccination programs have been effective in preventing clostridial diseases. Further research is proposed to understand the relationship between culture phase and antigenic components produced by CS.