Evaluation of the humoral and cellular immune response to different antigens of Corynebacterium pseudotuberculosis in Canindé goats and their potential protection against caseous lymphadenitis.

Corynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis, a disease that affects goats and sheep, and can cause severe economic losses. In this study, four different antigenic extracts were obtained from the attenuated strain T1, which was isolated in the state of Bahia (Brazil). Forty-four Canindé breed goats were divided in five groups, each receiving a different antigen solution and saline buffer as a control. The humoral response was monitored through the identification of specific IgG by indirect ELISA and Western Blotting, and the production of IFN-gamma was followed in order to observe the activation of cellular response. After twelve weeks of antigen inoculation, the animals were challenged with 2 x 10(5)CFU of a wild strain, also isolated in Bahia, and necropsy was performed on all animals twelve weeks afterwards. It was observed that the attenuated bacteria gave a protection of 33.3%, in addition to the weak humoral response elicited. Animals inoculated with secreted antigen associated with Freund's incomplete adjuvant and oligodeoxynucleotide containing unmethylated CpG dinucleotides (CpG ODN) showed a strong humoral response, but this inoculation could not prevent the spread of challenge bacteria in the majority of animals. These results demonstrate the immunogenic potential of the attenuated T1 strain in the development of a vaccine against caseous lymphadenitis in goats.

Effects of different stressors in haematological variables in cultured Oreochromis aureus S.

Since haematological variables can be used to assess the health state in cultured fish, a haematological characterization of clinically healthy Oreochromis aureus was done to establish the reference indices of this species. Fish were subjected to different stressed conditions (bacterial infection, nitrite intoxication, malachite green overdose) to study the changes in the haematological indices and its relation with the health condition. This species showed microcytic anaemia under experimental bacterial infection by Corynebacterium sp.; anaemia, neutrophilia and erythrocytes deformation following nitrite intoxication and medication overdose with malachite green.