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The immune responses of indigenous naked neck (NaNa and Nana) and normally feathered (nana) chickens against a Salmonella Gallinarum (SG) infection were evaluated and compared with those of a commercial line (B-380). Groups of 28-day-old chickens (NaNa, Nana, nana, and B-380) were immunized orally and subcutaneously with 50 microg of SG antigens. Control non-immunized animals were inoculated with sterile saline solution. All chickens were challenged with 1 LD(50) of SG and mortality was recorded daily for 20 days. Antibodies to SG were measured in sera before immunization, before the challenge, 10 days after the challenge, and at sacrifice. Peripheral blood lymphocyte proliferation assays were performed using concanavalin A and SG antigens. Results showed that non-immunized Nana chickens exhibited the best natural resistance to Salmonella infection, since only 30% of them died. In contrast, all control B-380 chickens died by the 13th day. Immunization with SG induced immunity in chickens of all genotypes. Indigenous naked neck and normally feathered chickens showed a higher survival rate when compared with B-380 chickens. Immunized Nana chickens showed the highest antibody titres (P<0.05) as well as the highest thymidine incorporation in peripheral blood lymphocytes stimulated with con A or SG antigens (P<0.05). The results show that Nana chickens are the most resistant to SG infection and the best responders to vaccination with SG antigens.

The aim of this study was to report a diffuse unilateral seminoma in a 4-year-old fighting rooster (Gallus gallus) by considering the anatomic, pathological and ultrastructural features. A significant decline in the viability of the bird's embryos was reported during the last year. The bird died with a marked abdominal distention. During necropsy, a firm ovoid neoplasm of approximately 9 cm long, 8 cm wide and 5 cm thick was found in the region adjacent to the pronephros, replacing the left testicle. The neoplasia was soft and encapsulated, and the cut surface showed extensive areas of haemorrhage interspersed with necrotic areas. Histologically, the neoplastic cells formed large mantles or cords with moderate and eosinophilic cytoplasm. The nuclei were pleomorphic, and some of them were central, while others were eccentric. Mitoses were scarce. Some important findings in the ultrastructural study were nuclei exhibited an elongated, electrodense, rope-like nucleoli and the presence of scarce intracytoplasmic glycogen. The anatomo-pathological and ultrastructural findings of the tumour were consistent with a seminoma. The ultrastructural study provided important support for the diagnosis, as other tumours were ruled out. The early diagnosis of malignant or benign testicular tumours in birds is the key for a timely treatment, as these tumours can metastasize or grow to such an extent that they compromise the lives of birds, as in the present case.

Three chicken infectious anemia (CIA) virus strains were isolated from 10 different sick broiler and replacement chicken flocks with the MDCC-MSB1 cell line. One-day-old specific-pathogen-free chicks were inoculated later, with the three original samples being positive in tissue culture; one induced signs and lesions, another only lesions typical for CIA. One isolate was selected for further trials and showed resistance to chloroform and heat (75 C for 5 min) and passed through a 45-nm filter membrane but did not pass through the 22-nm filter. These characteristics were similar to the Del Rose reference strain of chicken anemia virus. By electron microscopy, the diameter of particles obtained from the pellet of infected cell cultures was between 22 and 27 nm. Serology survey carried out with 580 serum samples from different poultry farms all over the country with a commercial enzyme-linked immunosorbent assay kit gave proof of widespread seroconversion, indicating that CIA should be considered endemic to Mexico.

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