Evaluation of glycerin as preserving agent of chicken serum for plate agglutination test
Freitas, E. S. deSoldá, ACalegari, D. L.Munaretto, F. C.Dietrich, G. F.Back, A
Serum is widely used for the purpose of monitoring and diagnosis support for most of poultry diseases. In the case of the serum plate agglutination test (SPA), commonly used to detect antibodies for Salmonella Pullorum (SP), Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS), serum cannot be frozen because it may result in false positive. Without freezing, serum can last only for a few days. In this experiment, glycerin was evaluated as a serum preservering agent. About 50 samples for each disease and analyzed by SPA test previously were separated. Glycerin was added to serum from commercial chickens, with and without antibodies for SP, MG and MS, in the proportion of 1:1 (serum:glycerin) and kept at refrigerated conditions (2 to 8 ºC). For four years they were tested by the SPA, initially weekly, afterward monthly and then annually. The results show that serum with glycerin give consistent and valid results according to the kind of antibodies present for the period tested. Sera that glycerin was not added to, the results were valid only for the first week. From the second week on, microbial growth affected the test results of the sera without glycerin. Our investigation shows that glycerin can be used to preserve chicken serum for SPA under refrigerated conditions. It is an easy, simple and cheap procedure that can extend serum shelf life, useful mainly for control sera.(AU)
Texto completo