Meeting Abstract
Altricial birds are blind and naked when they hatch and must defend themselves against a pathogen-rich world with an immature immune system. Little is known about lymphoid system development in altricial birds and how it is affected by antigenic challenges. The cockatiel (Nymphicus hollandicus) is an excellent model for studying altricial birds because their amenability to handling, popular for aviculturists to breed, and a study has been done to compare the development of their lymphoid tissues to chickens. This study explores lymphoid system development of cockatiels following an antigenic challenge. Sixteen one-day old cockatiels were used for the study. Cockatiels were assigned to one of two treatments in a completely randomized design (n=8). To elicit an immune response, the experimental treatment group was immunized with dinitrophenyl keyhole limpet hemocyanin (DNP-KLH) on the seventh day of age by subcutaneous injection to the inner thigh. Seven and 30 days post-immunization (day 14 and 37 days post-hatching), four cockatiels from each treatment group were euthanized by CO2 asphyxiation. The bursa of Fabricius and thymus were collected, weighed, and sectioned for Hemotoxylin and Eosin (H&E) staining to quantify number of lymphocytes present. Blood was collected and the plasma was used in the bacteria-killing assay to evaluate efficacy of innate immunity against non-pathogenic E.coli. There was a significance in bactericidal activity between treatment groups with the KLH-challenged group having a higher killing rate. The thymus mass and thymus mass to body mass ratio was significantly lower in 37 day old KLH-challenged birds relative to control birds. Comparisons of altricial bird development and precocial bird developed will be discussed.
