MAST CELLS IN THE SUBEPIDERMAL LAYER OF THE BUDGERIGAR (MELOPSITTACUS UNDULATUS) DURING MOULTING

摘要

We used histological methods to examine skin from the head region of budgerigars (Melopsittacus undula-tus) during their feather regeneration (moulting period). Sixteen birds were included in the study; 8 were treated with thy-roxine to accelerate moulting and another 8 represented the control group. Paraffin-embedded tissue samples were stained with haematoxylin and eosin, trichrome stain (after Goldner) and toluidine blue, Light microscopy was used to locate mast cells and their numbers were assessed by a Lucia-M computer-assisted image analysis system (Optoteam, Vienna). Mast cells, which were found to be a regular component of budgerigar skin, were predominantly located in subepidermal connective tissue; however, they were also found near the dermal blood vessels, Thyroid hormones are elevated during moulting and lymphocytic infiltrations can be found in the skin, however, we found that the number of mast cells was significantly higher (P < 0.01) in thyroxine-treated animals, Although clinically healthy, 37 % of the animals investigated were infected with ectoparasites of the Cnemidocoptes genus. In those animals, which were found in both the thyroxine-treated and control groups, the number of mast cells was also significantly higher, probablyas a consequence of their immune responses.