Hhistological aspects of thymus in japonese quail (Coturnix coturnix japonica) from one to 180 days of age

Abstract

Thymus, described from antiquity, has long time been considered a mysterious organ because its role in the body was unknown. The first microscopic description of the thymus belongs to Hassal, and in the first half of the 20th century the thymectomy was performed to treat "myasthenia gravis." In 1962, the role of thymusin the production of T-lymphocytes which are responsible for the cell mediated immunitywas revealed. Bird's thymus represents 2% of the body weight at hatching and continues to develop until the time of sexual maturity. Coturnix japonica is a species used in the laboratory as an experimental animal, and it is economically important because of the nutritional value of the eggs which are recommended to be consumed in various diseases. The japonese quail reaches sexual maturity at the age of 7 weeks when signs of thymic involution should be observed. The present study aimed to describe some histological particular features of thymus in the japonese quail. In the study, 25 quail wereeuthanized at the age of 1, 7, 15, 24 and 60 days for thymus prelevation. The fragments were prepared by paraffin embeding and stained HEA, Giemsa and PAS. This has highlighted some of the particularities of this species. In most species thymus regresses under physiological conditions due to sex hormones action at puberty. The histological aspects obtained in this study demonstrated that in this species the thymus involution was not present even in the individuals sacrificed at the age of 6 months. The dimensions of the cortical and medullary areas of the thymus at 24 and 60 days wereapproximately constant.