Studies on the structure and development of the thymus in the Indian runnert duck

Abstract

A study on the structure and development of thymus in the Indian Runner Duck during embryonic and post - embryonic period was conducted. Thymus from 60 birds ranging in age from day old to 180 days were collected for the study and embryonic studies were carried out in embryos of third, eighth, 15th and 22nd days of incubation. There were five pairs of lobes, on an average lying in the lower half of the neck. The weight of the thymus increased with age upto 180 days and the posteriormost lobe was the largest. There was a significant difference between the weights of anterior and posterior and middle and posterior lobes. Histological structure was more or less similar to that in mammals. The diameter of Hassall’s corpuscle was found to be positively correlated with age. The thymic primordium appeared by the third day of incubation. Lobulation was evident by the 15th day and by 22nd day of incubation cortex and medulla were discriminated.