D. Dimitrov

Abstract. In this study, 24 Harderian glands obtained from 12 sexually mature clinically healthy turkey-broilers (6 of each gender) of the BUT-9 stock hybrid (France) were investigated. Glands were weighed and measured prior to fixation. Permanent histological preparations were made from fixed glands using routine techniques. Histometric studies of the main microstructural elements of the Harderian gland were performed by means of a light microscopy with built-in eyepiece micrometer. Data were statistically processed. The histometric investigation demonstrated that the average size of lobules of turkey Harderian gland was 474.28 μm. The mean outer diameter of glandular acini was 34.68 μm, whereas those of tertiary, secondary and primary secretory ducts – 41.14 μm, 48.28 μm and 50.66 μm, respectively. The mean outer diameter of lobular ducts was 257.63 μm, while that of gland’s excretory duct –415.35 μm. The results from this histometric study of 13 parameters allowed us to assume that by the time of turkey hybrid BUT-9 marketing, (210-240 days) the Harderian gland was a structurally mature and functionally active organ.