Morphological features of the thymus, bursa of fabricius and spleen in quails of the pharaoh and phoenix breeds at the growth stage

The article contains information about the morphological parameters of the thymus, bursa of Fabricius and spleen in 28-day-old quails of the Pharaoh and Phoenix breeds. Using the methods of organometry and histometry, the dimensions and weight of the bursa of Fabricius were clarified. The average length of this organ is 1.47 ± 0.08 cm, and its volume is 1.0 ± 0.2 cm3. The bursal ratio in Phoenix and Pharaoh quails a 28 days of age does not exceed 0.175 ± 0.009%. The thymus in the studied quails is presented in the form of separate round formations in the amount of 5-7, located in the subcutaneous fatty tissue of the neck area on the right and left. Literature data indicate significant variability in the macromorphological parameters of the thymus due to age and the functional state of the immune system. Without refuting these data, we clarify that the functional activity of the thymus organ during the growth stage of a bird is determined by the individual lobes of the organ, as a set of independent individual organs. The general picture presented on histological preparations of the spleen of quails corresponded to those previously described in some species of birds, including quails, but there were also some peculiarities. Single islands of lymphoid tissue, including cells at different stages of differentiation, did not have a capsule. The size of the lymphoid formations occupied the area of the white pulp on average 35.92 ± 3.51 µm2 per formation. Around the pulp arteries, the cells were located diffusely - small sinuses were located between them. Our observational data do not contradict the results obtained by other researchers who studied the organs of the central and peripheral parts of the immune system in birds.