Thumbnail Image

Thesis

Browse

20111
Reset filters
Author: ARUNIMA. S. S. × End date: 2011 × Start date: 2010 ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    POSTNATAL DEVELOPMENT OF LYMPH NODES IN KUTTANAD DUCK (Anas platyrhynchos domesticus)
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2011) ARUNIMA. S. S.; N. Ashok
    Postnatal development of lymph nodes was studied in Kuttanad ducks using 104 birds from day-old to 24 weeks of age. The material was collected from eight birds in each group at fortnightly interval. Two pairs of elongated, spindle shaped lymph nodes, namely the cervico-thoracic, and the lumbar lymph nodes were present. Size and weight of the lymph nodes increased with age. The relative weight of both the pairs of lymph nodes increased up to 18 weeks of age and thereafter it slightly decreased until the end of study. There was a progressive increase in the body weight upto 16 weeks of age, before the beginning of egg laying and the maximum mean was attained at 20 weeks week. The weight of the lymph nodes was highly correlated with the body weight during postnatal period (p ≤ 0.05). The weight of the lymph nodes increased sharply up to four weeks of age followed by a gradual increase upto 18 weeks and thereafter it decreased till 24 weeks. There was a significant positive correlation between the age and the length and breadth of cervical (r=0.83, r=0.83) and the lumbar (r=0.87, r=0.87) pairs of lymph nodes (p ≤ 0.05). On the day of hatch, the lumbar nodes were less differentiated compared to the cervical lymph nodes. Both the nodes were enclosed by a thin connective tissue capsule comprising of collagen and a very few elastic fibers. It was comparatively thinner in lumbar lymph nodes than the cervical ones. Towards the cranial part of the nodes, the capsule was slightly thicker. The delicate connective tissue capsule presented two distinct compartments that presented a little amount of lipids and lymphoid tissue. A clear demarcation between the cortex and the medulla as seen in mammals was absent in the lymph nodes of ducks. However, the compact central part had a little resemblance to the cortex and the spongy peripheral part, to the medulla. The primary and secondary follicles were chiefly concentrated in the dense compact area. The cavity system of the lymph nodes mainly consisted of a central or axial sinus, numerous intermediary and marginal sinuses. The endothelium lined intermediate sinuses acted as channels connecting marginal sinus to the central sinus. Parenchyma consisted of highly coiled lymphoreticular cords. These cords originated from the capsule and penetrated deep into the parenchyma. They frequently anastamosed with one another and with the surface of lymphatic nodules. In between the lymphoreticular cords, small channel like lymphatic sinuses were present. Trabeculae and hilus were absent. The lymph vessels and blood vessels entered the lymph nodes from different sites and penetrated the capsule. The round or ellipsoidal lymphatic nodules were distributed throughout the parenchyma with a higher frequency towards the central part of the node. The nodules were fewer in lumbar lymph nodes compared to the cervical ones. However, the number of these nodules increased from day-old to 24 weeks of age, in both pairs of lymph nodes. From fourth week onwards, secondary nodules with germinal centers appeared with a nodular capsule, clearly demarcating them from the surrounding parenchyma. The cellular populations of lymph nodes included lymphocytes, erythrocytes, reticular cells, macrophages, plasma cells and a few mast cells. Plasma cells were noticed in the lymphatic nodule, lymphatic cord and the germinal centers of both the lymph nodes. In day-old ducklings, plasma cells were very few however, their number increased with the advancement of age. The lymphocytes exhibited a weak reaction for PAS from the day of hatch onwards reaching a maximum at 24 weeks of age. Glycogen was not detected in the lymph nodes of day old ducklings. Capsule as well as the lymphoreticular cords was positive for neutral mucopolysacrides. Acid and alkaline phosphatase activities were weak in the cells of the lymphoreticular cords and lymphatic nodules of both lymph nodes from the day of hatch itself. As age advanced, the alkaline phosphatase activity gradually increased reaching a peak activity in the lymph nodules, lymphoreticular cords and capillary endothelium by 24 week of age. The activity was strong in the germinal centers of both pairs of lymph nodes.