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Kerala Veterinary and Animal Sciences University, Wayanad

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Subject: Veterinary Anatomy × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    POSTNATAL DEVELOPMENT OF THYROID GLAND IN KUTTANAD DUCK (Anas platyrhynchos domesticus)
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2011) FIRDOUS AHMAD DAR; K. M. Lucy
    Postnatal development of thyroid gland in the Kuttanad duck was studied using 104 female birds from day-old to 24 weeks of age. The material was collected from eight birds in each group at fortnightly intervals. The paired thyroid glands in the day-old Kuttanad duckling were placed at the base of the neck between the common carotid artery and the jugular vein. The right thyroid was cranially situated than the left one. Out of the 104 ducks studied, the left thyroid glands were absent in two birds. The thyroid glands were round to oval, flat bodies and coloured yellow to reddish brown. Maximum contribution of thyroid gland to the body weight was noticed in 24 weeks old birds. Upto four weeks of age, the weight of thyroid increased gradually but a spurt in growth was noticed between four and six weeks and from there onwards, it increased slowly upto 20 weeks of age. From 22 weeks although the body weight showed a slight decrease, thyroid weight remained the same until 24 weeks. The result showed that there were three phases of activity for the thyroid gland. First phase was at the day of hatch itself. The second phase coincided with the fast growth rate of the birds between four to six weeks. The third phase coincided with the beginning of egg laying. Length, breadth and thickness of the thyroid increased about 3.5, 3.6 and 4.5 times, respectively from day-old birds to 24th week of age. Size of the thyroid gland showed more correlation with the age than the weight of the gland. Weight of the thyroid was more correlated with the body weight than with the age. Histologically, the thyroid glands were enclosed by a thin capsule consisting of well developed collagen, reticular and a very few elastic fibres. The capsule was made of three layers which were evident from the day-old bird itself. The external layer was a mesothelial layer, the middle layer was rich in fat cells, blood vessels and nerves and the inner layer was closely adherent to the gland. In adult birds, the subcapsular areas of thyroid gland disclosed a non-follicular type of parenchymal 90 cell. Substance of the gland consisted of roughly spherical thyroid follicles. In dayold birds follicles were small and dispersed towards the periphery of the gland with a few larger follicles seen towards the centre. A distinct basement membrane was evident. As age advanced, small and medium sized follicles were found throughout the gland while larger follicles were restricted more to the periphery. Extra large follicles could be identified from eighth week onwards. The blood vessels were present around the follicle in a basket-like manner. Each follicle was lined by a single layer of cells. Based on the type of epithelium and nature of colloid, the follicles were categorized as active and inactive follicles. The active follicles were lined by simple cuboidal epithelium with a basophilic colloid, while the inactive follicles were lined by simple squamous epithelium with acidophilic colloid. Most of the large follicles were inactive from fourth week onwards. Mean epithelial height of the active follicles increased upto sixth week. From eight weeks onwards there was a gradual decrease in the height upto 24th week. Colloid cells of Langendorff were seen from 4th week onwards. From the TAI it was inferred that the thyroid was moderately active from day-old to four weeks old birds. From four weeks onwards the glands became very strongly active upto eight weeks, which coincided with the rapid growth phase of the bird. From eight weeks onwards the glands were categorized as strongly active upto 20 week but the activity was comparatively less than the previous group. This can be correlated with the fact that thyroid hormones, grouped under morphogenetic hormones having direct effect on the growth of reproductive system. By 20 weeks, development of the oviduct is complete and all the birds started laying by this age. A homogenous translucent colloidal mass filled the thyroid follicles. Vacuoles of variable sizes and numbers were seen in the periphery and occasionally in the central part of the colloid. In the follicles lined with simple cuboidal or columnar epithelium, the colloid was predominantly basophilic, while in the follicles lined with simple squamous epithelium it was acidophilic. The quantity of colloid varied according to the activity of the gland. In the inactive follicles, it was more and thick due to accumulation of large amount of colloid, whereas in active follicles it was lesser and thinner. The colloid was amphoteric also. Clusters of polyhedral cells, the parafollicular cells were present in the interfollicular zone of thyroid and were seen from day-old birds itself. Groups of blood cells, including RBCs and lymphocytes could be seen in the interfollicular area at different ages. No thymic tissue could be detected within the thyroid gland of Kuttanad ducks during postnatal period. Histological parameters of thyroid gland such as thickness of capsule and number of total, large, small, active and inactive follicles showed greater correlation with age than with the body weight. Histochemically, the colloid showed a strong PAS positive reaction. Glycogen was present in the follicular epithelium. Lipid accumulation was observed in the capsule and interfollicular area. Acid and alkaline phosphatases’ activity was shown by the lining epithelium of the thyroid follicles. Alkaline phosphatase activity was maximum in six weeks old birds.
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    ThesisItemOpen Access
    POST-HATCH DEVELOPMENT OF PREEN GLAND IN THE DUCK {Anas platyrhynchos)
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2005) S. RAJATHI; N. ASHOK
    Studies on the post-hatch development of the preen gland in ducks were conducted using 44 ducks from the day of hatch till 150 days of age. The project was taken up to trace the structure and development of the glands and their relationship with the age and body weight. After recording gross relations and measurements, the material was fixed using various fixatives for studying the cellular details, arrangement of cells, connective tissue framework, micrometry and histochemistry. The preen gland was a paired organ with a common cylindrical papilla. The two glands together formed a 'V shaped structure. Each gland was pear shaped and pale yellow in colour, in fresh state. They were located on the dorsal surface of the pygostyle. Both the right and left glands had separate ducts. The uropygial circlet was seen at the tip of the papilla. The glands were vascularized through a pair of branches from the caudal artery and innnervated through the medial caudal nerve. The weight of the preen glands increased progressively from the day of hatch to 150 days of age. This weight was positively correlated with the age and body weight. The proportion of the gland weight to the body weight showed a decreasing trend. The right gland was slightly heavier, longer, wider and thicker than the left. The length, breadth and thickness were positively correlated with the age and body weight. Structurally, the glands were simple, branched, tubular and holocrine type. The richly vascularised connective tissue capsule was eomposed of collagen and reticular fibres. Elastic and smooth muscle fibres were absent. The secretory tubules showed two zones, an outer zone or zone I, near the capsule and an inner zone or zone II, towards the primary cavity. The epithelium of the tubules consisted of basal, intermediate and transitional layers. The papilla had two ducts, which were lined by glandular epithelium initially and keratinized stratified stratified squamous epithelium at the tip. The glandular epithelium was surrounded by longitudinally arranged smooth muscle fibres and skin. Lamellar corpuscles and circlet feather follicles were noticed in the papilla. Capsule, trabeculae and the parenchyma were PAS positive. Glycogen and acid mucopolysaccharides were not detected. Lipids were evident uniformly in all the cell layers. The acid phosphatase activity was moderate in the basal and intermediate layers and strong in the transitional layer. The alkaline phosphatase activity was moderate in the basal and intermediate layers and weak in transitional layer of outer zone. It was moderate in the basal and intermediate layers and intense in the transitional layer of inner zone. Statistical analysis showed a significant increase in the thickness of capsule, width of the two zones and the primary cavity with the advance of age.
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    ThesisItemOpen Access
    ANATOMY AND HISTOLOGY OF RUMINANT STOMACH OF GOAT
    (1981-07-31) JOSE JOHN, CHUNGATH; Radhakrishnan, K
    Gross and microscopic anatomy of the stomach of twenty adult goats, including blood supply and nerve sup ply have been investigated. Linear, weight and capacity measurements were recorded in relation to body length and weight. The disposition of inner mucosa of various stomach compartments was also studied. The caudo-ventral blind sac of rximen of goat, unlike that of other ruminants, extended more caudally than the dorsal one. Dorsal coronary grooves were absent. The right ventral coronary groove was distinct and reached the ventral border of rumen. The omasum was the smallest and oval in shape. The a}x>masum was comparatively larger in goats. The conpoiand stomach in adult goat weighed 3,45 per cent of intact body weight. The volume of different stomach con^artments as percentage of total stomach were 73, 7, 2 and 18 for rumen, reticulxam, omasiim and abomasum respectively. The wet tissue weights of different compart ments as percentage of total stomach were about 66, 9, 8 and 17 for rumen, reticuliim, omasum and abomasum respectively.Basically, the mlcrosTOpic structure of goat stomach resembled closely that of other uruminaats. The forestomach had the non-glandular cutaneous mucous membrane, a connective tissue sxib mucosa, a two layered muscvilar tunic and a serosa. The omasum and abomasum presented the muscularis raucosae. The abomasum had glandular epithelium with the cardiac, fiindic and pyloric regions. The different con^jartments of stomach of goats was innervated by the dorsal and ventral branches of the vagus. The arterial supply was by the branches of coelic artery.