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ThesisItem Open Access COMPARATIVE HISTOMORPHOLOGY AND ULTRASTRUCTURE OF THE SKELETAL MUSCLE OF BROILER AND KUTTANAD DUCKS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, KERALA VETERINARY ADN ANIMAL SCIENCES UNIVERSITY, 2023-03-23) ALPHINE JOSEPH; Dr. S. MayaThe present study was conducted to investigate the comparative histomorphology and ultrastructure of the skeletal muscles from selected areas in meat type and spent Kuttanad ducks, to determine the comparative proportion of fibre types in skeletal muscles using histochemical methods and to compare the physical, chemical and mechanical properties of the skeletal muscle between the groups by assessing the correlation of meat quality like tenderness and juiciness with muscle fibre properties. A total of 72 birds comprising of 12 birds each of males and females from broiler Vigova SuperM ducks (six to eight weeks of age), Kuttanad ducklings (six to eight weeks) and spent Kuttanad ducks (over 72 weeks) selected at random were used for the study. Muscle samples from six selected regions, viz. neck (Longus coli posticus- LCP), back (Scapulohumeralis caudalis- SHC), breast (Pectoralis- PEC), wing (Biceps brachii- BB), thigh (Iliofibularis- IF) and drumstick (Gastrocnemius lateralis- GL) were collected from the Meat Technology Unit, College of Veterinary and Animal Sciences, Mannuthy, after humane slaughter, processed appropriately and the data collected were analysed statistically using SPSS version 24.0. Morphologically, the breast muscles were the longest among all muscles. The mean length of the muscles was significantly different between groups, in all the regions. Breast muscle was the heaviest muscle in all the groups and among groups, the heaviest was the pectoralis muscle in Kuttanad duckling males. Mean thickness of muscle was maximum for broiler ducks for the breast muscle. Histologically, the muscle was composed of muscle fibres, connective tissue, blood vessels and nerves in all the groups. The connective tissue covering identified were epimysium, perimysium and endomysium with varying degree of thickness in different muscles. Three types of muscle fibres were identified using enzyme histochemical staining techniques, viz. type I, IIA and IIB. Glycogen content was found copious in type IIB fibres under PAS reaction, while fat droplets in the type I fibres were noticed on Oil red O staining. Alkaline phosphatase and acid phosphatase activity showed negative for muscle fibres indicating the absence of any regenerative or degenerative stages of muscles fibres respectively. The endothelial lining of capillaries amidst the muscle fibres showed a positive reaction for alkaline phosphatase in almost all muscles.On micrometry, maximum average fibre density was observed in breast muscle in spent Kuttanad duck males. In all other regions, the maximum average fibre density was seen in broiler duck males with decreasing order of PEC>SHC>BB>GL>LCP>IF. The maximum average fibre diameter was noticed in breast muscle. In breast, wing and drumstick muscles, broiler ducks showed the maximum average fibre diameter whereas in neck and thigh by Kuttanad duckling males and in back by Kuttanad duckling females. The average fibre diameter from maximum to minimum from PEC>GL>SHC>IF>BB>LCP. Kuttanad duckling males showed the highest mean cross-sectional area of muscle fibres in the neck muscle. The order of average cross-sectional area of different muscles were LCP>IF>SHC>BB>GL>PEC. The average cross-sectional area of muscle fibres was minimum for broiler duck males in all the muscles except breast muscle. However, the mean cross-sectional area did not differ between groups and between genders in the breast muscle. The highest mean fascicle cross-sectional area was obtained for spent Kuttanad duck females in the iliofibularis muscle. Myosin ATPase, SDH and NADH-TR enzyme histochemistry staining of muscle fibres revealed type I, IIA and IIB fibres in neck, back, thigh and drumstick. Type I fibres were noticed concentrated in particular portions of stained tissue sections of back and drumstick muscles. Breast and wing muscles were identified with only type IIA and type IIB fibres. The presence of type I fibres in neck, back, thigh and drumstick musclesand clear absence of type I fibres in wing and breast muscles were confirmed by immunohistochemistry (IHC). Both immunohistochemistry and enzyme histochemistry staining showed relatively similar qualitative results of different fibre types, with IHC method being the more accurate method. Overall, the breast muscle and wing muscle showed type IIA> IIB pattern except in broiler ducks, where the IIA and IIB are found almost equal. The back and drumstick muscles showed IIB>IIA>I pattern. Considering the ratio of IIA and IIB fibres, more IIB fibre component was observed as SHC>GL>BB> PEC. Both in neck and thigh muscles, spent Kuttanad muscle showed more type I fibres followed by broiler ducks and then by Kuttanad ducklings. Neck muscle showed higher proportion of cross-sectional area for type I fibres than thigh muscle. Scanning electron microscopy of muscle fibres revealed the thick and thin filament arrangement of connective tissue amongst muscle fibres. Under transmission electron microscopy, the, myofibrils, sarcomere, triad, myonuclei and interfibrillar, perinuclear and subsarcolemmal mitochondrial populations were identified in the duck muscle. Interfibrillar mitochondrial concentration was comparatively higher in drumstick muscle than breast muscle that too in spent Kuttanad ducks than Kuttanad ducklings.Serum biochemical analysis showed all the parameters examined within the normal level among all the groups indicating the absence of any injury to the muscles. The pre-slaughter live weight, defeathered weight, mean dressed weight were significantly higher in broiler ducks. The mean carcass yields showed significant interaction with a significantly higher values for spent Kuttanad ducks males (77.44 ± 1.50 per cent) than others in male groups. Physical properties of muscle such as colour and pH were analysed in the study. The highest colour L* value was given by back muscle of broiler duck males and the lowest colour L* value was noticed in the breast muscle of male spent Kuttanad ducks. The highest mean colour a* value was obtained for spent Kuttanad duck (14.6 ± 0.13) males in the neck region and the value was significantly higher than other male groups. Mean b* value was maximum for the neck region of broiler duck and in the wing region of spent Kuttanad ducks. The pH of breast muscle had a drastic fall within the first three hours. Initially, the pH was higher in breast muscle in spent Kuttanad duck males and females. The pH of back, thigh and drumstick muscles showed a higher ultimate pH at 24 h. At 15 minutes, the comparison of pH in hot-boned and intact muscle showed significant differences in the wing, back, thigh and drumstick regions. The pH value of intact muscle showed a significantly higher value than hot-boned muscle. Mechanical property of muscle was analysed by measuring the sarcomere length at 15 min, 1 h, 3 h, 6 h and 24 h. At all the intervals, wing muscle showed the highest sarcomere length in broiler ducks. The R value reached to the value of one in almost all muscles within one hour which indicated the fast onset of rigor mortis. R value was higher in neck muscle in spent Kuttanad ducks. The highest mean moisture content was obtained for broiler ducks males in the neck region. The intramuscular fat was obtained highestin the neck muscle by the spent Kuttanad duck females. The collagen content was evidently and copiously detected in the drumstick muscle of Kuttanad duckling males. The highest mean myoglobin content was obtained for drumstick region followed by thigh region in spent Kuttanad duck males. On SDS PAGE analysis, bands were observed in between 180 to 245 kDa molecular weight and the thigh muscle showed thick and differentiated band in all the groups. The migration of myosin heavy chain isoform bands was greatly affected by the quality of the frozen sample and the temperature of the apparatus.The mean flavour scores did not differ significantly between groups except in the thigh region. There was no significant difference observed in the juiciness and mouth coating score between groups and genders. In the back region, the highest mean ease of fragmentation score was obtained for broiler duck males. The overall tenderness score showed significant difference (p<0.05) in breast muscle and back muscle between groups. The overall tenderness score was significantly higher in broiler ducks in the back region. Overall acceptability score was significantly highest in back muscle followed by breast muscle in broiler ducks compared to spent Kuttanad ducks and similar to Kuttanad ducklings. The correlation study showed that the collagen content had significantly positive correlation on muscle fibre length and negative correlation on cross sectional area. The present study indicated that the muscles can be ranked for better meat quality according to the score of individual muscle fibre properties like the proportion of different fibre types, density of fibres and the cross-sectional area of fibres. Apart from that, meat quality was not only affected by a single factor, but by a number of factors and its combinations, that play a major role in the conversion of muscle to meat as well as its tenderness. Differences in muscle fibre properties may be attributed to the anatomical function of particular muscles. In the present study, the different combination of muscle fibre properties like the increased proportion of fibre type IIB, decreased density of fibres and decreased cross sectional area of fibres of the muscle, together resulted in the overall acceptability of the meat from that muscle. Overall, broiler duck showed better meat quality traits than Kuttanad ducks. Since, each muscle was different in muscle fibre properties, selection of breeds with increased quantity of back and breast muscle will increase the quality of duck meat.ThesisItem Open 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. LucyPostnatal 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.ThesisItem Open Access PRENATAL DEVELOPMENT OF SPIRAL CORD IN GOATS (Capra hircus)(COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2005) S. MAYA; T Josu John ChungathThe multipolar neurons first appeared in the ventral horn, by 40 days. The cells had clear boundaries by fourth month. Among neuroglia, the ependyma presented a stratified layer around the central canal from the beginning of gestation. The astrocytes and oligodendrocytes appeared by 40 days. Oligodendrocytes formed myelin sheath towards the end of gestation.Microglia appeared by fourth month.ThesisItem Open Access PRENATAL DEVELOPMENT OF BRAIN IN GOATS (Capra hircus)(COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2005) K. M. LUCY; K.R. HarshanThe project was undertaken to trace the developmental pattern of brain and its relationship with age, body weight cranial size and other body parameters. After recording the body measurements and cjaniometry the material was fixed in 10 percent neutral buffered formalin. Then encephalometry was recorded and standard procedures were adopted for histoarchitectural and histochemical studies.ThesisItem Open Access POST-HATCH DEVELOPMENT OF PREEN GLAND IN THE DUCK {Anas platyrhynchos)(COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2005) S. RAJATHI; N. ASHOKStudies 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.
