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Kerala Veterinary and Animal Sciences University, Wayanad
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ThesisItem Open Access HISTOMORPHOLOGY AND ULTRASTRUCTURE OF THYROID AND ADRENAL GLANDS IN LARGE WHITE YORKSHIRE PIGS REARED AT HIGH AND LOW ALTITUDES(COLLEGE OF VETERINARY AND ANIMAL SCIENCES POOKODE, 2022-04-04) SIMANTA PATGIRI; Rajani C.V.Thyroid and adrenal glands of the Large White Yorkshire pigs reared at high and low altitude was studied to investigate the comparative morphology, micrometry and ultrastructure and serum hormone level in animals reared at low and high altitude. Materials for the study were collected from 24 Large White Yorkshire pigs of one year old categorized into four groups with respect to sex and altitude. Each group consisted of 6 animals. The thyroid and adrenal glands were collected from each animal. Observations on morphology, histology, histochemistry, electron microscopy, morphometry and micrometry were carried out and data were analyzed statistically to find out any significant difference. The thyroid gland in Large White Yorkshire pig was laterally covered by the cranial thymus. The position of the gland varied from the caudal border of the larynx to a position dorsal to the manubrium sterni. Thyroid resembled a single centrally-placed gland but after dissection, it revealed two lobes connected by an indistinct isthmus. The average weight of the thyroid gland of both male and female animals in low altitude was more than high altitude. The average length of intact thyroid gland in male and female was more in high altitude compared to low altitude. The average width and thickness of the intact thyroid gland in both male and female groups were more in low altitude than the corresponding high altitude group. The capsule of thyroid gland extended as fine trabeculae of interlobular connective tissue into the parenchyma of the gland and separated it into numerous lobules. The thyroid follicle had a maximum diameter of 301.35 μm. The diameter of thyroid follicles was more in the central area and it reduced towards the peripheral area. Parafollicular or C-cells were present in 3 locations viz. interfollicular, intrafollicular and parafollicular position. The diameter of the thyroid follicle in the high altitude male group was significantly higher than that of the low altitude male group but it was reverse in case of female animal. The thyroid follicle diameter was higher in female compared to male animals irrespective of altitude. The adrenal glands were detected either cranio-medial or entirely on the medial surface of the kidney and embedded entirely within the perirenal fat of the kidney. In low altitude male group, the average weight of right and left adrenal was higher than the corresponding high altitude group but it was reverse in case of low altitude female animals. In the low altitude, the average thickness of right and left adrenal was higher than that of high altitude for both male and female groups. In low altitude female group, the average length of right and left adrenal was lower than that of high altitude female group. In low altitude female group, the average thickness of right and left adrenal was more than that of high altitude group. Histologically, the adrenal gland presented outer cortex and inner medulla. The gland was entirely surrounded by a dense and distinct fibrous connective tissue capsule. The inner zone of the capsule extended very thick trabeculae enclosing blood vessels at right angles from the capsule, at regular intervals into the cortex towards the medulla. However, trabeculae were indistinct from zona fasciculata inwards. A few trabeculae enclosing blood vessel extended even upto the medulla. The boundary between the deeper part of the capsule and zona glomerulosa layer revealed a group of relatively undifferentiated 'capsular' cells. The junction of zona glomerulosa and zona fasciculata presented lightly stained undifferentiated cells were observed. For both male and female animals, the average thickness of zona glomerulosa of right and left adrenal gland were significantly higher in high altitude group than the respective low altitude group. The zona reticularis in the sow was usually wider than that in the boar in all the groups studied. In male pigs, the average serum T3, T4 and cortisol level were significantly higher in low altitude group compared to that of high altitude group. In female pigs, the average serum T4 and cortisol level were significantly higher in low altitude group compared to the high altitude group. The average serum cortisol level in males were significantly higher than that of female animals in both low and high altitude. Irrespective of sex, the average serum T3, T4 and cortisol level were significantly higher in low altitude group than that of high altitude group.ThesisItem Open Access STRUCTURAL AND PHYSICO-CHEMICAL EVALUATION OF RAW AND DECELLULARISED PORCINE TUNICA VAGINALIS AS A NOVEL ACELLULAR MATRIX(COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, 2021-12-30) ABHIN RAJ K.P.; Sreeranjini A.RThe current research was aimed to develop a novel acellular matrix from porcine tunica vaginalis by a standardised decellularisation protocol and to study the structural and physico-chemical properties of raw tunica vaginalis and the developed acellular matrix. Due to the intimate association of visceral layer of tunica vaginalis with testicular capsule, parietal layer of tunica vaginalis (PTV) were collected for the development of the acellular matrix from the testes of six adult healthy pigs slaughtered at the Meat Technology Unit, College of Veterinary and Animal Sciences, Mannuthy. Grossly PTV was found as an extensive, thin, elastic, flask shaped serous sac with numerous blood vessels and nerves. It lined the scrotum and the inguinal canal and was attached to the tail of epididymis and vas deferens. Histologically PTV comprised mesothelium and dense regular connective tissue composed of thick collagen bundles, a few elastic, reticular and smooth muscle fibres, blood vessels, and nerves. PTV was decellularised by two protocols using aqueous solution of bovine bile and Trypsin EDTA. After decellularisation, physico-chemical properties of the acellular matrix were evaluated and compared with that of raw PTV. Thickness, tensile strength, collagen content and resistance to collagenase enzyme of the decellularised matrix were less when compared with the raw PTV, whereas the collagen solubility was higher. Efficiency of decellularisation was assessed by routine and special histological staining methods, nuclear staining using 4, 6-Diamidino-2-phenylindole dihydro chloride, estimation of glycosaminoglycans, analysis of DNA content and by scanning electron microscopy. Lack of cellularity, lowest DNA content (<50 ng/µL) and increased porosity of acellular matrix revealed that efficiency of decellularisation using Trypsin-EDTA was better than that with bile treatment.ThesisItem Open Access FACTORS OF ANATOMICAL AND GENETIC ORIGIN PREDISPOSING TO INFERTILITY IN CROSSBRED DAIRY COWS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR -, 2021-03-08) ANNIE V. RAJ; K.M. LucyFactors of anatomical and genetic origin predisposing to infertility in crossbred dairy cows were studied using the genitalia collected from 100 dairy cows / heifers from the Meat Technology Unit, Mannuthy. This included six animals culled on account of factors other than infertility with normal reproductive system (control group) and the remaining animals with a known history of infertility. Morphology, morphometry, histology and histochemistry of genitalia, immunohistochemistry of IGFBP-2, scanning electron microscopic peculiarities of various regions of affected genitalia, biochemical analysis of follicular fluid and validation of SNPs of candidate genes were studied. Standard procedures were adopted for histoarchitectural and histochemical studies. Among the group of 100 animals under study, 14 animals showed anatomical defects in the genitalia. Considering the total number of female animals maintained in the farms, the overall incidence of anatomical abnormalities of genitalia was estimated to be 1.24 per cent. Crossbred Holstein Friesian showed a higher incidence of anatomical defects in the genitalia followed by Frieswal and crossbred Jersey. Cervical abnormality was the most common type noticed followed by ovarian hypoplasia, Mullerian duct abnormalities viz., bicornis bicorpus unicollis, uterus unicornis and tubal obstruction. Histologically, fibrous tissue proliferation was the characteristic feature of hypoplastic ovary with the absence of cyclical structures. In the genitalia with tubal obstruction, lamina epithelialis was detached from the mucosa to form clumps in the lumen. The tunica muscularis was approximately twice thicker than the normal oviduct. In uterus unicornis condition, the ovaries showed degenerated primary follicles and degenerating corpora lutea with hyalinised masses. Left uterine horn was absent and in its position, a membranous structure was seen. Right uterine horn revealed an unusual architecture. In the case of bicornis bicorpus unicollis, all the regions were normal. In kinked cervix condition, the cervical wall showed abundance of fibrous tissue and signs of degeneration. Histochemically, carbohydrates, lipids and phosphatases were demonstrated in different regions of the affected genitalia. IGFBP-2 was localized in the primordial and atretic follicles in the hypoplastic ovary. In uterus unicornis condition, invading granulosa cells into the regressing CL and atretic follicles in the cortical region showed a highly positive immunoreaction. Scanning electron microscopic structure of different regions of genitalia with anatomical defects was also explored. Biochemical analysis of follicular fluid revealed that the mean concentrations of potassium, triglycerides, urea, nitrogen, cholesterol, copper and magnesium were higher in group 2 animals. Single nucleotide polymorphisms reported in the study population by ddRADseq in four candidate genes viz., wnt7a, emx2, hoxa13 and lhx1 affecting the development of female reproductive tract were selected for validation. To identify the single nucleotide variations in bovine wnt7a, PCR was performed and the sequence analysis of 273 bp amplicon revealed the targeted SNP at position 89 (A→G transition) and three novel SNPs at positions 119 (A→G transition), 195 (C→ T transition) and 196 (T→A transversion). For identifying the SNP in bovine emx2, PCR - RFLP was performed and confirmed the population as homozygous. To identify the SNP in bovine hoxa13 and lhx1, HRM was performed and did not show any polymorphism. Amplification of exon 2 of foxa2 by PCR revealed polymorphism at 168th position (T→C transition) of the 320 bp product. This highlights the vital role of wnt7a in regulation of reproduction in bovines. The information gathered by this study will provide insights to the extent and causes of infertility among crossbred dairy cattle of Kerala. Biochemical analysis of follicular fluid is a potent tool for assessing reproductive status. The candidate gene wnt7a can be used for genome-wide scans of anatomical abnormality in bovine species at early stages itself so that the route cause can be eliminated by culling such animals. The findings will also be useful for diagnosing and minimizing the anatomical causes of reproductive disorders so that conception rate of the herd can be increased thus reducing economic loss to the farmers.ThesisItem Open Access HISTOMORPHOLOGY AND PHYSICO-CHEMICAL EVALUATION OF RAW AND DECELLULARISED TUNICA VAGINALIS OF BUFFALO FOR USE AS A BIOMATERIAL IN REGENERATIVE MEDICINE(COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, 2021-09-30) LHINGNEIVAH DOUNGEL; Indu V RajThe present study was undertaken to develop an acellular matrix from buffalo bull tunica vaginalis by a newly standardised decellularisation technique. Ten pairs of testes were collected hygienically from ten healthy adult Murrah buffalo bulls slaughtered at the Meat Technology Unit, College of Veterinary and Animal Sciences, Mannuthy. For decellularization, the fresh parietal layer of tunica vaginalis removed from the testes samples were processed as per the newly standardised protocol using trypsin-EDTA with triton-X-100 as detergent. The histomorphological, ultrastructural and physico-chemical characteristics of the raw and decellularised tunica vaginalis were compared and efficiency of decellularisation was evaluated by histological staining techniques, total DNA quantification and scanning electron microscopy. It was observed that the average weight of the left testis in adult Murrah buffalo bulls with and without parietal layer of tunica vaginalis (PTV) was more than that of the right testis and exhibited a statistically significant difference. The outer parietal layer of tunica vaginalis that lined the scrotum could easily be separated out from the testis. The vertical span of PTV of left testis was more than that of the right and the difference was statistically significant. Histologically the PTV consisted of a thin mesothelium and dense regular connective tissue made up of thick collagen bundles, a few elastic fibres and reticular fibres supported by blood vessels, smooth muscle fibres and nerves. It was observed that the decellularised PTV were devoid of cells and genetic materials such as DNA while maintaining its overall tissue histoarchitecture. The physico-chemical characteristics like mean thickness, tensile strength and collagen concentration of decellularised buffalo PTV samples were significantly reduced while the collagen solubility per cent and percentage weight loss after collagenase degradation were significantly higher in decellularised PTV than raw PTV samples. It was concluded that the samples of parietal layer of tunica vaginalis of buffalo prepared by using the newly standardised decellularisation technique showed acceptable physico-chemical properties required for a biologic scaffold. It may be used as a biomaterial in regenerative medicine after extensive clinical screening.ThesisItem Open Access COMPARATIVE STUDIES ON THE SKIN AND FEATHERS OF BROILER AND LAYER DUCKS(COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2018) ALPHINE JOSEPH; K.M. LucyComparative studies on the skin and feathers of broiler Vigova Super-M ducks of six to eight weeks of age and spent Kuttanad ducks above 40 weeks of age were conducted using 24 birds comprising of six males and females in each group. Histomorphology of skin and morphological, physical, chemical, spectroscopic and scanning electron microscopic peculiarities and radiolucency of feathers were compared. Skin samples of all the four groups of birds were collected from eight representative areas of the body viz., dorsal neck, alar, dorsal abdomen, ventral abdomen, pelvic, dorsal wing, ventral wing and lateral thigh regions. Standard procedures were adopted for histoarchitectural and histochemical studies. Total skin thickness was more in Kuttanad ducks than broiler ducks. Skin was thicker on the ventral surface of the body and was slightly thicker in male birds. Maximum thickness was recorded in ventral abdominal region. Epidermis was very thin and formed of two layers, stratum germinativum and stratum corneum. Dermis comprised three layers viz., stratum superficiale, stratum profundum (containing stratum compactum and stratum laxum) and lamina elastica. Stratum laxum was the thickest layer of skin in all groups and all regions under study. Feathers were implanted in the skin in feather follicles and always lay in the epidermis and dermis. Feather had an outer epidermis and inner dermis. The epidermis of the feather was found adjacent to the epidermis of the follicle with an outer layer of sheath cells called feather sheath. Several layers of intermediate cells and inner cylindrical cell layer surrounded the dermal pulp. Attached to the feather follicle were the smooth muscles known as arrectores plumorum muscles which ran in different directions. Herbst corpuscles were exclusivelyfound adjacent to the feather follicles in close association with these muscles. The subcutis was characterized by numerous blood vessels andadipose tissue. The moisture content was found to be more in the skin of broilers than layer group and fat percentage was more in layer skin than broiler skin. Hydroxyproline and collagen contents were more in the skin of layer ducks than in broiler ducks. Wing feathers showed a shaft, which was divided into upper rachis and lower calamus. To the rachis was attached the barbs, and the barbules were in turn attached to the barbs. Average length of barbs in broiler and Kuttanad ducks in the right side of right wing feather was 2.32±0.10 cm and 1.83±0.07 cm, respectively and duck feather rachis and barbs are found to be suitable for spinning into thread, can be used for weaving clothing, preparing slab or mat after mixing with other synthetic materials.The average diameter of barbs was 0.06±0.004 mm which falls under spinnable diameter range which is suitable for textile application. The diameter and spacing of barbs played major role in the water repellence property of feathers. Aspect ratio of barbs of duck feathers was in the desired range to be used in textile manufacturing. The percentage contribution of total feathers to the body weight was maximum in female broiler duck (5.47±0.26%). Rachis and barb fractions contributed equally to the weight of a single feather. The fineness of barbs showed almost similar valuesamong the groups.The relative density of whole feather fractions in ducks was 0.65±0.01g/cm3 . The moisture regaining capacity of barb fraction of broiler and Kuttanad ducks was the highest followed by whole feather fraction and was minimum for the rachis. SEM studies showed hollow cells on cross section of barbs measuring maximum diameter of 13.11µm in broiler ducks and 19.23µm in Kuttanad ducks and spacing between two adjacent barbules was maximum in Kuttanad ducks. Proximate analysis of feather of both groups showed similar composition. Elemental analysis showed equal amount of sulphur in broiler and Kuttanad duck feather barbs. Amino acid analysis revealed higher percentage of hydrophobic amino acids when compared to hydrophilic amino acids and a high content of serine in both the groups. FTIR-ATR studies indicated the presence of amide and carboxylic groups confirming the proteinaceous nature of material. X-ray diffractogram showed semicrystalline nature of the feather. Wing feathers of female birds showed more radio-opacity than males. Mechanical and thermal tests revealed high tensile strength and high heat stability for duck barbs. All these results implied the possibility of duck feather as a valuable raw material in the textile, nonwoven and composite manufacture.ThesisItem Open Access COMPARATIVE STUDIES ON THE SKIN AND FEATHERS OF BROILER AND LAYER CHICKEN(COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2018) S. V. BHARATHI; Indu V. RajThe present study was undertaken to compare the histomorphology of skin, physical, chemical, thermal and mechanical properties and radiolucency of wing feathers in broiler and layer chicken. Skin samples and wing feathers were collected from commercial broiler chicken of six to eight weeks of age and from culled White Leghorn birds above 64 weeks of age, slaughtered at Meat Technology Unit, Mannuthy. Samples were collected from a total of 24 birds comprising of six male and female birds from the broiler and layer groups. From each bird, 12 wing feathers were collected. The skin thickness, weight and per cent contribution of skin to the total body weight and the average number of feather follicles in unit area of skin, showed a significant difference between broiler and culled White Leghorn chicken and was more in the latter in all the regions but no significant difference was noted between the sexes. In histological sections the skin consisted of an outer thin epidermis and inner thick dermis. The epidermis presented two major layers viz., stratum germinativum and stratum corneum. The dermis consisted of three distinct layers from superficial to deep viz., stratum superficiale, stratum profundum and lamia elastica. The stratum profundum consisted of a superficial stratum compactum and a deep stratum laxum which was the thickest among all the layers of skin. Histochemical studies revealed the presence of glycogen, neutral mucopolysaccharides and abundant amount of cutaneous lipids. Layer birds possessed higher collagen content in the skin than broilers. The scanning electron microscopy (SEM), of broiler and layer feather barbs showed honeycomb shaped hollow cells, a unique cross-section not seen in other natural fibres. The physical properties of feather like length, diameter, aspect ratio of the rachis and barbs, feather weight and density, and mean fineness of feather fractions was more in White Leghorn birds. Moisture content and moisture regain values were similar in both groups and varied between eight to eleven per cent. Relative radio-opacity at the base of the feather was found to be slightly increased in layer birds. The proximate analysis, amino acid composition, FTIR-ATR (Fourier Transform Infrared Spectroscopy- Attenuated Total Reflectance), X-ray diffraction studies, tensile strength and thermal stability were similar in both the groups. The results of the present study confirmed that both broiler and White Leghorn chicken feathers could be beneficiated as good source of protein and energy and were suitable for use as a raw material in textile sizing bioplastics, biomedical materials, enzyme production, pharmaceuticals and cosmetics industry.ThesisItem Open Access PRE-HATCH DEVELOPMENT OF LOWER DIGESTIVE TRACT IN TURKEY (Meleagris gallopavo)(COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD, 2018) HELNA MARIA WILSON; S. MayaPre-hatch developmental pattern of lower digestive tract in Beltsville White turkey was studied to investigate the morphogenesis and histogenesis and to derive its relationship with age and body weight. Materials for the study were collected from 60 embryos on third, fourth, sixth, ninth, twelfth, fifteenth, eighteenth, twenty-first, twenty-fourth and twenty-seventh day of incubation, and compared with those from six, day-old poults. Observations on morphology, histology, histochemistry, electron microscopy, morphometry and micrometry were carried out and data were analysed statistically to find out the relationship. In the present study, all the divisions of the primitive gut viz., foregut, midgut and hindgut were apparent during the fourth day of incubation. The regional differentiation of the primitive gut into different segments of lower digestive tract viz. duodenum, jejunum, ileum, caeca, colo-rectum and coprodeum, occurred by sixth day of incubation. The parameters of the segments of the lower digestive tract became grossly measurable by 15th day of incubation. The intestines were completely retracted into the body cavity by 27th day of incubation. There was significant increase in the weight and length of lower digestive tract and that of its segments as the age advanced. The histological examination of the segments revealed well developed tunica mucosa, tunica muscularis, tunica serosa and an inconstant tunica submucosa. The longitudinal folds of the tunica mucosa indicating future villi were obvious by 15th day of incubation in the present study, which differentiated further with advancement of age. All layers of the small and large intestines increased in thickness as age advanced and became similar to the adult structure by 21st day of incubation. The intestinal epithelium presented three types of cells, viz. chief cells, goblet cells and argentaffin cells and the epithelium of the villi formed crypts of Lieberkuhn by 24th day of incubation. The study revealed that the growth of the segments of the lower digestive tract was highly correlated with increase in body weight and age of the embryo during the prehatch period, confirming the early maturing nature of the digestive system.ThesisItem Open 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. AshokPostnatal 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.ThesisItem Open Access DEVELOPMENTAL STUDIES AND EXPRESSION PROFILE OF ALFA-FETOPROTEIN GENE ON LIVER OF EMBRYONIC AND DAY-OLD TURKEY (Meleagris gallopavo)(COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR, 2017) PONNADA SRIDEVI; Sreeranjini., A.RCurrent research was aimed to comprehend the hepatogenesis in Beltsville Small White turkey embryos during different pre-hatch periods and in day-old poult, using various morphological, histological and histochemical techniques along with temporal analysis of Alpha-feto protein expression in liver. Six embryos each on 3rd, 6th, 9th, 12th, 15th, 18th, 21st, 24th and 27th day of incubation and six day-old poults collected from the University Poultry and Duck Farm, Mannuthy were utilized for morphological, histological and histochemical studies. For expression studies six embryos each on 9th and 15th day of incubation and six day-old poults were used. Liver was noticed grossly on ninth day of pre-hatch period but primordium could be appreciated histologically by day third of pre-hatch life. Lobation of liver could be observed from ninth day with two distinct lobes. Adult topography and lobation of liver was attained by 18th day of pre-hatch period. During pre-hatch development, colour of liver varied from ginger colour to red but it became yellowish by the day of hatch. On sixth day of incubation liver parenchyma showed a few branching hepatic cords and several acini with wide sinusoidal spaces in between. Central vein, portal vein and portal triad were first recognized on 9th, 12th and 18th day of pre-hatch period, respectively. By 12th day of development a thin layer of Glisson’s capsule appeared and by 15th day it became thicker. From 21st day onwards most of the hepatocytes were arranged as cords of two cells thickness. As age advanced, number of hepatic cords increased and was arranged compactly with narrow sinusoidal spaces separating them. Histochemical studies showed the presence of glycogen granules in hepatocytes during pre-hatch and post-hatch periods whereas phosphatases could be observed only in day-old poult. Liver parenchyma showed initiation of haemopoiesis by sixth day, reached peak by 15th day and got reduced by the day of hatch. Present study revealed that liver of turkey attained histological characteristics similar to that of adult birds by 21st day of pre-hatch development. Analysis of temporal expression of AFP transcript revealed a decreasing trend towards the end of the incubation period suggesting that the biological role of AFP was most during pre-hatch period for hepatogenesis.
