<div>Background: The agro-climatic condition of Assam is suitable for duck rearing. Duck rearing contributes a major part to uplift the socio-economic condition of the rural poor people of Assam as well as others states located in the coastal regions of India. The Pati duck (Anasplatyrhynchos domesticus) population constitutes a major indigenous non-descript economically important duck variety in the state of Assam. The Harderian gland acts as a part of the Head Associated Lymphoid Tissue (HALT) <a href="#olah_1992">Olah et al. (1992)</a> and provides local innate immunity to the upper respiratory system, to the eye and oral cavity. Since literature on the postnatal development of Harderian gland of Pati duck is scant, hence the present study was designed to establish the basic anatomical details on Harderian gland at different stages of postnatal development of Pati duck of Assam.&nbsp; 
 
Methods: The present study was conducted on total forty five (45) numbers Pati duck of Assam at different stages of postnatal development. The experimental birds were brought to the Department of Anatomy and Histology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-22 and was sacrificed according to the method of <a href="#gracy_1986">Gracy (1986)</a>. After slaughter, the birds were placed on a clean dissecting table and skin and fascia were reflected carefully without disturbing the other organs of the head region. The Harderian gland was collected by opening the orbital cavity. Thereafter, length, breadth and thickness of the Harderian gland of all age group were recorded with the help of the Vernier Callipers <a href="#mcCance_1974">(McCance, 1974)</a> and topographical location of the gland was observed. The weight of the Harderian gland of all age group was also recorded with the help of electronic balance.&nbsp; 
 
Result: The Harderian gland of Pati duck (Anas platyrhynchos domesticus) was located &nbsp;within the orbit. The gland was flat, oval and coma shaped with irregular border. The gland had two surfaces i.e. the parietal and visceral surfaces, two borders and two blunt poles. The parietal surface was found convex and attached to fascia covered by the nasal bones and interorbital septa. The visceral surface was concave and it was attached loosely to the eye ball with fascia. The lobes of the Harderian gland became more prominent with the advancement of the age. The gland was light pink in colour. The arterial blood and the venus drainage was by provided by the ophthalmic artery and vein, respectively. The slender branch of oculomotor nerve innervated the Harderian gland. The result reflected an ascending trend from 0 week age group to 42 week age group in regard to all the gross parameters. There were slight difference between left and right glands for all the gross parameters but such variations were not statistically significant (P&gt;0.05). Each lobe of the Harderian Gland of Pati duck (Anas platyrhynchos domesticus) had a single short duct which opened into the conjunctival sac at the base of the 3rd eyelid.&nbsp;</div>

<div>Post Natal Gross Anatomical Studies on the Harderian Gland of Pati Duck (Anas platyrhynchos domesticus) of Assam</div>

<div>Background: The farmers are rearing duck in small scale in semi intensive system without investing more capital but it contributes a major part to uplift the socio-economic condition of the rural poor people of Assam. The Pati duck (Anas platyrhynchos domesticus) population constitutes a major indigenous non-descript economically important duck variety in the state of Assam. The Harderian gland acts as a part of the head associated lymphoid tissue (HALT) and provides local innate immunity to the upper respiratory system,&nbsp;to the eye and oral cavity. Since literature on histological study of Harderian gland of Pati duck is scant, hence the present study was designed to establish the basic histological details on Harderian gland at different stages of postnatal development of Pati duck of Assam. 
 
Methods: The present study was conducted on total forty five (45) numbers Pati duck of Assam at different stages of postnatal development. The experimental birds were brought to the Department of Anatomy and Histology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-22 and was sacrificed according to the method of Gracy (1986). For histological study the tissue samples from the Harderian gland of all the age group were fixed in 10% neutral buffered formalin solution and processed to prepare paraffin blocks as per the procedure described by Luna (1968). The paraffin blocks were sectioned in Shandon Finesse microtome in 5 &micro;m thickness and the sections were stained by different methods as described by Luna (1968).&nbsp; 
 
Result: The Harderian gland of Pati duck had a capsule, the thickness of the capsule of the Harderian gland was increased slightly along the advancement of the age. The capsular connective tissue penetrated the parenchyma of the Harderian gland in the form of septa. The collagen, reticular, elastic and nerve fibers were observed along with the capsule and as well as in the septa. The Harderian gland of the Pati duck was compound tubular gland. The columnar epithelial cells lined the tubules. There was no cortex and medulla in the gland and the tubular structure were uniformly distributed within the lobules. A central canal was present in the gland which converged to the duct of the gland. The lymphocytes, plasma cells were found in the intertubular connective tissue. The numbers or population of plasma cell and lymphocytes were accelerated by the advancement of age. The myoepithelial cells with spindle shaped nucleus were present near the basement membrane close to the secretary cells. The histology of the duct of the Harderian gland of Pati duck was like that of typical hollow tubular organs. There were few lymphatic nodules very distinctly present extended from the lamina propria to the muscle layer.</div>

Histological Study of the Harderian Gland of Pati Duck (Anas platyrhynchos domesticus) of Assam during Postnatal Development

<div>Background: It is known that balance diet is the key success for better production in poultry. The digestive physiology is regulated by the neurocrine and endocrine secretions. Growth, secretion, motility, cell signalling, vasoregulation, cell proliferation and differentiation of the epithelial cells of the alimentary canal are reported to be controlled by the peptides or amines released from the gut endocrine cells and enteric neurons. References particularly on systematic study of gastrointestinal endocrine cells in duck as regards to histomorphology and cytochemistry are gravely scanty. Hence the present investigation envisages authenticating the histomorphological characters and cytochemical behaviour of the gastrointestinal endocrine cells in duck. 
 
Methods: For this study the abdomen of six Khaki campbell ducks from either sex was cut open following euthanasia. Tissue pieces from different segments of gut were collected and processed routinely to get 7-8&micro; thick serial paraffin sections. The tissue sections were stained for evaluation of histomorphological and histochemical characters of the entero-endocrine cells. 
 
Result: A panel of seven cytochemical stains identified nine endocrine cell types in the digestive mucosa of Khaki Campbell duck i.e. basally granulated oval cell, densely granulated spindle shaped cell, densely granulated oval cell, diffusely granulated oval cell, pyramidal cell, densely granulated elongated cell, densely granulated pyriform cell, peripherally granulated spherical cell and non-argentaffin chromaffin oval cell. The cells occurred in single or in small clusters in the basal or middle or neck part of glandular epithelium or in the surface epithelium. All the endocrine cells were &lsquo;close type&rsquo;. Cytochemically they were four types i.e. argentaffin, argyrophil, chromaffin and APUD (Amine precursor uptake and decarboxylation) cells.</div>

<div>Histomorphological and Cytochemical Characters of Endocrine Cells of the Gastrointestinal Mucosa of Duck (Anas platyrhynchos)</div>

<div>Background: The Pati duck constitutes a major indigenous duck variety in the state of Assam. The study of the gut associated lymphoid tissue (GALT) of Pati duck of Assam is of great value in regard to normal academic and bio-medical research aspects. It is also pre-requisite for correct diagnosis and evaluating the treatment of certain diseases like duck virus enteritis, duck cholera, aflatoxicosis, botulism etc, caused by different types of pathogens, food poisoning and food allergy. 
 
Methods: The study was conducted on Pati duck of Assam in where 45 numbers of ducks were selected by irrespective of sex at different stages of development. The birds were divided into five groups depending on its age viz., 1st week, 4th week, 16th week, 24th week and 42nd weeks old. The pieces of gut having lymphoid tissue or Peyer&rsquo;s patches were collected immediately after slaughter. Samples were made cryosections (-20oC) at 10&micro;m in thickness and were temporally stored at (-22oC). The histochemical staining was done after that. 
 
Result: The acid phosphatase activity was weak in the lymphoid follicles of 1st and 4th week of age of Pati duck, while its activity was moderate in 16th, 24th and 42th week of age.The alkaline phosphatase activity was moderate reaction in the lymphoid follicles of 1st and 4th week of age of Pati duck, while its activity was intense in 16th, 24th and 42th week of age of duck. The lymphoid follicles of both Peyer&rsquo;s patches and solitary lymphoid nodules were showed moderate activity for adenosine tri-phosphatase activity in 1st and 4th week old Pati duck and strong activity in 16th, 24th and 42th week of age of Pati duck, respectively. The lymphoid nodules of intestine showed strong reaction for non-specific esterase activity in all the age groups of Pati duck.&nbsp;</div>

Histochemical Studies on Post Natal Development of Gut Associated Lymphoid Tissue (GALT) of Intestine of Pati Duck (Anas platyrhynchos domesticus) of Assam

<div>Background: The study on Gut Associated Lymphoid Tissue (GALT) of Pati duck of Assam is of great value in regard to normal academic and bio-medical research aspects. The aim of the study was to evaluate the gross, histomorphological and scanning electronic microscopic examination of gut-associated lymphoid tissue of the intestine of Pati duck at different age group. 
 
Methods: For this study, forty five Pati ducks were divided into five groups depending on its age viz., 1st week, 4th week, 16th week, 24th week and 42nd weeks old. The pieces of gut having lymphoid tissue or Peyer&rsquo;s patches were collected immediately after slaughter. These samples were fixed in 10% neutral buffered formalin solution and were processed as per the standard technique of procedure (<a href="#luna_1968">Luna, 1968</a>). The paraffin blocks were sectioned in Shandon Finesse microtome at 5 &micro;m thickness and the sections were stained with Mayer&rsquo;s Haematoxylin and Eosin staining technique for Cellular details, Van Gieson&rsquo;s method for collagen fibres, Gomori&rsquo;s method for reticular fibres, Hart&rsquo;s method for elastic fibres and Bielchowsky&rsquo;s method for axis cylinder and dendrites as per the method of <a href="#luna_1968">Luna (1968)</a>.&nbsp; 
 
Result: Gut-associated lymphoid tissue was found in the duodenum, jejunum, ileum, caecum and the terminal part of the rectum in all the age group of Pati duck. The lymphoid compartment of the gut-associated lymphoid tissue in duck included a follicular structure, dome, follicle associated epithelia and interfollicular area. Lamina propria of jejunum was heavily infiltrated with diffuse lymphatic tissue in the 16th, 24th and 42nd week of age of Pati duck. The scattered and diffuse lymphatic infiltration occurred in all age groups. The lamina propria of the colorectum revealed an extensive network of reticular fibre with diffused lymphatic tissue in all the age group of duck. In Scanning Electron Microscope, the lumen of the jejunum was covered by finger-like villi with numerous opening of goblet cells. The lymphoid follicle of Lamina propria contains numerous lymphocytes along with connective tissue fibres.&nbsp;</div>

Gross, Histomorphological and Scanning Electronic Microscopic Studies on Gut Associated Lymphoid Tissue of Intestine of Pati Duck (Anas platyrhynchos domesticus) of Assam

<div style="text-align: justify;">An experiment was conducted at the University Poultry and Duck Farm, Mannuthy, Kerala to study the effect of individual selection on growth and carcass characteristics in Kuttanad ducks. One thousand and eighty-eight day-old Kuttanad ducklings procured from progressive farmers of Kerala formed the base generation (S0). Based on body weight at eighth week, top 150 females and 25 males were selected through individual selection. From the 25 sire families, 979, 969 and 1610 ducklings were produced by artificial insemination in S1, S2 and S3 generation in pedigreed hatches. Body weight was recorded at fortnightly intervals till 12th week of age and at 18th and 40th week of age in each generation. Carcass characteristics were evaluated at 8, 10 and 12 weeks of age in four generations. An improvement of 270.51 g could be recorded at 8 weeks in S3 generation. The period of active weight gain shifted to 4th and 6th week in S3 generation whereas it was 8th week in the previous generations. The results also indicated that a compensatory growth mechanism is present in ducks and they attain 90 per cent of the adult body weight by 12 weeks of age. The carcass characteristics showed that there was improvement in the dressing percentage over generations and S3 generation attained the highest yield at 8 weeks. Hence, selection for body weight at 8 weeks was effective in improving the body weight and they could attain its optimum meat production characteristics at 8 weeks and hence it could be considered as the ideal age for processing. &nbsp;</div>

<div style="text-align: justify;">Effect of Individual Selection on Growth and Carcass Characteristics in Kuttanad Ducks (Anas platyrhynchos domesticus)</div>

<div>Background: Pati ducks have been playing a vital role in Assam&rsquo;s rural economy. It is an established fact that the liver is an important organ in the body. Since literature on a detailed anatomical study of the liver in Pati ducks of Assam is scare, hence the present study was designed to establish the gross, histological and histochemical details on liver with advancement of age. 
 
Methods: The present study was conducted on 24 numbers of Pati ducks of Assam. They were divided into four (4) groups, each group containing six birds and kept for different ages i.e. 1 week, 8 weeks, 16 weeks and 24 weeks. The gross morphometry viz. length, breadth, thickness and weight of liver were observed. For histological study, tissue samples were fixed in 10% neutral buffered formalin. The processing and various methods staining were used according to <a href="#luna_1968">Luna (1968)</a>. For histochemical study, samples were stored at -80&deg;C in a deep freeze immediately after collection and they were treated according to <a href="#singh_1978">Singh and Sulochana&rsquo;s method (1978)</a>. 
 
Result: Morphometrical parameters showed an increasing trend with age. The lobules of liver were not distinct. Strong Alkaline phosphatase and Acid phosphatase activity were observed in the capsular area and bile canaliculi respectively.</div>

Gross Morphological, Histological and Histochemical Studies on Liver of Pati Ducks (Anas platyrhynchos domesticus) of Assam

<div style="text-align: justify;">Morphological and morphometrical study of pelvic limb bones from adult birds viz., ostrich (n=4), emu (n=6), domestic fowl (n=8) and duck (n=8) were carried out. Pubic symphysis was a distinctive feature of os coxae in ostrich. Medial surface of ilium was united to lumbosacral mass in ostrich and emu, whereas, only medial border made fusion in domestic fowl and duck. Post acetabular ilium was an elongated triangle in ostrich and emu, whereas, quadrilateral plate in domestic fowl and duck. Iliac fossae for kidneys were lacking in ostrich and emu. Ischium was a long rod in ostrich and emu. Ilio-ischiatic notch was present in ostrich and emu, while, ilio-ischiatic foramen was found in domestic fowl and duck. Caudal extremity of pubis was free in all the species studied excluding ostrich. Ostrich and emu exhibited a distinct pneumatic foramen on femur which was lacking in domestic fowl and duck. Length ratio of femur to tibiotarsus was 1:1.75, 1:1.88, 1:1.38 and 1:1.69 in ostrich, emu, domestic fowl and duck correspondingly. Lateral cnemial crest was a large tuberosity in ostrich; whereas, in other species it was a thick curved spine. &nbsp;Hypotarsus was in the form of spine in ostrich and emu. Bony spur of tarsometatarsus observed in male domestic fowl was lacking in the other species. Distal extremity showed two trochleae in ostrich, whereas, three trochleae, in the other species. Ostrich is the only didactyl bird with two digits. Emu possessed three digits, while, domestic fowl and duck possessed four. Our present study revealed pneumatic femur, longer tibiotarsus and tarsometatarsus and less number of digits in ostrich and emu. &nbsp;Reduction in number of phalanges also led to reduce the number of muscles and tendons associated to digits. The above mentioned features may aid ostrich and emu for high-speed locomotion.</div>

<div style="text-align: justify;">Comparative morphological studies of the pelvic limb bones in ostrich (Struthio camelus), emu (Dromaius novaehollandiae), domestic fowl (Gallus gallus domesticus) and duck (Anas platyrhynchos domesticus)&nbsp;</div>

<div style="text-align: justify;">TLR repertoire of duck, profiling of their mRNA expression in a range of duckling tissues and cytokine gene expressions upon TLR agonists stimulation in in vitro assay have been investigated. All ten TLR genes orthologous to chicken TLR repertoire were found in duck. Duck TLR genes showed 77-83% similarity at amino acid level to their chicken counterparts. All ten TLRs-TLR1LA, 1LB, 2A, 2B, 3, 4, 5, 7, 15 and 21 mRNA expressions were significantly higher in bursa than other tissues studied, whereas in muscle all TLRs mRNA expressions were significantly lower except for TLR15 (P&lt;0.01). TLR7 gene expression was significantly higher in spleen, bursa and also in lung tissues (P&lt;0.01). The cytokine gene expression levels in duck PBMCs upon LPS and poly I:C stimulation have been quantified. IL-1g gene expression level in LPS stimulated duck PBMC culture was significantly higher at both 12 h and 24 h time intervals (P&lt;0.05). However, there were no significant changes in IFN-&atilde; gene expression levels in poly I:C stimulated duck PBMC culture at both the intervals. TLR gene expression in young ducklings together with cytokine response upon LPS stimulation demonstrates the innate preparedness of younger birds to encounter pathogens and their functional ability to respond to their ligands.</div>

Molecular characterization of duck (Anas platyrynhos) Toll-like receptors, mRNA expressions profile in day-old duckling&rsquo;s tissues and cytokine response to in vitro TLR agonsists stimulation

Background: Due to their morphological and structural characteristics, birds possess a respiratory system distinct from that of mammals. Their nasal structures are highly specialized respiratory tissue sections designed. In these animals, the cartilaginous conchae exhibit a helical morphology. This special structure enables efficient heat exchange and moisture transfer. 
&nbsp; 
Methods: The nasal cavity ducts were removed and routine histological procedures were performed in Carnoy fixative. Triple staining technique was applied to sections to determine the histological structure. PAS, PAS-diastase, Alcian Blue-PAS, Alcian Blue-Aldehyde Fuchsin and Best Carmin stainings were applied to determine the mucin content of the glands. 
&nbsp; 
Result: Histological examination revealed that it was lined by squamous keratinized epithelium, which formed tubular glands containing secretory epithelium. A large amount of Grandry and Herbst corpuscles were found. The cartilage in the concha showed convoluted, were covered by pseudostratified prismatic epithelium. Unlike mammals, alveolar glands were found instead of goblet cells. It was determined that the intraepithelial glands in carboxylic acid mucin and neutral mucin. Acid mucins in the concha mucosa, while neutral mucins were in the alveolar glands. No difference was observed in the PAS staining of in the concha, while glycogen in concha and the Bowman glands were found not to contain mucin.

Post Natal Gross Anatomical Studies on the Harderian Gland of Pati Duck (Anas platyrhynchos domesticus) of Assam

Histological Study of the Harderian Gland of Pati Duck (Anas platyrhynchos domesticus) of Assam during Postnatal Development

Histomorphological and Cytochemical Characters of Endocrine Cells of the Gastrointestinal Mucosa of Duck (Anas platyrhynchos)

Histochemical Studies on Post Natal Development of Gut Associated Lymphoid Tissue (GALT) of Intestine of Pati Duck (Anas platyrhynchos domesticus) of Assam

Gross, Histomorphological and Scanning Electronic Microscopic Studies on Gut Associated Lymphoid Tissue of Intestine of Pati Duck (Anas platyrhynchos domesticus) of Assam

Effect of Individual Selection on Growth and Carcass Characteristics in Kuttanad Ducks (Anas platyrhynchos domesticus)

Gross Morphological, Histological and Histochemical Studies on Liver of Pati Ducks (Anas platyrhynchos domesticus) of Assam

Comparative morphological studies of the pelvic limb bones in ostrich (Struthio camelus), emu (Dromaius novaehollandiae), domestic fowl (Gallus gallus domesticus) and duck (Anas platyrhynchos domesticus)

Molecular characterization of duck (Anas platyrynhos) Toll-like receptors, mRNA expressions profile in day-old duckling’s tissues and cytokine response to in vitro TLR agonsists stimulation

Histochemical Structure of the Nasal Concha Mucosa in Ducks (Anas plathyrinchos)