<div>Background: The favorable climatic condition and fertile land resources of Assam plays a significant role for agricultural and livestock production in the region. Assam is one of the regions of north-eastern India, famous for different varieties of indigenous ducks reared by farmers under traditional system. Due to hot-humid climatic condition of Assam along with extensive availability of resources like ponds, river, marshy wet lands etc. provides a suitable natural habitats for duck rearing in rural areas of the states. Pati Duck was recognized as a breed by the National Bureau of Animal Genetic Resources in the year 2017. 
 
Methods: The study was conducted at Govt. Duck and Poultry Farm, Joysagar, Sivasagar district of Assam. Ducklings were hatched at the Hatchery unit present at the farm. Eggs were been collected from different farmer&rsquo;s house where they reared ducks in the backyard systems. Ducklings born were been studied for the different morphological characteristics and their body weight were been measured in weekly interval. All ducks received adlibitum feed from day one onwards.&nbsp; 
 
Result: Pati ducks were divided into five major groups based on their body coat colour. They are Whitish light brown, White, Blackish brown, Black and white and Khaki coloured. The different body measurement shows the male to be superior to the females in different parameters with different coat colour. The major colour pattern of bill, shank and feet was found to be yellow, whereas skin was mostly white in colour and plumage colour pattern found to be white, black and brown in different parts of the body.&nbsp;</div>

Morphological Characteristics of Pati Duck

<div style="text-align: justify;">The present investigation was conducted on the comparative anatomical study of vagina (sperm storage organ) of Pati and Chara-Chemballi ducks during laying periods. The vagina was collected immediately after death and anatomical studies were made on it. The vagina was a narrow muscular tube, sharply curved and was tightly bound by ligament. The length, width thickness and weight of vagina of Chara-Chemballi ducks were significantly (p&lt;0.01) higher than Pati duck. The lining epithelium consisted of pseudostratified columnar epithelial cells with few goblet cells. The mean height of lamina epithelialis mucosae of vagina of the present study was significantly (p&lt;0.01) higher in Chara-Chemballi duck (26.508&plusmn;0.298 &micro;m) than Pati duck (23.058&plusmn;0.330 &micro;m). A weak PAS positive reaction was noticed in the lining epithelium of vagina of Pati and Chara-Chembali ducks.</div>

Anatomical Studies on the sperm storage organ of Pati and Chara-Chemballi Ducks

<div>Background: The study on Thymus of Pati duck of Assam is of great value in regard to normal academic and vaccine production. The aim of the study was to evaluate the gross and histo-morphological examination of thymus of Pati duck at different age group. 
 
Methods: The present studies were conducted on 36 numbers of Pati duck of Assam of irrespective of sex at different stages of development. The ducks were divided into six groups viz., day old, 15th day, 4th week, 8th week, 16th week and 24th week of age. For histomorphological studies, tissue samples were fixed in 10% NBF and then processed as per the standard technique andprocedure of Luna (1968). The paraffin blocks were sectioned in Shandon Finesse microtome at 5 micrometer (&micro;m) thickness and the tissue 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 and Verhoeff&rsquo;s method for elastic fibers and Bielchowsky&rsquo;s method for axis cylinder and dendrites.&nbsp; 
 
Result: The thymus, a primary lymphoid organ of Pati duck of Assam was arranged in two long chains on either side of the neck embedded in the sub dermal connective tissue as chains of lobes connected to each other by connective tissue. The thymus of Pati duck consisted of a capsule made up of connective tissue fibres and cells from which trabeculae entered the parenchyma dividing that organ into a number of incomplete lobules. The unique structure of the thymus, the Hassall&rsquo;s corpuscles, was formed by the hypertrophied reticulo-epithelial cells and was very common in the medulla.</div>

Anatomical Study of Thymus at Different Stages of Development in Pati Duck of Assam

Background: Pati duck population constitutes a major indigenous non-descript economically important duck variety in Assam. Harderian gland acts as a part of the head associated lymphoid tissue (HALT) and provides local innate immunity to the upper respiratory system, to the eye and oral cavity. Since literature on histoenzymic or histochemical study of harderian gland of Pati duck was scant, hence the present study was designed to establish the basic histoenzymic details on harderian gland of Pati duck of Assam. 
 
Methods: The present study was conducted on total forty five (45) Pati duck of Assam. Ducks were divided into five groups: 0, 4, 16, 24, and 42 weeks. For histochemical parameters, tissue samples were preserved in deep freeze maintained at -80oC (except for PAS-alcian blue, where paraffin sections were utilized) immediately after collection. The preserved tissue samples were shifted directly to cryostat microtome maintained at -22oC. The frozen sections were cut at 7 &micro;m thickness and were collected on clean slides and were treated as per the method of Singh and Sulochana (1978). 
 
Result: Histochemical studies revealed that the reaction of Alkaline phosphatase enzyme was mildin Harderian land of Pati duck. The reaction of the acid phosphatase was absent. The Adenosine triphosphatase (ATPase) activity was observed moderate in all the age groups. The activity of non specific esterase was observed strong in all the age groups. The periodic acid-Schiff (PAS-Alcian Blue 2.5 pH) stain revealed positive reaction in all the age groups which indicated the presence of acid sulfated mucosubtances in the cells.

Histochemical Study of the Harderian Gland of Pati Duck of Assam

<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: 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>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

Background: The study of hormone and blood parameters in male Pati duck was carried out to investigate the changes that occur in these parameters during the post-natal development as better understanding of physiology is necessary for improving the productivity.&nbsp; 
 
Methods: The blood and serum sample were collected from Pati duck at 1 month, 6-8 weeks, 20 weeks, 30 weeks and 40 weeks age groups. For each age group 6 representative samples were collected from the jugular vein. Hormones (testosterone, cortisol, triiodothyronine and thyroxine) were estimated using Radioimmunoassay (RIA) and haematological parameters were studied using digital analyser.&nbsp; 
 
Result: Age related change observed with Testosterone hormone with maximum level observed in 40 weeks age group. T3 and T4 hormone were higher in younger age; T3 was highest in 20 weeks while T4 was highest in 1 month age group. Cortisol was higher in older groups and maximum level observed in 40 weeks age group. Among the haematological parameters significant changes was observed in packed cell volume (PCV), white blood cells (WBC), monocyte and neutrophils.&nbsp;