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Assam Agricultural University, Jorhat
Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level.
Genesis of AAU -
The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati.
Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.
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ThesisItem Open Access Pathomorphological and molecular detection of avian leukosis virus infection in chicken(College of Veterinary Science, Assam Agricultural University, Khanapara Campus, 2022-09) Tamuly, Nibedita; Dutta, BiswajitAvian Leukosis being a common neoplastic disease of the commercial poultry farm, causes significant economic losses to the farmers. The present study was undertaken to determine the status of the infection in the poultry population from 7 different locations in Kamrup district of Assam. During the period of study, twenty two (22) outbreaks of avian leucosis were recorded from seven (7) different locations of undivided Kamrup district of Assam. A total 243 numbers of post mortem was conducted from which 65 positive cases were reported on the basis of gross examination, histopathological alteration and molecular detection. The overall mortality percentage was recorded as 4.11%. Among different age groups maximum mortality was reported in adult birds above 20 weeks of age (7.36%). However few cases were also reported below 16 weeks of age. Breed/strain wise study revealed highest mortality was reported in BV-380(6.17%) followed by BV-300 (4.47%) which was further followed by Kamrupa (3.49%) and Daothigir (3.47%). Season wise occurrence of the infection was more during winter (4.86%) followed by pre-monsoon (4.11%) and post monsoon (3.68%). Clinically, affected birds did not exhibit any typical clinical signs, however some of the affected birds showed signs like anaemia with pale comb, emaciation with decrease growth rate and productivity and osteopetrosis. The gross pathological study gives a presumptive diagnosis of the diseases where prominent lesions were found in liver, spleen, kidney and heart. In all the cases hepatomegaly was most commonly seen. The affected liver also showed nodular, eucosis or diffuse form of lesions. Spleen, kidney and heart also showed enlargement, necrosis and the presence of nodular growth. Even though the bursal involvement could not be detected due to its rudimentary form in adult birds but in two cases the lesions in bursa was prominent. Microscopic alterations were severe in liver, spleen, kidney, heart and lung characterized diffuse infiltration of immature lymphoid cells, causing distortion of normal parenchyma. Molecular detection by targeting gp85 env gene produced amplification bands at 229 bp. The phylogenetic analysis of the resultant sequences showed 99-100% homology with the endogenous forms of isolates from China, USA and South Korea. Virus can be isolated on 6th day old embryo where replication of the virus was showed by severe hemorrhages and mortality 48-96 hours of post infection. In field condition presence of other neoplastic diseases like Marek’s disease produces similar lesions which complicates proper diagnosis of avian leucosis. In such situations differential diagnosis can be made on the basis of cell cytology, histopathology and Polymerase chain reaction. In histopathology Marek’s diseases affected tissue showed infiltration of pleomorphic cells and on molecular detection positive samples produced bands at 225bp. Myeloid form and erythroid forms were not found during the study. And the present study reveals that infective form of subgroup E of avian leucosis is circulating in the residential poultry population which might undergo mutation along with exogenous forms and create a more severe form of the disease.ThesisItem Open Access Pathomorphological and molecular studies of respiratory mannheimiosis in goats(College of Veterinary Science, Assam Agricultural University, Khanapara Campus, 2022-09) Mazumder, Amdedul Islam; Begum, Shameem AraThe present investigation was conducted to study the pathomorphological and molecular studies of respiratory Mannheimiosis in goats for a period of one year from March 2021 to February 2022. The materials for the present study were collected from various sources such as slaughter houses in and around Guwahati and from postmortem examinations carried out in the Department of Veterinary Pathology, College of Veterinary Science, A.A.U., Khanapara, Guwahati-22. Based on gross observation 30 lungs showing lesions of pneumonia were collected during post mortem examination. Twenty one lung samples showing pneumonic lesions were also collected from slaughter houses. For detailed bacteriological and pathological studies all of the 51 pneumonic lungs were chosen. A total of 43 isolates of bacteria were obtained in the present study out of which seven isolates were morphologically and biochemically positive for Mannheimia haemolytica (16.28%). Apart from this, other bacteria isolated were Pasteurella multocida (23.26%), E. coli (20.93%), Klebsiella spp. (18.60%), Staphylococcus spp. (13.95%) and Streptococcus spp. (6.98%). All the 7 isolates of Mannheimia haemolytica were screened for Lkt and 16s rRNA gene respectively. The Lkt gene with amplicon size 206 bp and the 16s rRNA gene with amplicon size 1500 bp was detected in all the 7 isolates of Mannheimia haemolytica. The Phylogenetic analysis of 16s rRNA gene of Mannheimia haemolytica isolated from goats in the present study showed percent identity above 97 percent with other strains of Mannheimia haemolytica present in the NCBI Gene Bank throughout the world. Different types of pneumonia associated with respiratory Mannheimiosis recorded during the present study were bronchophneumonia (37.25%), interstitial pneumonia (27.45%), haemorrhagic pneumonia (19.61%), suppurative pneumonia (11.76%), and fibrinous pneumonia (3.92%). Patchy areas of consolidation in the cranioventral portion of lungs were the most commonly observed gross lesion in bronchopneumonia. Microscopically, bronchopneumonia was characterized by neutrophils and mono-nuclear cell infiltration with presence of fibrin in the bronchi, bronchiole, alveolar lumen and pleura. Interstitial pneumonia cases were characterized by enlarged and rubbery lungs which do not collapse when the thorax is opened. The interlobular septa were distended with exudate. Microscopically, alveolar wall was thickened due to infiltration of polymorphonuclear cells and lined by cuboidal epithelial cells. Alveolar lumen was also filled with polymorphonuclear cells, macrophages and desquamated epithelial cells. Haemorrhagic pneumonia cases revealed multifocal, patchy to diffuse areas of haemorrhage throughout the lung surface. Microscopically, there was hemorrhage within the alveoli and inter alveolar septa with leukocytic infiltration in the bronchus. The wall of the bronchus also showed the inflammatory changes. Areas of emphysema were also observed. Gross pathological alterations observed in suppurative pneumonia were multiple focal abscess formation on lung surface. Presence of creamy suppuration could also be noticed in tracheal lumen. Microscopically, heavy infiltration of neutrophils could be seen in bronchial and alveolar lumen. In some cases necrotic mass admixed with bacterial colonies surrounded by thick connective tissue capsule were also recorded with infiltration of polymorphonuclear cells, mononuclear cells, plasma cells and macrophages. In fibrinous pneumonia, lungs were covered with stringy net like material. Excess serous fluid was present in the pleural and peritoneal cavities. In few cases the lungs was tightly adhered to the thoracic wall due to deposition of fibrin. The interlobular septa were prominent due to accumulation of fibrin. Microscopically, fibrinous pneumonia was characterized by the presence of intra alveolar fibrin in the form of “fibrin balls” within the alveolar spaces. The traditional ‘oat cells’ and necrotic macrophages were present inside the damaged alveoli.ThesisItem Open Access PATHOLOGY OF HEPATO-RENAL DYSFUNCTION IN DOGS (Canis lupus familiaris)(College of Veterinary Science, Assam Agricultural University Khanapara, Guwahati-781022, 2016-07) Umesh, Tari Chubita; Tamuli, Sarojini MahantaAn investigation was carried out in naturally occurring hepatic and renal dysfunctions in dogs from in and around Guwahati city; to study the prevalence, clinical symptoms, hemato-biochemical changes, urine pathology, gross and histopathology and histoenzymic activity. During the period from June, 2015 to May, 2016; a total of 9564 dogs were surveyed for incidence of hepato-renal dysfunction; 511(5.34%) were recorded as positive out of which 148 (1.55%) were positive for hepatic, 182 (1.82%) for renal and 181 (1.89%) for hepato-renal dysfunction. This revealed that hepato-renal dysfunction is prevalent in the dogs of Guwahati region. In a detailed examination of 155 dogs, 87 (56.13%) were reported positive for both hepatic and renal dysfunctions, out of which 31 (20%) were positive for hepatic, 35 (22.58%) for renal and 21 (13.54%) were positive for hepato-renal dysfunctions. Hepatic dysfunction showed highest prevalence in pre-monsoon season (21.95%); renal dysfunction showed highest prevalence in winter season (27.02%) and hepato-renal dysfunction showed highest prevalence in post-monsoon (23.08%) season. The age-wise prevalence for hepatic dysfunction was highest in dogs belonging to age group of 1-˂3 years of age (33.33%), for renal dysfunction it was the age group of 9 years and above (37.04%) and in hepato-renal dysfunction highest prevalence was seen in the age group of 6-˂9 years (23.53%). Sex wise prevalence of hepatic dysfunction was higher in males (22.47%) whereas prevalence of renal dysfunction was higher in females (25.76%). But the prevalence of hepato-renal dysfunction was found to be almost equal in both males (13.48%) and females (13.64%). Breed wise prevalence of hepatic dysfunction was highest in German Shepherd breed, for renal dysfunction it was highest in Pug breed and for hepato-renal dysfunction, highest prevalence was also seen in German Shepherd breed. Mortality due to hepatic, renal and hepato-renal dysfunction was found to be 18.06%, with 3.87% mortality for hepatic dysfunction, 3.22% mortality for renal dysfunction and 10.96% mortality for hepato-renal dysfunction. The clinical symptoms observed were elevated body temperature, anorexia, dehydration, dull and depressed appearance, rough body coat, pale mucous membrane, rapid pulse rate, shallow breathing, emaciation, anaemia, vomiting, diarrhoea, edema, melena, dark yellow to coffee colored urine. Some cases showed exclusive hepatic dysfunction signs of jaundice, ascites and abdominal pain. Some cases showed signs of renal dysfunction like stranguria, oliguria, urea breath and ulcers in the mouth. Giemsa’s stain and Modified Knott’s method were used for detecting hemoparasites like Babesia gibsoni, Babesia canis, Ehrlichia canis and Dirofilaria immitis in the blood of affected dogs. Hematological parameters like hemoglobin, packed cell volume, total erythrocyte count, mean corpuscular volume and mean corpuscular hemoglobin concentration revealed that dogs suffered from normocytic and normochromic anaemia. Biochemical markers included in liver and kidney function tests revealed that affected dogs showed mild to severe dysfunction of liver and kidneys. Postmortem study revealed several changes in liver like centrilobular necrosis, bridging necrosis, steatosis, acute hepatitis, portal cirrhosis, Glissonian cirrhosis, biliary cirrhosis, cholangitis, hemosiderosis and glucocorticoid hepatopathy; and also in kidneys like acute interstitial nephritis, acute glomerulonephritis, chronic interstitial nephritis, membranous glomerulonephritis, membrano-prolifereative glomerulonephritis, sclerotic glomerulonephritis, protein losing nephropathy, oxalate nephrosis, amyloidosis and calcification of tubules and glomeruli. Other organs like spleen, lungs, heart, stomach, intestine and brain were also observed to be affected. Three dogs revealed neoplastic changes like hepatocellular carcinoma, renal carcinoma and metastatic cancer of liver, kidneys and lungs. Special stains like Masson’s Trichome, Periodic acid Schiff’s, Von Kossa’s and Prussian blue stains were used to differentiate the specific changes in the affected tissues which did not appear very pronounced by routine staining methods. Histoenzymic study revealed mild to no activity of LDH in degenerated cells and AKP enzyme showed moderate to high activity in the degenerated cells and sinusoidal spaces of the liver and kidneys.ThesisItem Open Access STUDIES ON THE PREVALENCE, PATHOLOGY AND MOLECULAR DIAGNOSIS OF DUCK VIRUS ENTERITIS IN ASSAM(Assam Agricultural University, Khanapara,Guwahati, 2016-06) SAHARIAH, PARAG JYOTI; Upadhyaya, T.N.Duck plague or duck viral enteritis is an acute and contagious and economically important viral disease of ducks having high morbidity and mortality rate. A total thirty nos. of duck plague outbreaks occurring in certain district of Assam were attended during the period of February, 2014 to March 2016. Out of a total 5252 ducks at risk, 2956 (56.28%) were affected clinically and 2449 (46.62%) died. The overall morbidity and mortality were 56.28% and 46.62% respectively, however the cause specific mortality for DP in the present study was found to be 82.85%. Highest mortality was recorded in duckling (55.80%) followed by grower (51.24%) and adult ducks (35.43%) respectively. In the present investigation, altogether 445 serum samples were collected from the ducks from affected as well as some other ducks from the surrounding areas of the outbreak from different parts of Assam. All the serum samples were subjected to indirect ELISA test for detection of the duck plague viral antibody. Out of the total 445 serum samples tested for detection of DP viral antibody, 171 (38.42%) serum samples showed positive in ELISA. A total of 131 numbers of duck carcasses were subjected to necropsy examination. Externally, the carcasses were markedly emaciated, the vent was soiled with greenish-white faecal materials and occulo-nasal discharges were also observed. Grossly, the vascular changes were invariably present in all the visceral organs including the brain. The longitudinal folds of the esophagus showed presence of thick yellowish-white patchy diphtheritic membrane. In a few cases, the intestinal annular bands appeared as intensely reddened rings due to haemorrhages and were visible from external and internal surfaces. The liver was moderately enlarged with presence of scattered petechiae and focal greyish-white necrotic areas. The coronary vessels of the heart were engorged. There was presence of petechiael to echymotic haemorrhages in the epicardium particularly in and around the coronary groove, which give the heart a characteristics paint brush appearance. Microscopic lesions were characterized by haemorrhages, congestion, degeneration and necrotic changes of the parenchymatous organs. Liver showed varying degrees of degeneration with multiple areas of focal coagulative necrosis. Intra-nuclear, eosinophilic inclusion bodies with a distinct halo were observed inside the degenerated hepatocytes. Congestion of the blood vessels in the myocardium, haemorrhages between the muscle fibres and epicardium of heart were evident. There were rupture of the blood vascular wall and escape of blood into the surrounding musculature. The intestinal annular band showed congestion, haemorrhages and depletion of the lymphocytic cell populations. Lymphocytic depletion was also observed in the spleenic and bursal follicles. For in-situ demonstration of the DP virus Fluorescence Antibody Test was used. On fluorescent microscopy (FAT) DP virus was demonstrated in the liver, spleen, bursa of Fabricius, brain, thymus and intestinal annular band. A total of 380 numbers of samples were collected from clinically affected (107) and dead ducks (273) for molecular diagnosis of the disease. Out of total 380 samples, 231 (84.61%) post mortem samples and 68 (63.55%) clinical samples showed positive for duck plague virus specific nucleic acid. Highest numbers of tissue samples that showed positive for PCR were liver (91.80%) and spleen (91.53%). In clinical samples 79.10 per cent was positive in whole blood, 40.91 percent was positive in cloacal swabs and 33.34 percent in tracheal swab. In biochemical study, the ALT and AST activities in serum and tissues were significantly higher in DP affected ducks in comparison to the healthy ducks. The virus could be successfully isolated in 9-11 day old duck embryos from the field samples. The infected CAM and the embryos showed extensive haemorrhages throughout the body. Embryopathy was observed within 4-8 days post infection.ThesisItem Open Access PREVALENCE, PATHOLOGY AND MOLECULAR STUDIES OF PESTE DES PETITS RUMINANTS IN GOATS OF ASSAM(Assam Agricultural University, Khanapara, Guwahati, 2015-07) ISLAM, MUZAHARUL; Pathak, D. C.Peste des petits ruminants is an acute, febrile, emerging and economically important viral disease of goats having high morbidity and mortality rate. In the present investigation, 456 serum samples collected from affected and apparently healthy goats from different places of Assam were screened for seroprevalence of PPR in goats by HI test and c ELISA test. Out of 456 serum samples screened, PPR viral antibody could be detected in 269 samples by HI test (145 serum samples from affected goats and 124 from apparently healthy goats) and 209 samples by c ELISA test (136 from affected goats and 73 from apparently healthy goats). 60 serum samples (9 from affected goats and 51 from apparently healthy goats) showed positive in HI test but were found negative by c ELISA test. In comparative study it was revealed that HI test was more sensitive than c ELISA. The haematological study of 26 affected goats showed significant increase in total erythrocyte count, haemoglobin, packed cell volume and significant decrease in total leucocytes count. Lymphopenia was constant finding in differential leucocytes count. Biochemical study revealed significant decrease in serum protein and significant increase in serum potassium level, with nonsignificant increase of serum sodium level. All the 10 necropsied carcasses showed emaciation and dehydration with soiled hindquarters and sunken eye balls. Ulcerative lesions on gum, lips, dental pad and tongue, enteritis and linear haemorrhages on the crests of the folds of large intestine were invariably observed. The liver was enlarged with engorged gall bladder. Spleen and lymph nodes were enlarged. The lungs showed congestion and consolidation of anterior and cardiac lobes with emphysema in diaphragmatic lobes. On cut section, lung showed large quantities of white frothy exudate particularly in the bronchi. The histopathological study showed degeneration, necrosis, ulceration and sloughing off lining epithelium in lips, tongue, small intestine and large intestine. Below the ulcerated areas severe infiltration of mononuclear and polymorphonuclear cells were observed. Some cells of stratum granulosum showed presence of intracytoplasmic eosinophilic inclusion bodies. Hepatocytes showed coagulative necrosis with cytoplasmic and nuclear degeneration. The lungs showed broncho-interstitial pneumonia and presence of intracytoplasmic eosinophilic inclusion bodies. Renal tubular degeneration with coagulative necrosis and atrophy of glomeruli were observed. Edema in both the cortical and medullary areas with severe depletion lymphocytes was observed in the lymph node. Syncytial giant cells were also found in the lymph nodes. Spleen showed depletion of lymphoid population. Some lymphoid follicles were completely destroyed, leaving cystic cavities. In RT-PCR, out of 79 post mortem samples, 58 showed amplification of PPR viral nucleic acid at 463 bp for N gene using N gene specific primers.
