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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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20161
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Subject: Veterinary Microbiology × Author: SARMAH, HIRAMONI × End date: 2019 × Type: Thesis × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    MOLECULAR AND BIOLOGICAL CHARACTERIZATION OF WILD STRAIN OF DUCK PLAGUE VIRUS
    (Assam Agricultural University, Khanapara, Guwahati, 2016-07) SARMAH, HIRAMONI; DAS, S. K.
    Duck plague or duck viral enteritis is an acute and contagious viral disease of ducks, geese swan and other waterfowl. The disease is responsible for significant economic losses in duck husbandry due to decrease in egg production, condemnation and mortality in duck. The present study was undertaken to study the molecular and biological characterization of wild strains of duck plague virus. In the present study 6 wild strains of DPV (DP/As-Km/0010, DP/As-Nal/0012, DP/As-Km/0016, DP/As-Km/0019, DP/As-By/0022, DP/As-Km/0025) were revived in ducklings. All the inoculated ducklings developed distinct clinical signs like nasal discharge, lacrimation, pested eyelids, greenish watery diarrhea, soiled vents and sometimes sudden death etc. Post mortem examination revealed gross lesions in brain, oesophagus, liver, spleen, heart, bursa of Fabricious and in intestine. Presence of viral nucleic acid was detected by PCR and detection of duck plague virus antigen in post mortem samples was done with indirect FAT. All the isolates revived in ducklings were further propagated in DEF upto 5th serial passage. The clear CPE was observed from 1st passage onwards. On the basis of DID50 and TCID50, a VV strain of DPV was selected for further study. DID50 of DP/As-Km/0019 was found to be 10-2 and DID50 in case of DP/As-By/0022 and DP/As-Km/0025 was 10-1. Highest TCID50 was found to be 106.33 in case of DP/As-Km/0019. On the basis of these parameters (DID50, TCID50). The strain DP/As-Km/0019 was selected as VV strain of DPV. The pathodynamics of the VV strain was studied by using mean clinical and pathological scores and virus excretion pattern in blood and other clinical samples like tracheal swab and cloacal swab, nasal and ocular swab. Highest mean pathological score was observed in Liver and oesophagus (2.33±0.51) and lowest was observed in thymus and bursa (1.00±0.00).Molecular characterization of selected VV strain of DPV was done by sequencing two genes (UL30, US10) from different region of the virus. Phylogenetic analysis showed close relation with other isolates of DPV and vaccine strain. VNT50 titre of VV strain of DPV (DP/As-Km/0019) was found to be 1:223 which is similar to VNT50 of the vaccine strain and for other moderate virulent strains (DP/As-By/0022 and DP/As-Km/0025), VNT50 was 1:188 and 1:112 respectively. The selected VV strain of duck plague virus was adapted in 9-11 days old embryonated chicken eggs. Different changes like thickening of CAM with extensive haemorrhages, Haemorrhage and congestion throughout the body of infected embryos were observed from 3rd passage onwards. The chicken embryo adapted VV wild strain of DPV was again adapted and propagated in the CEF upto 10th serial passage. The most common CPEs were rounding of cell, vaculation in the cell, syncytia formation and finally detachment of cell monolayer which was observed from 3rd passage onwards.