Thumbnail Image

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.

Browse

2013 - 20163
Reset filters
Subject: Veterinary Parasitology × End date: 2017 × Start date: 2013 × Type: Thesis × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemOpen Access
    STUDIES ON Dirofilaria immitis IN DOGS AND ITS ASSOCIATION WITH Wolbachia SPECIES
    (College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781022, 2013-06) Borthakur, Sonjoy Kumar; Deka, Dilip Kr.
    Dirofilaira immitis is an important canine filarial nematode. An epidemiological study was carried out to record the prevalence of D. immitis in dogs in two different geographical locations viz., Guwahati, Assam and Aizawl, Mizoram of North Eastern Region in India, from February, 2011 to July, 2012. The study also included to evaluate the persistence of Wolbachia endosymbiont with D. immitis. In the present study, dogs were grouped into three categories, i.e., stray, pet and working dogs, their respective numbers being 413, 266 and 103 irrespective of the study regions. Three different methods were used for the study, i.e., microscopy (wet film and KCT), immunological (Ag ELISA by SNAP®4Dx kit) and molecular techniques (PCR). The study revealed overall heartworm prevalence in Guwahati to be higher (18.23%) than in Aizawl (17.68%) irrespective of categories of dogs. Sex-wise, the infection was higher in male (18.12%) than in female (17.90%), though the difference was statistically non-significant. The overall efficacy percentage for detection of heartworm by wet film, KCT, Ag ELISA and PCR test revealed 6.26, 11.38, 18.03 and 13.93 percent, respectively. Ag ELISA test was found to be the best amongst the three types of tests compared. Using molecular tools, prevalence of D. immitis in dogs was 13.52 percent in Guwahati and in Aizawl was 14.62 percent. With PCR, 4 cases of D. repens could be diagnosed in stray dogs from Guwahati. The study revealed overall 22.69 percent occult infection, of which, highest cases were recorded in working dogs (60%). Occult infection was calculated by finding the difference between heartworm prevalence based on Ag ELISA and PCR test. Dot ELISA test using monoclonal antibody of D. immitis for detection of heartworm antigen in dog blood samples was standardized. The test revealed 72% specificity against known positive D. immitis blood samples at SNAP®4Dx commercial kit. Molecular technique using PCR was standardized to detect D. immitis using published primers with slight modification of thermal condition. Two different primers were used viz., specific primers for D. immitis only and another, pan filarial primers for detecting six different canine filariids. Both the primers resulted desired amplification product size against different filarial parasites. Molecular cloning and characterization of D. immitis for ITS-2 region of Guwahati isolates were conducted. The results showed the Guwahati isolates had a close relationship with that of South Asian isolates of D. immitis. Pair-wise homology analysis revealed 98.6 - 98.9% similarity with a few sequences available at NCBI GenBank. Similarly, phylogenetic analysis of D. repens encountered in Guwahati isolate was also done. Endosymbiont Wolbachia association with D. immitis worm as well as in heartworm infected blood was revalidated by PCR method. The findings were substantiated with the presence of the organisms in the worm’s lateral cord by fine structural studies conducted through transmission electron microscopy (TEM). Molecular evidence followed by sequence analysis of Wolbachia revealed 99.4 to 99.8% similarities with other sequences available in NCBI GenBank for Wolbachia endosymbiont of D. immitis. Finding of the present studies establish the endemicity of D. immitis in North East India and validates the association of Wolbachia endosymbiont in D. immitis. Record of D. repens warrants further detail studies owing to its zoonotic significance.
  • Thumbnail Image
    ThesisItemOpen Access
    EPIDEMIOLOGY OF LEECH INFESTATION AND EVALUATION OF ANTI LEECH EFFECTS OF SOME LOCALLY AVAILABLE PLANTS
    (Assam Agricultural University, Khanapara, Guwahati, 2016-07) PATHAK, PALLABI; Islam, Saidul
    An epidemiological study was conducted to record the prevalence of aquatic and terrestrial leech species in fifteen districts of Assam. Out of 1991 number leeches collected five aquatic e.g., Hirudinaria manillensis (57.86%), H. granulosa (11.85%), H. javanica (2.71%), Whitmania laevis (2.61%) and Hemiclepsis marginata (0.80%) and one terrestrial leech e.g., Haemadipsa sylvestris (24.16%) was found prevalent in the study area. Molecular identification of H. manillensis based on coI sequence was done. Phylogenetic analysis showed 95.5% sequence similarity with P. manillensis (Accession No: KT693108.1) and lowest with H. manillensis (GQ368747.1). The sequence was submitted into the GenBank, and assigned the Accession No. GenBank KX579976. Bionomics of H. sylvestris was studied in laboratory conditions. The incidence of leech infestation in man and animal in different leech infested areas was conducted using interview method by means of questionnaire. Total protein concentration of crude antigen of H. granulosa, H. sylvestris and H. manillensis was found to be 4.14g/dl, 4.05g/dl and 3.6g/dl. Total protein concentration of E/S antigen of H. manillensis, H. granulosa and H. sylvestris was 3.39g/dl, 3.44g/dl and 3.4g/dl, respectively. Discontinuous gel electrophoresis revealed protein profile of crude antigen of H. manillensis, H. granulosa and H. sylvestris being almost same. The number and size of peptides varied from 9-10 and 12.5 to 96 kDa, respectively. The number of peptides of E/S antigen for H. manillensis, H. granulosa and H. sylvestris were 5 and size varied from 14-96 kDa. PAS staining of glycoprotein antigen could not be detected for E/S product for all three species. Two glycoprotein antigens could be detected in crude H. manillensis and H. granulosa and three in H. sylvestris which ranged from12.5-26 kDa. A total of two immune-reactive peptides were detected for H. manillensis and H. granulosa crude antigens and one in E/S product of H. sylvestris. Hirudinicidal effect of aqueous and methanolic extracts of leaves of Nicotiana sp., seeds of Camellia sinensis and stems of Carica papaya was evaluated against H. manillensis and compared with ivermectin and nicotine. The methanolic extract of Nicotiana sp. and C. sinensis; aqueous extract of Nicotiana sp. and C. sinensis possessed effective hirudinicidal properties. While the concentration and extraction procedure was considered, the aqueous extract of Nicotiana sp. at 5000 mg/ml and 2500 mg/ml showed faster killing effect. While the method of extractions and the level of concentrations were considered against time of repellency, it was found that barring the methanolic extract of C. papaya at the concentrations of 50 mg/ml and 100 mg/ml, all the other extracts at different concentrations showed highly significant (p<0.001) leech repellent effects. Expression of HSP was evaluated by Dot-ELISA in stressed organism using a panel of monoclonal antibodies which comprised of HSP-60, HSP-70 and HSP-90. After application of pure compounds (nicotine and ivermectin) and extracted products (methanolic and aqueous) of Nicotiana sp., C. sinensis and C. papaya, HSP-60, HSP-70 and HSP-90 were detected in excretory and secretory (E/S) product of leeches. HSP-60, HSP-70 and HSP-90 were also detected both in crude and excretory and secretory (E/S) products of the cold stressed leeches. Extracts of Nicotiana sp. and C. sinensis were subjected to in vitro cytotoxicity studies on Vero cell lines using MTT assay. Two fold dilution of the extracts were used from 10.00 µg/µl up to 0.0096 µg/µl. Both the aqueous and methanolic extracts of Nicotiana sp. and metahnolic extract of C. sinensis had more per cent viability of Vero cells than the aqueous extract of C. sinensis. In no case the per cent viability was below 70. The efficacy of extracts against H. sylvestris and aquatic leech was evaluated on human volunteers. The methanolic extract of C. sinenesis failed to exhibit minimum 50% leech repellent effect. Aqueous extract of C. sinenesis exhibited inconsistent effect with 45.83% repellent effect at 20% concentration, but 26.19% effect at 30% concentration. Both the methanolic and aqueous extract of Nicotiana sp. exhibited 100% repellent effect at all the three levels of concentrations which was comparable with DEET (12% concentration).
  • Thumbnail Image
    ThesisItemOpen Access
    STUDIES ON Indoplanorbis exustus AND ITS ASSOCIATED SCHISTOSOMES
    (Assam Agricultural University, Khanapara, Guwahati, 2016-07) Bulbul, Kamal Hashan; Das, Manoranjan
    A study on ecology, biology and bionomics of Indoplanorbis exustus along with its associated schistosomes was undertaken for a period of two years i.e. from March 2014 to February 2016 in Barpeta, Nalbari and Kamrup district of Assam. A total of 12 aquatic macrophyte species were recorded from the study area. The highest frequency percent (f %) relative frequency percent (RF %) of different macrophytes was found to be 86.67% and 19.70% respectively. Population density of I. exustus in terms of f% and RF% and man hour collection per meter square area (MHC/m2) showed an increasing trend from July to September and then gradually declining towards November. While the snails were reared in biologically balanced aquarium at constant temperature of 15, 20, 25, 30 and 35C and room temperature (20.02-31.75C), all the snails died before attainment of sexual maturity at 15oC. The growth rate in terms of shell diameter and body weight attained maximum size 10.63+0.162 mm and 435.83+23.367 mg, respectively at room temperature at 6th week of age. Egg to egg cycle ranged from 50 days at 30C and 125 days at 20C. Room temperature was found to be more conducive for fecundity wherein as many as 22833 numbers of eggs were hatched out from 1033numbers of egg capsules. The temperature, pH, DO, free CO2 and total alkalinity of ambient water had direct bearing on population density of snails. The ANOVA of physicochemical properties of water was highly significant (p<0.01) between months and areas of water bodies. Out of 161500 numbers of snails collected in two years showed incidence rate of cercariae of Schistosoma spindale (0.72%), S. indicum (0.50%) and S. nasale (0.17%). The cercariae were identified on the basis of morphological and molecular method. The RS data indicated that the distribution of cercariae of S. indicum group was more in the northern bank of Brahmaputra compared to the Southern bank. By means of molecular dissection, brevifurcate cercaria was identified as Trichobilharzia sp. and the longifurcate as Alaria alata with 87-88% clonal relationship with Denmark, Lithuania and Germany isolates. A total of 420 cattle, 179 buffaloes and 171 goats slaughtered at local abattoirs revealed visceral schistosomosis in 37.38, 35.20 and 12.28%, respectively. In regards to coprological examination it was 14.52, 12.85 and 4.68% in order of same sequence as above. The incidence rate in terms of adult parasites present and faecal examination was the highest in monsoon season and the lowest in pre-monsoon season. Concentration of eggs was more in liver (45.45%) followed by ileocaecal junction (37.50%), caecum (25.97%) and small-intestine (18.18%). Based on worm count methods, mild types of intensity was found to be highest followed by moderate and heavy intensity in slaughtered animals. The incidence of nasal schistosomosis was highest in July (18.92%) and lowest in December (2.70%) when nasal swab was examined for the presence of eggs in 363 cattle irrespective of sex and age. Like visceral schistosomosis, nasal schistosomosis also had a higher infection rate in monsoon season and in animals above 8 years of age. The second internal transcribed spacer (ITS2) sequence of S. spindale, S. indicum and S. nasale were found to be amplified showing different repeatitive band patterns. While the mitochondrial cytochrome c oxidase subunit 1 (CO1) genes and the ribosomal gene repeat, part of the 28S RNA gene (28S) were amplified on 372 bp and 1225 bp when subjected to PCR. Phylogenetic analysis of Schistosoma indicum group based on nucleotide sequences of COI and 28S genes revealed Assam isolates of S. indicum showed a clonal relationship with Bangladesh isolates and S. spindale and S. nasale with Nepal isolates. RAPD-fingerprinting using different random primers showed specific polymorphic markers for susceptible and non-susceptible I. exustus to Schistosoma infection due to genetic variability.