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20193
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Subject: Fisheries × End date: 2019 × Start date: 2017 ×
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    ThesisItemOpen Access
    STUDY OF COMBINED EFFICACY OF SYNTHESIZED DOUBLE STRANDED RNA (dsRNA) SPECIFIC TO STRUCTURAL AND NON-STRUCTURAL GENES OF WSSV IN PROTECTING LITOPENAEUS VANNAMEI FROM WSSV INFECTION
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2019) SHAIK THAHUR AHAMED; M.N.VENUGOPAL
    RNA interference (RNAi) is a potential strategy to control shrimp viral diseases, including the white spot disease (WSD) caused by White Spot Syndrome Virus (WSSV). Although a significant progress has been achieved on dsRNA mediated anti-virus strategy development, there is still no treatment available to control spread of the disease. This investigation has mainly focused on utilizing viral structural and non-structural proteins subunit vaccines to protect the host. In the present study the protective and therapeutic efficacy of double-stranded RNAs (dsRNAs) targeting structural (VP281) and nonstructural gene (RR2) of WSSV singly and in combination in controlling viral multiplication in Litopenaeus vannamei was investigated by intramuscular injection. The suppression effects of shrimp mortality by either combined dsRNAs of RR2 and VP281 or dsRNA-RR2 & VP281 alone was monitored for 15 days after viral challenge in both protective and therapeutic experiments. Targeting the combination of RR2 and VP281 genes provided better protection (90% survival) compared to RR2 (80%) and VP281 (70%) in protective experiment indicating that targeting a combination of RR2 and VP281 would be effective in limiting WSSV multiplication. In therapeutic experiment, 80% of shrimp survivals were detected from combined dsRNAs treatment, while RR2, VP281 showed survival rates of 70% and 60 % respectively, suggesting that the combination of dsRNAs can therapeutically clear existing WSSV in shrimp after a relatively short time of injecting.
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    ThesisItemOpen Access
    IMPACT OF SHRIMP FARM EFFLUENTS ON WATER QUALITY IN THE COASTAL WATER OF UTTAR KANNADA
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2019) MORE RUTUJA.,; LAKSHMIPATHI M.T)
    Impact of shrimp farm effluent on the receiving coastal waters was studied from stocking to harvesting period for one complete culture cycle (120 days). The present study was conducted on three shrimp farms in the Uttar Kannada district at Ankola and Kumta, an area representative for the impacts of shrimp culture. Fortnightly sampling was carried out at eight stations from March 2019 to June 2019. During this study period shrimp farm effluent was subjected to detailed analysis and its possible impact was recorded. Physico-chemical and biological characteristics in relation with hydrographical parameters were studied to determine the water quality of inlet and outlet area of adjacent creek waters. The present study revealed that the shrimp farm directly release effluent into creek water during water exchange without any treatment. This discharge of effluent made an impacts on water and sediment quality (Temperature, dissolved oxygen, pH, salinity, ammonia-nitrogen, nitrite-nitrogen, nitrate-nitrogen, phosphate-phosphorous, organic carbon, plankton and chlorophyll-a). The values of Do (< 3 mg/L), ammonia (< 40.26 μg-at/l), BOD (˃ 18 mg/L), COD (˃ 30 mg/L) and sediment organic carbon (4.4%) and planktonic biomass (0.54 – 5.12 mg/m³)) the chlorophyll-‘a’ (˃ 0.33 mg/m³) was observed. The investigation showed increased load of receiving waters by direct release of shrimp farm effluent to surrounding coastal waters. The effluents contained high amount of solids and nutrients generated from uneaten food material, shrimp excreta, which increased the concentration during discharge period. The water and sediment values were found to be increasing with the end of culture period. Among this parameters water temperature, DO, BOD, salinity, pH and nutrients showed wide range of fluctuations at outlet in creek. The study revealed that the shrimp farm effluent discharge have negative impact on receiving coastal waters bodies.
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    ThesisItemOpen Access
    SCREENING OF FRESHWATER ORNAMENTAL FISHES FOR VIRAL DISEASES
    (KARNATAKA VETERINARY, ANIMAL & FISHERIES SCIENCES UNIVERSITY, BIDAR, 2019) KUSHALA, K. B; S.K.GIRISHA
    In the international ornamental fish trade, more than 90% of the freshwater fishes are farm bred and about 4000 species of freshwater ornamental fishes were traded every year. Hence, the global ornamental fish trade had become the platform for spread of exotic pathogens especially viral pathogens. Major DNA viruses viz., cyprinidae herpes virus-2, koi herpes virus (KHV), carp edema virus(CEV), epizootic haematopoietic necrosis virus (EHNV), infectious spleen and kidney necrosis virus (ISKNV), and RNA viruses viz., spring viraemia of carp virus (SVCV), viral haemorrhagic septicemia (VHS) and viral nervous necrosis virus(VNN) are causing diseases and results in significant economic loss in ornamental fish trade. Therefore, to develop a strategy to controls the diseases, the present study has been undertaken to screen the viral pathogens present in ornamental fishes traded in Karnataka. In this present study, moribund and dead ornamental fishes were collected from three districts viz., Dakshina Kannada, Bengaluru Central and Ramanagar. Totally 146 different ornamental fishes were screened for seven viral pathogens which were showing different clinical signs like haemorrhages, sunken yes, body discoloration, scale erosion and swelling gills. Out of 146 ornamental fish, ISKNV was detected in 20 samples (13.6%) and CEV was detected in 4 samples (2.37%) by PCR targeting specific genes but there was no co-infection of the both virus in a single fish. None of the samples were found to be positive for DNA viruses’ viz., KHV, EHNV and RNA viruses viz., SVCV, VHS and VNN. NCBI-BLAST analysis of sequenced CEV strains were more similar (97.4-99.94%) to the India and Germany CEV strains whereas ISKNV strains were more similar (98.76%- 100%) to ISKNV strains from Japan and Australia. Phylogenetic tree revealed that our CEV strains belong to lineage 1 of koi carp whereas our ISKNV strains belong to genotype I of Megalocytivirus. This is the first report of ISKNV and second report of CEV from India.