R. Vignesh

Deep insight into white spot syndrome virus vaccines: A review

Abstract White spot syndrome virus (WSSV), the causative virus of the disease, is found in most shrimp farming areas of the world, where it causes large economic losses to the shrimp farming industry. The potentially fatal virus has been found to be a threat not only to all shrimp species, but also to other marine and freshwater crustaceans, such as crab and crayfish. To date, no effective prophylactic treatment measures are available for viral infections in shrimp and other crustaceans. Due to current aquaculture practices and the broad host range of WSSV, intervention strategies including vaccination against this virus would be pivotal to save and protect shrimp farming. Several achievements have been attained in the search of novel vaccines for WSSV. DNA vaccination, recombinant vaccines, oral vaccination techniques and gene therapy are some of the thrust areas of focus for scientists and researchers. This review article highlights the recent trends in the development of WSSV vaccines either as DNA vaccines or recombinant vaccines and their functioning strategies as suggested by the researchers worldwide.

Real time PCR quantification of WSSV infection in specific pathogen free (SPF) Litopenaeus vannamei (Boone, 1931) exposed to antiviral nucleotide

Abstract Objective To investigate the level of WSSV transmission from the infected tiger prawn Penaeus monodon ( P. monodon ) to specific pathogen free Litopenaeus vannamei ( L. vannamei ) in laboratory captivity condition in relation to PCR detection, histopathological observation and viral genome sequence. Methods Viral DNA was isolated from purified virions by treatment with proteinase K (0.2 mg/mL) and Sarkosyl (1%). The purity and concentration of the DNA were determined by agarose gel electrophoresis. Moribund and dead shrimp were removed and processed for indirect immunofluorescence (IIF) analysis. Histological observation of infected L. vannamei shrimps were revealed by the degenerated cells which were characterized by intranuclear inclusions in the tissues of WSSV infected mid-gut gland, lymphoid organ, gill lamellae and gut epithelium. Total DNA was extracted, from shrimp hemolymph and tissues, with a High Puree PCR template preparation kit. WSSV-DNA was detected using a commercial 2-step PCR detection kit. Results The present study compares the real-time PCR results with SYBR Green I concentration ranging from 0.2 to 0.7×. The positive standard was used in the range of 10 2 , 10 4 10 6 , 10 8 and 10 10 copies/ng of DNA in general. The PCR analysis showed the appearance of a prominent band from the PCR amplified product of WSSV-DNA at internal control band of 848 bp. Moderate and severe levels were observed as 650 bp and 910 bp (200 & 2 000 copies) in various transmission routes. The WSSV content in moribund shrimp of all the experimental species ( L. vannamei ) approximately ranged in nucleotide application by quantification method from 0.000 001 WSSV copies/μg of total DNA. In whole moribund infection animal, approximately 0.02 WSSV copies/μg of DNA was detected in nucleotide applied animal. Conclusion These results indicate that wild brood stock and native culture shrimp P. monodon may be infected with WSSV and can get transferred into the SPF L. vannamei farming environment. Based on the studies, we made in captivity condition in different WSSV transmission route in dissimilar infection range with the use of nucleotide for antiviral drugs. There is an urgent need to address and develop antiviral drugs and molecular based viral genome technique for control measures to salt away the aquaculture environments.

Report on the distribution of essential and non essential fatty acids in common edible fishes of Porto-Novo coastal waters, southeast coast of India

Abstract Objective The objective of the study was to evaluate the essential and non essential fatty acids and the distribution of Omega-3 and Omega-6 fatty acids in twenty commonly consumed edible fishes of parangipettai coastal waters. Methods For fatty acid analysis, each fish specimens were beheaded, eviscerated and filleted manually. The tissue samples were oven dried at 67°C for 24hrs. After that the samples ware grounded finely with pestle and mortar. The saponified samples were cooled at room temperature for 25 min, they were acidified and methylated by adding 2 ml 54% 6 N Hcl in 46% aqueous methanol and incubated at 80°C for 10 min in water bath. Following the base wash step, the FAMEs were cleaned in anhydrous sodium sulphate and then transferred in to GC sample vial for analysis. FAMEs were separated by gas chromatograph. Results The results of the present study revealed that the most abundant individual FAs were Palmitic acid, Oleic acid, Arachidonic acid (AA), Docosahexaenoic acid (DHA) in most the tissues. The total Arachidonic acid (C20:4ω−6) was found to be higher proportion (0.17−4.86%), when compared with other Omega-6 fatty acids. The values found for Linoleic acid (C18:2 ω−6) ranging from 0–7.23%. Siganus javus has 7.23% of Linoleic acid. Conclusion Fatty acids are the principle components in lipids. The nutritional importance of fish consumption is in great extent associated with the content of omega-3 fatty acids. Sea food is an important dietary food for human beings. It constitute higher amount of protein, lipids, vitamins and essential and nonessential metals and low concentration of carbohydrates.

Effect of Probiotics against Marine Pathogenic Bacteria on Artemia franciscana

Presently an effort has been made to determine the effectiveness of probiotics against marine pathogenic bacterial load ingested by Artemia franciscana nauplii. In this experiment Artemia franciscana nauplii was allowed to ingest pathogenic bacterial strains, viz. Escherichia coli, Salmonella typhi, Salmonella paratyphi, Vibrio cholerae and Shigella sp. Probiotic organism (Bioremid) was used against the pathogenic strains on Artemia franciscana nauplii. On completion of the experiment it was observed that the use of Probiotic organism (Bioremid) reduced the pathogenic bacterial load, especially that of Shigella sp. on Artemia franciscana.

Occurrence of white spot syndrome virus in shrimp culturing waters and its brunt in specific pathogen free Litopenaeus vannamei with particular allusion to molecular verdicts

Abstract Objective To detect the water samples and shrimp samples in white spot syndrome virus (WSSV) affecting and non-affecting zone. Methods A total of 12 samples specific pathogen free Litopenaeus vannamei (L. vannamei); adult shrimp and larvae were randomly collected. Their genomic DNA was isolated and subjected to PCR. Histopathological identifications were carried out, and the hematopoietic tissues with basophilic intranuclear inclusion bodies characteristic were observed in moderate WSSV infected L. vannamei Results The PCR analysis showed the appearance of a prominent band from the PCR amplified product of WSSV-DNA at internal control band 848 bp at non-infected areas. Although low infection positive bands (20 copies) were shown at 296 bp continued from initial stage of the infection region. On a moderate and ascetic level were observed as 650 bp and 910 bp (200 and 2 000 copies), during the severe out break periods. The gill epithelial cells were edematous and nuclei were hypertrophied with basophilic inclusions, but no pathological changes or hypertrophied nuclei were observed in any of L.vannamei tissues in WSSV uninfected region. The Intranuclear inclusion bodies characteristics of high level of WSSV infection presented in the gill region. Conclusions The present study is significant, which investigated the level of WSSV transmission from the infected tiger prawn P.monodon to SPFL. vannamei in the WSSV impact region of Tamil Nadu coastal waters.