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Nur-Nazifah M.,University Putra Malaysia | Sabri M.Y.,University Putra Malaysia | Siti-Zahrah A.,National Fish Health Research Center sH
Fish and Shellfish Immunology | Year: 2014

This study was carried out to determine the antibody responses and protective capacity of an inactivated recombinant vaccine expressing the cell wall surface anchor family protein of Streptococcus agalactiae following oral vaccination against streptococcosis in tilapia. Tilapia were vaccinated orally with 106CFU/mL of the recombinant vaccine incorporated in feed (feed-based recombinant vaccine) (vaccinated group or Group 1), 106CFU/mL of pET-32 Ek/LIC vector without cell wall surface anchor family protein (control group or Group 2), 106CFU/mL of formalin-killed cells of S.agalactiae vaccine incorporated in feed was also prepared (feed-based vaccine) (vaccinated group or Group 3), and unvaccinated control group or Group 4 (fed with commercial pellets). During the course of study, serum, mucus and gut lavage fluid were collected to evaluate the antibody levels via enzyme-linked immunosorbent assay (ELISA). The results showed that tilapia immunized with the feed-based recombinant vaccine developed a strong and significantly (P<0.05) higher IgM antibody response in serum, mucus and gut lavage fluid samples compared to groups 2, 3 and 4. Following heat intervenes and intraperitoneal challenge, the rate of survivors (RPS) was 70% for the vaccinated group, and 0% for the rest of the groups. Therefore, the study revealed that the feed-based recombinant vaccine significantly provides high protection against high dose challenge in heat stress environment and enhances the production of the mucosal and humoral immunity. © 2014 Elsevier Ltd.

Azila A.,National Fish Health Research Center sH | Way K.,CEFAS - Center for Environment, Fisheries and Aquaculture Science | Wood G.,CEFAS - Center for Environment, Fisheries and Aquaculture Science | Ainol Y.M.Y.,Biosecurity Division | And 4 more authors.
Pertanika Journal of Tropical Agricultural Science | Year: 2012

Koi herpesvirus (KHV), which is also known as Cyprinid herpesvirus 3 (CyHV-3) infection, is an OIE (international des epizootis) listed disease that caused high losses in common and koi carp in Indonesia and Japan in 2002 and 2003. Since the mid of 2006, the polymerase chain reaction (PCR) has been used in Malaysia for surveillance of koi fingerlings to detect virus nucleic acid, but it has been found to produce unreliable results. Following this, an alternative enzyme-link immunosorbent assay (ELISA) technique for the detection of antibody against KHV was used to find evidence of KHV infection in koi carp stocks on farms that had been sampled for the PCR. For this purpose, a total of 245 serum samples from koi carp stocks were collected and tested for the antibody to KHV by the ELISA at the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) laboratory, Weymouth, UK. Two hundred and eight samples were found to be negative but 37 others were either definitely positive or close to borderline positive and all were retested. The final results showed that 222 (90%) samples were confirmed as negative and 19 (8%) others were definitely positive. Meanwhile, four samples (1.6%) were positive at dilutions of 1:400 or 1:200, but cross reactions with CyHV-1 (causing herpesviral epidermal hyperplasia) could have occurred at those dilutions. Three of the samples were the only positive fish at two sites, but the fourth sample came from a site at which there were 4 definite positive samples (from 20 fish sampled). Thus this study confirmed that Malaysian koi stocks have previously been exposed to KHV. With the lack of bio-security measures and awareness, there was a high probability that the koi carp had been exposed to KHV, leading to subclinical infections and some fish might possibly have become carriers of the virus. Hence, further surveillance needs to be conducted to determine the true situation of the KHV infection in Malaysia. © Universiti Putra Malaysia Press.

Ransangan J.,Universiti Malaysia Sabah | Manin B.O.,Universiti Malaysia Sabah | Abdullah A.,National Fish Health Research Center sH | Roli Z.,National Fish Health Research Center sH | Sharudin E.F.,National Fish Health Research Center sH
Aquaculture | Year: 2011

Golden pompano, Trachinotus blochii is a new marine fish candidate for aquaculture in Malaysia. The fingerlings of the fish are not yet produced locally but imported from neighboring countries and Taiwan. In the present study we report the first molecular detection of betanodavirus from diseased golden pompano fingerlings cultured in a deep-sea cage culture facility in Langkawi, Malaysia. The virus caused the fish fingerlings to exhibit abnormal swimming behavior, dark skin coloration and loss of appetite prior to mass mortality. Histopathological examination revealed acute cell vacuolation in both brain and retina tissues of the affected fingerlings. Results of viral culture, RT-PCR and DNA sequencing further confirmed the role of betanodavirus infection in the outbreak. Although phylogenetic analysis and mean nucleotide sequence of RNA2 genome of the betanodavirus showed high similarity to RGNNV betanodavirus isolated from Taiwan, origin of infection is difficult to establish since the RGNNV is also commonly reported in the Southeast Asian region and has the widest range of host marine fish species. Nevertheless, the finding of the present study requires a review of procedures in importing fish fingerlings for sustainable growth of the marine aquaculture industry in Malaysia. © 2011 Elsevier B.V.

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