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dc.contributor.authorPakingking, Rolando V., Jr.
dc.contributor.authorde Jesus-Ayson, Evelyn Grace
dc.contributor.authorReyes, Ofelia
dc.contributor.authorBautista, Norwell Brian
dc.identifier.citationPakingking Jr., R., de Jesus-Ayson, E. G., Reyes, O., & Bautista, N. B. (2018). Immunization regimen in Asian sea bass (Lates calcarifer) broodfish: A practical strategy to control vertical transmission of nervous necrosis virus during seed production. Vaccine, 36(33), 5002-5009.en
dc.description.abstractOutbreaks of viral nervous necrosis (VNN) in Asian sea bass (Lates calcarifer) at the larval stages via vertical transmission of nervous necrosis virus (NNV) from asymptomatic broodfish remain as a major deterrent during seed production. A five-year study was conducted to produce NNV-specific-free sea bass broodfish reared in land-based tanks through an annual immunization regimen with the formalin-inactivated NNV. We primarily immunized (intraperitoneal injection) sea bass juveniles (5 g) and monitored the neutralizing antibody (Nab) titers in the sera of these fish at scheduled intervals post-immunization. Nab titers in the sera of immunized fish peaked at Month 2 (titer: 1:4480 ± 1185) but thereafter gradually declined and significantly dropped (1:260 ± 83) at Month 12 post-primary immunization. Booster immunization of these fish at Month 12 post-immunization led to abrupt increases in Nab titers in booster immunized (B-Im) fish at Month 1 (1:12800 ± 6704) but thereafter declined and dropped at Month 12 (1:480 ± 165) post-booster immunization. The annual booster injections with the inactivated vaccine or L-15 (Unimmunized [U-Im]) were consecutively conducted for 4 years until the fish became sexually mature. Mature fish from both groups were successively induced to spawn twice (1-month interval) via intramuscular injection with luteinizing hormone-releasing hormone analogue (LHRH-a; 100 µg/kg BW). NNV was not detected by RT-PCR in oocytes and milts, and spawned eggs of B-Im fish. In contrast, oocytes and milts, and spawned eggs of U-Im fish were NNV positive. Spawned eggs of B-Im broodfish exhibited Nab titers ranging from 1:192 ± 34 to 1:240 while such was not detected (<1:40) in eggs of U-Im fish. Taken together, current data clearly demonstrate that annual immunization regimen with inactivated NNV vaccine is a pragmatic approach for sustaining immunocompetent sea bass broodfish reared in land-based tanks and circumvent the risk of vertical transmission of NNV from asymptomatic broodfish to their offspring under stress of repetitive spawning.en
dc.description.sponsorshipThis study was funded by Government of Japan Trust Fund V through the Regional Fish Disease Project (study code: FH02-F2010-T) and in part by SEAFDEC/AQD. We express our heartfelt gratitude to Dr. Takuro Shibuno and Dr. Chihaya Nakayasu, former and current GOJ-TF managers, respectively, and the Marine Fish Hatchery staff especially Mr. A. Gamuza.en
dc.subjectsea bassen
dc.subjectLates calcariferen
dc.subjectinactivated vaccinesen
dc.subjectViral nervous necrosisen
dc.titleImmunization regimen in Asian sea bass (Lates calcarifer) broodfish: A practical strategy to control vertical transmission of nervous necrosis virus during seed productionen
dc.subject.asfadisease transmissionen
dc.subject.asfaseed productionen
dc.subject.asfaculture tanksen
dc.subject.scientificNameLates calcariferen

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  • Journal Articles [1221]
    These papers were contributed by Department staff to various national and international journals.

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