Now showing items 1-4 of 4

    • Book chapter

      Bacterial diseases 

      EV Alapide-Tendencia & LD de la Peña - In GD Lio-Po, CR Lavilla & ER Cruz-Lacierda (Eds.), Health Management in Aquaculture, 2001 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Fish and crustaceans that are not weakened by poor environmental conditions, or by other causes, such as parasitic infestation, nutritional deficiency, handling stress, or chemical intoxication, are more resistant to bacterial infections. This is due to the presence of a large amount of bactericidal substances in the blood, which helps overcome infections. So, the best precaution against the occurrence of bacterial infections is to provide the fish with optimum environmental conditions, adequate amounts of the right kinds of food and avoidance of stress, including overcrowding. Vaccination/ immunization and genetic manipulation (i.e., the development of specific pathogen resistant fry) are also some ways of preventing bacterial diseases. The use of antibiotics should always be an option of the last resort.
    • Article

      Dietary onion and ginger enhance growth, hemato-immunological responses, and disease resistance in brown-marbled grouper, Epinephelus fuscoguttatus. 

      MJS Apines-Amar, EC Amar, JP Faisan Jr., RV Pakingking Jr. & S Satoh - Aquaculture, Aquarium, Conservation and Legislation, 2012 - Bioflux
      A 12-week (September to December 2009) feeding trial was conducted to evaluate theimmunostimulatory effects of different substances administered orally through the diet in the brown-marbled grouper, Epinephelus fuscoguttatus. Five experimental diets containing either onion, ginger, β–glucan, or vitamin C and a control diet (without immunostimulants) were fed to the fish weighing about 44 g for 12 weeks. Onion-fed fish showed significantly increased weight gain, hematocrit, and total Ig compared to the control group; however, leukocyte differential count and ROS production were unaffected. Ginger-fed fish likewise significantly increased total Ig, ROS production and lysozyme activity. However, it did not affect growth and hematocrit value. β-glucan significantly increased growth and total Ig but had no effect on the other parameters. Vitamin C significantly increased hematocrit, total Ig and ROS production but did not increase growth. Upon challenge with a bacterial pathogen Vibrio harveyi, mortality was significantly reduced in the onion, ginger and vitamin C-fed fish but not in the β–glucan-fed fish. This study demonstrated that onion and ginger could positively affect the innate immune responses and protect grouper against Vibrio harveyi infection.
    • Article

      Immunization regimen in Asian sea bass (Lates calcarifer) broodfish: A practical strategy to control vertical transmission of nervous necrosis virus during seed production 

      R Pakingking Jr., EG de Jesus-Ayson, O Reyes & NB Bautista - Vaccine, 2018 - Elsevier
      Outbreaks 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.
    • Article

      Induction of immunity and resistance to white spot syndrome virus (WSSV) in shrimp Penaeus monodon (Fabricius) by synthetic oligodeoxynucleotide and bacterial DNA 

      EC Amar & JP Faisan Jr. - Philippine Agricultural Scientist, 2012 - University of the Philippines Los Baños
      Shrimps like all invertebrates are believed to lack true adaptive immunity but recent evidence indicate that they can be protected against pathogenic organisms by priming their immune system with immunostimulatory substances. Here, we describe results of investigation aimed to strengthen shrimp immunity as a preventive strategy against white spot syndrome virus (WSSV) infection. Oligodeoxynucleotides (ODNs) with and without Cytosine-Guanine (CpG) motifs, and Vibrio harveyi genomic DNA (VHD) were administered by intramuscular injection and shrimp responses were assessed by ex vivo assays and experimental infection trials. Results showed that CpG ODN significantly increased ex-vivo immunity indices such as total hemocyte count (THC), plasma agglutination titer (PAT) and hemocyte lysate agglutination titer (HLAT). VHD significantly increased immune indices such as THC, plasma total protein (PTP) and HLAT. Reverse (GpC) motifs increased THC only. At a lower viral challenge dose, both CpG and GpC motifs, and VHD, were able to reduce shrimp mortality significantly but only CpG and VHD did so at a higher challenge dose. Strengthening shrimp immunity by the use of immunostimulatory nucleotides and bacterial genomic DNA could be a feasible preventive approach in the management of WSSV infections in shrimp.