Now showing items 1-9 of 9

    • Article

      Abdominal segment deformity syndrome (asds) and fused body segment deformity (fbsd) in cultured Penaeus indicus 

      The abdominal segment deformity disease (ASDD) is a new shrimp disease reported only in cultured Penaeus vannamei in Thailand. Shrimp with ASDD have deformed abdominal segment, jagged gut line and bumpy surfaces. Similar signs were observed in cultured P. indicus in the Philippines. However, aside from the signs described for ASDD, some P. indicus showing abdominal segment deformity syndrome (ASDS) had more severe deformities up to the extent that the number of body segments was reduced due to fusion. Shrimp with fused body segment deformity (FBSD) had four instead of five pairs of legs. To account the prevalence of the deformities in P. indicus, shrimp were classified into grossly normal shrimp (NS), shrimp with abdominal segment deformity syndrome (ASDS) and shrimp with fused segments (FBSD). Out of the shrimp sampled, 83.4 ± 5.4% was NS, 10.9 ± 6.2% was ASDS and 5.7 ± 3.0% was FBSD. Morphometric characteristics of the shrimp were measured. There was no significant difference in body weight (BW) among male and female NS, ASDS and FBSD. In both sexes, total length (TL) of FBSD was significantly shorter compared to NS and ASDS. Shrimp samples were also screened to be negative for known infectious viral diseases including white spot syndrome virus (WSSV), infectious hypodermal and haematopoietic necrosis virus (IHHNV), infectious myonecrosis virus (IMNV), P. vannamei nodavirus (PvNV), Macrobrachium rosenbergii nodavirus (MrNV) and Taura syndrome virus (TSV). Occurrence of ASDS and FBSD in post-larvae (PL) produced from captive and wild spawners were also determined. Based on a tank experiment, no significant difference was detected between the percentages of ASDS in PL produced from wild or captive spawners but FBSD was only noted in PL produced from the latter. Deformities generally did not affect the size of P. indicus except for the reduced length of shrimp with FBSD which when coupled with missing pleopods could lead to major economic loss for shrimp farmers if not addressed properly.
    • Article

      Efficacy of an inactivated vaccine and nutritional additives against white spot syndrome virus (WSSV) in shrimp (Penaeus monodon) 

      EC Amar & JP Faisan Jr. - The Israeli Journal of Aquaculture-Bamidgeh, 2011 - SIAMB
      Although the immune system of shrimps is not comparable to that of vertebrates, shrimps can acquire protection against pathogenic challenge by building up immunity. In this study, formalin-inactivated virus (FIV) was administered by injection, bath-immersion, or orally to determine levels of vaccination-mediated protection against the pathogenic white spot syndrome virus (WSSV). Diets supplemented with alfalfa, methyl sulfonyl methane (MSM), or wheat grass were provided with or without FIV. Shrimp injected with FIV and challenged 3, 15, or 30 days after vaccination had cumulative and relative survivals of 83%, 67%, and 33%, respectively. Survival of shrimp challenged by bath-immersion 3-45 days after vaccination by immersion was significantly higher than in the unvaccinated control. Orally vaccinated shrimp challenged by bath-immersion were partially protected up to 45 days after vaccination (cumulative survival 63.7%, relative 61.7%) but not til 60 days after vaccination (cumulative 8%, relative 3.2%). Survival of unvaccinated shrimp challenged by bath-immersion improved when shrimp were fed a diet supplemented with wheat grass or MSM, but not alfalfa. Survival was further enhanced when FIV was provided together with diets supplemented with wheat grass (cumulative 72.7%, relative 94.8%) or MSM (cumulative 73.3%, relative 96.3%).
    • Article

      Evidence of WSSV transmission from the rotifer (Brachionus plicatilis) to the black tiger shrimp (Penaeus monodon) postlarvae and means to control rotifer resting eggs using industrial disinfectants 

      V Corre Jr., J Faisan Jr., RJ Carton-Kawagoshi, BJ Elle, RF Traifalgar & CM Caipang - Aquaculture, Aquarium, Conservation and Legislation, 2012 - Bioflux
      Rotifers are considered possible vectors of the white spot syndrome virus (WSSV) and have been implicated in its recurrence in pond-cultured shrimp. However, direct evidence of the transmission and the pathogenicity of this virus from rotifers to shrimp has been lacking. In the present study, the pathogenicity of WSSV transmitted from infected rotifers (Brachionus plicatilis) to post larval black tiger shrimp (Penaeus monodon) was investigated. Results show that WSSV transmitted from infected rotifers to post-larval P. monodon caused an 82% cumulative mortality as compared to a 9% mortality in the non-infected control group. We also investigated the possibility of industrial disinfectants (sodium hypochlorite, granulated calcium hypochlorite and formalin) as possible means to inhibit the viability of rotifer resting eggs, considered a biological reservoir of WSSV in earthen ponds. Among the disinfectants that were tested, granulated calcium hypochlorite at 5 mg/L was the most effective. The present study provides direct evidence of the high pathogenicity of WSSV transmitted from rotifers to post larval P. monodon and shows the potential use of granulated calcium hypochlorite in pond disinfection. This treatment could be a promising strategy to inhibit the spread and recurrence of WSSV outbreaks in P. monodon culture.
    • Article

      Growth, plasma cortisol, liver and kidney histology, and resistance to vibriosis in brown-marbled grouper, Epinephelus fuscoguttatus fed onion and ginger 

      MJS Apines-Amar, EC Amar & JP Faisan Jr. - Aquaculture, Aquarium, Conservation and Legislation, 2013 - Bioflux
      The health-promoting effects of dietary onion and ginger were studied in brown marbled grouper, Epinephelus fuscoguttatus. An eight-week feeding trial was conducted to evaluate the effects of dietary onion and ginger on growth, cortisol levels, histology and disease resistance in the fish. Five experimental diets were formulated to contain either onion (2%), ginger (2%), β-glucan (1%) or vitamin C (3%) and a control diet (without immunostimulants). Each diet was fed to triplicate groups of fish with an average weight of 10.85±0.69 g. Fish supplemented with either of the immunostimulants exhibited a significantly higher growth compared to the control group. Specific growth rate (SGR) and feed conversion efficiency (FCE) were significantly higher in the onion and ginger-supplemented fish than the control. Cortisol level was higher in the control compared to the immunostimulant-fed groups with onion and ginger-fed fish showing significantly lower cortisol levels. When experimentally infected with Vibrio harveyi, fish fed onion or ginger exhibited significantly reduced mortality when compared with the control and β-glucan, but not when compared with the vitamin C-fed group. Liver sections sampled 4 days postinfection showed no remarkable pathology except for the slight reduction in glycogen granules in the supplement-fed fish. The liver of non-supplemented infected fish showed necrosis, fatty globule deposition, vacuolation, and presence of short rod-shaped bacteria. Kidney sections in the supplemented groups, likewise, did not show significant pathology similar to the uninfected control, whereas those of infected control fish showed necrosis of the tubules and glomeruli resulting in severely altered morphology of the tissues and presence of bacteria in the necrotic areas. As a result of circumventing tissue damage, wound healing was faster in fish supplemented with ginger, onion, and vitamin C compared to the β-glucan and the control groups. This study showed the benefits of onion and ginger in promoting growth and alleviating stress and severity of vibriosis in grouper.
    • 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.
    • Article

      Mortality of pond-cultured Litopenaeus vannamei associated with acute hepatopancreatic necrosis disease (AHPND) and white spot syndrome virus (WSSV) infection in the Philippines 

      LD de la Peña, NAR Cabillon, EC Amar, DD Catedral, RC Usero, JP Faisan Jr., JI Arboleda, WD Monotilla, AT Calpe, DD Fernandez & CP Saloma - Fish Pathology, 2017 - Japanese Society of Fish Pathology
      Mortalities of up to 60% were observed in pond-cultured Litopenaeus vannamei in Bohol, Philippines. Histopathological examination revealed typical acute hepatopancreatic necrosis disease (AHPND) pathology. PCR test generated 1,269 bp and 230 bp amplicons confirmative for the toxin-producing AHPND strain of Vibrio parahaemolyticus among shrimp sampled from eight ponds. The same samples were subjected to PCR analyses for the presence of other viruses, namely WSSV, IHHNV, IMNV, and TSV. The samples were negative for the viruses except WSSV, which was detected after one-step PCR in six out of eight ponds. These results suggested that shrimp were infected dually with AHPND V. parahaemolyticus and WSSV.
    • Conference paper

      Strategies to reduce disease incidence in mud crab culture 

      EC Amar, MD Somera, SB Madero, EA Tendencia & JP Faisan Jr. - In ET Quinitio, FD Parado-Estepa & RM Coloso (Eds.), Philippines : In the forefront of the mud crab industry development : proceedings of the 1st National Mud Crab Congress, 16-18 November 2015, Iloilo City, Philippines, 2017 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Mud crab hatchery suffers from low survival due to susceptibility to bacterial infection in the early larval stages among many causes. Despite food safety issues, antibiotics continue to be used in the absence of effective alternatives. In this study, screening of plant extracts was conducted to determine their suitability as antimicrobial agents against pathogens causing low survival in the hatchery. In addition, potential probionts were isolated from the gastrointestinal tract of mud crab, and water and sediments of mud crab grow-out ponds.

      Crude ethanolic extracts from various terrestrial and mangrove trees were tested for in vitro antimicrobial activity and toxicity to mud crab zoea and megalopa. In addition, the in vivo antimicrobial efficacies of the selected extracts were tested by oral administration followed by experimental challenge with Vibrio harveryi. On the other hand, the putative probionts, were tested for pathogenicity against mud crab zoea and megalopa and quorum sensing inhibition activity against V. harveyi. Finally the extracts and probionts were tested for their efficacy in simulated hatchery and grow-out trials.

      Results showed that extracts of Terminalia cattapa and the potential probiont Bacillus subtilis G100R11 showed antimicrobial and probiotic activity in in vitro and in vivo tests. In simulated hatchery trials, T. cattapa administration successfully produced crab instar with a survival of 1.3-1.8% in trials 1 and 2 comparable to antibiotic control. B. subtilis produced crab instar with survival of 0.8-1.0% in trials 1 and 2, better than the commercial probiotic with 0-0.13% survival. Using T. cattapa and B. subtilis, survival was above 30% until zoea 5 but suddenly dropped below 5% during metamorphosis to megalopa where high incidence of incomplete molting was observed. If difficulty affecting the molting process is addressed, high survival from zoea to megalopa and crab instar will be achievable.
    • Article

      Surveillance of emerging fish viral pathogens in some Southeast Asian countries 

      G Lio-Po, E Amar, L de la Peña, ZG Orozco, J Faisan, V Suarnaba & DB Tubo - The Israeli Journal of Aquaculture-Bamidgeh, 2009 - Society of Israeli Aquaculture and Marine Biotechnology
      Preventing the transboundary movement of fish viral pathogens in a global environment requires active surveillance. This study examined the presence of three emerging viral pathogens among koi, common, grass, and silver carp in Cambodia, Lao PDR, Myanmar, Philippines, and Vietnam. The studied viruses included koi herpesvirus (KHV), spring viremia of carp virus (SVCV), and grass carp reovirus (GCRV). Detection methods consisted of virus isolation by cell culture, infection assay in naive fish, polymerase chain reaction (PCR), and reverse-transcriptase PCR (RT-PCR). Tissues were collected and pooled from 193 fish samples in Dec. 2004 to Feb. 2005, 406 in Sep. 2005 to Feb. 2006, and 1302 in Oct. 2006 to Feb. 2007. For cell culture, tissue filtrates were prepared from pooled spleens, kidneys, livers, and gills and inoculated onto koi fin (KF-1), grass carp kidney (GCK), and fat head minnow (FHM) cells. For infection assay, tissue filtrates were injected intraperitoneally to healthy, naive common carp. No virus was detected after three cell culture passages and the infection bioassays. One-step and nested-step PCR was used to detect KHV in gills of fish samples. One-step and semi-nested RT-PCR was used to detect SVCV and GCRV in the spleens, kidneys, and livers of fish samples. Samples from all three years from all five countries yielded negative results for all three viruses, indicating that KHV, SVCV, and GCRV were not present in these five countries during the period of the study although KHV outbreaks had been detected in Indonesia, Taiwan, Japan, Thailand, China, and Malaysia.
    • Article

      Temporal changes in innate immunity parameters, epinecidin gene expression, and mortality in orange-spotted grouper, Epinephelus coioides experimentally infected with a fish pathogen, Vibrio harveyi JML1 

      EC Amar, JP Faisan Jr., MJS Apines-Amar & RV Pakingking Jr. - Fish and Shellfish Immunology, 2017 - Elsevier
      Changes in innate immunity parameters and epinecidin mRNA transcript levels were examined to characterize the non-specific immune response of E. coioides to pathogenic V. harveyi JML1 isolated from affected cage-cultured fish. After fish had been injected with bacteria at a dose causing 30% mortality, blood and tissue samples were collected at 0, 6, 12, 24, 48, 72, 96, 120, and 240 h post-infection (hpi) for assessment of indices such as the oxidative burst (OB) and phagocytic index (PI) of head kidney cells, and lysozyme activity (LYS) and total immunoglobulin (Total Ig) levels of the plasma. The epinecidin mRNA transcript levels (EGE) from skin, gills, liver, kidney, and spleen tissues were also determined by gelbased RT-PCR. Lastly, daily mortality (DM), liver total bacterial load (TBC), and presumptive Vibrio count (TVC) were monitored up to 240 hpi. The results revealed that bacteria proliferated rapidly in fish tissue, reaching peak densities at 24 hpi for both TBC and TVC but was on a downward trend thereafter. The pattern in fish mortality closely correlated with TBC and TVC. Total Ig, OB, and PI in E. coioides were suppressed in the early part of infection when V. harveyi load was high but recovered and later increased as bacterial density declined. LYS and EGE were consistently high and their activities were not hampered by bacterial infection. The study demonstrated that V. harveyi JML1 interacts with E. coioides by transiently inhibiting some immune parameters resulting in mortalities. However, consistently high LYS, upregulated EGE, and resurgent PI, OB and Total Ig conferred resistance and subsequent recovery in the fish. The study provides new insights on the interaction between E. coioides and V. harveyi JML1 that can aid in formulating health management strategies for groupers. Further studies on prophylactic interventions to enhance the innate immune response in grouper during infection with V. harveyi JML1 are suggested.