Southeast Asian Fisheries Development Center
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Interactive influence of dietary protein and lipid on maturation of Indian white prawn, Penaeus indicus broodstock
No full textThe establishment of protein and lipid requirements for growth of penaeid species is essential in maximizing productivity but information on the effects of these nutrients on gonad maturation is still lacking. Indian white prawn, Penaeus indicus (H. Milne Edwards) broodstock, were fed formulated maturation diets containing varying levels of dietary protein (35, 45 and 55%) and lipid (6, 12 and 18%) combinations following a 3×3 factorial design. Control group was fed with fresh mussel, squid and polychaete. Results indicate that treatment groups receiving diets of 45/18 and 55/12 protein/lipid combinations and the control exhibited higher maturation rates than the other treatments (p = 1.9 × 10−4). Shrimp broodstocks fed diets containing the lowest protein or lipid levels exhibited poor gonad maturation. Hepatopancreas damage and gonadal atresia were apparent in treatments with high dietary lipid based on histological and biochemical analyses. The diet with 55/12 protein/lipid combination is therefore best recommended for P. indicus gonad maturation. This study demonstrated that a well‐formulated diet that satisfies the protein and lipid requirements can support successful gonadal maturation comparable with feeding the broodstocks fresh maturation diets.This study was funded by Department of Science and Technology-Accelerated Science and Technology Human Resource Development Program, Student Research Support Fund and SEAFDEC/AQD (FD-02-C0219T). The help of the staff from the Shrimp Hatchery and Nutrition and Feed Development Section and the assistance of Vince Louie Sumalinog and Elmer Ajerra during the conduct of this study are gratefully acknowledged. We thank the valuable advice of Mr. Vicente Balinas for the statistical analysis and Ms. Erish Estante-Superio (DP-01-C2017T) for providing the test animals
Efficacy of the inactivated nervous necrosis virus vaccine against viral nervous necrosis in pond-reared orange-spotted grouper Epinephelus coioides
Get PDFThe field efficacy of the formalin-inactivated nervous necrosis virus (NNV) against viral nervous necrosis (VNN) in orange-spotted grouper (Epinephelus coioides) reared in floating net cages in earthen pond was investigated. Seroneutralization assay conducted on the sera of vaccinated fish exhibited the occurrence of neutralizing antibody titers from Day 30 (mean titer 1:1792±701) to Day 150 (1:704±351) with the highest titer observed at Day 60 (1:6656±3435) post-vaccination. Because mortality attributed to VNN was not encountered during the pond experiment, intramuscular challenges of vaccinated and unvaccinated (L-15 injected) fish with NNV (106.5 TCID50/fish) were conducted in indoor tanks at Day 30 (Mean body weight [MBW]: vaccinated [21±3.4 g]; unvaccinated [20.6±1 g) and Day 120 (MBW: vaccinated [178±27 g]; unvaccinated [176±19 g) postvaccination, respectively, to demonstrate the in vivo efficacy of the inactivated vaccine. Nil and 25 % mortality rate were obtained in vaccinated and control fish, respectively, challenged with NNV at Day 30 post-vaccination. On the contrary, nil mortality were obtained in both groups challenged with NNV at Day 120 post-vaccination. Although nil mortality was obtained in NNV-challenged unvaccinated fish, 30 % of the fish manifested dark coloration of the skin and abnormal swimming behavior that commenced and disappeared at Day 3 and Day 7 post-NNV challenge, respectively, suggesting an age/ weight-dependent resistance to the disease. Our current data illustrate that single vaccination with inactivated vaccine could mount the production of protective antibodies and concomitant conferment of protection against VNN in groupers especially during the early phase of grow-out culture in earthen ponds where they are highly susceptible to the disease.This study was funded by Government of Japan Trust Fund VI through the Regional Fish Disease Project (study code: FH01- F2015-T) and in part by SEAFDEC/ AQD. We express our heartfelt gratitude to Dr. Takuro Shibuno and Dr. Chihaya Nakayasu, former GOJ-TF managers, Dr. Koh Ichiro Mori, current GOJ-TF manager, and the Marine Fish Hatchery staff especially Mr. A. Gamuza
Acute hepatopancreatic necrosis disease (AHPND)) and hepatopancreatic microsporidiosis (HPM):): Two threats to sustainable shrimp aquaculture
Get PDFInfectious diseases caused by viruses and bacteria are a major threat to sustainable shrimp farming globally. Since early 80’s viral diseases such as White Spot Disease, Taura Syndrome disease have caused enormous losses to shrimp aquaculture both in eastern and western hemisphere. As the shrimp industry tried to recover from the onslaught of these diseases, a bacterial, Acute Hepatopancreatic Necrosis Disease (AHPND), also known as Early Mortality Syndrome, and a fungal disease Hepatopancreatic Microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP) are now posing new threat to shrimp aquaculture.
Acute Hepatopancreatic Necrosis Disease is caused by Vibrio spp. expressing plasmidborne binary toxins, PirA and PirB that is similar to entomopathogenic bacterium, Photorhabdus encoded toxin. In 2009, AHPND emerged in China and since then spread to many countries in East Asia and in the Americas. Another disease that has caused alarm in recent year is Hepatopancreatic Microsporidiosis (HPM) caused by Enterocytozoon penaei (EHP), a microsporidium. While AHPND causes acute infection and large-scale mortalities, EHP causes chronic infection and results growth retardation and size variation in population reducing marketability of the infected shrimp. Both diseases affect hepatopancreas, an organ involved in metabolism and humoral immunity in shrimp. The binary toxin, PirA/ PirB are the primary virulence factor for AHPND, but specific virulence factor(s) for EHP is not known. It is, however, known that EHP does not have mitochondria and appears to transport ATP from the cytoplasm of infected cells as it contains ATP transporter genes in its genome. EHP has been shown to be a risk factor for AHPND. Due to lack of therapeutics, preventative measures remain as a corner stone for managing these diseases and efforts are underway to develop genetically improved lines of shrimp having resistance to AHPND and EHP
Research update on emergent shrimp pathogens in Thailand
Get PDFAbstract only.Recent evidence suggest that the emergent microsporidian, Enterocytozoon hepatopenaei (EHP) is a component cause of white feces syndrome (WFS) in shrimp. The natural WFS shrimp were found to be infected with EHP. At the laboratory level, shrimp induced to be heavily infected with EHP showed no WFS symptom suggesting that the causes of WFS is complex involved with other cause, not only EHP. The other component causes are under investigation. Better understanding of virulence mechanism of EHP infection in shrimp will assist in establishing innovative strategies to reduce its viability and potential infectivity in shrimp farms. Transmission of microsporidia is involved ingestion of spores in the water and the site of initial infection being the gastrointestinal tract. EHP spore is having a thick, protective chitinous wall around the cell membrane that allows them to survive outside their hosts and involve with the microsporidian pathogenesis. Here we describe successful purification of active EHP spores with a novel spore viability assay based on polar-tube extrusion or germination triggered by Phloxin B. The physical conditions such as temperature and PH, and chemical factors such as KMnO4, and chlorine that affect spore germination were examined as a practical guideline for the inactivation of the spores at a farm level. The potential environmental reservoir of EHP were found to be a mussel of the genus Mytilopsis, which is found frequently in the water canal or pipe in the shrimp rearing system. Recent evidence demonstrates that the mussel can be infected by EHP and can transmit EHP to shrimp in the laboratory model
Towards increased production of milkfish fry in the Philippines: SEAFDEC/AQD technology through the lens
No full textAlthough the Philippines has a long coastline and is surrounded by rich waters, its capture fisheries subsector is just second to aquaculture which is the main driver for growth in the fish production industry of the country. In 2019, aquaculture production accounted for 53.20 % of the total Philippine fisheries production and the top two aquaculture commodities that the country produced were seaweeds and milkfish. Even though milkfish is among the top two commodities, this does not mean that there are no problems with its production. One of the major aspects that hinder sustainability is the harrowing concern regarding milkfish seed supply which is highly unpredictable. The local production of milkfish fry could not adequately supply the national demand, leading to the import of fry from nearby countries. To reduce the reliance on imports, the Government of the Philippines through its Department of Agriculture-Bureau of Fisheries and Aquatic Resources (DA-BFAR) came up with the “National Bangus Fry Sufficiency Program” with the goal of building legislated multispecies hatcheries in strategic locations in the country. DA-BFAR then tapped the services of SEAFDEC Aquaculture Department (AQD) to provide training and technical assistance, especially in undertaking the feasibility studies of proposed sites where hatcheries are to be established. So far, eight out of the 16 sites have had their feasibility studies submitted to DA-BFAR and their respective local government units (LGUs). To date, there are three ongoing hatchery projects that are in various stages of construction. Out of the three, two are for marine and one is for freshwater aquaculture commodities. In the SEAFDEC/AQD compound, multispecies hatcheries have also been constructed to supply the Western Visayas region with high quality milkfish fry as well as other commodities. Apart from building hatcheries, SEAFDEC/AQD has also partnered with the regional office of DA-BFAR in Western Visayas to revive abandoned/unproductive hatcheries which would then serve as milkfish satellite hatcheries once rehabilitation is completed
The information-seeking behavior and levels of knowledge, precaution, and fear of college students in Iloilo, Philippines amidst the COVID-19 pandemic
No full textCOVID-19 pandemic is devastating the health, social, and economic well-being of citizens worldwide. The high rates of morbidity and mortality and the absence of vaccines cause fear among the people regardless of age, gender, or social status. People's fear is heightened by misinformation spread across all media types, especially on social media. Filipino college students are one of the top Internet users worldwide and are very active in social media. Hence they are very prone to misinformation. This paper aims to ascertain the levels of knowledge, precaution, and fear of COVID-19 of the college students in Iloilo, Philippines, and determine the effects of their information-seeking behavior on the variables above. This paper is a cross-sectional survey that used a qualitative-quantitative method and snowball sampling technique. Data were gathered among 228 college students using an online survey instrument a few months after the pandemic began. College students were knowledgeable of the basic facts about the highly infectious COVID-19. However, the majority were inclined to believe the myths and misinformation regarding the pandemic. Television was the primary, most believable, and preferred source when seeking information. The Internet as a preferred source of information was significantly associated with a high level of knowledge. In contrast, the information sourced from interpersonal channels were found to make college students very cautious. The local presence of COVID-19 cases had caused college students to fear, likely exacerbated by the plethora of information about the pandemic, mostly from Facebook. This is the first study conducted on the effects of the information-seeking behavior on the levels of knowledge, precaution, and fear of COVID-19 of the college students in Iloilo, Philippines
Numerical study of diurnal tidal currents on the Pacific shelf off the southern coast of Hokkaido, Japan
No full textWe developed a triply nested, high-resolution (1/50°) ocean model to reproduce tides and tidal currents under realistic oceanographic conditions, mainly on the Pacific shelf around Hokkaido, Japan. The model reproduced observed properties of tides and tidal currents reasonably well. Dominant diurnal tidal currents were simulated and accounted for mainly by propagation of coastal-trapped waves (CTWs) of the first mode. The first-mode CTWs were generated mainly around the Four Islands, which are located to the east of Hokkaido, where the massive energy of gravity waves was scattered to CTWs. After leaving the forcing area around the islands, diurnal CTWs propagated along the Hokkaido coast to Cape Erimo. Around the cape, CTWs were also excited via scattering of gravity waves and superposed with first-mode CTWs propagating from the Four Islands. The K1 (O1) currents associated with the CTWs weakened (strengthened) around and west of the cape because of out-of-phase (in-phase) superposition. The K1 currents therefore ended up being smaller than the O1 currents by one order of magnitude. Moreover, the first-mode CTWs generated around the Four Islands were attenuated along the propagation route through complicated processes. The unsteadiness of the K1 and O1 currents related to their 13.67-day beats therefore increased gradually along the propagation route. The unsteadiness on the shelf west of the cape was further enhanced by superposition with CTWs forced around the cape, which were occasionally unstable.This work was supported by a Grant-in-Aid for Scientific Research KAKENHI (17H00775 and 19K06216) and by the Environment Research and Technology Development Fund (4-2102) of the Ministry of the Environment, Japan. This work was also partially supported by the Fisheries Agency (Promotion project to precisely estimate fish stock size around Japan (no grant number)), but the contents of this study do not necessarily reflect the views of the Fisheries Agency
Determination of poly‐beta‐hydroxybutyrate assimilation by postlarval whiteleg shrimp, Litopenaeus vannamei using stable 13C isotope tracing
No full textA preliminary study was conducted to demonstrate fate of the bacterial storage compound poly-β-hydroxybutyrate (PHB) once ingested and degraded in vivo in crustaceans. The 2% supplementation of 13C-labeled Ralstonia eutropha DSM545 containing 75% PHB on dry weight in postlarval whiteleg shrimp, Litopenaeus vannamei resulted in consistent enrichment of two fatty acids (containing 14–24 carbons [C] in length) pentadecanoic acid (15:0) and palmitic acid (16:0) in all lipid fractions. This could indicate that 13C signal may not only originate from the PHB but partly from the structural components of the bacterial cell. There was a trend of lower 13C enrichment in various lipid fractions of the postlarvae as compared to the diet. These findings may have important implications as to potential of PHB as energy source rather than as building block. There was a rapid transfer of 13C in the postlarvae as seen by the significant 13C enrichment in the tissues 4 hr after feeding with labeled bacterial cells. Overall, the assimilation of PHB in crustacean tissues is demonstrated for the first time. Our results indicate that PHB once ingested is rapidly assimilated in the tissues and could probably act as an energy source rather than as a building block
[The Philippines recommends for mangrove crab:] Philippine exporters of mangrove crabs; BFAR, July 2018
No full textAQD Matters 2021 March - April
No full textIn this issue: 1) Council commends SEAFDEC/AQD projects during 53 CM; 2) Chief Baliao, SEAFDEC/AQD experts extend help to BFAR 6; 3) Heated tanks lead to productive milkfish spawning in cold months; 4) New broodstock facility stocked with hundreds of milkfish breeders; 5) Expert presents aquaculture innovations in APFIC webinar; 6) Youth called to engage in aquaculture to secure fish supply