Southeast Asian Fisheries Development Center
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Development of a giant grouper Luteinizing Hormone (LH) Enzyme-Linked Immunosorbent Assay (ELISA) and its use towards understanding sexual development in grouper
No full textA recombinant giant grouper Luteinizing Hormone (LH) consisting of tethered beta and alpha subunits was produced in a yeast expression system. The giant grouper LH β-subunit was also produced and administered to rabbits for antibody development. The recombinant LH and its antibody were used to develop an Enzyme Linked Immunosorbent Assay (ELISA). This ELISA enabled detection of plasma LH levels in groupers at a sensitivity between 391 pg/ml and 200 ng/ml. Different species of grouper were assayed with this ELISA in conjunction with gonadal histology and body condition data to identify links between circulating LH levels and sexual development. We found that circulating levels of LH decreased when oocytes began to degenerate, and sex-transition gonadal characteristics were apparent when LH levels decreased further. When circulating LH levels were related to body condition (body weight/ body length), transitioning-stage fish had relatively high body condition but low plasma LH levels. This observation was similar across multiple grouper species and indicates that plasma LH levels combined with body condition may be a marker for early male identification in the protogynous hermaphrodite groupers.This project was funded by the Australian Centre for International Agricultural Research (ACIAR) under project FIS 2012 101: Developing technologies for giant grouper (Epinephelus lanceolatus) aquaculture in Vietnam, the Philippines and Australia (SEAFDEC/AQD study code: 6149-T-RD-ACIAR4). LD was a recipient of the University of the Sunshine Coast, Australia, APA Ph.D. scholarship, PP was an ACIAR John Allwright Fellow. Samples were graciously provided by Dr. Kiyoshi Soyano’s lab in Nagasaki, Dr. Evelyn Grace de Jesus-Ayson of SEAFDEC/ AQD, Tigbauan, Philippines, Dr. Stewart Fielder, Port Stephens Fisheries Centre: NSWDPI, Dr. Richard Knuckey from The Company One, Cairns, Australia, and Mr. Josh McNally from Ecomarine, Noosa, Australia
Aeromonas load and species composition in tilapia (Oreochromis niloticus) cultured in earthen ponds in the Philippines
No full textAeromonas load and species composition in the rearing water, sediment, gills and intestines of healthy tilapia Oreochromis niloticus collected every 2 weeks from Days 30 to 120 after stocking in six earthen ponds in the Philippines were determined. Presumptive Aeromonas counts (PACs) in the water and sediment ranged from 101–103 c.f.u./ml and 101–103 c.f.u./g while in the gills and intestines, PACs ranged from 104–107 c.f.u./g and 102–105 c.f.u./g, respectively. Presumptive Aeromonas counts in the water, sediment, and gills of tilapia varied among days of culture while in the intestines of tilapia, PACs markedly dropped by approximately 2 logs at Day 75 and either remained in the same level or decreased by another 1 log at Day 120 of grow‐out culture. Aeromonas hydrophila predominantly constituted 94% of all presumptive Aeromonas spp. examined (n = 343), followed by A. sobria (4%) and A. salmonicida (2%). Taken together, current data provide some putative threshold levels of tilapia reared in earthen ponds to Aeromonas spp. The dominance of A. hydrophila together with negligible population of A. salmonicida and A. sobria indicate that Aeromonas are common commensal bacteria in tilapia and their environment which under conditions of stress could instigate disease epizootics.This study was funded by the Department of Science and Technology-National Research Council of the Philippines (DOST-NRCP; NRCP project no. E-225) and partly by SEAFDEC AQD (study code: FH02-F2013-T). We would like to thank Dr. Evelyn Grace de Jesus-Ayson for the critical review of the manuscript, and Mr. Eric Ledesma and the laboratory staff of NPPMCI for the invaluable assistance during our sampling
Biosecurity policy and legislation for the global seaweed aquaculture industry
No full textEach year a significant proportion of global food production is lost to pests and diseases, with concerted efforts by government and industry focussed on application of effective biosecurity policies which attempt to minimise their emergence and spread. In aquaculture the volume of seaweeds produced is second only to farmed fish and red algal carrageenophytes currently represent approximately 42% of global production of all seaweeds. Despite this importance, expansion of the seaweed sector is increasingly limited by the high prevalence of recalcitrant diseases and epiphytic pests with potential to emerge and with the demonstrated propensity to spread, particularly in the absence of effective national and international biosecurity policies. Developing biosecurity policy and legislation to manage biosecurity risk in seaweed aquaculture is urgently required to limit these impacts. To understand current international biosecurity frameworks and their efficacy, existing legislative frameworks were analysed quantitatively for the content of biosecurity measures, applicability to the seaweed industry, and inclusion of risks posed by diseases, pests and non-native species. Deficiencies in existing frameworks included the following: inconsistent terminology for inclusion of cultivated seaweeds, unclear designation of implementation responsibility, insufficient evidence-based information and limited alignment of biosecurity hazards and risks. Given the global importance of the cultivation of various seaweeds in alleviating poverty in low and middle income countries, it is crucial that the relatively low-unit value of the industry (i.e. as compared with other aquatic animal sectors) should not conflate with a perceived low risk of disease or pest transfer, nor the subsequent economic and environmental impact that disease transfer may impact on receiving nations (well beyond their seaweed operations). Developing a clear basis for development of robust international biosecurity policies related to the trade in seaweeds arising from the global aquaculture industry, by first addressing the gaps highlighted in this study, will be crucial in limiting impacts of pests and diseases on this valuable industry and on natural capital in locations where seaweeds are farmed
Production of microalgal paste in the Philippines
No full textTechnical advances have made possible the production of microalgal concentrate in paste form. Chaetoceros calcitrans was concentrated and made into an algal paste through centrifugation, chemical flocculation, and electrolytic flocculation. The paste can be stored up to three months when refrigerated, and is diluted with seawater for feeding to the tiger prawn, Penaeus monodon. This can also be done with other cultured diatoms, and they can be fed to other penaeid shrimp and other organisms such as the Sydney rock oyster and the Pacific oyster. The use of algal paste can simplify hatchery operations and reduce costs among hatcheries with no microalgal culture facilities
Dietary lipid requirement of whiteleg shrimp Litopenaeus vannamei juveniles cultured in biofloc system
No full textAn eight-week feeding trial was conducted to evaluate the contribution of biofloc on dietary lipid requirement in whiteleg shrimp Litopenaeus vannamei. Five diets with graded levels of dietary lipid (45, 60, 90, 120 and 150 g/kg) were fed to juvenile shrimp. Final weight, weight gain and specific growth rate of shrimp fed diets with 60, 90 and 120 g/kg lipid levels were significantly higher than those of shrimp fed diets with lipid levels 45 and 150 g/kg (p < .05). Feed efficiency and protein efficiency ratio of shrimp fed 60, 90 and 120 g/kg were higher than those fed 150 g/kg diet. Plasma total cholesterol and triglyceride levels were lower in shrimp fed 45 g/kg compared with those fed the 90 g/kg (p < .05). Also, lysozyme activity for 90 g/kg group was higher than the 15 g/kg group. Hepatopancreas lipase and amylase activities of shrimp fed 90 and 120 g/kg diets were significantly higher than those of shrimp fed 45 and 150 g/kg diets. Broken-line regression analysis for weight gain indicated that the dietary lipid requirement of whiteleg shrimp juveniles reared in a biofloc system was estimated to be higher than 56 g/kg but <60 g/kg
A social network analysis of the Philippine seaweed farming industry: Unravelling the web
No full textSeaweed farming is a major economic endeavor among the households in the key seaweed-production areas in the Philippines because of its high profitability potential relative to farming effort. This study used Social Network Analysis (SNA) to explore the social structure and the nature of support mechanism at the production segment of the seaweed value chain to understand the differential access of women and men to information, resources, and services. The data was obtained from Focus Group Discussions (FGD) with 115 seaweed farmers in Zamboanga City, Bohol, and Tawi-Tawi. The resulting social support maps show a strong reliance on internal support sources (e.g. family) across the selected parameters (training, farm preparations, product flow) and a gender difference on the extent of access to external sources. This study highlighted the relevance of using SNA in value chain analysis (VCA) to understand the relationship patterns among the actors and their implications on policy making and overall governance of the seaweed industry.This study forms part of a larger study under the GlobalSeaweed* - Safeguarding the future of seaweed aquaculture in developing countries program which is being funded by the UK Research and Innovation – Global Challenges Research Fund, United Kingdom (Grant Ref: BB/P027806/1)
Regional technical guidelines on early warning system for aquatic animal health emergencies
No full textThis set of guidelines is developed to help national regulators and stakeholders in responding to and managing suspected outbreaks of emergency aquatic animal diseases; thus improve national emergency preparedness in order to maximize the efficiency of response to serious outbreaks of aquatic animal diseases.
This document aims to provide guidance to Competent Authorities (CAs) in the decision-making and in issuing regulations that can minimize the impacts of serious aquatic disease occurrence and/or outbreaks through containment or eradication or mitigation whether at the regional, national, or farm level. It is envisaged that a harmonized guideline for aquatic EPRS among AMS is developed.
The purpose of this set of guidelines is to enumerate the actions to be undertaken by the AMS in case of the occurrence of known, unknown, existing, emerging or re-emerging disease(s).
The set of guidelines is based on the analysis of the FAO Emergency Preparedness and Response Systems audit for aquatic animal diseases completed by the AMS.This Regional Technical Guidelines for Early Warning System on Aquatic Animal Health Emergencies was developed to enumerate the actions to be undertaken by the AMS in case of the occurrence of known, unknown, existing, emerging or re-emerging disease(s). The guidelines identified the key players in aquatic emergency preparedness and response system including their roles and responsibilities. Actions to be undertaken during any disease emergencies were also described
AQD Matters 2020 July - August
No full textIn this issue: 1) Inside the quarantine facility for shrimp with a PCR testing laboratory to keep out pathogens; 2) SEAFDEC/AQD innovative technologies take spotlight in webinar for micro, small, and medium enterprises; 3) AQD Chief meets with lawmaker to discuss new house bills on legislated hatcheries; 4) AQD conducts in-house COVID-19 awareness webinar