Now showing items 1-20 of 3275

    • Article

      Fish performance, nutrient digestibilities, and hepatic and intestinal morphologies in grouper Epinephelus fuscoguttatus fed fermented copra meal 

      REP Mamauag, JA Ragaza & T Nacionales - Aquaculture Reports, 2019 - Elsevier
      Protein enhanced copra meal (PECM®) is an alternative, cheap, and sustainable source of plant protein for the aquafeed industry, albeit its use on carnivorous fish species has been very limited. A 70-day feeding trial using grouper Epinephelus fuscoguttatus (initial mean body weight of 1.86 ± 0.19 g) tested fermented copra meal as feed ingredient. Six isonitrogenous (crude protein of 45%) and iso-lipidic (crude fat of 11%) diets consisted of PECM®: a control diet at 0% soybean meal replacement (C); four diets replacing soybean meal at 25% (FC25), 50% (FC50), 75% (FC75), 100% (FC100) – all with methionine and lysine supplementation; and 100% soybean replacement without methionine and lysine supplementation (FCW100). Growth and feed performance were not significantly (P > 0.05) affected by PECM® replacement of soybean meal up to 100%, even without methionine and lysine supplementation. Chemical body composition was likewise not significantly (P > 0.05) altered. PECM® when used as a grouper feed ingredient has protein, lipid, carbohydrate and dry matter digestibilities of 89.28%, 78.63%, 82.57%, and 48%, respectively. Hepatic and intestinal morphologies displayed no apparent pathological changes. PECM® can be efficiently utilized by grouper and can replace soybean meal up to 100% (16% in diet) for normal fish performance and digestive organ functions.
    • Article

      Reproductive development of the threatened giant grouper Epinephelus lanceolatus 

      The giant grouper is presumed to follow the reproductive pattern of most Epinephelus species, characterized by protogynous hermaphroditism wherein male maturation is attained through sex reversal of a functional female. This hypothesis, however, has not been verified due to lack of biological data. The present study addresses this gap by investigating the reproductive development of giant groupers from juvenile stage through sexual maturity. Gonad histological analysis of hatchery-bred juvenile giant grouper from Queensland, Australia (0.8–5.2 kg, n = 43) have shown earliest occurrence of primary oocytes (i.e. ovarian differentiation) in 47.8 cm and 2.5 kg fish. Monitoring of sexual maturity by gonadal biopsy was performed in a stock of wild-caught giant groupers (2–52 kg) held in sea cages in the Philippines and Vietnam from 2015 to 2017. Onset of female sexual maturity was at 96.9 ± 1.6 cm and 23.5 ± 1.5 kg in the Philippines, and 103.0 ± 4.1 cm and 33.5 ± 2.5 kg in Vietnam. In both locations, development of primary males was observed wherein fish produced milt (or spermiated) without passing through a functional female phase. The ratio of primary males to females in both locations was about 1:2. Size at maturity of primary males is 86.5 ± 4.8 cm and 17.1 ± 2.1 kg in the Philippines, and 97.3 ± 1.3 cm and 34.3 ± 0.9 kg in Vietnam. To aid in the monitoring of female maturation, we developed a non-invasive method based on immunoassay of vitellogenin in skin mucus and this was shown to be effective in detecting female maturation 9 ± 2 months prior to first observation of oocytes through gonadal biopsy. Our findings suggest that giant grouper is a diandric protogynous hermaphrodite. This study provides novel information on the reproductive biology of giant grouper, an economically important and vulnerable species.
    • Article

      Gonadal response of juvenile protogynous grouper (Epinephelus fuscoguttatus) to long term recombinant follicle-stimulating hormone administration 

      P Palma, J Nocillado, J Superio, EGdJ Ayson, F Ayson, I Bar & A Elizur - Biology of Reproduction, 2019 - Oxford University Press
      The role of follicle stimulating hormone (FSH) in the gonadal development of protogynous hermaphroditic grouper (E. fuscoguttatus) was investigated. Recombinant giant grouper (E. lanceolatus) FSH (rggFSH) was produced in yeast. Its receptor binding capacity and steroidogenic potency were confirmed in vitro. Weekly injections of rggFSH to juvenile tiger grouper for 8 weeks (100 μg/kg body weight, BW) resulted in significantly larger and more advanced oocytes (cortical alveolar stage vs. primary growth stage in control). Sustained treatment with rggFSH (20 to 38 weeks at 200 μg/kg BW) resulted in significant reduction in gonad size, degeneration of oocytes and proliferation of spermatogonial cells, indicative of female to male sex change. Gene expression analysis showed that, while initiating female to male sex change, the rggFSH significantly suppressed the steroidogenic genes cyp11b, cyp19a1a and foxl2 which restrained the endogenous production of sex steroid hormones thus prevented the differentiation of spermatogonial cells. Expression profile of sex markers dmrt1, amh, figla and bmp15 suggests that the observed sex change was restricted at the initiation stage. Based on these results, we propose that the process of female to male sex change in the protogynous grouper is initiated by FSH, rather than sex steroids and likely involves steroid-independent pathway. The cortical alveolar stage in oocyte development is the critical point after which FSH-induced sex change is possible in grouper.
    • Book chapter

      Poly-beta-hydroxybutyrate (PHB) and infection reduction in farmed aquatic animals 

      JLQ Laranja & P Bossier - In H Goldfine (Ed.), Health Consequences of Microbial Interactions with Hydrocarbons, Oils, and Lipids, 2019 - Springer International Publishing
      There is a continuous effort in finding effective and sustainable strategies to control diseases in farmed animals, and in recent years, the application of the bacterial storage compound poly-β-hydroxybutyrate (PHB) was identified as a new disease control agent for aquaculture. The idea of using PHB as a biocontrol agent was conceived based on the knowledge that this biopolymer can be degraded into short-chain fatty acids (SCFAs), and SCFAs are known compounds with antimicrobial properties. At the beginning of this chapter, an overview about the PHB granule, its detection, quantification, production, and recovery in microorganisms is presented. The main topic focuses on the application and beneficial effects of PHB in farmed aquatic animals. The mechanisms by which PHB provides beneficial effects to the host are discussed.
    • Newsletter

      AQD Matters 2019 March - April 

      JMV de la Cruz (Ed.) - 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Newsletter

      AQD Matters 2019 January - February 

      RH Ledesma (Ed.) - 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Disaster management practices of academic libraries in Panay island, Philippines: Lessons from typhoon Haiyan 

      DL Superio, SB Alayon & MGH Oliveros - Information Development, 2019 - SAGE Publications
      A disaster management plan is essential because it can guide library personnel on what to do in a critical time. Using an eight-part survey instrument, this paper documents the impact of Typhoon Haiyan on 22 academic libraries in Northern Panay, Western Visayas, Philippines and the disaster management practices that were implemented. The results revealed that although the majority of the libraries do not have a disaster management plan, they all had common disaster management practices that enabled them to save parts of their collections. Moreover, the study revealed that librarians lacked knowledge and skills on disaster management. This paper was presented at the 40th International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC) Annual Conference, Noumea, New Caledonia, September 14–18, 2014.
    • Article

      Improved survival, prey selectivity and diel feeding cycle of silver therapon Leiopotherapon plumbeus (Perciformes: Terapontidae) larvae reared in tanks with substrate 

      FA Aya, VSN Nillasca, MJP Sayco & LMB Garcia - Ichthyological Research, 2019 - Springer Verlag
      Physical substrates in the rearing environment can influence the early survival and feeding patterns of captive-reared fish. In this study, we determined whether substrates affect the survival and growth of hatchery-reared silver therapon Leiopotherapon plumbeus larvae as well as examined their prey selectivity and diel feeding cycle. Newly hatched larvae [1.92 mm total length (TL)] were reared for 40 days in triplicate 4 m3 tanks with or without tropical almond Terminalia catappa leaves as substrate. Prey selectivity of larvae reared in tanks with substrate for 35 days from the yolk-sac stage was measured by the Chesson’s selectivity index (αi). Diel feeding cycle of 3-4 days post-hatch (dph) silver therapon larvae reared in tanks exposed to natural light cycle and fed wild zooplankton was also studied. Larvae reared in tanks with substrate had significantly higher survivorship (48.44 ± 7.85%) than those reared in tanks without substrate (26.73 ± 1.60%). However, total length, specific growth rate and body weight of silver therapon larvae from tanks with or without substrate were not significantly different. Silver therapon larvae are generalist predator, demonstrating a degree of prey selectivity in some prey items during early ontogeny. Prey selectivity of silver therapon larvae varied during larval ontogeny, with higher Chesson’s selectivity index for copepod nauplii among the smaller fish larvae (2–5 dph; 2.94–5.17 mm TL), cladocerans (Moina micrura and Bosmina coregoni) among intermediate (6–11 dph; 5.72–9.60 mm TL), and ostracod, cladoceran and insect larvae among larger fish (12–35 dph; 10.28–20.96 mm TL). Larvae showed a diel feeding cycle where they actively fed during daylight hours, with a peak in the late afternoon, and reached a minimum at dark. Together, these findings advance our understanding of the feeding predatory behavior and efficiency of silver therapon larvae and preference for tanks with substrate that improve their survival.
    • Article

      Artificial substratum consisting of poly-β-hydroxybutyrate-based biodegradable plastic improved the survival and overall performance of postlarval tiger shrimp Penaeus monodon 

      G Ludevese-Pascual, JL Laranja, E Amar, P Bossier & P De Schryver - Aquaculture Research, 2019 - Wiley
      The use of artificial substratum consisting of poly‐β‐hydroxybutyrate (PHB)‐based biodegradable plastic for penaeid shrimp culture was investigated in the present study. The survival of postlarval tiger shrimp Penaeus monodon (30 ± 5 mg) provided with PHB substratum made out of PHB type DP9002 (Metabolix GmbH, Köln, Germany) was 88.7 ± 3.4% and this was significantly higher as compared to postlarvae provided conventional substratum consisting of polyvinylchloride (PVC) pipes (67.3 ± 6.5%). However, no significant weight improvement was observed for the postlarval tiger shrimp indicating that PHB could not be used as growth promoter. Nevertheless, a trend of improved robustness against adverse environmental conditions (lethal ammonium chloride concentration) and increased resistance to pathogenic Vibrio was observed in postlarval tiger shrimp provided with PHB substratum as compared to postlarvae provided with PVC substratum. Results indicate higher preference by postlarvae on PHB substratum over PVC substratum. Overall, this study indicates the potential of artificial substratum consisting of PHB‐based biodegradable plastic as replacement for conventional substratum consisting of PVC pipes in enhancing the survival of postlarval tiger shrimp and improving its performance against adverse environmental conditions and disease resistance.
    • Book

      Nursery culture of tropical anguillid eels in the Philippines 

      ML Cuvin-Aralar, FA Aya, MR Romana-Eguia & DJ Logronio - 2019 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 65
      This technical publication focused on nursery production of anguillid eels from glass eels to elver using data gathered from eel farm surveys and rearing trials conducted by SEAFDEC/AQD as part of the JAIF (Japan-ASEAN Integration Fund) project on Enhancing Sustainable Utilization and Management Scheme for Tropical Anguillid Eel Resources in Southeast Asia.
    • Article

      Female-specific SNP markers provide insights into a WZ/ZZ sex determination system for mud crabs Scylla paramamosain, S. tranquebarica and S. serrata with a rapid method for genetic sex identification 

      Mud crabs, Scylla spp., are commercially important large-size marine crustaceans in the Indo-West Pacific region. As females have the higher growth rate and economic value, the production of all female stocks is extremely essential in aquaculture. However, the sex determination mechanism is still unclear. Development of sex-specific genetic markers based on next-generation sequencing proved to be an effective tool for discovering sex determination system in various animals.
    • 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.
    • AQD Matters 2018 September - October 

      RH Ledesma (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Newsletter

      AQD Matters 2018 January - February 

      RH Ledesma (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Newsletter

      AQD Matters 2018 March - April 

      JMV de la Cruz (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Newsletter

      AQD Matters 2018 May - June 

      RH Ledesma (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Newsletter

      AQD Matters 45th Anniversary Special Issue 

      RDB Dianala (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Newsletter

      AQD Matters 2018 July - August 

      JMV de la Cruz (Ed.) - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Book

      Biology and hatchery of mangrove crabs Scylla spp. 

      ET Quinitio, FD Parado-Estepa & JJ dela Cruz-Huervana - 2018 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 34
      This manual includes the biology of crab (Scylla serrata, S. tranquebarica, and S. olivacea), and describes principles and procedures for spawning the mature crabs and rearing the zoea to ‘fly’ size crabs. It focuses on the hatchery rearing of S. serrata as the farming of this species is more economically viable than the two other species. The techniques may be modified depending on the conditions or problems encountered in a specific site.