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  • Article

    Fire + water + bombs: Disaster management among academic libraries in Marawi City, Lanao del Sur, Philippines 

    DL Superio, EM Abaday, MGH Oliveros, AS Delgado, VEV Palcullo & JF Geromiano - International Journal of Disaster Risk Reduction, 2019 - Elsevier
    The academic libraries in Marawi City, Lanao del Sur, Philippines are vulnerable to disasters. In the last ten years, the majority of the 13 respondent libraries have sustained at least one disaster that may have been caused by civil unrest, war or terrorism, flood, earthquake, or fire. The majority were unprepared to face such disasters, may it be small-scale or catastrophic, and only one library has a disaster management plan. The lack of significant holdings of rare books, shortage of financial resources, no perceived risk, and the unavailability of staff to write a disaster management plan, are the reasons why most libraries do not have a plan. Moreover, the majority lacked staff that has undergone training in disaster preparedness and management. On the other hand, all of the libraries have disaster management practices that although not enough, will still enable them to lessen the effects of the disaster and save their library and parts of their collection when necessary. The respondents identified management support as an essential factor in their success in disaster management. The results of the study provide valuable information on the current state of the libraries in the Philippines with regards to disaster preparedness and management. Therefore, it is an essential addition to the literature on disaster management in the Philippines, which is very scarce as of the moment.
  • Article

    Evaluation of the bioremediation potential of mud polychaete Marphysa sp. in aquaculture pond sediments 

    MAE Mandario, VR Alava & NC Añasco - Environmental Science and Pollution Research, 2019 - Springer
    Organic enrichment from aquaculture could alter the chemical composition of the fishpond bottom by increasing the levels of organic matter (OM), sulfur (S), iron (Fe), and lower pH of the sediment. Polychaetes can contribute to the nutrient cycling and remediation of polluted sediment. A laboratory experiment was conducted to test the remediation potential of small and large mud polychaete Marphysa sp. introduced to two types of fishpond sediment. Initially, Sediment A had lower OM, S, Fe, and higher pH than Sediment B. After 30 days, in Sediment B, large polychaetes significantly decreased the OM level (27%) while both small and large polychaetes promoted significant decreases of S (71%) and Fe (70–73%) in both sediment types. The increase of sediment pH was promoted by the presence of polychaetes (0.53–0.69) although pH level in small polychaete was not significantly different with the no polychaete treatment. Regardless of polychaete treatment, the pH level of Sediment B (1.04 ± 0.10) was significantly improved than that of Sediment A (0.17 ± 0.02). In both sediments, large polychaetes (95%) had better survival rates than small polychaetes (73%). These findings reveal that large Marphysa sp. can significantly improve sediment quality by decreasing the levels of OM, S, and Fe and improve pH level to a more basic form without compromising its survival. Large polychaetes are recommended to be used as bioremediators of organically enriched aquaculture pond sediment.
  • Article

    Induction of gonadal development in protogynous grouper with orally delivered FSH DNA 

    P Palma, J Nocillado, J Superio, EG de Jesus-Ayson, F Ayson, A Takemura, MW Lu & A Elizur - Marine Biotechnology, 2019 - Springer
    The availability of sexually mature fish often dictates the success of its captive breeding. In this study, we induced reproductive development in juvenile protogynous tiger grouper through oral administration of a plasmid (p) containing an engineered follicle-stimulating hormone (FSH). An expression construct (pcDNA3.1) was designed to express a single-chain FSH consisting of giant grouper FSH β-subunit and glycoprotein subunit-α (CGα), linked by the carboxy-terminal peptide (CTP) sequence from the human chorionic gonadotropin (hCG). Single oral delivery of pFSH encapsulated in liposome and chitosan to tiger grouper yielded a significant increase in plasma FSH protein level after 4 days. Weekly pFSH feeding of juvenile tiger groupers for 8 weeks stimulated ovarian development as indicated by a significant increase in oocyte diameter and progression of oocytes to cortical alveolar stage. As the pFSH treatment progressed from 20 to 38 weeks, female to male sex change was initiated, characterized by oocyte regression, proliferation of spermatogonial cells, and occurrence of spermatogenic cysts. It was also associated with significantly lower mRNA expression of steroidogenic genes (cyp11b, cyp19a1a, and foxl2) and basal plasma levels of sex steroid hormones 17β-estradiol (E2), testosterone (T), and 11-ketotestosterone (11KT). Results suggest that pFSH stimulates ovarian development up to cortical alveolar stage and then initiates sex change in tiger grouper. These findings significantly contribute to our knowledge on the role of FSH in the development of protogynous hermaphroditic fish. This study is the first to demonstrate induction of reproductive development in fish through oral delivery of plasmid gonadotropin.
  • Article

    Solar irradiation as an alternative bleaching process for agar extracted from Gracilariopsis heteroclada in Iloilo, Philippines 

    LF Endoma, LM Nacional & MRJ Luhan - Botanica Marina, 2019 - De Gruyter
    The current industrial practice of using chemical bleach to achieve the pure white colour of agar is deleterious to both human and environmental health. This study evaluates the potential of solar irradiation as an alternative bleaching process for agar extracted from Gracilariopsis heteroclada in Iloilo, Philippines. The physico-chemical properties of agar obtained from alkaline-treated seaweed after exposure to different bleaching conditions (e.g. solar irradiation, hypochlorite solution, and ultraviolet and fluorescent lights) were examined and compared with commercial bacteriological agar. Photobleaching through solar irradiation produced agar with superior gel strength (1038.61 g cm−2), high 3,6-anhydrogalactose content (41.44%) and low total inorganic sulphate content (1.87%) without compromising agar yield (19.37%). Solar irradiation offers very promising results as a simple, low-cost, environmentally friendly alternative to the chlorine bleaching process for agar extraction.
  • 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.
  • 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.
  • Article

    Gonad development and size‐at‐maturity of silver therapon Leiopotherapon plumbeus (Kner 1864; Teleostei:Terapontidae) in tropical volcanic lakes in south Luzon, Philippines 

    PJT Denusta, EG de Jesus-Ayson, MA Laron, FA Aya & LMB Garcia - Journal of Applied Ichthyology, 2019 - Wiley
    Gonad development of the silver therapon Leiopotherapon plumbeus in two volcanic crater lake habitats (Sampaloc Lake, Taal Lake) in south Luzon, Philippines was examined during the annual reproductive cycle. The minimum body size‐at‐maturity of fish in these two lake habitats was also compared. Four gonad development stages were characterized as basis for the classification of ovarian (immature, maturing, mature, spawned) and testicular maturation (immature, maturing, mature) phases. The occurrence of all development stages in individual gonads suggest an asynchronous development whereby advanced stages are recruited continuously from a pool of younger stage germ cells to result in elevated female and male GSI throughout the annual cycle due to active gonadogenesis. Together with the increasing occurrence of advanced stage oocytes and spermatozoa from March until October, the elevated GSI of fish may indicate peak gonadal growth during the onset of the dry season (December–January) for eventual spawning from the beginning (May–June) until the end of the wet season (October–November). In both lake habitats, male fish were smaller than females but, regardless of sex, the minimum size‐at‐maturity of fish in Sampaloc Lake was significantly smaller than fish in Taal Lake. Overall, asynchronous development during oogenesis and spermatogenesis allows for year‐round reproduction of silver therapon, with elevated gonad growth in the dry season in preparation for spawning during the wet season. Compared with fish in Taal Lake, a smaller size‐at‐maturity of fish in Sampaloc Lake may be a response of the wild fishery stock to long‐term high fishing mortality and degradation of the lake habitat.
  • 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.
  • 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

    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

    The information-seeking behavior of aquaculture researchers at the Southeast Asian Fisheries Development Center 

    DL Superio, JB Canaman, JP Jaco & ML Estember - Information Development, 2019 - SAGE Publications
    Understanding the information-seeking behavior of library patrons is essential for the library to provide quality resources and services, and to satisfy its patrons’ information needs. A quantitative research was conducted to describe the information searching and using behaviors of the Filipino aquaculture scientists, researchers and research staff at the Aquaculture Department of the Southeast Asian Fisheries Development Center (SEAFDEC/AQD). The study revealed that although the respondents find it useful to go to the library to get assistance from the librarian, and to browse and read current acquisitions related to their research, they visited the library infrequently. However, remote library services, especially email and phone services, were highly utilized. When searching for information, the Internet, mainly via search engines, was highly preferred rather than visiting the Library and using its online public access catalog (OPAC) or its databases. The combination of print and electronic formats was highly preferred when reading, rather than print only or electronic-only. The majority would print and save the retrieved electronic copy.
  • 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.
  • Article

    The sea cucumber fishery in Palawan, Philippines 

    JBS Jontila, HM Monteclaro, GF Quinitio, SM Santander-de Leon & JP Altamirano - Kuroshio Science, 2018 - 高知大学大学院黒潮圏海洋科学研究科
    This paper presents the nature of sea cucumber fishery in Palawan, Philippines with information on gathering practices, commonly traded species and secondary accounts on wild populations. Current issues on sea cucumber fishery are also presented here along with recommended doable management measures.
  • Article

    Limit of colour vision in dim light in larvae of the giant freshwater prawn Macrobrachium rosenbergii 

    G Kawamura, TU Bagarinao, ASK Yong, AB Faisal & LS Lim - Fisheries Science, 2018 - Springer Verlag
    Colour vision depends on sufficient ambient light and becomes ineffective at a particular low light intensity. It is not known how decapod crustaceans see colour in dim light. In the present study we investigated the colour vision threshold in larvae of the giant freshwater prawn Macrobrachium rosenbergii in a tank under natural illumination. Plastic beads of different colours (blue, red, yellow and white) in various combinations were suspended in the tank. The larvae swam straight toward the beads and gathered around them. The number of larvae was highest on the blue and white beads. The luminance in the tank was then gradually decreased by covering it with different numbers of layers of black cloth, and the response of the larvae to the beads was video-recorded under infrared illumination. The preference for blue and white beads remained manifest as the luminance was reduced from 418 to 0.07 cd/m2, but not at 0.02 cd/m2, indicating a colour vision threshold between 0.07 and 0.02 cd/m2. The larvae have apposition compound eyes with large optical parameters, comparable to those of apposition eyes of nocturnal insects, which presumably capture more light and show enhanced sensitivity, enabling the larvae to see colour in dim light.
  • Article

    Characterisation of Vibrio isolates recovered from the eyes of cage-cultured pompano (Trachinotus blochii) infested with caligid parasites (Lepeophtheirus spinifer) 

    R Pakingking Jr., NB Bautista, D Catedral & EG de Jesus-Ayson - European Association of Fish Pathologists Bulletin, 2018 - European Association of Fish Pathologists
    Exophthalmia was documented among sea cage-cultured pompano (Trachinotus blochii) broodstocks with caligid parasite (Lepeophtheirus spinifer) infestation in the Philippines. Following sequencing, and based on the results of both diagnostic investigations and infection experiments, V. harveyi likely had a role in the reported exophthalmia cases, and this was initiated by L. spinifer infection.
  • Article

    Dietary onion or ginger modulates the stress response and susceptibility to Vibrio harveyi JML1 infection in brown-marbled grouper Epinephelus fuscoguttatus juveniles 

    EC Amar, MJS Apines-Amar & JP Faisan Jr. - Journal of Aquatic Animal Health, 2018 - American Fisheries Society
    Onion Allium cepa and ginger Zingiber officinale have health‐promoting properties that qualify them as functional foods. The effect of repeated acute stressors was examined in juvenile Brown‐marbled Grouper Epinephelus fuscoguttatus that were fed four diets supplemented with onion at 1.8%, ginger at 1.8%, vitamin C at 0.86%, and β‐glucan at 0.8% of the diet. The non‐supplemented diet served as the control. After 12 weeks of feeding, fish were exposed to stressors and were experimentally infected with a fish pathogen, the bacterium Vibrio harveyi JML1. After repeated exposure to hypoxia, cortisol levels rose significantly in the non‐supplemented fish compared to those fed onion, ginger, β‐glucan, or vitamin C. Within groups, postexposure cortisol levels in the onion‐, ginger‐, and vitamin C‐fed fish did not change relative to pre‐stress levels, whereas significant increases in poststress values were observed in the control and β‐glucan groups. The net cortisol increase was also significantly greater in the non‐supplemented group compared to the supplemented groups. The net cortisol increase did not vary among the supplemented groups except that the β‐glucan‐fed group exhibited a higher net increase than the onion‐fed group. Similarly, repeated acute exposure to osmotic stress significantly increased the plasma cortisol level in the non‐supplemented group compared to groups that received supplements; no differences were found in the supplemented groups except the β‐glucan group. Within groups, significant increases in poststress values relative to pre‐stress levels were found only in the control and β‐glucan groups. Repeated acute exposure to hypoxia significantly increased cumulative mortality in the control group compared to the supplemented groups (except the β‐glucan group), whereas repeated exposure to acute osmotic stress significantly increased cumulative mortality only in the control group 10 d after infection with V. harveyi JML1. Based on our collective results, most of the supplemented groups performed better than the control, but the best supplements were onion and ginger in terms of enhancing stress tolerance and increasing survival of Brown‐marbled Grouper upon infection with V. harveyi JML1.
  • Article

    Genetic assessment of milkfish (Chanos chanos Forsskal) stocks based on novel short tandem repeats for marker-aided broodstock management 

    MRR Romana-Eguia, BS Santos, M Ikeda, ZU Basiao & A Kijima - Aquaculture Research, 2018 - John Wiley and Sons
    Milkfish hatchery broodstock are either from on-grown wild-caught or hatchery-produced fry/juveniles. To determine if a marker-assisted management scheme can be formulated for improved milkfish hatchery production, milkfish stocks were genetically characterized using nine novel short tandem repeats or microsatellites. Eight wild-bred Philippine stocks (CLA, CUR, CAM, SIH, SBH-I1, HH, PAL and ZH-P0), four hatchery-bred stocks (SBH-I2, SBH-D, BoH and ZH-F1), two farm stocks of known mixed lineages (SPH and BDH) and one Indonesian hatchery-bred stock (WJH) were assessed. WJH was included since milkfish fingerlings from Indonesia reared in Philippine farms could be developed into future broodstock. Mean allelic richness (Ar) was highest in wild-bred stocks (9.5) and lowest in hatchery-bred spawners (9.1). Mean expected heterozygosities (He) were relatively similar in all stocks with wild-bred stocks slightly higher (0.67) than the others. An analysis of molecular variance indicated significant yet low genetic differentiation among stocks (FST = 0.013; p = .000) where variation (98.6%) was explained by intra-stock differences. In some of the domesticated stocks, reductions in mean allelic richness were observed in first generation hatchery broodstock (e.g. ZH-F1; Ar = 8.3), compared with their founder stock (e.g. ZH-P0; Ar = 9.4). The Indonesian stock was similar to local wild-bred stocks based on genetic variability indices; thus, it might be likely that the local stocks’ fitness traits could be comparable with the imported milkfish stock which has been perceived to be better. The quality of locally available farmed milkfish and prospects of formulating a broodstock management scheme for the production of good quality milkfish seedstock are herewith discussed.

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