Now showing items 1-14 of 14

    • Conference paper

      An artificial diet for larval rabbitfish Siganus guttatus Bloch. 

      MM Parazo - In SS De Silva (Ed.), Fish Nutrition Research in Asia. Proceedings of the Fourth Asian Fish Nutrition Workshop, 3-8 September 1990, Vijayawada, Andhra Pradesh, India, 1991 - Asian Fisheries Society. AFS Spec. Publ. 5
      A 21-day feeding trial was conducted to determine growth, survival and metamorphosis of larval rabbitfish (Siganus guttatus ) fed artificial diets containing approximately 40, 45, 50 and 55% crude protein. Artemia nauplii served as the control feed. Larvae performed equally well on all artificial diets with specific growth rate, % metamorphosis and % survival of 7.80-8.35, 95.2-97.9% and 59.9-70.3%, respectively. In contrast, Artemia -fed larvae exhibited poor growth (5.03) and low survival (51%) possibly due to inadequate feeding level or poor nutritional quality of Artemia . Hence, a diet with 40% protein and estimated energy content of 3,971 kcal kg super(-1) may be used with satisfactory results during hatchery production of rabbitfish.
    • Article

      Biological evaluation of three phytoplankton species (Chlorella sp., Tetraselmis sp., Isochrysis galbana) and two zooplankton species (Crassostrea iredalei, Brachionus plicatilis) as food for the first-feeding Siganus guttatus larvae 

      MN Duray - The Philippine Scientist, 1986 - University of San Carlos
      First-feeding Siganus guttatus larvae were given different species of phytoplankton (Chlorella, Tetraselmis, Isochrysis) and zooplankton (oyster trochophores, Brachionus) or a combination of both on the first day when they can feed. None of the phytoplankton species when used as the only food source for the larvae could support life beyond four days from hatching. Brachionus of sizes less than 90 microns was the most suitable food for the first-feeding larvae. A food mixture of the three phytoplankton species and Brachionus resulted in survival rates that were significantly higher than with other treatments. Larval growth, however, did not differ significantly (p>0.05).

      Different Brachionus densities were also used during the first-feeding days. Although the range of 10 to 15 Brachionus per ml gave better survival, no significant difference existed. Growth was slightly greater but not significantly different at higher densities.
    • Book

      Biology and culture of siganids 

      MN Duray - 1998 - Aquaculture Department, Southeast Asian Fisheries Development Center
      A 53-page monograph updating AQD's 1990 publication of the same title. The book includes siganid morphology, distribution and ecology; reproduction; fisheries; diseases and parasites; genetics. It also covers larval culture; fry and fingerling production; nutrition and feeds; and problem areas in aquaculture.
    • Article

      Differential expression of insulin-like growth factor I and II mRNAs during embryogenesis and early larval development in rabbitfish, Siganus guttatus 

      FG Ayson, EGT de Jesus, S Moriyama, S Hyodo, B Funkenstein, A Gertler & H Kawauchi - General and Comparative Endocrinology, 2002 - Academic Press
      In rodents, the expression of insulin-like growth factor II (IGF-II) is higher than that of insulin-like growth factor I (IGF-I) during fetal life while the reverse is true after birth. We wanted to examine whether this is also true in fish and whether IGF-I and IGF-II are differentially regulated during different stages of embryogenesis and early larval development in rabbitfish. We first cloned the cDNAs of rabbitfish IGF-I and IGF-II from the liver. Rabbitfish IGF-I has an open reading frame of 558 bp that codes for a signal peptide of 44 amino acids (aa), a mature protein of 68 aa, and a single form of E domain of 74 aa. Rabbitfish IGF-II, on the other hand, has an open reading frame of 645 bp that codes for a signal peptide of 47 aa, a mature protein of 70 aa, and an E domain of 98 aa. On the amino acid level, rabbitfish IGF-I shares 68% similarity with IGF-II. We then examined the relative expression of the two IGFs in unfertilized eggs, during different stages of embryogenesis, and in early larval stages of rabbitfish by a semiquantitative reverse transcription-polymerase chain reaction. Primers that amplify the mature peptide region of both IGFs were used and PCR for both peptides was done simultaneously, with identical PCR conditions for both. The identity of the PCR products was confirmed by direct sequencing. Contrary to published reports for seabream and rainbow trout, IGF-I mRNA was not detected in rabbitfish unfertilized eggs; it was first expressed in larvae soon after hatching. IGF-II mRNA, however, was expressed in unfertilized eggs, albeit weakly, and was already strongly expressed during the cleavage stage. mRNAs for both peptides were strongly expressed in the larvae, although IGF-II mRNA expression was higher than IGF-I expression.
    • Book chapter

      Effects of arachidonic acid supplementation on larval and survival and reproductive performance in rabbitfish, Siganus guttatus 

      DR Chavez, HY Ogata, ES Garibay, HT Sollesta, KR Tibubos, H Furuita & A Suloma - In K Nakamura (Ed.), Sustainable Production Systems of Aquatic Animals in Brackish Mangrove Areas, 2007 - Japan International Research Center for Agricultural Sciences
      Series: JIRCAS Working Report No. 56
      Fry of tropical marine fish needed for aquaculture still comes mostly from the wild. Thus, fry availability is a major constraint in the development and extension of aquaculture, especially in rural areas of developing regions. Although the mission of hatcheries is to provide a stable fry production and supply for farmers, fry production remains variable due to poor fecundity and low survival. For the last four years (2002-2005), SEAFDEC/AQD and JIRCAS have conducted the collaborative project that was aimed at developing advanced diets for improving egg production/quality (2002-2005) and larvae/fry quality (2004-2005) through dietary manipulation. Larval rearing tests: In 2005, larval rearing tests (4 trials with rotifers) were conducted to investigate the effects of enriched-live food (4treatments: low (CS) and high (DHAPS) HUFA with or without arachidonic acid supplementation) on survival and growth in rabbitfish Sigunus guttatus fry. Fry fed the rotifers enriched with a combination of DHAPS+5% ArA showed the best survival (44.4±4.5% for D17 fry in the 4th trial).Growth was not different among the treatments (CS, CS+5% ArA, DHAPS, DHPS+5% ArA). Broodstock tests: From March, 2005 to January,2006, a feeding test has been conducted to investigate the effects of dietary ArA supplementation (0% for diet 1, 0.3% for diet 2 and 0.6% for diet 3) on egg production and quality of wild-caught and hatchery-bled rabbitfish broodstock. The broodstock spawned 13 times for diet1 (six pairs), 14 times for diet 2 (five pairs) and 17 times for diet 3 (six pairs) during the period of May 2005 to January, 2006. The total numbers ofhatched-larvae were 3,818 x 103 for diet 1, 4,391 x 103 for diet 2 and 4,597 x 103 for diet 3. The % of normal larvae did not differ among the dietary treatments. Considering together with the results of mangrove red snapper (2003) and rabbitfish (2004), the optimum level of ArA incorporation appears to be between 0.5% and 0.7%. Judging from the results of fatty acid analysis, DHA and arachidonic acid should be supplemented to diets at the same time as to make DHA/arachidonic acid ratio appropriate. Thus, the present study clearly shows that dietary arachidonic acid supplementation is very promising for the development of fry production technologies in tropical areas.
    • Article

      Effects of salinity on egg development and hatching of Siganus guttatus 

      MN Duray, VM Duray & JME Almendras - The Philippine Scientist, 1986 - University of San Carlos
      Experiments were conducted to determine the tolerance of Siganus guttatus eggs to salinity changes. In the first run, the female was induced to spawn spontaneously by using human chorionic gonadotropin. The fertilized eggs were transferred to seawater of salinities ranging from 8 to 40‰ either at the blastomere or at the gastrula stage. In the second run, the eggs were stripped from the female and artificially fertilized following the dry method.

      Results indicated that eggs transferred at gastrula stage were more tolerant to salinity changes than those transferred at the blastomere stage. Hatching occurred at all salinities but was highest at 24‰. Percentage of viable larvae was highest at 24‰ and lowest at 8‰. The larvae that hatched at low salinities were relatively longer than those that hatched at ambient and higher salinities.
    • Article

      Evaluation of practical diets in the culture of the rabbitfish, Siganus guttatus (Bloch) (Pisces: Siganidae) using liver ultrastructural methods 

      EM Avila - Zoologischer Anzeiger, 1986 - Elsevier
      The starvation-induced ultrastructural modifications in the hepatocytes were reversed when Siganus guttatus resumed feeding on a suitable feed. The liver cells regained their structural integrity soonest when the fish was refed Chaetomorpha, whereas the other diets tested promoted inferior results or even caused deleterious effects. Prolonged feeding on sucrose provided insight on the nutritional orientation of this herbivorous fish.

      A 14-day starvation period resulted in the mobilization of fuel reserves indicated by a decrease and total loss of glycogen and lipids, respectively. Organelle morphology was slightly affected by the short-term fast, but was severely disturbed as the fish were deprived of food over prolonged periods . Severe starvation was demonstrated through the deformation of the nuclei and the swelling of the mitochondria. These findings provide support on the practicability of liver ultrastructural methods as supplementary tool in diagnosing the nutritional state of fish.
    • Article

      Growth and survival of milkfish (Chanos chanos), seabass (Lates calcarifer) and rabbitfish (Siganus guttatus) larvae reared at the same density in different sized tanks 

      CB Estudillo, MN Duray & ET Marasigan - The Israeli Journal of Aquaculture-Bamidgeh, 1998 - Society of Israeli Aquaculture and Marine Biotechnology
      Growth and survival of the larvae of milkfish (Chanos chanos), seabass (Lates calcarifer) and rabbitfish (Siganus guttatus) in 40, 200 and 500 liter rearing tanks were evaluated at day 14. Milkfish larvae survived better (46%) in 500 l than in 200 l (7%) tanks. All larvae died on day 6 in the 40 l tanks. Growth was better in the 200 l tanks than in the 500 l tanks. The survival rate of the seabass larvae was significantly different in the 40 l (47%), 200 l (61%) and 500 l (75%) tanks, but growth was highest in the 40 l tanks. Rabbitfish larvae had the highest survival in 500 l tanks (7%) but the same growth in all tank sizes.

      The optimum tank size may vary for different fish species. However, small containers are more convenient to use because they require less manpower, are easily manipulated and more cost- effective.
    • Article

      Hormone-induced spawning and embryonic development of the rabbitfish, Siganus vermiculatus (Pisces: Siganidae) 

      EM Avila - The Philippine Scientist, 1984 - San Carlos Publications, University of San Carlos
      Induced spawning experiments were conducted on captive Siganus vermiculatus with the use of human chorionic gonadotropin (HCG APL Ayerst). The hormone was administered intramuscularly and the intraovarioan oocyte development and milt conditions of the fish were monitored by in vivo methods. Likewise, the spawning behavior and early life history of the species were observed and documented.

      Spontaneous spawnings and natural fertilization of the eggs occurred following ovulation in the fish injected with 500 IU HCG between 17 and 18 hrs after the last of a series of injections delivered at 24-hour intervals. Accelerated oocyte maturation was indicated by progressive changes in the gross morphological characters of the eggs and further thinning of milt. Dominant and aggressive behavior of the female characterized the spawning activities which commenced in the mornings.

      Newly-fertilized demersal eggs measured 0.52 ± 0.01 mm in diameter and each had a narrow perivitelline space, the yolk containing several centrally-located oil globules. Embyonic development was basically similar to that exhibited in most bony fishes. Atretic eggs retained in the body cavity averaged 0.57 ± 0.01 mm in diameter. Yolksac larvae, 1.75 ± 0.14 mm in standard length, hatched 23 to 24 hrs after fertilization in 25-25 ppt sea water at ambient temperature (25.9-28.1°C).
    • Article

      Isolation, cDNA cloning, and growth promoting activity of rabbitfish (Siganus guttatus) growth hormone 

      FG Ayson, EGT de Jesus, Y Amemiya, S Moriyama, T Hirano & H Kawauchi - General and Comparative Endocrinology, 2000 - Elsevier
      We report the isolation, cDNA cloning, and growth promoting activity of rabbitfish (Siganus guttatus; Teleostei; Perciformes; Siganidae) growth hormone (GH). Rabbitfish GH was extracted from pituitary glands under alkaline conditions, fractionated by gel filtration chromatography on Sephadex G-100, and purified by high-performance liquid chromatography. The fractions containing GH were identified by immunoblotting with bonito GH antiserum. Under nonreducing conditions, the molecular weight of rabbitfish GH is about 19 kDa as estimated by SDS–PAGE. The purified hormone was potent in promoting growth in rabbitfish fry. Weekly intraperitoneal injections of the hormone significantly accelerated growth. This was evident 3 weeks after the start of the treatment, and its effect was still significant 2 weeks after the treatment was terminated. Rabbitfish GH cDNA was cloned to determine its nucleotide sequence. Excluding the poly (A) tail, rabbitfish GH cDNA is 860 base pairs (bp) long. It contained untranslated regions of 94 and 175 bp in the 5′ and 3′ ends, respectively. It has an open reading frame of 588 bp coding for a signal peptide of 18 amino acids and a mature protein of 178 amino acid residues. Rabbitfish GH has 4 cysteine residues. On the amino acid level, rabbitfish GH shows high identity (71–74%) with GHs of other perciforms, such as tuna, sea bass, yellow tail, bonito, and tilapia, and less (47–49%) identity with salmonid and carp GHs.
    • Conference paper

      Morphological development of the swimming and feeding apparatus in larval rabbitfish, Siganus guttatus. 

      The development of body parts for swimming and feeding in Siganus guttatus larvae was studied in samples reared in the laboratory at temperatures of 27.3-30 degree C. From the observations, the larval stage of S. guttatus may be divided into three phases: (1) inactive swimming and feeding by swallowing (to about 4-5 mm TL); (2) the transitional phase (to about 7-8 mm TL); and active swimming and feeding (8 mm TL and beyond). A change in feeding habits may be expected in S. guttatus larvae at sizes 7-8 mm TL as shown by this study.
    • Article

      mRNA expression patterns for GH, PRL, SL, IGF-I and IGF-II during altered feeding status in rabbitfish, Siganus guttatus. 

      FG Ayson, EGT de Jesus-Ayson & A Takemura - General and Comparative Endocrinology, 2007 - Elsevier
      Feeding time is a major synchronizer of many physiological rhythms in many organisms. Alteration in the nutritional status, specifically fasting, also affects the secretion rhythms of growth hormone (GH) and insulin-like growth factor-I (IGF-I). In this study, we investigated whether the expression patterns for the mRNAs of GH, prolactin (PRL) and somatolactin (SL) in the pituitary gland, and insulin-like growth factor I and II (IGF-I and IGF-II) in the liver of juvenile rabbitfish (Siganus guttatus) follow a rhythm according to feeding time and whether these hormone rhythms changes with starvation. Hormone mRNA levels were determined by real time PCR. The daily expression pattern for the mRNAs of GH, PRL and SL was not altered whether food was given in the morning (10:00 h) or in the afternoon (15:00 h). The daily GH mRNA expression pattern, however, was affected when food was not available for 3 days. In contrast, the daily expression pattern for IGF-I mRNA reaches its peak at roughly 5–6 h after feeding. This pattern, however, was not observed with IGF-II mRNA. During 15-day starvation, GH mRNA levels in starved fish were significantly higher than the control fish starting on the 9th day of starvation until day 15. The levels returned to normal after re-feeding. In contrast to GH, PRL mRNA levels in starved fish were significantly lower than the control group starting on the 6th day of starvation until 3 days after re-feeding. SL mRNA levels were not significantly different between the control and starved group at anytime during the experiment. Both IGF-I and IGF-II mRNA levels in starved group were significantly higher than the control fish on the 3rd and 6th day of starvation. mRNA levels of both IGF-I and II in the starved fish decreased starting on the 9th day of starvation. While IGF-I mRNA levels in the starved group continued to decrease as starvation progressed, IGF-II mRNA levels were not significantly different from the control during the rest of the starvation period. The results indicate that aside from GH and IGF-I, PRL and IGF-II are likewise involved in starvation in rabbitfish.
    • Book chapter

      The rabbitfishes 

      MN Duray & JV Juario - In CE Nash & AJ Novotny (Eds.), Production of aquatic animals: fishes, 1995 - Elsevier
    • Conference paper

      Studies on breeding and seed production of the new species of fish with high commercial value 

      CL Marte - In Studies on Sustainable Production Systems of Aquatic Animals in Brackish Mangrove Areas [Ibaraki, Japan], 2001 - Japan International Research Center for Agricultural Sciences
      Aquaculture contributes significantly to food production and provides the means to generate increased revenue for countries in Southeast Asia. As the catch from the capture fisheries stagnate and population growth rate in the region continue to be among the highest in the world, the requirement for cheap sources of protein is expected to come from increased production of low trophic level species such as milkfish (Chanos chanos) and tilapia (Oreochromis spp.). There is also an increasing demand for high value fish species such as groupers and snappers particularly for the live food fish markets of affluent and developing countries in Asia. In order to meet the demand for more food fish and to develop new products for the export market, the most important component of any culture system must be met - that of adequate supply of fry and juveniles for culture

      Fry availability has been a major constraint in the development of culture systems for new species and in further increasing production of established culture species. The SEAFDEC Aquaculture Department is addressing the problem of fry availability through its research on breeding and seed production of several marine species. To date, commercially viable technologies for breeding and. seed production of milkfish, sea bass (Lates calcarifer) and rabbitfish (Siganus guttatus) have been developed and continue to be refined. Captive breeding and experimental hatchery production of grouper (Epinephelus coiodes) and the mangrove snapper (Lutjanus argentimaculatus) have also been achieved.

      Another major focus of SEAFDEC AQD’s research is the development of breeding and seed production technologies of endangered marine species such as the sea horse (Hipocampus spp.) and other marine ornamental fish. The Philippines and other Southeast Asian countries are the major suppliers of marine ornamental fish for the aquarium trade and for medicinal use. These fish species are caught from coral reefs and seagrass beds using destructive fishing techniques such as cyanide fishing that has resulted in the destruction of vast areas of the marine coastal environment. Captive breeding of these endangered species will pave the way for future restocking and conservation programs to ensure their survival.

      This paper provides an overview of research accomplishments in marine fish breeding and seed production, current activities, and future directions for research at SEAFDEC AQD.