Now showing items 1-5 of 5

    • Book chapter

      Arachidonic acid distribution in seaweed, seagrass, invertebrates and dugong in coral reef areas in the Philippines 

      A Suloma, HY Ogata, H Furuita, ES Garibay & DR Chavez - In K Nakamura (Ed.), Sustainable Production Systems of Aquatic Animals in Brackish Mangrove Areas, 2007 - Japan International Research Center for Agricultural Sciences
      Arachidonic acid (ArA) was not a minor component, and ArA distributes widely in coral reef organisms. Seagrass had high linoleic acid and linolenic acid levels with low Ara, EPA and DHA levels, while some species of seaweed had intermediate or high ArA levels (5% to 12%). In starfish, sea cucumber and some species of corals, ArA was the first major fatty acid (20% to 30%), but DHA levels were very low. Bivalves, abalone and shrimps had intermediate ArA levels. Total lipids of abdominal muscle and liver of dugong had respectively ArA levels of 7.8% and 11.0%, which were higher than EPA levels (2.4% and 1.6%), but DHA levels (0.4% and 2.3%) were low. It is clear that ArA is a major fatty acid in coral reef animals. The present results suggest that the existence of an ArA-rich food chain may be widespread in coral reef areas, and that the widespread existence of ArA-rich food chain may lead to intermediate or high ArA contents in tropical species.
    • Book chapter

      Arachidonic acid is a major fatty acid in gonads of coral reef fishes and improves larval survival of rabbitfish Sigunus gutattus 

      A Suloma, DR Chavez, ES Garibay, H Furuita & HY Ogata - In SL Ortiz (Ed.), Coral reefs : ecosystems, environmental impact, and current threats, 2016 - Nova Science Publishers
      The supply of wild fry of coral reef fishes for aquaculture has resulted in the deterioration of their natural stock status, causing public concern. Through a series of studies on the establishment of artificial-fry production technologies for coral reef fishes, we found that ovary, testis, eggs and fry of coral reef fishes have high or intermediate levels of arachidonic acid (ArA), which is a relatively minor component in temperate and cold-water species. In gonadal polar lipids of selected coral reef, in particular demersal fishes (19 species), ArA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) levels ranged from 6.0% to 19.4%, from 0.9% to 6.2%, and from 7.9% to 27.8%, respectively. It is notable that the major highly unsaturated fatty acids (HUFA) of polar lipids in all coral reef fish gonads are DHA and ArA (not EPA) in a ratio of about 2:1. This result allowed us to speculate that not only DHA but also ArA may be nutritionally much important for egg development and larval growth in coral reef fishes.

      Thus, feeding trials were conducted to investigate the effects of dietary ArA supplementation on reproductive performance of coral reef rabbitfish (Siganus guttatus) broodstock. The number of spawning and the number of hatched larvae tended to be better in broodstock fed diets with ArA than in those fed a diet without ArA. Next, larval rearing tests were conducted to investigate survival and growth in rabbitfish fry fed live rotifers which had been enriched with or without ArA. Fry fed the rotifers enriched with a combination of DHA Protein Selco (Inve Aquaculture, Baasrode, Belgium) + 5% ArA (VEVODAR CRUDE ARACHIDONIC OIL, DSM Food Specialties, Delft, the Netherlands) showed significantly the best survival (44.4 ± 4.5% for Day 17 fry), although growth was not different among treatments. The present study indicates that ArA is not a minor component in coral reef fishes, and that dietary ArA is very promising for the improvement of fry production technologies of the coral reef fishes.
    • 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

      Hatchery-produced milkfish (Chanos chanos) fry should be fed docosahexaenoic acid-enriched live food: A case of the difficulty in the transfer of improved aquaculture technology in the Philippines 

      HY Ogata, DR Chavez, ES Garibay, H Furuita & A Suloma - Japan Agricultural Research Quarterly, 2006 - Ministry of Tropical Agricultural Research Centre
      Levels of highly-unsaturated fatty acids, the most important nutritional factors in fry production of marine fish, were compared between hatchery-produced and wild-caught milkfish Chanos chanos fry. The most striking difference found between the fry was in docosahexaenoic acid (DHA: 22:6n-3) levels: DHA levels in hatchery-produced fry were only 37% and 18% of those in wild-caught fry in the polar lipids and neutral lipids, respectively. However, high DHA levels were detected in ovary and spawned eggs from hatchery-reared broodstock. Investigation on the time course change in DHA levels of hatchery-produced fry revealed that the DHA levels of polar lipids drastically declined from 25% at day 0 posthatching to 5% at day 14 posthatching. Nannochloropsis sp. and rotifers Brachionus sp., which were used as live food from day 2 to day 14, did not contain DHA with relatively high eicosapentaenoic acid (EPA: 20:5n-3) levels. DHA level was restored to 13% in 45-day old fry by feeding of formulated diets with a substantial amount of DHA from day 15. Thus, the lack of DHA in the live food appears to lead to the low DHA level in hatchery-produced fry. On the other hand, the cost of DHA enrichment for one milkfish fry was estimated to be 2.6 Philippines centavos, which is equivalent to about 10% of the market price of milkfish fry. The increase of the production cost might not be accepted in domestic hatcheries under competitive marketing with imported fry. Financial and marketing support by the government will be one of the measures to encourage the stable production of domestic milkfish fry with high quality in the Philippines. It is also necessary to conduct institutional campaigns to inform local fry producers and milkfish farmers of the importance of DHA-enrichment.
    • Book chapter

      Studies on semi-intensive seed production of grouper (Epinephelus coioides) 

      JD Toledo, D Chavez & JC Rodriguez Jr. - In MA Rimmer, S McBride & KC Williams (Eds.), Advances in grouper aquaculture, 2004 - Australian Centre for International Agricultural Research
      Series: ACIAR Monograph 110
      This study was conducted to improve the hatchery survival of Epinephelus coioides by verifying and incorporating laboratory-scale experimental results to a hatchery-scale operation. Nine units of 200 m2 ponds were used to verify mass culture techniques for zooplankton. Three fertilization schemes were tested with 3 replicate ponds per fertilization treatment. To test copepod production in tanks, adults and copepodids were transferred into 6 production tanks at a density of 60 individuals/litre. Zooplankton in 3 of the tanks were fed daily with Nannochloropsis sp., Tetraselmis sp. and Chaetoceros sp., whereas zooplankton in the remaining 3 tanks were fed daily with half the amount of the mixture of algae and bread yeast. Larval rearing runs were performed from 2000-2002 to verify earlier experimental results. To propagate copepod nauplii in larval tanks, Acartia were inoculated in 4 larval rearing tanks, 2-3 days before stocking of grouper eggs or newly hatched larvae. Brachionus were added daily from day 2 to 18 at increasing densities. Artemia nauplii and metanauplii were fed to satiation from day 15 until metamorphosis. Pond-grown zooplankton was added in separate tanks from day 15 onwards as a supplement to Artemia. The population of copepods in ponds fertilized with various combinations of organic and inorganic fertilizers increased a week after flooding of ponds and fertilization. Zooplankton compositions in the treatments were Apocyclops, Oithona sp., Brachionus rotundiformis, Penilia and Pseudodiaptomus sp. Copepodids and adults of Acartia tsuensis fed a mixture of algae alone or in combination with bread yeast seemed to propagate well in tank conditions. Results suggested that bread yeast could be used in combination with algae for nauplii production of Acartia in tanks. Verification runs indicated that pond-grown copepods could be used as a supplement to Artemia. Larvae fed copepods and Artemia showed similar survival rates to those fed only with Artemia. Larval survival from days 5-15 was higher in larvae reared in 20-25 ppt compared to those reared in normal seawater. 39 out of 71 tanks were discarded in 2000, whereas 3 out of 12 and 8 out of 26 production runs were aborted in 2001 and 2002, respectively. Mean survival at harvest increased from 3.06% in 2000 to 5.33 and 10.39% in 2001 and 2002, respectively. Larvae in discarded or aborted tanks were positive for viral nervous necrosis (VNN).