Arachidonic acid is a Major Component in Gonadal Fatty acids of Tropical Coral Reef fish in the Philippines and Japan

International audienc

Efficient utilization of aquaculture effluents to maximize plant growth, yield, and essential oils composition of Origanum majorana cultivation

Aquaculture effluents are nutrient-rich water containing both inorganic and organic nutrients with a potential to replace chemical fertilizer applications under integrated agricultural systems. A field experiment was conducted to determine the effect of fish effluent as an irrigation water source on the growth, yield, and essential oil composition of sweet marjoram. A randomized complete block design was followed with three irrigation treatments and three replicates i.e. fertigation with chemical fertilizers (control), irrigation with effluents only (effluents), and mixed treatment with 50% effluent and 50% chemical fertilizers (mixed). Marjoram seedlings were transplanted, and two cuts were done at the flowering stage. Samples were analyzed for yield and essential oil. In the first cut, effluents recorded an average of 40.4 cm height and 30.2 branches. It also had significantly higher yields, reaching 12.5ton ha−1 and 2.8ton ha−1 for fresh and dry yields, respectively. For the second cut, mixed had the highest average number of branches (58.8) and average height (59.2 cm). It recorded the highest yields of 26.5ton ha−1 and 10.5ton ha−1 of fresh and dry yields, respectively. Similarly, mixed gave the highest oil content (0.98%), compared to the control (0.84%). Essential oil analysis showed six main constituents; terpinen-4-ol (27.11–32.38%), β-terpineol (9.84–17.22%), γ-terpinene (11.09–15.55%), α-terpinene (6.68–10.34%), sabinene (8.18–9.25%), and cis-sabinene hydrate (5.01–8.64%). The results, therefore, suggest that growing marjoram with a mixed treatment would give the best herbage yields and the highest essential oils with reduced environmental impacts

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

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

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

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

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

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.The present study was financially supported by the collaborative project titled “Studies on Sustainable Production Systems of Aquatic Animals in Brackish Mangrove Areas” between Japan International Research Center for Agricultural Sciences, Japan and the Aquaculture Department, SEAFDEC, Philippines

Fatty acid composition of Nile tilapia Orechromis niloticus muscles: A comparative study with commercially important tropical freshwater fish in Philippines

Six tropical freshwater species were collected from Philippines in order to study the characteristic of polyunsaturated fatty acids distributions. 16:0 and 18: l n-9 were the predominant saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) in both neutral lipids (NL) and polar lipids (PL). There was an absence or very low values of n3 highly unsaturated fatty acid (HUFA) in NL of all species. However these fatty acids found in PL of all species studied with higher levels. The high proportions of docosahexaenoic acid (DHA) in PL were found with catfish Arius (20.71%), ayungin (17.64%), and snakehead (17.09%) whereas anabas (4.21%) gave lower DHA content. In PL, arachidonic acids (ARA) was found in high proportions, and also is superior to eicosapentaenoic acid (EPA) (ranged from 3.35 to 10.67% and from 0.42 to 4.74%, respectively). Tilapia lipid appears to be intermediate in nutritional quality between all species studied; the proportions of DHA, EPA and ARA in PL were 16.27%, 4.52% and 9.36%, respectively. According to the n-3/n-6 ratio in both fractions, only ayungin is in the range typical of freshwater fish. Our results indicate that the wild tropical freshwater fish studied here are not good sources of n-3 HUFA fatty acids. Therefore, aquatic nutritionists and farmers should combine their efforts in order to manipulate the nutritional quality of these species to enhance their n-3 HUFAs concentrations especially when these species are reared in captivity system. The wash-out strategy may provide an adequate description of the changes in the fillet lipid fatty acid profiles of fatty fish

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

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