Arachidonic acid enrichment of rotifers and effects of dietary arachidonic acid on broodstock performance of rabbitfish Siganus guttatus
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Rotifers (Brachionus sp.) were cultured with various combinations of baker’s yeast, Nannochloropsis sp., Culture selco, and DHAPS with or without supplementation of arachidonic acid (triacylglycerol form). Rotifers were able to be enriched with emulsified- arachidonic acid supplemented to culture media. Considered the reciprocal ratios of arachidonic acid, EPA and DHA in rotifers, rotifers pre-cultured in Culture selco and then cultured in DHAPS had the best balance of essential fatty acids, and the optimum level of arachidonic acid supplementation to DHAPS appeared between 0% and 5%.
A feeding test was conducted to investigate the effects of arachidonic acid on the broodstock performance of rabbitfish (Siganus guttatus), one of the commercially valuable species in mangrove areas. A diet with 1.5% of arachidonic acid supplementation appeared to affect negatively the reproductive performance of S. guttatus broodstock, perhaps due to the excessive supplementation. Considered together with results of mangrove red snapper in 2003, the optimum supplementation of arachidonic acid in broodstock diets might be around 0.5%.
Keywords
EPA DHA essential fatty acid tropical fishType
Book chapterISSN
1341-710Xシリーズ
JIRCAS Working Report; No. 44Collections
- Books and Book Chapters [123]
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Series: JIRCAS Working Report;No. 35
Notable features of fatty acid composition in mangrove fish species
(Japan International Center for Agricultural Sciences, 2003)Fatty acid composition was determined in several mangrove and commercial species, mangrove red snapper, rabbitfish, milkfish and striped jack that were sampled in the Central Philippines, with special reference to arachidonic acid (AA) and eicosapentaenoic acid (EPA). As overall traits, the mangrove species had intermediate or high AA and docosahexaenoic acid (DHA) levels and low EPA levels compared to species in the high and temperate northern hemisphere, consequently having high AA/EPA ratios. The present results suggest that AA may be nutritionally much more important in tropical/mangrove species than in cold/cool water species. The information of the present study can be used as a guideline for development of appropriate artificial diets for broodstock and/or larvae in mangrove areas. -
Fatty acid composition of five candidate aquaculture species in Central Philippines
(Elsevier, 2004)Fatty acid composition was determined in five candidate aquaculture species, mangrove red snapper (Lutjanus argentimaculatus), two rabbitfish (Siganus guttatus and S. canaliculatus), coral trout (Plectropomus leopardus) and striped jack (Caranx fulvoguttatus) sampled in the Central Philippines. Special attention was paid to arachidonic acid (ARA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Total lipids of hatchery-produced eggs and newly hatched larvae of mangrove red snapper unexpectedly had equal levels of ARA and EPA. Ovarian polar lipids were subsequently found to have intermediate or high ARA (5.5–10.7%) and DHA (14.4–20.4%) levels but relatively low EPA levels (1.5–1.9%), consequently showing high ARA/EPA (4.4–6.0) and DHA/EPA (7.4–14.9) ratios in wild mangrove red snapper and rabbitfish (S. guttatus and S. canaliculatus). Similar trends were observed even in hatchery-reared mangrove red snapper, rabbitfish (S. guttatus) and coral trout. Not only ovary but also liver and muscle contained relatively higher ARA compared with EPA in mangrove red snapper, regardless of the sample source. ARA, EPA and DHA levels in the polar lipids of wild fry (whole body) ranged respectively from 3.2% to 4.0%, from 2.7% to 4.7% and from 23.5% to 27.6% with intermediate or high ARA/EPA (0.8–1.5) and DHA/EPA (5.9–8.8) ratios in mangrove red snapper, rabbitfish (S. canaliculatus) and striped jack. As overall traits, the five species in the Central Philippines appear to have intermediate or high ARA and DHA levels with low EPA level, consequently having high ARA/EPA and DHA/EPA ratios compared to species in high and temperate northern hemisphere. Thus, the present results indicate that ARA is not a minor component in the tropical species, suggesting that ARA may be nutritionally much more important for egg development and larvae growth in the tropical species than in cold water species. The information of the present study can be used as a guideline for development of appropriate broodstock and/or larval diets in the Philippines. -
Series: JIRCAS Working Report No. 56
Effects of arachidonic acid supplementation on larval and survival and reproductive performance in rabbitfish, Siganus guttatus
(Japan International Research Center for Agricultural Sciences, 2007)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.
