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Lipid classes and fatty acid levels were analyzed in freshly fertilized eggs, early and late embryo development, and freshly hatched larvae obtained from wild and captive silverside Chirostoma estor estor broodstock, as well as in plankton, Artemia, and pelleted feed. The concentration of triglycerides (TGs) and highly unsaturated fatty acids (HUFAs) in neutral lipid fraction significantly decreased during early development and especially after hatching, whereas phospholipids and HUFA in polar lipid fraction remained constant. These results indicate that TGs rather than PLs are used as energy sources and that all HUFAs [20:4n-6/arachidonic acid (ARA), 20:5n-3/eicosapentaenoic acid (EPA), and 22:6n-3/docosahexaenoic acid (DHA)] of polar lipids are selectively conserved during early development. High levels of DHA (30%, on average, of total fatty acids) and low levels of EPA (4%) were observed in eggs, embryos, and larvae and did not reflect the proportions of these fatty acids in food. Preferential accumulation of DHA from food consumed by broodstock, and then transference to eggs, was probably occurring. The main difference between eggs from both origins was a low level of ARA in eggs from captive fish (4% of total fatty acids) compared to wild fish (9%). This could be associated with a deficiency in the diet that is not compensated for by desaturation/elongation of 18:2n-6 and, possibly, with greater stress in captive fish. In any case, particular requirements of ARA should be determined to optimize the culture of C. estor. [ABSTRACT FROM AUTHOR]

Litopenaeus vannamei (Boone) grown in ponds are exposed to salinities of less than 5 g L−1 during inland shrimp culture or to more than 40 g L−1 from evaporation and reduced water exchange in dry, hot climates. However, dietary requirements for shrimp grown in low or high salinities are not well defined, particularly for fatty acids. Feeding shrimp postlarvae with highly unsaturated fatty acids (HUFA) enhances tolerance to acute exposure to low salinity, as a result of better nutritional status, or/and specific effects of HUFA on membrane function and osmoregulation mechanisms. This study analysed the effect of HUFA supplementation (3% vs. 34%) on L. vannamei juveniles reared for 21 days at low (5 g L−1), medium (30 g L−1) and high salinities (50 g L−1). Juveniles grown at 5 g L−1 had lower survival compared with controls (30 g L−1) or shrimp grown at 50 g L−1, but no significant effect on survival was observed as a result of HUFA enrichment. In contrast, growth was significantly lower for shrimp grown at 50 g L−1, but this effect was compensated by the HUFA-enriched diet. Osmotic pressure in haemolymph was affected by salinity, but not by HUFA enrichment. Shrimp fed HUFA-enriched diets had significantly higher levels of eicosapentaenoic acid and docosahexaenoic acid in hepatopancreas and gills. These results demonstrate that growth at high salinities is enhanced with diets containing high HUFA levels, but that HUFA-enriched diets have no effect on shrimp reared at low salinities. [ABSTRACT FROM AUTHOR]

Survival during first months after birth is one of the bottlenecks for consolidating the seahorse farming industry. In this work, Artemia metanauplii enriched with two highly unsaturated fatty acids (HUFA) rich commercial emulsions with different docosahexaenoic acid (DHA) levels (63% and 14% of total lipids), a vegetable oil with no DHA, and non-enriched Artemia as control, were used to feed 5-day-old juvenile Hippocampus erectus for 60 days. Enriched Artemia had similar levels of DHA (13% and 9%), despite great differences of DHA in the emulsions, with traces of DHA in non-enriched and vegetable oil enriched Artemia. More than 20% of DHA was found in 24 h starved juveniles fed both DHA-enriched treatments, similar to values in newly born juveniles, but those fed vegetable oil enriched Artemia or non-enriched Artemia had 5% of DHA. Total lipid and protein levels were similar in juveniles from the four treatments. The n-3/n-6 ratio was almost four-fold higher in seahorses fed DHA-enriched treatments compared to juveniles fed the non-enriched treatments. Survival of seahorses only partially reflected the DHA levels: it was lower in the vegetable oil treatment, similar in the seahorses fed Artemia with higher DHA and in the control treatment, and higher in seahorses fed the HUFA-enrichedArtemia with lower DHA levels, although growth was similar in the two DHA-enriched Artemia treatments. Juvenile H. erectus seahorses perform better when they have at least 20% of DHA in their tissues, and these levels can be attained with no more than 14% of DHA in emulsions, eliminating the need for more expensive emulsions with higher DHA levels. [ABSTRACT FROM AUTHOR]

The Pacific red snapper (Lutjanus peru) is very popular fishery that reaches high prices in the market that is distributed in tropical and subtropical climates. Most studies in fatty acid requirements for larval production are done in temperate species; in general, warm-water fish are given the same levels of DHA and EPA than cold-water fish, which increases considerably the costs of production, without apparent benefit. We analyzed spawns during lecithotrophic development, with emphasis on fatty acids, of L. peru. Three origins were compared, Wild spawns, used as the standard of better-quality larvae, Laboratory and Pond, each with some differences in the inductions of maturation and broodstock diet: Lab and Pond broodstock were fed sardines and squids and DHA-rich oil capsules were added once a week. A total of 87 spawns were sampled throughout three years of sampling. Egg and oil globule diameters before fertilization, in 1-h embryo (E) and before hatching (LE); larval total length and oil globule diameter at hatching (LH), and after 24 (L24h) and 48 h (L48h) were measured. Hatching and survival percentages were measured in triplicate for each spawn. Hatching were significantly higher from Pond spawns (75.7%) compared to Wild (60.8%). Survival at L48 hours was not significantly different among origins. Wild spawns had significantly more carbohydrates, but less phospholipids during development, compared to Lab and Pond spawns. ARA, EPA and DHA concentrations decreased in total lipids and triglycerides, but in Lab spawns they were accumulated in phospholipids. There was a more variable fatty acid composition in Pond spawns compared to Lab spawns, a result of more diversified diet in ponds. Viable eggs had two-fold higher proportion of ARA compared to non-viable eggs. A principal factor analysis revealed three positive associations between 1) female weight, egg oil globule diameter, and EPA:ARA in egg PL; 2) hatching, LH length, and DHA:ARA in egg PL; 3) L48h survival, TG and PL content in eggs. According to our results, subtropical L. peru needs less DHA and more ARA and monounsaturated fatty acids in their diet, compared to temperate marine fish. • Wild spawns had low % hatching and less phospholipids during development. • Viable eggs had two-fold higher proportion of ARA compared to non-viable eggs. • L. peru needs less DHA and more ARA in the diet, compared to temperate marine fish. [ABSTRACT FROM AUTHOR]