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Marine by-products can compose up to 70% of the total weight of products from fisheries, most of which are discarded. However, these by-products are rich in highly unsaturated fatty acids that are not synthetized by most marine animals produced by aquaculture. Here, we used three marine by-products (shrimp head, Catarina scallop viscera, and Pen shell viscera) to produce lipid-rich (72.9–144.6 g/kg) meals which were used to partially substitute commercial fishmeal (FM) on feeds that were used to grow Almaco Jack (Seriola rivoliana) juveniles for 10 weeks. The content of 20:5n-3 and 22:6n-3 in tissues of fish fed shrimp and Pen shell presented values similar to controls, but the former had a better effect on growth, lipid, and phytosterols levels. Catarina meal had lower concentration of 20:4n-6 and 22:6n-3 in feed but promoted higher proportion of 20:4n-6 in muscle and 22:6n-3 in liver, indicating a selective conservation in relation to other fatty acids. Catarina meal contained traces of 18:5n-3 (0.02 g/kg) indicating that scallops probably ingested dinoflagellates; after testing, phycotoxins like okadaic acid (OA) and dinophysistoxin 1 (DTX1) were detected by mouse bioassay, by lateral flow immunochromatography, and quantified by HPLC–MS/MS. The presence of these toxins at the detected concentrations (OA: 27.64 µg/g and DTX1: 10.31 µg/g) affected almaco jack juveniles, a setback that needs to be addressed before meal manufacturing from mollusks. Marine by-products rich in lipids can be used to reduce the use of FM in the diet, and their use improve the lipid content and growth compared to control diet with FM. [ABSTRACT FROM AUTHOR]

Changes in lipid reserves as a result of supplementing 3.4% Ulva clathrata meal in the diet (based on dry weight of all ingredienta) for Litopenaeus vannamei broodstock were evaluated in a commercial larval laboratory. The profile of fatty acids, sterols, carotenoids, and phenolic compounds in the gonad, hepatopancreas, and muscle of females with unilateral ablation was analyzed. Shrimp fed the Ulva supplemented diet had significantly higher proportions of arachidonic acid (20:4n-6) in the acylglycerides of mature gonads (84% increase) compared with mature controls. In the phospholipids of mature gonads, there was a 30% increase of 18:3n-3, 13% increase of 20:4n-6, and 10% of docosahexaenoic acid (22:6n-3) in Ulva-fed shrimp compared with controls. 22:6n-3 also increased 51% in the lipid reserves of hepatopancreas of Ulva-fed shrimp compared with controls. Carotenoids increased by 43% in the gonads and fivefold in the hepatopancreas of mature females fed Ulva. The proportion of fucosterol and isofucosterol went from undetectable in controls to 0.3 and 0.2%, respectively, in shrimp fed the algae. No significant differences were found in muscle. Phenolic compounds in the gonad were higher in mature gonads compared with immature, but no significant differences were found in relation to Ulva consumption. Carotenoids and phenolic compounds present in Ulva might be acting as antioxidants of highly unsaturated fatty acids (HUFAs), increasing the proportion of 20:4n-6 and 22:6n-3, but other mechanisms associated to these compounds and to fucosterol can be synchronizing oocyte maturation and increasing transport of HUFA during vitellogenesis, and together, they are further impacting the reproductive performance of shrimp. [ABSTRACT FROM AUTHOR]

The fatty acid composition of macrophytes is usually quite stable among different taxonomic groups, and thus, several fatty acids can been used as biomarkers. However, variations between species can be affected by seawater temperature and other ambient factors. With higher annual temperatures, we expect less polyunsaturated fatty acids, and changes in the fatty acid signature of algae. Here we analyzed seasonal and interannual variations, in two species of red ( Gelidium robustum and Gracilaria sp.), two brown ( Eisenia arborea and Macrocystis pyrifera), and two green macroalgae ( Ulva lactuca and Ulva sp.), and one species of seagrass ( Phyllospadix torreyi) sampled in a subtropical climate (Bahía Tortugas and Bahía Asunción, BCS, Mexico) from 2002 to 2004. We found that the fatty acid signatures of the red and brown algae were quite stable among seasons and years, in contrast to those of the green algae, which showed a strong annual variation in their fatty acid signature that affected their annual segregation in the factor analysis and are probably a result of net primary production (NPP), which was strongly correlated to individual fatty acids. The fatty acid signature in brown algae is affected by photosynthetically active radiation (PAR), but their variation in the factor analysis is fairly stable despite seasonal or interannual differences. The polyunsaturated fatty acids (PUFAs) were correlated to sea surface temperature (SST) in seagrass. The differences in fatty acid variations between macrophyte groups can provide useful biomarker information for use in trophic analyses. [ABSTRACT FROM AUTHOR]

Induction of triploidy in aquatic organisms has increased worldwide in the last two decades, mostly because triploids have better growth than diploids. According to a physiological hypothesis, partial or total sterility of triploids allows the accumulation of reserves in muscle and other tissues instead of being transferred to the gonad. The present study analyzes lipid, protein, carbohydrate, and fatty acid levels in muscle and gonads of Nodipecten subnodosus triploids and diploids over 18 months from June 2001 to December 2002. An important increase in gonadosomatic index of diploids scallops was observed from May to June 2002 reaching the highest values in August. Such increase was not observed in triploid scallops. Changes in biochemical composition in female gonad were in general related to the accumulation of reserves during gonad development of diploid scallops. This accumulation was lower for triploid scallops, in accordance to their sterility, especially for carbohydrates and acylglycerides. Adductor muscle index as well as protein and carbohydrate levels in muscle increased in both ploidy groups during the reproductive period indicating no mobilization of reserves to sustain gonad development in both ploidy groups. These results partially support the physiological hypothesis on the advantage of triploids: in a rich food locality no mobilization of reserves is needed to sustain gametogenesis. This, together with a possible lower efficiency of energy assimilation at high food concentration for triploids, may be the reason for an apparent lack of superiority of N. subnodosus triploids in terms of adductor muscle growth. Only the levels of particular highly unsaturated fatty acids levels (namely 20:4 n-6 and 20:5 n-3) in muscle of diploid and triploid decreased during the reproductive period, indicating a possible transfer of selected fatty acids to gonads, even in triploids. The muscle of triploids has a slightly but significantly higher proportion of 22:6 n-3 compared to diploids, which can have implications for the nutritional and commercial value of triploid adductor muscle. [ABSTRACT FROM AUTHOR]

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]