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Long-chain polyunsaturated fatty acids (LC-PUFA) are critical for the health of aquatic and terrestrial organisms; therefore, understanding the production, distribution, and abundance of these compounds is imperative. Although the dynamics of LC-PUFA production and distribution in aquatic environments has been well documented, a systematic and comprehensive comparison to LC-PUFA in terrestrial environments has not been rigorously investigated. Here we use a data synthesis approach to compare and contrast fatty acid profiles of 369 aquatic and terrestrial organisms. Habitat and trophic level were interacting factors that determined the proportion of individual omega-3 (n-3) or omega-6 (n-6) PUFA in aquatic and terrestrial organisms. Higher total n-3 content compared with n-6 PUFA and a strong prevalence of the n-3 PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) characterized aquatic versus terrestrial organisms. Conversely, terrestrial organisms had higher linoleic acid (LNA) and alpha-linolenic acid (ALA) contents than aquatic organisms; however, the ratio of ALA:LNA was higher in aquatic organisms. The EPA + DHA content was higher in aquatic animals than terrestrial organisms, and increased from algae to invertebrates to vertebrates in the aquatic environment. An analysis of covariance (ANCOVA) revealed that fatty acid composition was highly dependent on the interaction between habitat and trophic level. We conclude that freshwater ecosystems provide an essential service through the production of n-3 LC-PUFA that are required to maintain the health of terrestrial organisms including humans.

Fatty acid content of raw and cooked zander (Sander lucioperca) was studied. Special attention was paid to long-chain polyunsaturated fatty acids: eicosapentaenoic, 20:5 n-3 (EPA) and docosahexaenoic, 22:6 n-3 (DHA), and also to the n-6/n-3 ratio, which are regarded as indicators of nutritive value. As found, the heat treatments, boiling, stewing and frying, including those in a convection steam oven (CSO), did not significantly decrease the content of EPA and DHA in the products. Boiling and stewing appeared to give products of a higher nutritive value, regarding the above indicators, than frying and cake preparation. Frying of zander in CSO was found to be more beneficial for nutrition compared to pan-frying. The cooked zander had higher EPA and DHA contents than many other popular food fish species, and also had a high nutritive value due to the low n-6/n-3 ratio when boiled and stewed.

Chemical composition and fatty acid profile of fillets from farmed and wild common carp were assessed in the course of four seasons. Ten wild and ten farmed fish were collected in the middle month of each season (except summer due to unavailability of wild fish) during the year. Protein and lipid concentrations in the samples decreased from summer to spring as follows: protein conc.: from 17.6+/-0.3% to 15.9+/-1.6% (farmed fish) and from 18.2+/-0.1% to 17.9+/-1.4% (wild fish); lipid conc.: from 5.1+/-0.2% to 1.5+/-0.5% (farmed fish) and from 3.8+/-0.6% to 2.8+/-0.9% (wild fish), moisture conc. of both samples increased in this period as follows: from 76.7+/-1.4% to 81.4+/-0.4% (farmed fish) and from 75.5+/-0.6% to 78.5+/-0.2% (wild fish). Protein conc. of wild carp fillet was higher and moisture conc. was lower than those of the farmed counterparts (17.7+/-0.8% vs. 16.2+/-1.2% and 77.65+/-0.6 vs. 79.3+/-0.1, resp., P less than 0.05). In all seasons, MUFA were higher than SFA and PUFA. In the wild carp fillet, PUFA was higher than SFA in winter and spring but in the farmed carp it was higher in all seasons except the spring. Palmitic, oleic, and DHA were the major fatty acids in the wild carp fillet, resp. In the farmed carp fillet, the major SFA and MUFA were similar to those in the wild one but linoleic acid was the major PUFA in all seasons. Omega-3/omega-6 PUFA ratios in the wild carp fillet were higher than in the farmed counterparts.

The yellow-green alga Trachydiscus minutus (class Xanthophyta) was cultivated in a standard medium and in media without sulfur and nitrogen. Its yield after a 16-d cultivation reached 13 g dry mass per 1 L medium. The content of oligoenoic fatty acid, i.e. eicosapentaenoic, was in excess of 35 % of total fatty acids; the productivity was thus 88 mg/L per d. This result makes the alga a very prospective organism that may serve as a new biotechnological source of single cell oil.

The urea complexation was used to concentrate n-3 fatty acids (FA) from crude and refined commercial salmon oils. The experimental procedure included salmon oil saponification, free fatty acid (FFA) collection, formation of urea-FFA inclusion complexes, extraction of free n-3 FA and further analysis by gas-liquid chromatography of the corresponding FA methyl esters. Differences between crude and refined salmon oil could be observed. Crude oil provided higher typical odour, viscosity and suspension particle values, whereas crude salmon oil showed higher FFA and impurities content while p-anisidine and iodine values, moisture content and formation of conjugated dienes and trienes did not provide any significant differences between both oils; refined oil showed lower a* and b* scores when compared to its counterpart crude oil. Related to the n-3 PUFA concentration, a decrease in saturated fatty acids C 14:0, C 16:0, and C 18:0 and monounsaturated fatty acids C 18:1 9c, and C 18:1 11c, as well as a high yield of n-3 PUFA, EPA+DHA and total PUFA recovering could be observed starting from both crude and refined oils, which confirmed salmon oil to be a profitable source of such highly valuable constituents. Factors such as reaction temperature and ureaFFA ratio showed to be markedly significant to achieve higher value concentrations.

This study aimed at comparing fatty acid contents of rotifers cultured with different methods after nutritional enrichment in order to evaluate the rotifer quality produced by these methods. Rotifers were cultured using either a batch or a continuous culture. From the batch culture, three experimental subpopulations were used, sampled from the culture at 1, 24, and 48 h after rotifer inoculation. The continuous culture was performed with two tanks; one was for cultivation with continuous feeding and water supply (cultivation tank), and another was for harvesting from the cultivation tank by overflow (harvest tank). From the continuous culture, two subpopulations were used: one from the cultivation and one from the harvest tank. Nutritional enrichment was performed after each culture. Each population was enriched with Nannochloropsis oculata or a commercial enrichment diet. When the enrichment was performed with N. oculata on populations at 24 h after inoculation originating from either of the two tanks of continuous culture or the batch culture tank, a higher quantity of arachidonic acid (ARA) and eicosapentaenoic acid (EPA) was obtained from the two tanks of continuous culture. The same results obtained when enrichment diet was used, this including docosahexaenoic acid (DHA).

:  The total lipid content and fatty acid composition were determined in the flesh and skin of wild and cultured rainbow trout in Turkey. The effect of diet content was also investigated on cultured trout. Gas chromatography‐mass spectrometry (GC‐MS) was used for fatty acid analyses. Total lipid content of skin was higher than flesh in both types and when compared appreciably higher in cultured fish. The predominant fatty acid was palmitic acid (C16:0) in saturated fatty acids and oleic acid (C18:1n‐9) in monounsaturated fatty acids. The amount of eicosapentaenoic acid was double in wild and docosahexaenoic acid (DHA) 1.5 times higher in cultured fish flesh. The n‐3/n‐6 ratio was higher in cultured fish than wild fish. The levels of palmitic, oleic, linoleic (C18:2n‐6) and palmitoleic (C16:1n‐7) acids were high in skin. The level of EPA was the same in skin of wild fish but 5.5 times higher in cultured fish, whereas the proportion of DHA in skin was lower for wild and 3.5 times higher in cultured fish. Wild fish had a high level of linoleic, arachidonic (C20:4n‐6) and linolenic (C18:3n‐3) acids. The total amount of n‐3 and n‐6 polyunsaturated fatty acids was higher in flesh of wild fish than cultured fish, contrary to skin of cultured fish. The data obtained demonstrated that fatty acid composition of cultured fish did not depend on that of feed.

Effects of 1, 3, 5 or 7% of linseed oil in the diet on the content of fatty acids in breast and thigh meat were studied in broiler chickens. Oils made either of seeds of the linseed cultivar Atalante (A) with a high content of alpha-linolenic acid or of the cultivar Lola (L) with a predominating content of linoleic acid were fed from 25 to 40 days of age. When feeding A, the contents of all n-3 polyunsaturated fatty acids (PUFA), including eicosatrienoic acid, were significantly higher, those of n-6 PUFA were lower, and the ratio of n-6/n-3 PUFA was narrower (P less than 0.001) than when L was fed. The narrowest n-6 to n-3 PUFA ratio was observed at the content 36 g of alpha-linolenic acid (58 g A) per kg of the diet while the widest one at 2 g of alpha-linolenic acid (70 g L) per kg of the diet. When using L, the increasing level of linoleic acid in feed was associated with significantly increasing levels of all n-6 PUFA in meat. The content of all n-3 PUFA increased after the application of oil A, but the dependence for eicosapentaenoic acid in thigh meat was expressed significantly more precisely by the second degree parabola with the maximum at the level of 37 mg of alpha-linolenic acid and for clupanodonic and docosahexaenoic acids by parabolas with maxima at the level of alpha-linolenic acid in the diet 41 g and 30 g for breast meat and 35 g and 27 g for thigh meat, respectively. By means of the inclusion of linseed oil with a high content of alpha-linolenic acid in the feed mixture it would be possible to produce poultry meat with a high content of n-3 PUFA as a functional food.

The putative EPA synthesis gene cluster was mined from the entire genome sequence of Shewanella oneidensis MR-1. The gene cluster encodes a PKS-like pathway that consists of six open reading frames (ORFs): ORFSO1602 (multi-domain beta-ketoacyl synthase, KS-MAT-4ACPs-KR), ORFSO1600 (acyl transferase, AT), ORFSO1599 (multi-domain beta-ketoacyl synthase, KS-CLF-DH-DH), ORFSO1597 (enoyl reductase, ER), ORFSO1604 (phosphopentetheine transferase, PPT), and ORFSO1603 (transcriptional regulator).

The principal aim was to analyse the chemical composition (dry matter, protein, fat, saccharides, ash) and to calculate the energy value of 6 topographically distinct parts (cranial, medial and caudal dorsal/ventral part above/below the lateral line) of the fillets of the silver carp in two weight categories, i.e. lightweight (LW) fish of 3.50 kg live weight, and heavyweight (HW) fish of 4.50 kg live weight. Another aim was to evaluate the lipid profile of the muscle tissue and internal fat (separated from the internal organs). The study demonstrated differences (P less than 0.05) in the chemical composition (with the exception of saccharides) and energy values between the relatively lean dorsal sections of silver carp fillets, which rank the silver carp among medium to low-fat fish (fillet fat content: LW = 46.06+/-5.54 g/kg, HW = 50.62+/-5.51 g/kg), and the fatter ventral sections which, in contrast, rank the silver carp among high-fat fish (fillet fat content: LW = 158.14+/-11.28 g/kg, HW = 157.42+/-9.65 g/kg). The study showed that the internal fat lipids are an interesting alternative source of PUFAn-3 and, in particular, of alpha-linolenic acid C18:3n-3 (LW = 4.79+/-0.25, HW = 5.28+/-0.33), EPA C20:5n-3 (LW = 2.70+/-0.17, HW = 3.04+/-0.15), and DHA C22:6n-3 (LW = 3.08+/-0.20, HW = 3.41+/-0.18).