The European eel (Anguilla anguilla Linnaeus 1758) is a species typical for waters of Western Europe. Thanks to early expeditions on the Atlantic Ocean by the Danish biologist Johannes Schmidt who found small (<10 mm) leptocephali larvae in the Sargasso Sea about 100 years ago, we have now a strong indication

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BackgroundIn this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated.MethodsThe fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (Caulerpa taxifolia, Sargassum natans) was determined using GCMS. Four independent replicates were taken from each seaweed species.ResultsOmega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs), were in the concentration range of 2-14 mg/g dry matter (DM), while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6) and/or eicosapentaenoic acids (EPA, C20:5, n-3), the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3) at ≈ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed.ConclusionMarine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6) FA: (n-3) FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3), while in S. natans also docosahexaenoic acid (DHA, C22:6, n-3) was detected.

Eel populations worldwide are dangerously close to collapsing. Our study is the first to show that current levels of dioxin-like contaminants are strong candidates because of their devastating effects on development and survival of eel embryos. Female and male silver eels were artificially stimulated to maturation and reproduction by treatment with carp pituitary extracts and hCG, respectively. During maturation of female European silver eels, about 60 g fat per kg eel is incorporated in the oocytes. Together with the fat, however, persistent organic pollutants such as dioxin-like polychlorinated biphenyls (PCBs) are incorporated too. The total dioxin-like toxic potency of the individual gonad batches was determined as 2,3,7,8-tetrachlorodibenzo-p-dioxine equivalents (TEQs), using an in vitro reporter gene assay. The observed differences in development and survival showed a significant negative correlation with the TEQ levels in the gonads, already at levels far below the maximal allowable level for fish consumption, i.e., 4 ng TEQ/kg fish. The clear inverse relationship between the TEQ level and the survival period of the fertilised eggs strongly suggests that the current levels of dioxin-like compounds seriously impair the reproduction of the European eel. The peak of the environmental levels of dioxin-like PCBs and the decline of eel coincide worldwide, further suggesting that, in addition to other threats, these contaminants contributed significantly to the current collapse in eel populations.

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shorter than those who have at least one child (ANOVA: childedness, F 1,3198 ǃ25.5, P<0.001; education, F 1,3198 ǃ93.1, P<0.001). Multiple regression with number of children as the dependent variable, with height and age as independent variables, provides quantitative confirmation of these results (one-tailed tests: city, r 2 ǃ0.136, nǃ1,826; height, P<0.001; age, P<0.001; rural, r 2 ǃ0.208, nǃ1297; height, Pǃ0.041; age, P<0.0001).Comparisons of means for individual age cohorts (Fig. 1b) reveals that men with children are significantly taller than childless men in each case (twenties, t 1157 ǃǁ2.97, Pǃ0.005; thirties, t 1115 ǃǁ3.49, Pǃ0.001; forties, t 514 ǃǁ3.06, Pǃ0.002), except for men in their fifties (t 409 ǃ0.17, Pǃ0.863). Because these men were born during the 1930s, they entered the marriage market shortly after the Second World War when the population sex ratio was highly skewed in favour of women and sexual selection on males would have been greatly reduced as a result: the sex ratio for adults of working age (18-64 for men, 18-60 for women) in Wroclaw was 114.3 women to 100 men in the post-war decade, but fell to 104-105:100 in subsequent decades 12 .These results indicate that the effect of height on reproductive output might be due to shorter men being disadvantaged in Evolutionary fitness

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African catfish (Clarias gariepinus) were fed four isonitrogenous diets (34 % crude protein), each containing one of two lipid (100 or 180 g/kg) and two L-carnitine (15 or 1000 mg/kg) levels. After 81 d of feeding, thirty-two fish (body weight 32 g) from each dietary group were randomly selected, sixteen fish were induced to a 3-h swim (speed of 1·5 body length (BL)/s), while the other sixteen fish were kept under resting condition. Fish fed 1000 mg L-carnitine accumulated 3·5 and 5 times more L-carnitine in plasma and muscle, respectively, than fish fed the 15 mg L-carnitine. Muscle L-carnitine content was significantly lower in exercised fish than in rested fish. High dietary lipid level (fish oil) led to an increase in muscle n-3 PUFA content and a decrease in SFA and MUFA content. In liver, the increase in dietary lipid level resulted in an increased levels of both n-6 and n-3 PUFA. L-carnitine supplementation significantly decreased n-3 PUFA content. Exercise decreased n-3 PUFA in both muscle and liver. Plasma lactate and lactate dehydrogenase, normally associated with increased glycolytic processes, were positively correlated with exercise and inversely correlated with dietary L-carnitine level. L-carnitine supplementation reduced significantly the RQ from 0·72 to 0·63, and an interaction between dietary L-carnitine and lipid was observed (P, 0·03). Our results indicate that an increase in fatty acids (FA) intake may promote FA oxidation, and both carnitine and exercise might influence the regulation of FA oxidation selectivity.African catfish: L-carnitine metabolism: Lipid metabolism: Exercise Fish are subjected to many changes in energy demand throughout their lifespan. As the lipid content of their diet increases so does the optimal dietary level of L-carnitine (1 -3) , a multi-physiological, bioactive additive compound, synthesised from two essential amino acids, protein-bound lysine and methionine. It is not entirely understood whether animals require exogenous L-carnitine, and over the past 20 years, the scientific discussion regarding this subject continued with ambiguous arguments.L-Carnitine plays several important physiological roles like shuttling the long-chain fatty acid (FA) across the inner mitochondrial membrane for ATP production (4,5) and inhibition of superoxide radical formation (6) . According to Heo et al. (2,7) , L-carnitine biosynthesis might be sufficient to maintain growth of 20-kg pigs during optimum husbandry conditions. Nevertheless, extra dietary L-carnitine is efficiently retained in body tissues, playing a role in nutrient utilisation and thus on growth performance and body composition. The rate of lipid oxidation is determined by the energy requirements of working muscles and by the availability of free L-carnitine delivery to muscle mitochondria (8,9) .Since exogenous L-carnitine may influence energy utilisation efficiency, several studies using birds and mammals as animal models tested the effect of dietary L-carnitine supplementation on the exercise performance and on l...