Preliminary Estimation of Nutritional Quality of the Meat, Liver, and Fat of the Indigenous Yakutian Cattle Based on Their Fatty Acid Profiles.

The Yakutian cattle is an indigenous Siberian cattle breed living in an extremely cold climate in some parts of Yakutia. There are only a few thousand animals of this breed, and the conservation of the Yakutian cattle is embedded in the international agenda. We studied the fatty acid profiles in the meat, liver, and fat of the Yakutian cattle (five individuals) of different ages and their main food resource-pasture plants. The fatty acid profile of the tissues of the Yakutian cattle differed from that of pasture plants: 16:0, 18:2n-6, and 18:3n-3 dominated in the pasture plants; 16:0, 18:0, 18:1n-9, 18:2n-6, 20:4n-6, 20:5n-3, and 22:5n-3 dominated in the meat and liver; and 16:0, 18:0, and 18:1n-9 dominated in the fat. The fatty acid composition of food products is related to the risk of developing cardiovascular disease (CVD). The meat and liver of the Yakutian cattle are health food products that contribute to decreasing the risk of developing CVD because of their rather high content of eicosapentaenoic and docosahexaenoic fatty acids, optimal n-6/n-3 and polyunsaturated fatty acids/saturated fatty acids ratios, low values of indexes of atherogenicity and thrombogenicity, and high values of hypocholesterolemic/hypercholesterolemic and health-promoting indexes. The results of the present study support the importance of preserving this valuable cattle breed. Actions should be taken to increase their population while retaining their contemporary housing and feeding conditions.

Fatty Acid Profiles of Some Siberian Bryophytes and Prospects of Their Use in Chemotaxonomy.

The composition of fatty acids (FAs) in gametophyte samples of 20 Siberian bryophyte species from four orders of mosses and four orders of liverworts collected in relatively cold months (April and/or October) was examined. FA profiles were obtained using gas chromatography. Thirty-seven FAs were found, from 12:0 to 26:0; they included mono-, polyunsaturated (PUFAs) and rare FAs, such as 22:5n-3 and two acetylenic FAs, 6a,9,12-18:3 and 6a,9,12,15-18:4 (dicranin). Acetylenic FAs were found in all examined species of the Bryales and Dicranales orders, dicranin being the predominant FA. The role of particular PUFAs in mosses and liverworts is discussed. Multivariate discriminant analysis (MDA) was performed to determine whether FAs can be used in the chemotaxonomy of bryophytes. Based on the MDA results, FA composition is related to the taxonomic status of species. Thus, several individual FAs were identified as chemotaxonomic markers at the level of bryophyte orders. These were 18:3n-3; 18:4n-3; 6a,9,12-18:3; 6a,9,12,15-18:4; 20:4n-3 and EPA in mosses and 16:3n-3; 16:2n-6; 18:2n-6; 18:3n-3 and EPA in liverworts. These findings indicate that further research into bryophyte FA profiles can shed light on phylogenetic relationships within this group of plants and the evolution of their metabolic pathways.

Ecological Role of Cyprideis torosa and Heterocypris salina (Crustacea, Ostracoda) in Saline Rivers of the Lake Elton Basin: Abundance, Biomass, Production, Fatty Acids.

Saline rivers are highly productive ecosystems in arid regions. The meiobenthic community (bottom meiofauna) and its dominant representatives are one of the least studied components of these aquatic ecosystems. Ostracods Cyprideis torosa and Heterocypris salina are major consumers among the species of bottom meiofauna in saline rivers flowing into the hyperhaline Lake Elton (Volgograd Region, Russia). We estimated the abundance, biomass and production of C. torosa, the dominant species at the mouth of the polyhaline Chernavka River (average salinity is ~30 g l-1), and H. salina, the dominant species at the mouth of the mesohaline Bolshaya Samoroda River (~13 g l-1), in spring (May) and summer (August). Additionally, we studied the composition and content of fatty acids of the ostracods and their potential food sources (bottom sediments with bacterial-algal mats). We found that the abundance and biomass (wet weight with shells) of C. torosa in the Chernavka River and H. salina in the Bolshaya Samoroda River reached 3.5 × 106 ind. m-2 and 117 g m-2, and 1.1 × 105 ind. m-2 and 12 g m-2, respectively. The first species formed on average about 85% of the total abundance and 96% of the total biomass of the meiobenthos, and the second one, about 13% and 31%, respectively. The daily production of C. torosa and H. salina can reach 249 and 36 mg m-2 ash-free dry weight, respectively. The results indicate that these species may play an important role in the total flow of matter and energy in the studied habitats. Based on the fatty acid (FA) composition of the ostracods and their food sources, it was found that C. torosa mainly consumed diatoms, while H. salina preferred bacteria, cyanobacteria, and green algae. Differences between the species were greater than differences between the bottom sediments from the rivers. It may mean that the ostracods selectively consumed different food items that may be related to the different nutrient requirements of the species. Seasonal changes in the FA compositions of the ostracods were higher than in their food sources (bottom sediments), which also indicates selective feeding of the species.

Comparison of Fatty Acid Contents in Major Lipid Classes of Seven Salmonid Species from Siberian Arctic Lakes.

Long-chain omega-3 polyunsaturated fatty acids (LC-PUFA) essential for human nutrition are mostly obtained from wild-caught fish. To sustain the LC-PUFA supply from natural populations, one needs to know how environmental and intrinsic factors affect fish fatty acid (FA) profiles and contents. We studied seven Salmoniformes species from two arctic lakes. We aimed to estimate differences in the FA composition of total lipids and two major lipid classes, polar lipids (PL) and triacylglycerols (TAG), among the species and to evaluate LC-PUFA contents corresponding to PL and TAG in muscles. Fatty acid profiles of PL and TAG in all species were characterized by the prevalence of omega-3 LC-PUFA and C16-C18 monoenoic FA, respectively. Fish with similar feeding spectra were identified similarly in multivariate analyses of total lipids, TAG and PL, due to differences in levels of mostly the same FA. Thus, the suitability of both TAG and total lipids for the identification of the feeding spectra of fish was confirmed. All species had similar content of LC-PUFA esterified as PL, 1.9-3.5 mg g-1, while the content of the TAG form strongly varied, from 0.9 to 9.8 mg g-1. The LC-PUFA-rich fish species accumulated these valuable compounds predominately in the TAG form.

Fatty Acid Content and Composition of the Yakutian Horses and Their Main Food Source: Living in Extreme Winter Conditions.

: For the first time, seasonal changes in the content of total lipids (TLs) and phospholipids (PLs) were studied in fodder plants growing in Central Yakutia-a perennial cereal, smooth brome (Bromopsis inermis L.), and an annual cereal, common oat (Avena sativa L.). Both species have concentrated TLs and PLs in autumn under cold hardening. In addition, a significant increase in the content of fatty acids (FAs) of B. inermis was observed during the autumn decrease in temperature. The Yakutian horses, which fed on cereals enriched with nutrients preserved by natural cold (green cryo-fodder), accumulated significant amounts of 18:2n-6 and 18:3n-3, the total content of which in cereals was 75% of the total FA content. We found differences in the distribution of these two FAs in different tissues of the horses. Thus, liver was rich in 18:2n-6, while muscle and adipose tissues accumulated mainly 18:3n-3. Such a distribution may indicate different roles of these FAs in the metabolism of the horses. According to FA content, meat of the Yakutian horses is a valuable dietary product.

Fatty Acid Composition and Contents of Seven Commercial Fish Species of Genus Coregonus from Russian Subarctic Water Bodies.

In several Russian northern lakes and rivers, Arctic cisco Coregonus autumnalis, least cisco C. sardinella, peled C. peled, tugun C. tugun, broad whitefish C. nasus, whitefish C. lavaretus and vendace C. albula were sampled in periods of officially permitted commercial fishery. Special attention was paid to contents (mg g-1 of wet weight) of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in muscle tissues (filets), which are essential for human nutrition. The highest values of EPA + DHA content in semi-anadromous fish and freshwater fish were recorded for C. autumnalis from the Yenisei River, 17.60 mg g-1 wet weight, and for C. lavaretus from the Sobachye Lake, 16.61 mg g-1 wet weight, respectively. Intra-genus variations of EPA + DHA contents of Coregonus species were from 1.87 to 17.60 mg g-1 wet weight. Since the congeneric species were genetically close to each other, the variations in EPA and DHA contents were thought to be caused primarily by ecological factors: migrational capability, type of feeding and trophic status of aquatic ecosystems. In general, the majority of studied species appeared to be of a high nutritive value for humans, although unfavorable environmental conditions could considerably diminish this value.

Export of aquatic productivity, including highly unsaturated fatty acids, to terrestrial ecosystems via Odonata.

Based on 31-year field study of the abundance and biomass of 18 species of odonates in the Barabinsk Forest-Steppe (Western Siberia, Russia), we quantified the contribution of odonates to the export of aquatic productivity to surrounding terrestrial landscape. Emergence varied from 0.8 to 4.9g of wet biomass per m2 of land area per year. Average export of organic carbon was estimated to be 0.30g·m-2·year-1, which is comparable with the average production of herbivorous terrestrial insects in temperate grasslands. Moreover, in contrast to terrestrial insects, emerging odonates contained high quantities of highly unsaturated fatty acids (HUFA), namely eicosapentaenoic acid (20:5n-3, EPA), and docosahexaenoic acid (22:6n-3, DHA), which are known to be essential for many terrestrial animals, especially for birds. The export of EPA+DHA by odonates was found to be 1.92-11.76mg·m-2·year-1, which is equal to an average general estimation of the export of HUFA by emerging aquatic insects. Therefore, odonates appeared to be a quantitatively and qualitatively important conduit of aquatic productivity to forest-steppe ecosystem.

Production of EPA and DHA in aquatic ecosystems and their transfer to the land.

Most omnivorous animals, including humans, have to some degree relied on physiologically important polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from food. Only some taxa of microalgae, rather than higher plants can synthesize de novo high amounts of EPA and DHA. Once synthesized by microalgae, PUFA are transferred through trophic chain to organisms of higher levels. Thus, aquatic ecosystems play the unique role in the Biosphere as the principal source of EPA and DHA for most omnivorous animals, including inhabitants of terrestrial ecosystems. PUFA are transferred from aquatic to terrestrial ecosystems through riparian predators, drift of carrion and seaweeds, emergence of amphibiotic insects, and water birds. The essential PUFA are transferred through trophic chains with about twice higher efficiency than bulk carbon. Thereby, PUFA are accumulated, rather than diluted in biomass of organisms of higher trophic levels, e.g., in fish. Mankind is faced with a severe deficiency of EPA and DHA in diet. Although additional sources of PUFA supply for humans, such as aquaculture, biotechnology of microorganisms and transgenic terrestrial oil-seed producing plants are developed, natural fish production of aquatic ecosystems will remain one of the main sources of EPA and DHA for humans. Aquatic ecosystems have to be protected from anthropogenic impacts, such as eutrophication, pollution and warming, which reduce PUFA production.

Comparison of polyunsaturated fatty acids content in filets of anadromous and landlocked sockeye salmon Oncorhynchus nerka.

Fatty acid composition and content of 2 forms of sockeye salmon Oncorhynchus nerka from lakes in Kamchatka Peninsula (Russia) were compared. One form of sockeye salmon was anadromous ("marine"), that is, adult fish migrated in ocean to feed and grow and than return in the lake to breed. Fish of another form, kokanee, never migrate in the ocean. Per cent levels of the main indicators of nutritive value, eicosapentaenoic acid (EPA, 20:5n-3), and docosahexaenoic acid (DHA, 22:6n-3), were significantly higher in the landlocked O. nerka. However, concentrations of EPA and DHA per wet weight of filets were higher in the marine form, because of the relatively higher content of sum of fatty acids in their muscle tissue. As concluded, fish fed in marine environment had higher contents of long-chain n-3 fatty acids per wet weight than fish of the same species, fed in fresh waters. In general, both the anadromous sockeye salmon and the landlocked kokanee salmon can be recommended for human diet as a valuable product concerning contents of EPA and DHA.

Stable isotope composition of fatty acids in organisms of different trophic levels in the Yenisei River.

We studied four-link food chain, periphytic microalgae and water moss (producers), trichopteran larvae (consumers I), gammarids (omnivorous--consumers II) and Siberian grayling (consumers III) at a littoral site of the Yenisei River on the basis of three years monthly sampling. Analysis of bulk carbon stable isotopes and compound specific isotope analysis of fatty acids (FA) were done. As found, there was a gradual depletion in (13)C contents of fatty acids, including essential FA upward the food chain. In all the trophic levels a parabolic dependence of δ(13)C values of fatty acids on their degree of unsaturation/chain length occurred, with 18:2n-6 and 18:3n-3 in its lowest point. The pattern in the δ(13)C differences between individual fatty acids was quite similar to that reported in literature for marine pelagic food webs. Hypotheses on isotope fractionation were suggested to explain the findings.

Is the fatty acid composition of freshwater zoobenthic invertebrates controlled by phylogenetic or trophic factors?

We studied the fatty acid (FA) content and composition of ten zoobenthic species of several taxonomic groups from different freshwater bodies. Special attention was paid to essential polyunsaturated fatty acids, eicosapentaenoic acid (EPA, 20:5n-3), docosahexaenoic acid (DHA, 22:6n-3), and arachidonic acid (ARA, 20:4n-6); and the n-3/n-6 and DHA/ARA ratios, which are important for consumers of higher trophic levels, i.e., fish. The content and ratios of these FA varied significantly in the studied zoobenthic species, consequently, the invertebrates were of different nutritional quality for fish. Eulimnogammarus viridis (Crustacea) and Dendrocoelopsis sp. (Turbellaria) had the highest nutrition value for fish concerning the content of EPA and DHA and n-3/n-6 and DHA/ARA ratios. Using canonical correspondence analysis we compared the FA profiles of species of the studied taxa taking into account their feeding strategies and habitats. We gained evidence that feeding strategy is of importance to determine fatty acid profiles of zoobenthic species. However, the phylogenetic position of the zoobenthic species is also responsible and may result in a similar fatty acid composition even if species or populations inhabit different water bodies or have different feeding strategies.

Efficiency of transfer of essential polyunsaturated fatty acids versus organic carbon from producers to consumers in a eutrophic reservoir.

One of the central paradigms of ecology is that only about 10% of organic carbon production of one trophic level is incorporated into new biomass of organisms of the next trophic level. Many of energy-yielding compounds of carbon are designated as 'essential', because they cannot be synthesized de novo by consumers and must be obtained with food, while they play important structural and regulatory functions. The question arises: are the essential compounds transferred through trophic chains with the same efficiency as bulk carbon? To answer this question, we measured gross primary production of phytoplankton and secondary production of zooplankton and content of organic carbon and essential polyunsaturated fatty acids of ω-3 family with 18-22 carbon atoms (PUFA) in the biomass of phytoplankton and zooplankton in a small eutrophic reservoir during two summers. Transfer efficiency between the two trophic levels, phytoplankton (producers) and zooplankton (consumers), was calculated as ratio of the primary production versus the secondary (zooplankton) production for both carbon and PUFA. We found that the essential PUFA were transferred from the producers to the primary consumers with about twice higher efficiency than bulk carbon. In contrast, polyunsaturated fatty acids with 16 carbon atoms, which are synthesized exclusively by phytoplankton, but are not essential for animals, had significantly lower transfer efficiency than both bulk carbon, and essential PUFA. Thus, the trophic pyramid concept, which implicitly implies that all the energy-yielding compounds of carbon are transferred from one trophic level to the next with the same efficiency of about on average 10%, should be specified for different carbon compounds.

Content of essential polyunsaturated fatty acids in three canned fish species.

Three canned fish species--Pacific saury (Cololabis saira), Pacific herring (Clupea harengus) and Baltic sprat (Sprattus sprattus)--most common and popular in Russia, were analyzed for fatty acids. Special attention was paid to long-chain essential polyunsaturated fatty acids: eicosapentaenoic acid (20:5omega3) and docosahexaenoic acid (22:6omega3). Sums of eicosapentaenoic acid and docosahexaenoic acid in saury, herring and sprat were, on average, 2.42, 1.80 and 1.43 g/100 g product, respectively. Contents of these essential acids in all the canned fish species were found to be very high compared with many other fish reported in the available literature. All the canned fish appeared to be highly valuable products for human nutrition concerning the content of eicosapentaenoic and docosahexaenoic acids.