Fatty Acid Profiles in the Gonads of Red King Crab (Paralithodes camtschaticus) from the Barents Sea

Fatty Acids in the Eggs of Red King Crabs from the Barents Sea

The red king crab, Paralithodes camtschaticus, was introduced into the Barents Sea where, after a period of 30 years of adaptation, it has established a new population. This population has been commercially exploited over the past two decades, supporting profitable fisheries in both Russia and Norway. Biochemical studies aimed at assessing fatty acid profiles have been conducted, focusing primarily on the edible parts of red king crabs. Only recently have by-products been included in this research. Capture of female red king crabs is prohibited in Russia but is allowed in Norway. The fatty acids of the egg masses carried by these females have not yet been studied. To fill this knowledge gap, we assayed the fatty acid composition of eggs using gas-liquid chromatography. Our results showed a predominance of polyunsaturated fatty acids, while the concentrations of saturated and monounsaturated fatty acids were similar. Multivariate comparisons showed no significant differences in fatty acid profiles in terms of egg developmental stage (nauplius vs. metanauplius), habitat conditions (soft vs. hard bottoms), female size class, or number of autotomized limbs. However, individual comparisons showed some differences in fatty acids, the most important being the lower content of docosahexaenoic acid in eggs at the metanauplius stage compared to eggs at the nauplius stage, which is likely due to its essential role in the development of red king crab embryos. The total fatty acid content (53.94 mg g-1) was 2-87 times higher in eggs than in other red king crab tissues, confirming the critical role that fatty acids play in maintaining physiological processes during vitellogenesis. The high content of essential fatty acids and an optimal omega-3-to-omega-6 ratio (4.9) suggest that red king crab eggs are a good product for a healthy diet and a valuable source for extracting essential fatty acids.

Nutritional Quality and Fatty Acids Composition of Invasive Chinese Mitten Crab from Odra Estuary (Baltic Basin)

The Chinese mitten crab (Eriocheir sinensis) is recognized as an invasive species in Europe but increasing fishing efforts may hold economic benefits and yield positive ecological and nutritional outcomes. The objective of this study was to determine the yield of edible parts and the compositional and nutritional characteristics of this crab, especially as a source of n-3 PUFA. The overall yield of edible parts amounted to 38.09%, with males (27.72%) exhibiting a higher meat content compared to females (25.30%). The gonads displayed the highest protein content (24.12%), while the hepatopancreas (11.67%) showcased the highest fat content. Furthermore, the fatty acid composition varied depending on the distribution within different crab segments and gender and individual size. Notably, the gonad lipids contained the most nutritionally valuable n-3 fatty acids, followed by muscle and hepatopancreas lipids. The determined index of atherogenicity (IA) from 0.2 for gonadal lipids to 0.42 for hepatopancreas lipids, index of thrombogenicity (IT) in the range of 0.10 for gonads to 0.41 for hepatopancreas, and flesh lipid quality (FLQ) from 6.9 for hepatopancreas to 23 for muscle lipids indicate their pro-health properties. The ratio of n-3 to n-6 fatty acids showed Chinese mitten crab as an excellent source of oil that can be used for food fortification and dietary supplement production.

Fatty Acid Composition of Northern Pike from an Arctic River (Northeastern Siberia, Russia)

We assayed the fatty acid composition of muscles of the northern pike Esox lucius Linnaeus, 1758 inhabiting the Gyda River, Siberia, Russia using gas-liquid chromatography. Of 43 fatty acids identified in the pike samples, 23 fatty acids accounted for 99.3% of the total content. The most abundant saturated fatty acids (SFA, 31.6%) were palmitic (C16:0, 20.0%) and stearic (C18:0, 7.3%) acids. Among monounsaturated fatty acids (MUFA, 15.1%), oleic acid (C18:1n9, 10.2%) and palmitoleic acid (C16:1, 4.1%) demonstrated the highest levels. The most represented polyunsaturated fatty acids (PUFA, 53.3%) were arachidonic acid (C20:4n-6, 7.6%), eicosapentaenoic acid (EPA, C20:5n-3, 7.3%), and docosahexaenoic acid (DHA, C22:6n-3, 26.3%). The fatty acid profile of specimens from the Gyda River was different in comparison to profiles found in other pike populations, most likely due to different diets. Pike flesh has good nutrition quality in terms of a low n-6/n-3 ratio (0.36), low atherogenic (0.39), and thrombogenic (0.22) indices, and a high ratio of hypocholesterolemic to hypercholesterolemic fatty acids (2.83), and this species can be recommended as a replacement or alternative to other fish sources in traditional diets.