Comparison of fatty acid profiles of spawning and non-spawning Pacific herring, Clupea harengus pallasi

Lipids Extracted from Aptocyclus ventricosus Eggs Possess Immunoregulatory Effects on RAW264.7 Cells by Activating the MAPK and NF-κB Signaling Pathways

This study was conducted to evaluate the potential anti-inflammatory and immune-enhancement properties of lipids derived from Aptocyclus ventricosus eggs on RAW264.7 cells. Firstly, we determined the fatty acid compositions of A. ventricosus lipids by performing gas chromatography analysis. The results showed that A. ventricosus lipids contained saturated fatty acids (24.37%), monounsaturated fatty acids (20.90%), and polyunsaturated fatty acids (54.73%). They also contained notably high levels of DHA (25.91%) and EPA (22.05%) among the total fatty acids. Our results for the immune-associated biomarkers showed that A. ventricosus lipids had immune-enhancing effects on RAW264.7 cells. At the maximum dose of 300 µg/mL, A. ventricosus lipids generated NO (119.53%) and showed greater phagocytosis (63.69%) ability as compared with untreated cells. A. ventricosus lipids also upregulated the expression of iNOS, IL-1β, IL-6, and TNF-α genes and effectively upregulated the phosphorylation of MAPK (JNK, p38, and ERK) and NF-κB p65, indicating that these lipids could activate the MAPK and NF-κB pathways to stimulate macrophages in the immune system. Besides their immune-enhancing abilities, A. ventricosus lipids significantly inhibited LPS-induced RAW264.7 inflammatory responses via the NF-κB and MAPK pathways. The results indicated that these lipids significantly reduced LPS-induced NO production, showing a decrease from 86.95% to 38.89%. Additionally, these lipids downregulated the expression of genes associated with the immune response and strongly suppressed the CD86 molecule on the cell surface, which reduced from 39.25% to 33.80%. Collectively, these findings imply that lipids extracted from A. ventricosus eggs might have biological immunoregulatory effects. Thus, they might be considered promising immunomodulatory drugs and functional foods.

Bioenergetic status of swordfish (Xiphias gladius) during the El Niño Southern Oscillation (ENSO) in the Southeast Pacific Ocean: An interannual scale

The bioenergetic status of fishes has been used to study their physiological responses to temporal changes at interannual scales. We evaluated the physiological responses of swordfish at an interannual scale from the El Niño Southern Oscillation (ENSO): warm phase "El Niño" in 2015 to the cold phase "La Niña" in 2017 and under neutral conditions as well in 2019. Herein, muscle samples from females and males were analyzed to evaluate the bioenergetic status from their biochemical constituents (L: lipids, P: proteins and G: glucose, E: total energy, and FAs: fatty acid profile), elemental composition (C: carbon, N: nitrogen, H: hydrogen), and nutritional indices (L:P, C:N, DHA/C18:1n-3, DHA/C16:0 and ω3/ω6 FAs). The physiological response of swordfish showed an interaction between the year and sex. Herein, the L and E showed similar trends, with the lowest female values found in 2015 and the highest in 2019. Contrary, males showed their highest values in 2015 and lowest in 2019. FA profile differed among years and highlighted significant differences between females and males in 2019. Although the female L:P and C:N ratios were lower in 2015 than in 2017, a decreasing trend in these ratios was found from 2017 to 2019. Moreover, DHA/C18:1n-3, DHA/C16:0 and ω3/ω6 showed higher ratios in females than males in 2019. Our results coincide with the beginning of the ENSO phases; it is therefore likely that the swordfish diet changed in response to the disturbances in environmental conditions. Furthermore, the degree of individual dietary specialization found under the neutral conditions could indicate differences in the feeding behaviors of males vs. females, which may be an adaptive strategy in this species. These findings will aid in understanding the bioenergetic status of swordfish under different climatic scenarios and the current global warming, providing relevant information for the management of this resource.

Liver and Plasma Fatty Acid Characterization in Cultured Brown Trout at Distinct Reproductive Stages

Fatty acids are energy sources, and their profiles are used as biomarkers of metabolic status and physiological changes in fish. Within this context, the main aim of this study was to identify the fatty acids that best discriminate the reproductive status of male and female farmed brown trout. The fatty acid composition in liver and plasma samples from the adults of both sexes was monitored along four distinct reproductive stages, namely the spawning capable (December), regressing (March), regenerating (July), and developing (November) stages. Irrespective of the sex and stage, the most representative fatty acids were palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1 n-9), arachidonic acid (20:4 n-6), eicosapentaenoic acid (EPA, 20:5 n-3), and docosahexaenoic acid (DHA, 22:6 n-3). There were no significant sex differences in fatty acid classes in the liver and plasma. Despite this, there were several changes in individual fatty acid levels between the sexes. In the liver, both males and females showed high monounsaturated fatty acid and low polyunsaturated fatty acid (PUFA) levels during the regressing and regenerating stages. At spawning capable and developing stages, a reverse profile was noted. The plasma profiles were mainly influenced by changes in saturated fatty acids and PUFAs in males and by PUFA in females. Based on the most representative fatty acids, four patterns were established for female plasma samples, one for each reproductive stage. This scenario suggests that female plasma samples are promising for the discrimination of gonadal reproductive status, and this potential can be further explored in aquaculture and environmental monitoring studies.

Variability in the energy reserves of swordfish (Xiphias gladius) of the southeastern Pacific Ocean: A temporal and intra-individual perspective

The temporal dynamics of energy reserves are associated with the physiological processes (i.e., reproduction) in marine fishes, in which storage organs play a key role for efficient energy investment. We evaluated the temporal (i.e., seasons) and intra-individual (i.e., organs) dynamics of adult female swordfish (Xiphias gladius) during its feeding period off the Chilean coast in the southeastern Pacific Ocean (SEPO). The biochemical composition (i.e., lipids, proteins, and glucose), energy content and fatty acid profile of the muscle, liver and gonad were evaluated during the austral autumn, winter, and spring. Our results showed principally an intra-individual effect in both the muscle and liver in the autumn and spring. Herein, a trend of higher amounts of lipids and total energy were found in the muscle, while the liver showed greater protein and glucose contents. Consequently, the muscle showed a higher saturated, monounsaturated, and polyunsaturated fatty acid contents than the liver. Although the gonad showed no significant temporal effect in the lipids and proteins contents, an increasing trend of each biochemical constituent, fatty acid group and gonadosomatic index were found from autumn to winter. Consistently, the glucose and total energy content as well Fulton's condition factor were significantly higher in winter. These findings reflect the spatial-temporal physiological dynamic of swordfish based on the storage of energy reserves in different organs during its feeding period. In this way, the products obtained from swordfish could have an added value depending on the season and capture zone, which could benefit the exploitation and regulation measures of this resource under an ecological approach of conservation and sustainability in the SEPO.

Pickering Emulsion Stabilized by β-Cyclodextrin and Cinnamaldehyde/β-Cyclodextrin Composite

A Pickering emulsion was prepared using β-cyclodextrin (β-CD) and a cinnamaldehyde (CA)/β-CD composite as emulsifiers and corn oil, camellia oil, lard oil, and fish oil as oil phases. It was confirmed that Pickering emulsions prepared with β-CD and CA/β-CD had good storage stability. The rheological experiments showed that all emulsions had G' values higher than G″, thus confirming their gel properties. The results of temperature scanning rheology experiments revealed that the Pickering emulsion prepared with β-CD and CA/β-CD composites had high stability, in the range of 20-65 °C. The chewing properties of Pickering emulsions prepared by β-CD and corn oil, camellia oil, lard, and herring oil were 8.02 ± 0.24 N, 7.94 ± 0.16 N, 36.41 ± 1.25 N, and 5.17 ± 0.13 N, respectively. The chewing properties of Pickering emulsions made with the CA/β-CD composite and corn oil, camellia oil, lard, and herring oil were 2.51 ± 0.05 N, 2.56 ± 0.05 N, 22.67 ± 1.70 N, 3.83 ± 0.29 N, respectively. The texture properties confirmed that the CA/β-CD-composite-stabilized-emulsion had superior palatability. After 28 days at 50 °C, malondialdehyde (MDA) was detected in the emulsion. Compared with the β-CD and CA + β-CD emulsion, the CA/β-CD composite emulsion had the lowest content of MDA (182.23 ± 8.93 nmol/kg). The in vitro digestion results showed that the free fatty acid (FFA) release rates of the CA/β-CD composite emulsion (87.49 ± 3.40%) were higher than those of the β-CD emulsion (74.32 ± 2.11%). This strategy provides ideas for expanding the application range of emulsifier particles and developing food-grade Pickering emulsions with antioxidant capacity.

Lipid and fatty acid composition of muscle, liver, ovary, and peritoneal fat in wild flathead grey mullet (Mugil cephalus) according to ovarian development

Wild adult females of a low trophic omnivore teleost species, the flathead grey mullet (Mugil cephalus), caught in the western Mediterranean were sampled. The lipid and fatty acid composition of ovaries, liver, muscle, and peritoneal fat were analysed at previtellogenesis, early-vitellogenesis -first observed at mid-summer (early August)-, late-vitellogenesis, and the post-spawning period -from mid-September to mid-October-. During ovarian development, the lipid content of muscle was low and constant (3.85%-4.92%), indicating that the muscle was not used to store lipids for gonadal growth. Although constant, lipid content in the liver was higher (18.46%-22.62%) than in the muscle, and HSI% increased during gonad development, suggesting a dynamism in the mobilization of the hepatic lipids. Total lipids in the gonads significantly increased with maturation (from 4.90% to 34.59%) in parallel with the GSI (from 0.8% to 15.5%) to decrease after spawning. Peritoneal fat was probably transitional fat that could be rapidly metabolized or transferred to other tissues but no specific function could be assigned because its presence in previtellogenic and early-vitellogenic females varied greatly. One of the main sources of lipids accumulated in the ovary was most likely diet. The total percentage of ΣMUFA, mainly 17:1 -previously not identified in high quantities in teleost vitellogenic ovaries and likely of bacterial origin- and 16:1, strongly increased in the ovaries with maturation. The 16:1 might be an important source of lipids for embryo development. High percentages of DHA, EPA, and ARA were found in the ovary during previtellogenesis available to be used during gonadal maturation. Understanding lipid and fatty acid changes in broodstock tissues can increase our knowledge of the nutritional requirements of the fish used in aquaculture breeding programs.

Determination of trace element and fatty acid levels in tissues of mirror and scaly carp (Cyprinus carpio L., 1758) living in Keban Dam Reservoir (Elazig)

This study investigated the concentrations of some accumulated trace metals (iron, manganese, zinc and copper) and fatty acids in liver and muscle tissues of mirror and scaly carp varieties (Cyprinus carpio L., 1758) living in Keban Dam Reservoir (Elazig), which is the second-largest artificial lake in Turkey that hosts commercially valuable and preferred fish varieties for human consumption. The inductively coupled plasma mass spectrometry (ICP-MS) method was used to analyse the concentrations of trace elements. Fatty acid levels were measured in a gas chromatography mass spectrometry (GC-MS) device, using a flame ionization detector (FID). Considering the two fish varieties and tissues that were studied, the mean metal concentrations (μg g^-1 ) were found in the following ranges: Fe 12.32-49.97, Mn 0.12-0.62, Zn 10.45-86.59 and Cu 2.74-11.86. Although the lowest levels were detected in the muscle tissue for all the metals examined, the levels in the liver tissue were significantly higher. According to the results of the analyses on fatty acid concentrations, the mean total saturated fatty acid levels in the muscle tissue of the scaly carp and mirror carp varieties were found to be 31.07 and 31.43 (%), respectively, whereas these values for the liver tissue were consecutively 22.36 and 22.08 (%). Successively, the mean total levels of unsaturated fatty acids were determined as 68.93 and 68.40 (%) in the muscle tissue and 77.64 and 77.92 in the liver tissue. This study, with the finding that the trace (metallic) element accumulation rates were below the upper limits of the tolerable range, and the examined fish varieties were rich in fatty acids, shows that mirror carp and scaly carp living in Keban Dam Reservoir are highly nutritious for human diets.

Effects of Non-Heated and Heat Processed Krill and Squid Meal-Based Diet on Growth Performance and Biochemical Composition in Juvenile Pacific Bluefin Tuna Thunnus orientalis

This study investigated the effects of krill and squid meal and their heat processing on the growth performance and biochemical composition of juvenile Pacific bluefin tuna (PBT) Thunnus orientalis. An experiment using a 2 × 2 factorial design examined the effects of two dietary protein sources (squid and krill meal) and heat treatment (heated and non-heated). Prey fish were provided to a reference group. Fish with an initial mean weight of 74.1 mg were fed one of the five diets. After six days of the feeding trial, the fish fed with krill meal and non-heated diets showed improved growth compared to those fed with the squid meal and heated diets. Fish fed the non-heated diets showed significantly higher whole-body crude protein and crude lipid contents than fish fed the heated diets. These results suggest that nutrient availability could be improved by using krill meal and the non-heated treatment to improve the growth performance of juvenile PBT.

Impact of spawning season on fillet quality of wild pikeperch (Sander lucioperca)

Pikeperch (Sander lucioperca) is a freshwater fish that has become increasingly popular as a food fish. Within this study, the influence of the spawning process on meat quality was investigated. For this purpose, adult pikeperch was examined directly before and after spawning, and compared regarding physical meat parameters and lipid composition. The results indicate that after spawning, the values of the pH, the electrical conductivity and the yellowness value of fillet were significantly higher than those of the animals sampled before spawning. Analysis of the sum of the total lipid content indicates no differences before and after closed season, but differences in the fatty acid profile were present. Despite significant lower MUFA concentrations, the EPA and DHA showed unaffected high contents. Therefore, the fish muscle indicated an equivalent meat quality. Nevertheless, the significant changes of some physical meat quality parameters after spawning season could have a particular impact on the shelf life and storage of the pikeperch fillet, highlighting the need for further research.

Incorporation of dietary lipids and fatty acids into red drum Sciaenops ocellatus eggs

Embryonic and early larval development and metabolism are fueled entirely by maternally derived nutritional resources (yolk and oil) before the onset of exogenous feeding. Composition of these maternally derived nutrients depends partly on maternal diet. Diet-egg relationships for fatty acids are well described for some species, but little is known about lipid transfer to eggs. To examine the effects of maternal diet on the egg composition, we fed adult red drum Sciaenops ocellatus six different diets, and measured lipid class and fatty acid composition of eggs they produced. Egg lipid class profiles remained relatively stable with only subtle differences in the concentrations of several lipid classes. Neutral lipid classes (wax ester/steryl ester (WE/SE), triglyceride (TG), sterol) varied more than polar lipid classes, with egg TG content being directly related to TG content of maternal diets. Dietary variations rapidly affected fatty acid composition of all major lipid classes in eggs (TG, WE/SE, phosphatidylcholine), with greater effects on neutral lipids than on the polar lipid. Results suggest a degree of maternal control over the provisioning of lipids as structural components (phospholipids) and energy substrates (neutral lipids), which may ensure proper development of larvae. But, egg fatty acid composition within lipid classes is more variable, and this may have consequences for larval survival and performance. This study also suggests that the pathways of maternal-offspring nutrient transfer are likely different for neutral and polar lipids.

Immunomodulatory Activities of Ammodytes personatus Egg Lipid in RAW264.7 Cells

Ammodytes personatus, known as the Pacific sand lance, thrives in cold areas of the North Pacific. In this study, the total lipid was extracted from A. personatus eggs and the fatty acid composition was determined using gas chromatography (GC)-flame ionization detection (FID). The results showed that the extracted lipid contained high content of polyunsaturated fatty acids (PUFAs). The immunomodulatory activities of the A. personatus lipid were investigated using rodent macrophages. First, immune enhancement was analyzed, and the A. personatus lipid significantly and dose-dependently increased the NO production in RAW264.7 cells, and this lipid also regulated the transcription of immune-associated genes in RAW264.7 cells by activating the NF-κB and MAPK pathways. Additionally, flow cytometry revealed that this lipid stimulated phagocytosis. Conversely, the anti-inflammatory activity of the A. personatus lipid was also analyzed and the results showed significantly decreased NO production and gene expression in a dose-dependent manner in LPS-stimulated RAW264.7 cells. In addition, the A. personatus lipid suppressed the LPS-induced phosphorylation of proteins related to the NF-κB and MAPK pathways in LPS-stimulated RAW264.7 cells. Further, flow cytometry demonstrated the lipid-regulated anti-inflammatory activity via inhibition of CD86 expression. The results indicate that A. personatus egg lipid is a potential source of immunomodulation.

Cellular pathways during spawning induction in the starlet sea anemone Nematostella vectensis

In cnidarians, long-term ecological success relies on sexual reproduction. The sea anemone Nematostella vectensis, which has emerged as an important model organism for developmental studies, can be induced for spawning by temperature elevation and light exposure. To uncover molecular mechanisms and pathways underlying spawning, we characterized the transcriptome of Nematostella females before and during spawning induction. We identified an array of processes involving numerous receptors, circadian clock components, cytoskeleton, and extracellular transcripts that are upregulated upon spawning induction. Concurrently, processes related to the cell cycle, fatty acid metabolism, and other housekeeping functions are downregulated. Real-time qPCR revealed that light exposure has a minor effect on expression levels of most examined transcripts, implying that temperature change is a stronger inducer for spawning in Nematostella. Our findings reveal the potential mechanisms that may enable the mesenteries to serve as a gonad-like tissue for the developing oocytes and expand our understanding of sexual reproduction in cnidarians.

Herring Milt and Herring Milt Protein Hydrolysate Are Equally Effective in Improving Insulin Sensitivity and Pancreatic Beta-Cell Function in Diet-Induced Obese- and Insulin-Resistant Mice

Although genetic predisposition influences the onset and progression of insulin resistance and diabetes, dietary nutrients are critical. In general, protein is beneficial relative to carbohydrate and fat but dependent on protein source. Our recent study demonstrated that 70% replacement of dietary casein protein with the equivalent quantity of protein derived from herring milt protein hydrolysate (HMPH; herring milt with proteins being enzymatically hydrolyzed) significantly improved insulin resistance and glucose homeostasis in high-fat diet-induced obese mice. As production of protein hydrolysate increases the cost of the product, it is important to determine whether a simply dried and ground herring milt product possesses similar benefits. Therefore, the current study was conducted to investigate the effect of herring milt dry powder (HMDP) on glucose control and the associated metabolic phenotypes and further to compare its efficacy with HMPH. Male C57BL/6J mice on a high-fat diet for 7 weeks were randomized based on body weight and blood glucose into three groups. One group continued on the high-fat diet and was used as the insulin-resistant/diabetic control and the other two groups were given the high-fat diet modified to have 70% of casein protein being replaced with the same amount of protein from HMDP or HMPH. A group of mice on a low-fat diet all the time was used as the normal control. The results demonstrated that mice on the high-fat diet increased weight gain and showed higher blood concentrations of glucose, insulin, and leptin, as well as impaired glucose tolerance and pancreatic β-cell function relative to those on the normal control diet. In comparison with the high-fat diet, the replacement of 70% dietary casein protein with the same amount of HMDP or HMPH protein decreased weight gain and significantly improved the aforementioned biomarkers, insulin sensitivity or resistance, and β-cell function. The HMDP and HMPH showed similar effects on every parameter except blood lipids where HMDP decreased total cholesterol and non-HDL-cholesterol levels while the effect of HMPH was not significant. The results demonstrate that substituting 70% of dietary casein protein with the equivalent amount of HMDP or HMPH protein protects against obesity and diabetes, and HMDP is also beneficial to cholesterol homeostasis.

Fatty-acid Profiles and Fingerprints of Seven Types of Fish Roes as Determined by Chemometric Methods

The fatty acids in seven species of fish roes were determined by GC-MS in combination with principal component and cluster analyses in order to derive their fatty-acid profiles and fingerprints. Twenty-three common chromatography peaks were identified in the fatty-acid fingerprints of the seven fish roes. A total of 19 typical fatty acids were identified in the fish roes studied. The fatty acid contents of the roes were significantly different, with saturated-fatty-acid contents in the seven roes ranging from 26.69% to 41.81%, and the unsaturated-fatty-acid contents ranging from 57.65% to 72.21%, the total EPA and DHA content (37.20%) is high in E. cypselurus roe, especially. The seven roe species were clearly distinguished according to fatty-acid composition and content by principal component analysis (PCA) and divided into two groups by cluster analysis (CA). PCA of the fatty acid data yielded three significant PCs , which together account for 94% of the total variance; with PC1 contributing 54% of the total.

Belly flap from Norwegian spring-spawning herring (Clupea harengus L.): A potentially new product with high content of vitamin D, EPA and DHA

Processing Norwegian spring-spawning herring (NSSH) yields large amounts of rest raw material which currently is used mainly for production of fish oil and fish meal for feed in aquaculture. However, belly flaps from NSSH might be a profitable resource as a food product. This study investigates the nutritional composition of the belly flaps.

NSSH was harvested in the main season between September and February. Chemical analyses of fatty acids, protein and vitamin A and D in belly flaps were conducted.

Belly flaps from NSSH had a mean fat and protein content of 32.3 ± 6.9 g/100 g and 12.6 ± 0.9 g/100g, respectively. Mean vitamin D level was 53.5 ± 8.5 μg/100 g and mean eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels were 2.0 ± 0.8 g/100g and 2.3 ± 1.0 g/100g, respectively. Belly flap from NSSH contains twice the amount of vitamin D, EPA and DHA compared to NSSH fillet. There were large seasonal variations in the amount of both vitamin D, EPA and DHA. Mean level of vitamin A was 45.0 ± 8.9 μg/100 g. Belly flap from NSSH is a potential product for human consumption with a high nutritional value.

The chemical composition and lipid profile of the chub mackerel (Scomber colias) show a strong seasonal dependence: Contribution to a nutritional evaluation

The seasonal variation in chemical and lipid composition of chub mackerel (Scomber colias) was evaluated monthly over one year (proximate chemical composition and lipid profile: fatty acid (FA) and lipid classes distribution). Significant seasonal changes regarding fat content were noticed (1.3-10.3 g/100 g), with the lowest fat content obtained in February (during spawning period), and the highest in September. Regarding the FA profile, the main fluctuations were recorded in saturated (SFA) and polyunsaturated fatty acids (PUFA). The highest SFA content was registered between March and August (25.3-32.3%). PUFA (the most abundant group) reached its maximum percentual content between December and February (60.9 and 66.9%, respectively). In absolute terms, PUFA attained 5352.6 mg/100 g edible part in September, where 2473.8 mg/100 g of docosahexaenoic acid (DHA, C22:6n-3), representing 46.2% of total PUFA. DHA lowest level was 519.8 mg/100 g, registered in low-fat chub mackerel. Together DHA and EPA (eicosapentaenoic acid, C20:5n-3) represented 75% of the total PUFA and 84% of n-3 PUFA. Triacylglycerols (TAG) with 82.2-92.1% of total lipid content) and phospholipids (4.4-8.4%) were the main lipid classes. Polar lipid fraction (phospholipids), was predominantly constituted by PUFA (68.6-74.5%), mainly DHA (45.2-55.1%), with the highest percentage recorded in low-fat chub mackerel. High relative contents of PUFA (36.6-49.1%) were also found in TAG. Having into account the data obtained, chub mackerel is a privileged source of DHA even in a lean species whereby its consumption should be recommended as part a healthy dietary regime.

Neutral Lipids, Glycolipids, and Phospholipids, Isolated from Sandfish (Arctoscopus japonicus) Eggs, Exhibit Anti-Inflammatory Activity in LPS-Stimulated RAW264.7 Cells through NF-κB and MAPKs Pathways

Total lipids were extracted from sandfish (Arctoscopus japonicus), and then they were separated into the following three lipid fractions: neutral lipids, glycolipids, and phospholipids. In this study, we analyzed the lipid fractions of A. japonicus eggs and we determined their anti-inflammatory activity in RAW264.7 macrophage cells. In these three lipid-fractions, the main fatty acids were as follows: palmitic acid (16:0), oleic acid (18:1n-9), docosahexaenoic acid (DHA, 22:6n-3), and eicosapentaenoic acid (EPA, 20:5n-3). Among the lipid fractions, phospholipids showed the highest concentration of DHA and EPA (21.70 ± 1.92 and 18.96 ± 1.27, respectively). The three lipid fractions of A. japonicus significantly suppressed the production of NO in macrophages. Moreover, they also significantly inhibited the expression of iNOS, COX-2, IL-6, IL-1β, and TNF-α, in a dose-dependent manner. Furthermore, the lipid fractions of A. japonicus suppressed the nuclear translocation of NF-κB p65 subunits in a dose-dependent manner. In addition, they attenuated the activation of MAPKs (p38, ERK1/2, and JNK) phosphorylation in LPS-stimulated RAW264.7 cells. These results indicate that all the lipid fractions of A. japonicus exert anti-inflammatory activity by suppressing the activation of NF-κB and MAPK pathways. Therefore, the lipid fractions of A. japonicus might be potentially used as anti-inflammatory agents.

Dynamics of diet-egg transfer of fatty acids in the teleost fish, red drum (Sciaenops ocellatus)

Eggs of marine organisms are increasingly being recognized as important components of marine food webs. The degree to which egg fatty acid profiles reflect maternal diet fatty acid profiles, and therefore the value of fatty acids in eggs as trophic biomarkers, depends on the species' reproductive strategy and the extent of modification of ingested fatty acids. We measured the dynamics of transfer of recently ingested fatty acids to spawned eggs in a batch-spawning teleost, red drum (Sciaenops ocellatus). Results of 21 diet-shift experiments, from which the fatty acid profiles of the diets and eggs were compared, showed that 15 of 27 fatty acids measured (one saturated, two monounsaturated and 12 polyunsaturated fatty acids) in eggs were correlated with their levels in the recent diet, and the rate of incorporation into eggs was proportional to the magnitude of the diet shift. Large shifts in diet might occur naturally during spawning migrations or when prey communities vary over time. Results of this study indicate that fatty acids in red drum eggs can be useful for studying adult diet and exploring trophic linkages in marine systems. This article is part of the theme issue 'The next horizons for lipids as 'trophic biomarkers': evidence and significance of consumer modification of dietary fatty acids'.

Biogenic Amine, Fatty Acid, and Volatile Compound Contents in Ivorian Traditionally Fermented Fish "Adjuevan"

This study identified biogenic amines, fatty acids, and volatile compounds in adjuevan, an Ivorian traditionally salted and fermented fish. Samples were obtained from two processing methods (method 1: entire fish adjuevan; method 2: both sides filleted adjuevan) with the fish species Galeoides decadactylus. Biogenic amines found in freshly produced adjuevan were histamine, putrescine, cadaverine, tyramine, β-phenyl ethylamine, and spermidine. Among these, the most prevalent were β-phenyl ethylamine and cadaverine. Biogenic amine contents varied according to the processing method but remained lower than levels considered hazardous for human health. The major fatty acids present in adjuevan from method 1 were docosahexaenoic acid, palmitic acid, and oleic acid. In adjuevan from method 2, the major fatty acids were oleic acid, stearic acid, and palmitic acid. The omega (w)-3/w-6 ratio was 8.87 and 4.12 for adjuevan from methods 1 and 2, respectively. Most of the fatty acids are considered healthy fats, making adjuevan a useful food for treating and preventing lifestyle diseases. The volatile compounds found composed of 19 aldehydes, 12 alcohols, 7 esters, 7 ketones, 3 furans, 10 aromatic compounds, and 7 acids with aldehyde, alcohol, and ester compounds as the predominant groups. Among the aldehydes, 2,4-heptadienal (E,Z), octanal, and 2-octenal (E) were most prevalent in adjuevan from method 1, whereas 2-nonenal (E), 2,4-heptadienal (E,Z), and octanal were most prevalent in adjuevan from method 2.

Quantification and Distribution of Omega-3 Fatty Acids in South Pacific Fish and Shellfish Species

Fatty acid composition and distribution in edible species of fish and shellfish captured in the South Pacific were studied, with a focus on n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA). Fatty acids were quantified using gas-chromatography coupled with flame ionization detection (GC-FID), and the distribution of different fatty acids within lipid classes (neutral and polar lipids) was achieved after oil extraction using the Folch method and separation of lipid classes via solid-phase extraction for further GC-FID analysis. Red cusk-eel was the fish species with the lowest content of both EPA and DHA (40.8 and 74.4 mg/100 g, respectively) whereas mackerel contained the highest amount (414.7 and 956.0 mg/100 g for EPA and DHA, respectively). Sea squirt was the shellfish species with the highest content of EPA and DHA (375.0 and 165.7 mg/100 g, respectively) whereas the lowest amount of EPA + DHA was found in Chilean abalone (63.6 mg/100 g). PUFA were mostly found in neutral or polar lipids depending on the studied species. Indexes used to discuss the nutritional quality of lipids (PUFA/SFA, n-6/n-3 ratio and the hypocholesterolemic/hypercholesterolemic fatty acid index) were calculated and reported in the manuscript. This information provides a novel nutritional insight which may be useful to help nutritionists and other health professionals give more accurate counseling for the population to reach the recommended daily intakes of EPA and DHA.

Marine omega-3 (n-3) phospholipids: A comprehensive review of their properties, sources, bioavailability, and relation to brain health

For several decades, there has been considerable interest in marine-derived long chain n-3 fatty acids (n-3 LCPUFAs) due to their outstanding health benefits. n-3 LCPUFAs can be found in nature either in triglycerides (TAGs) or in phospholipid (PL) form. From brain health point of view, PL n-3 is more bioavailable and potent compared to n-3 in TAG form, as only PL n-3 is able to cross the blood-brain barrier and can be involved in brain biochemical reactions. However, PL n-3 has been ignored in the fish oil industry and frequently removed as an impurity during degumming processes. As a result, PL products derived from marine sources are very limited compared to TAG products. Commercially, PLs are being used in pharmaceutical industries as drug carriers, in food manufacturing as emulsifiers and in cosmetic industries as skin care agents, but most of the PLs used in these applications are produced from vegetable sources that contain less (without EPA, DPA, and DHA) or sometimes no n-3 LCPUFAs. This review provides a comprehensive account of the properties, structures, and major sources of marine PLs, and provides focussed discussion of their relationship to brain health. Epidemiological, laboratory, and clinical studies on n-3 LCPUFAs enriched PLs using different model systems in relation to brain and mental health that have been published over the past few years are discussed in detail.

Anti-Inflammatory Effects of Lipids Extracted from Arctoscopus japonicus Eggs on LPS-Stimulated RAW264.7 Cells

Arctoscopus japonicus is a cold-water marine fish. The present study investigated the fatty acid composition of A. japonicus egg lipids and their anti-inflammatory effects on LPS-stimulated RAW246.7 macrophages. The results showed that A. japonicus egg lipids contained primarily polyunsaturated fatty acids (52.9% of the total fatty acid content; mostly eicosapentaenoic acid [EPA, 21.2 ± 0.5%] and docosahexaenoic acid [DHA, 25.9 ± 0.1%]), followed by monounsaturated fatty acids and saturated fatty acids (23.7% and 23.4%, respectively). A. japonicus egg lipids significantly decreased nitric oxide (NO) production and suppressed the expression of immune-associated genes such as iNOS, COX-2, IL-1β, IL-6, and TNF-α LPS-stimulated RAW246.7 macrophages in dose-dependent manner. A. japonicus egg lipids also reduced the phosphorylation levels of NF-κB p-65, p38, ERK1/2, and JNK, key components of the NF-κB and MAPK pathways, suggesting that the lipid-induced anti-inflammatory activity is related to these signaling pathways. These results indicate that the lipids extracted from A. japonicus eggs have potential biofunctions and might be useful for regulating inflammation in macrophages.

Herring Milt Protein Hydrolysate Improves Insulin Resistance in High-Fat-Diet-Induced Obese Male C57BL/6J Mice

Protein consumption influences glucose homeostasis, but the effect depends on the type and origin of proteins ingested. The present study was designed to determine the effect of herring milt protein hydrolysate (HPH) on insulin function and glucose metabolism in a mouse model of diet-induced obesity. Male C57BL/6J mice were pretreated with a low-fat diet or a high-fat diet for 6 weeks. Mice on the high-fat diet were divided into four groups where one group continued on the high-fat diet and the other three groups were fed a modified high-fat diet where 15%, 35%, and 70%, respectively, of casein was replaced with an equal percentage of protein derived from HPH. After 10 weeks, mice that continued on the high-fat diet showed significant increases in body weight, blood glucose, insulin, and leptin levels and exhibited impaired oral glucose tolerance, insulin resistance, and pancreatic β-cell dysfunction. Compared to mice fed the high-fat diet, the 70% replacement of dietary casein with HPH protein reduced body weight, semi-fasting blood glucose, fasting blood glucose, insulin, leptin, and cholesterol levels and improved glucose tolerance, homeostasis model assessment of insulin resistance (HOMA-IR), and homeostasis model assessment of β-cell function (HOMA-β) indices. The 35% replacement of dietary casein with HPH protein showed moderate effects, while the 15% replacement of dietary casein with HPH protein had no effects. This is the first study demonstrating that replacing dietary casein with the same amount of protein derived from HPH can prevent high-fat-diet-induced obesity and insulin resistance.

Change of Various Characteristics between Spawning and Non-spawning Season in Diploid and Induced Triploid Far Eastern Catfish, Silurus asotus

The purpose of this study is to investigate the differences fatty acids and hormonal parameters in the spawning and non-spawning season between the diploid and induced triploid Far Eastern catfish, Silurus asotus. The measured triploids were produced by cold shock for 50 min at 4℃ in May 2014, the spawning season of diploid was in May, and the non-spawning season was designated in January. Estradiol and testosterone and gonadosomatic index of diploid were higher than those of induced triploid in spawning season (P<0.05), and those of diploid in spawning season were higher than non-spawning season. On the other hand, thyroid stimulating hormone and thyroxine of induced triploid were higher than those of diploid in spawning season (P<0.05). Erythrocyte count of diploid was higher than that of induced triploid in spawning season and non-spawning seasons. Mean corpuscular volume and mean corpuscular hemoglobin of induced triploid were higher than those of diploid in both seasons (P<0.05). Percentages of total saturated fatty acids and n-3 polyunsaturated fatty acids of induced triploid were higher than those of diploid in spawning season, but those of diploid were higher in non-spawning season (P<0.05). Percentages of total mono unsaturated fatty acids and total n-6 polyunsaturated fatty acids of diploid were higher than those of induced triploids in spawning season, while those of induced triploid in non-spawning season were higher (P<0.05). Therefore, induced triploids in the spawning season tend to concentrate on growth and lipid-synthesization, whereas, diploids concentrate on reproduction and gonadal maturation rather than on growth. In non-spawning season, growth and lipid-synthesization were not significantly different between diploid and induced triploid.

Fatty-acid profiles of white muscle and liver in stream-maturing steelhead trout Oncorhynchus mykiss from early migration to kelt emigration

The profiles of specific fatty acids (FA) in white muscle and liver of fasting steelhead trout Oncorhynchus mykiss were evaluated at three periods during their prespawning migration and at kelt emigration in the Snake-Columbia River of Washington, Oregon and Idaho, to improve the understanding of energy change. Twenty-seven FAs were identified; depletion of 10 of these was positively correlated in liver and white muscle of prespawning O. mykiss. To observe relative changes in FA content more accurately over sampling intervals, the lipid fraction of tissues was used to normalize the quantity of individual FA to an equivalent tissue wet mass. Saturated and monounsaturated FAs were depleted between upstream migration in September and kelt emigration in June, whereas polyunsaturated FAs were more conserved. Liver was depleted of FAs more rapidly than muscle. Three FAs were detected across all sampling intervals: 16:0, 18:1 and 22:6n3, which are probably structurally important to membranes. When structurally important FAs of O. mykiss are depleted to provide energy, physiological performance and survival may be affected.

Effect of heat treatment on the n-3/n-6 ratio and content of polyunsaturated fatty acids in fish tissues

The aim of this study was to compare the effect of different heat treatments (pan-frying, oven-baking, and grilling) on the contents of polyunsaturated fatty acids (PUFAs) in fish tissue. Four fish species were examined: pike, carp, cod, and herring. High performance liquid chromatography, coupled with electrospray ionization and mass spectrometric detection (HPLC/ESI/MS), was employed for determination of intact lipid molecules containing n-3 and n-6 PUFAs. Although mostly non-polar lipids (triacylglycerols, TGs) were present in the fish tissue, the PUFAs were present preferentially in the phospholipid fraction. Omnivorous fish species (carp, herring) contained more TGs than did predatory ones (pike, cod). Higher amounts of PUFAs were detected in the marine species than in the freshwater ones. The impact of heat treatments on the lipid composition in the fish tissue seems to be species-specific, as indicated by multivariate data analysis. Herring tissue is most heat-stable, and the mildest heat treatment for PUFA preservation was oven-baking.

Temporal trends in dioxins (polychlorinated dibenzo-p-dioxin and dibenzofurans) and dioxin-like polychlorinated biphenyls in Baltic herring (Clupea harengus)

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyl (dl-PCBs) concentrations in Baltic herring (Clupea harengus) have been relatively stable since the mid to late 1990s. It is unclear why concentrations in Baltic herring are not following the observed decreases in other environmental matrices. Here, changes in long-term temporal trends in Baltic herring were examined. A number of biological variables were examined alongside the temporal trends to investigate whether fish biology e.g., growth (length, weight, age), lipid content, reproductive phase or fishing date may provide an explanation for the temporal trends observed. Significant (p<0.05) decreasing trends were observed for PCDD/F toxic equivalents (TEQPCDD/F) at three of the four sites (lipid weight (lw) and wet weight (ww), Swedish west coast lw only); however, other TEQ values e.g., TEQPCDD, TEQPCDF, TEQdl-PCB, TEQPCDD/F+dl-PCB were inconsistent, decreasing at some sites but not others. In the most recent 10 years of data, fewer significant decreases were seen overall. Over the examined time period, significant decreases (Bothnian Bay, p<0.01, southern Baltic Proper, p<0.02) and increases (Swedish west coast, p<0.02) in lipid content, growth dilution or lack thereof, and significant changes in age were observed. However herring were not randomly selected which biases this result. Continual efforts to decrease PCDD/F and dl-PCB emissions and to locate/reduce hotspots are necessary, while bearing in mind that herring biology may be impeding faster decreases of these chemicals.

Seasonal variations of fatty acid profile in different tissues of farmed bighead carp (Aristichthys nobilis)

Bighead carp (Aristichthys nobilis) is one of the major farmed species of freshwater fish in China. Byproduct volume of bighead carp is significant at up to 60 % of whole fish weight. A better understanding of the nutritional composition is needed to optimize the use of these raw materials. The objective of this research was to characterize seasonal variations of fatty acid profile in different tissues (heads, bones, skin, scales, viscera, muscle and fins) of farmed bighead carp. The fatty acid composition of farmed bighead carp varied significantly with seasons and tissues. The highest lipid content was determined in viscera while the highest EPA and DHA composition were observed in muscle compared to the other tissues. Significantly higher ΣEPA+DHA (%) was recorded in all tissues in summer (June) when compared with those of the other three seasons (p < 0.05). The n-3/n-6 fatty acid ratios in summer ranged from 3.38 to 3.69, nearly three times the ratios of the other three seasons. The results indicated that farmed bighead carp caught in summer could better balance the n-3 PUFA needs of consumers. The byproducts of bighead carp can be utilized for the production of fish oil.

Effect of spawning on furan fatty acid profile of edible muscle and organ tissues from sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus)

The total fatty acid compositions, especially the furan fatty acid (F-acids) profile, from edible muscle (fillet) and organ tissues (brain, eye, ovaries, and testes) of spawning and nonspawning sardine and anchovy were examined. The spawning season had no effect on F-acid profiles of the fillet and all organ tissues, for both fishes. However, differences among the F-acid fraction of the organ tissues were revealed. The F-acid portion was less than 1% of total fatty acid in all samples. Five F-acid congeners were detected in the fillet, eye, and gonads, while the brain contained only four F-acids. Unlike the F-acids, spawning season affected the docosahexaenoic acid (DHA) abundance in fillet and gonads. DHA enrichment occurred in fillets and gonads from spawning sardine and anchovy. The ratio ω3 PUFA/ω6 PUFA decreases between spawning and nonspawning fillets, thus the fillets from spawning fish have higher nutritional value.

Seasonal variation in proximate composition and fatty acid profile of grey triggerfish (Balistes capriscus) captured along the coast of Portugal

Proximate composition (ash, moisture, total protein, and fat contents) and fatty acid profile of Balistes capriscus (grey triggerfish) were assessed over a 6-months period (April to September, 2011) in animals captured along the coast of Peniche (Portugal). High protein (18.9% to 21.4%) and low lipid (0.5% to 0.8%) contents were determined. The highest lipid level was found in June-captured animals. High proportions of n-3 polyunsaturated fatty acids (n-3 PUFA) were observed (53.87 ± 2.00%) together with substantial quantities of oleic acid (27.58 ± 1.09%) and palmitic acid (16.52 ± 0.93%). Docosahexaenoic acid accounted for 77% of the total PUFA and was 7 times more abundant than eicosapentaenoic acid, and the n-3/n-6 ratio was 7.2. Gender did not influence lipid levels and the fatty acid profile, but seasonal variations were observed for PUFA and monounsaturated fatty acid contents. Overall, the nutritional properties of this underexploited species may be comparable to those of other lean fish species with higher economic value.

Development of gas chromatography analysis of fatty acids in marine organisms

The gas chromatographic analysis of fatty acids has attracted considerable interest. In this analysis, the common derivatives of fatty acids, such as fatty acid methyl esters, can be detected using a flame ionization detector and the mass spectra can indicate the true structure of fatty acids. This paper reviews gas chromatographic methods for obtaining fatty acids from marine organisms. The stationary phase and detector for applications in gas chromatography are discussed. This article also reviews the components of fatty acids in marine animals, marine plants and marine microorganisms.

Nutritional evaluation of commercially important fish species of Lakshadweep archipelago, India

Estimation of nutrition profile of edible fishes is essential and thus a bio-monitoring study was carried out to find out the nutritional composition of commonly available fishes in Agatti Island water of Lakshadweep Sea. Protein, carbohydrate, lipid, ash, vitamin, amino acid and fatty acid composition in the muscle of ten edible fish species were studied. Proximate analysis revealed that the protein, carbohydrate, lipid and ash contents were high in Thunnus albacares (13.69%), Parupeneus bifasciatus (6.12%), Hyporhamphus dussumieri (6.97%) and T. albacares (1.65%), respectively. Major amino acids were lysine, leucine and methionine, registering 2.84-4.56%, 2.67-4.18% and 2.64-3.91%, respectively. Fatty acid compositions ranged from 31.63% to 38.97% saturated (SFA), 21.99-26.30% monounsaturated (MUFAs), 30.32-35.11% polyunsaturated acids (PUFAs) and 2.86-7.79% branched fatty acids of the total fatty acids. The ω-3 and ω-6 PUFAs were ranged 13.05-21.14% and 6.88-9.82% of the total fatty acids, respectively. Hence, the fishes of Lakshadweep Sea are highly recommended for consumption, since these fishes are highly enriched with nutrition. The results can be used as a baseline data for comparing the various nutritional profiles of fishes in future.

Restriction fragment length analysis of the cytochrome b gene and muscle fatty acid composition differentiate the cryptic flatfish species Solea solea and Solea aegyptiaca

Overlapping external morphometric characters easily confound the flatfishes Solea aegyptiaca and Solea solea (Soleidae) in areas of the Mediterranean Sea where both species live in sympatry. This leads to uncertainties in the fisheries and marketing of the species, in addition to misinterpretations in biogeography and conservation studies. This paper describes a simple restriction fragment length-based diagnostic test that differentiates S. solea from S. aegyptiaca, as well as from other species of the Soleidae family. Furthermore, the two species living in sympatry in the Gulf of Kavala (North Aegean Sea, Greece) present significant qualitative differences in muscle fatty acid composition, a property that can also be used to distinguish the two cryptic species.

Effects of a diet lacking HUFA on lipid and fatty acid content of intestine and gills of male gilthead seabream (Sparus aurata L.) broodstock at different stages of the reproductive cycle

A feeding experiment was carried out to determine the effect of a diet lacking n-3 and n-6 highly unsaturated fatty acids (HUFA) on lipid and fatty acid content in intestine and gills of male gilthead seabream (Sparus aurata L.) broodstock at different stages of the reproductive cycle: November (pre-spermatogenesis), March (spermatogenesis), and June (post-spermatogenesis). For this purpose, gilthead seabream broodstock were fed either a control diet (C) or an n-3 and n-6 HUFA-deficient diet (D). The results showed no changes in fatty acid content of polar lipids of intestine and gills from fish fed diet C at different stages of the reproductive cycle. However, significant changes were observed in the fatty acid content of neutral lipids in intestine but not in gills in this group. Thus, between November and March, saturates and n-3 HUFA decreased while monoenes increased. In June, the contents of these fatty acids had returned to their initial values (November). Moreover, in fish fed diet D, the fatty acid content of neutral lipid changed in both intestine and gills. In intestine NL, a decrease in saturates and n-3 HUFA and an increment in monoenes were observed from November to June. In gills, a decrease was also observed in n-3 HUFA from NL along the cycle. Nevertheless, n-6 HUFA content remained unchanged. These results show both tissue specificity in seasonal mobilization of fatty acids linked to reproductive processes and the influence of dietary fatty acids on body composition.

Risks and benefits of fish consumption for childbearing women

Pregnant women's fish consumption provides both benefits and risks to the developing fetus. Docosahexaenoic acid (DHA) from fish may enhance fetal neurodevelopment, while methylmercury (MeHg) can have detrimental effects. Dietitians would benefit from information on the frequency with which fish species may be consumed to increase DHA intake among Canadian women of childbearing age, and on minimizing the risks from MeHg, especially for those who consume fish frequently. Eighteen fish species were selected for DHA and mercury analysis from retail markets in the Toronto area. Consumption scenarios using analytical results for these fish species indicate that women of childbearing age can consume nine of 18 fish species every day (14 servings a week) or often (up to four servings a week) and remain below toxicological benchmarks for mercury. Moreover, women can also attain the recommended DHA level by consuming six of those nine fish: four 75-g servings of smelt, porgie, or bluefish a week, or two 75-g servings of milkfish, silver pomfret, or tilapia a day. Our analysis indicates that the DHA level recommended for childbearing women can be attained through fish consumption alone, without the need for supplementation and without posing a risk to the woman (or the fetus) from mercury.