Lipase selectivity toward fatty acids commonly found in fish oil

The main objective of this study was to compare the fatty acid selectivity of numerous commercially available lipases toward the most ubiquitous fatty acids present in fish oils in form of their corresponding ethyl esters. Special interest was taken in their ability to separate the n‐3 long‐chain polyunsaturated fatty acids (PUFA), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), from the more saturated fatty acids as well as exploiting the putative discrimination between these highly valuable n‐3 PUFA. Hydrolysis of sardine oil ethyl esters in a Tris buffer solution by 12 microbial lipases is described. The results reveal that all of the lipases strongly discriminate against the n‐3 PUFA and prefer the more saturated fatty acids as substrates. Most of the lipases discriminate between EPA and DHA in favor of EPA, however, 2 bacterial lipases from Pseudomonas were observed to prefer DHA to EPA. Digestive lipolytic enzymes isolated from salmon and rainbow trout intestines displayed reversed fatty acid selectivity when their fish oil triacylglycerol hydrolysis was studied. Thus, the n‐3 PUFA including EPA and DHA were observed to be hydrolyzed at a considerably higher rate than the more saturated fatty acids.     

The effects of season on fat and fatty acids contents of shrimp and prawn species

The effects of seasons on the lipid content and fatty acid compositions of five different shrimp and prawn species (green tiger prawn – Penaeus semisulcatus, kuruma prawn – Marsupenaeus japonicus, caramote prawn – Melicertus kerathurus, deepwater pink shrimp – Parapenaeus longirostris, speckled shrimp – Metapenaeus monoceros) were evaluated. Results showed that lipid content ranged from 0.89 to 1.55% in muscle, showing that all species were considered as lean. There were significant differences (p<0.05) in the levels of saturated fatty acids (SFA), monounsaturated fatty acids and polyunsaturated fatty acids (PUFA) in terms of season and species. They were rich in n‐3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The highest proportions of EPA were obtained from kuruma prawn (180.9 mg/100 g) in spring and deepwater pink shrimp (173.2 mg/100 g) and caramote prawn (146.3 mg/100 g) in summer. Kuruma prawn had the highest DHA in spring (140.8 mg/100 g) followed by deepwater pink shrimp (132.2 mg/100 g) and caramote prawn (129.6 mg/100 g) in summer. The results also showed that the seasons affected lipid content and the fatty acid composition of shrimp and prawn species. Practical Application: The beneficial effect of seafood consumption on human health has been related to the high content of n‐3 fatty acids, especially EPA (20:5n‐3) and DHA (22:6n‐3). The ratios of n‐6/n‐3, PUFA/SFA and EPA + DHA are considered as useful criteria for comparing relative nutritional and oxidation values of marine oils. In the current study, the influence of seasonality on the lipid content and the fatty acid compositions of shrimp and prawn were investigated in order to find the best source of n‐3 fatty acids during the year.     

Fatty Acid-Specific Alterations in Leptin,PPARα, and CPT-1 Gene Expression in the Rainbow Trout

It is known that fatty acids (FA) regulate lipid metabolism by modulating the expression of numerous genes. In order to gain a better understanding of the effect of individual FA on lipid metabolism related genes in rainbow trout (Oncorhynchus mykiss), an in vitro time‐course study was implemented where twelve individual FA (butyric 4:0; caprylic 8:0; palmitic (PAM) 16:0; stearic (STA) 18:0; palmitoleic16:1n‐7; oleic 18:1n‐9; 11‐cis‐eicosenoic 20:1n‐9; linoleic (LNA) 18:2n‐6; α‐linolenic (ALA) 18:3n‐3; eicosapentenoic (EPA) 20:5n‐3; docosahexaenoic (DHA) 22:6n‐3; arachidonic (ARA) 20:4n‐6) were incubated in rainbow trout liver slices. The effect of FA administration over time was evaluated on the expression of leptin, PPARα and CPT‐1 (lipid oxidative related genes). Leptin mRNA expression was down regulated by saturated fatty acids (SFA) and LNA, and was up regulated by monounsaturated fatty acids (MUFA) and long chain PUFA, whilst STA and ALA had no effect. PPARα and CPT‐1mRNA expression were up regulated by SFA, MUFA, ALA, ARA and DHA; and down regulated by LNA and EPA. These results suggest that there are individual and specific FA induced modifications of leptin, PPARα and CPT‐1 gene expression in rainbow trout, and it is envisaged that such results may provide highly valuable information for future practical applications in fish nutrition.     

GC-EI-MS Analysis of Fatty Acid Composition in Brain and Serum of Twitcher Mouse

Globoid cell leukodystrophy or Krabbe disease is an inherited autosomal recessive disorder caused by mutations in the galactosylceramidase gene. The objective of the study was to present information about the fatty acid (FA) composition of the brain and serum of twitcher mice, a mouse model of Krabbe disease, compared to wild type, in order to identify biomarker of disease progression. We defined the FA profiles by identifying the main components present in serum and brain using GC‐EI‐MS analysis. The FA percentage composition was measured and data were analyzed considering the disease and the mouse age as experimental factors. Significant correlations were established, both in brain and in serum, in the fatty acid percentage composition of twitcher compared to wild type mice. The most abundant saturated fatty acid in brain was the palmitic acid (C16:0) with mean values significantly increased in twitcher mouse (p = 0.0142); moreover, three monounsaturated, three polyunsaturated (PUFA) and a plasmalogen were significantly correlated to disease. In the serum highly significant differences were observed between the two groups for three polyunsaturated fatty acids. In fact, the docosahexaenoic acid (C22:6n3c) content was significantly increased (p = 0.0116), while the C20 PUFA (C20:3n6c and C20:5n3c) were significantly decreased in twitcher serum samples. Our study shows a specific FA profile that may help to define a possible pattern that could distinguish between twitcher and wild type; these data are likely to provide insight in the identification of new biomarkers to monitor the disease progression and thereby permit the critical analysis of therapeutic approaches.     

White Bass (<Emphasis Type="Italic">Morone chrysops</Emphasis>) Preferentially Retain n-3 PUFA in Ova When Fed Prepared Diets with Varying FA Content

We evaluated the fatty acid (FA) composition of broodstock white bass ova fed one of six commercial diets with increasing polyunsaturated FA content (n‐6/n‐3 ratio; 0.36, 0.39, 0.46, 0.83, 1.07, 1.12) eight weeks prior to sampling. Fatty acid profiles of ova from brooders fed each of the six diets were significantly altered according to canonical discriminant analysis. Ova FA profiles resulting from the 0.39 diet separated those from the 0.36 diet based on lower 18:2n‐6 (LNA) and higher 20:1n‐9 concentrations from the 0.36 diet. Ova profiles were further separated based on lower concentrations of 22:5n‐3 (DPA) from the 0.46 diet, lower concentrations of 20:5n‐3 (EPA) in the 1.12 and 0.83 diets, and lower concentrations of 22:6n‐3 (DHA) in all other diets relative to the 0.46 diet. Changes in ova FA profile at four and eight weeks were consistent with dietary intake with an approximate 2% increase in any given FA class with increasing time on individual diet. There was no correlation between dietary ARA concentrations (0.7–1.1 mol%), or dietary EPA/ARA ratios (7–15), and the concentrations (1.4–1.7 mol%) or ratios (3.3–4.4) found in the ova by diet. Our results suggest that white bass females have the ability to preferentially incorporate n‐3 PUFA, particularly DHA, suggesting mobilization of this FA from other tissues for ova deposition or preferential dietary incorporation of PUFA into ova. These results will add to the limited FA information available in white bass and enable nutritionists to formulate broodstock diets that maximize reproductive potential in this species.     

Application of Silver Ion High-Performance Liquid Chromatography for Quantitative Analysis of Selected n-3 and n-6 PUFA in Oil Supplements

The aim of this study was to develop a simple method for simultaneous determination of selected cis/cis PUFA–LNA (18:2), ALA (18:3), GLA (18:3), EPA (20:5), and DHA (22:6) by silver ion high‐performance liquid chromatography coupled to a diode array detector (Ag‐HPLC‐DAD). The separation was performed on three Luna SCX Silver Loaded columns connected in series maintained at 10 °C with isocratic elution by 1 % acetonitrile in n‐hexane. The applied chromatographic system allowed a baseline separation of standard mixture of n‐3 and n‐6 fatty acid methyl esters containing LNA, DHA, and EPA and partial separation of ALA and GLA positional isomers. The method was validated by means of linearity, precision, stability, and recovery. Limits of detection (LOD) for considered PUFA standard solutions ranged from 0.27 to 0.43 mg L^?1. The developed method was used to evaluate of n‐3 and n‐6 fatty acids contents in plant and fish softgel oil capsules, results were compared with reference GC‐FID based method.     

Preferential effect of lead exposure during lactation on non-essential fatty acids in maternal organs

This study determined the effects of lead exposure during the lactational period on maternal organ FA compositions in rat dams that were fed either an n−3 adequate (n−3 Adq) or deficient (n−3 Def) diet prior to conception. On giving birth, dams were subdivided into four groups in a 2×2 design with n−3 FA supply and Pb exposure as the dependent variables. Pb acetate (0.2 wt%) was administered in the drinking water from the time they gave birth to weaning 3 wk later. Following weaning, the dams were decapitated. and the liver, plasma, kidney, brain, and retina analyzed for FA composition. The n−3 deficient diets markedly decreased the percentages of total n−3 FA, including docosahexaenoic acid (DHA), and increased total n−6 FA including both arachidonic (AA) and n−6 docosapentaenoic acids in all tissues (P<0.05). The principal effects of Pb occurred in the liver and plasma, where 20–32% losses in total FA concentration concurrent with increased relative percentages of AA (P<0.05) were observed. In kidney, the percentages of AA and DHA also increased after Pb exposure (P<0.05) with lesser effects in the nervous system. There was a diet x Pb interaction for liver, plasma, and retinal 20-C n−6 PUFA (P<0.05). Generally, shorter-chain saturated and monounsaturated FA concentrations were decreased after Pb exposure. An analysis of the changes in the tissue concentrations induced by Pb indicated that the increases in the percentages of PUFA likely reflected a preferential loss of non-EFA. The mechanisms by which Pb affects saturated and monounsaturated FA concentration are unknown.     

Effect of dietary organic selenium on fatty acid composition in nutria (Myocastor coypus Mol.) livers

Young, female nutrias (n = 13) were fed a diet supplemented with 0.36 mg/kg selenium in selenium‐enriched yeast (SeY; Sel‐Plex; Alltech, Inc., Nicholasville, KY) for 60 days (total Se concentration in the basal diet was ～0.1 mg/kg). Concentrations of fatty acids (FA) in the liver were compared to those of nutrias on a control diet (n = 11). Animals were sacrificed at 8 months of age and liver samples (approximately 30 g) were collected. The gas‐chromatographic analysis of tissue samples from the experimental group revealed a significant decrease in saturated fatty acids (p<0.001), monounsaturated fatty acid (p = 0.006), and polyunsaturated fatty acid (PUFA) (p = 0.02) compared to controls. The linoleic and linolenic acids, which are precursors of n‐6 and n‐3 PUFA, respectively, were significantly lower (p = 0.01 and p<0.001, respectively) in the supplemented group. The n‐6 to n‐3 PUFA ratio was significantly affected (p = 0.001) by the SeY dietary supplement (13.17 vs. 8.93, respectively).     

HPLC‐APCI analysis of triacylglycerols in milk fat from different sources

Triacylglycerols (TAG) from milk‐fat from different sources (cow, goat and human milks) were characterised using non‐aqueous reversed phase high‐performance liquid chromatography–atmospheric‐pressure chemical ionisation, coupled to MS/MS (RP HPLC‐APCI MS/MS). The fatty‐acid content of all samples was also established by methyl transesterification and GC‐MS analysis. Optimisation of the HPLC gradient, combined with APCI tandem MS, enables TAGs complex mixtures to be analysed without prior separation. More than 160 different glycerides were identified; between 50 and 70 compounds were identified in the chromatograms of each sample. This method also enabled the principal TAG regioisomers to be recognized. The study focused on the investigation of the structure of TAGs containing very‐long‐chain PUFA, namely all cis‐ 4,7,10,13,16,19‐ DHA (DHA, C_{22:6, n‐3}) and all cis‐5,8,11,14,17‐eicosapentaenoic acid (EPA, C_{20:5, n‐3}), both in human and in n‐3‐enriched cow's milks. Ten TAGs containing DHA were identified in human milk and only one in milk from cows fed an n‐3 enriched diet.     

Dietary Linseed Oil Reduces Growth While Differentially Impacting LC-PUFA Synthesis and Accretion into Tissues in Eurasian Perch (Perca fluviatilis)

The aim of this study was to evaluate the impact of replacing dietary fish oil (FO) with linseed oil (LO) on growth, fatty acid composition and regulation of lipid metabolism in Eurasian perch (Perca fluviatilis) juveniles. Fish (17.5 g initial body weight) were fed isoproteic and isoenergetic diets containing 116 g/kg of lipid for 10 weeks. Fish fed the LO diet displayed lower growth rates and lower levels of DHA in the liver and muscle than fish fed the FO diet, while mortality was not affected by dietary treatment. However, DHA content recorded in the liver and muscle of fish fed the LO diet remained relatively high, despite a weight gain of 134 % and a reduced dietary level of long‐chain polyunsaturated fatty acids (LC‐PUFA), suggesting endogenous LC‐PUFA biosynthesis. This was supported by the higher amounts of pathway intermediates, including 18:4n‐3, 20:3n‐3, 20:4n‐3, 18:3n‐6 and 20:3n‐6, recorded in the liver of fish fed the LO diet in comparison with those fed the FO diet. However, fads2 and elovl5 gene expression and FADS2 enzyme activity were comparable between the two groups. Similarly, the expression of genes involved in eicosanoid synthesis was not modulated by dietary LO. Thus, the present study demonstrated that in fish fed LO for 10 weeks, growth was reduced but DHA levels in tissues were largely maintained compared to fish fed FO, suggesting a physiologically relevant rate of endogenous LC‐PUFA biosynthesis capacity.     

Fatty Acids in Liver,Muscle and Gonad of three Tropical Rays including Non-Methylene-Interrupted Dienoic Fatty Acids

Scientific investigation of lipids in Elasmobranchs has been conducted mainly on shark species. Because rays seem to be neglected, this study was performed to examine the complete fatty acid (FA) composition with a particular interest for long-chain polyunsaturated FA (PUFA) content in different tissues of three ray species including parts usually discarded. The total FA and PUFA profiles of total lipids were determined in muscle, liver, and gonad of Rhinobatos cemiculus, Rhinoptera marginata, and Dasyatis marmorata, the most often caught ray species from the East Tropical Atlantic Ocean. Fifty FA were characterized as methyl esters and N-acyl pyrrolidides by gas chromatography/mass spectrometry, showing significant levels of 20:5n-3 (EPA) (up to 5.3%) and 22:5n-3 (DPA) (up to 7.3%), high levels of 20:4n-6 arachidonic (ARA) (4.8–8.6% of total FA) and 22:6n-3 (DHA) (up to 20.0%). The results show that muscle, liver and gonad of rays can provide high amounts of essential PUFA, specially DHA, for direct human nutrition or the food processing industry. High proportions of DHA were particularly found in all samples of R. cemiculus (11.6–20.0%), and in muscle and liver of D. marmorata (11.1–16.1%). Regarding the high amounts of (n-3) PUFA, this study shows that these rays deserve a better up-grading, including the normally discarded parts, and describes the occurrence of unusual NMID FA in all tissues studied. Five non-methylene-interrupted dienoic fatty acids (NMID FA) (0–3.4%) were reported, including previously known isomers, namely 20:2 Δ7,13, 20:2 Δ7,15, 22:2 Δ7,13, 22:2 Δ7,15, and new 22:2 Δ6,14. These acids are quite unusual in fish and unprecedented in rays. The 22:2 Δ6,14 acid occurred in gonads of male specimens of R. cemiculus at 2.9%.     

Differential Response to an Algae Supplement High in DHA Mediated by Maternal Periconceptional Diet: Intergenerational Effects of n-6 Fatty Acids

Algae high in docosahexaenoic acid (DHA) may provide a source of long‐chain omega‐3 polyunsaturated fatty acids (LCn‐3PUFA) for inclusion in the diet of lambs to improve the LCn‐3PUFA status of meat. The effect of background LCn‐3PUFA status on the metabolism of high DHA algae is, however, unknown. The aim of the current study was to determine whether the response to a high in DHA algae supplement fed to lambs for six weeks prior to slaughter was mediated by a maternal periconceptional diet. Forty Poll Dorset × Border Leicester × Merino weaner lambs were allocated to receive either a ration based on oat grain, lupin grain, and chopped lucerne (control) or the control ration with DHA‐Gold? algae included at 1.92 % DM (Algae) based on whether the dams of lambs had previously been fed a diet high in n‐3 or n‐6 around conception. LCn‐3PUFA concentration was determined in plasma and red blood cells (RBC) prior to and following feeding. The concentrations of EPA and DHA in the plasma and RBC of lambs receiving the control ration were significantly (p < 0.001) lower when lambs received the ration for 14 days compared with pre‐feeding concentrations. The concentrations of EPA and DHA were also significantly (p < 0.001) higher when lambs consumed the Algae ration compared with the control ration for 42 days. The increase in EPA and DHA was, however, significantly (p < 0.05) lower if lamb dams had previously been fed a diet high in n‐6 at conception. Assessing the previous nutrition and n‐3 status of lambs may allow producers to more accurately predict the likely response to supplements high in LCn‐3PUFA, particularly, DHA.     

Seasonal fat and fatty acids variations of seven marine fish species from the Mediterranean Sea

Seasonal variations of proximate compositions, muscle lipids and fatty acids (FA) of seven seawater species (Silllago sihoma, Upeneus pori, Sparus aurata, Saurida undosquamis, Epinephelus auneus, Mullus barbatus, Solea solea) from the Mediterranean Sea, were determined in all seasons. The results showed that the fatty acid compositions of each species ranged from 26.41 to 38.70% saturated (SFA), 13.78 to 26.52% monounsaturated (MUFAs) and 25.02 to 50.83% PUFAs. The highest proportions of EPA were obtained from M. barbatus (8.34%) in spring, S. sihoma (7.54%), U. pori (6.75%), S. aurata (6.31%), S. undosquamis (5.12%), E. auneus (5.10%) in summer, and also S. solea (6.19%) in spring. The highest proportions of DHA were found in spring, ranging from 25.14% for M. barbatus to 34.87% for S. aurata, except for S. solea (30.44%) in winter and S. sihoma (15.83%) in summer. The results showed that from a quality point of view, all species were suitable for human nutrition, since muscle lipids are rich in EPA + DHA in all seasons. Practical application : The American and Canadian Dietetic Associations recommend two servings of fatty fish per week and a daily combined intake of EPA and DHA of 500 mg. This follows a trend of numerous publications and other guidelines recognizing the health benefits of long‐chain n‐3 PUFA from fish or marine microbial sources with respect to cardiovascular health, neurological diseases, infant health and development, inflammation and cancer and other health effects. The seven species analyzed here provide muscle lipids that are rich in EPA and DHA. Only minor season‐to‐season changes in the total content of n‐3 and n‐6 PUFA were observed for the same species. The results provide valuable information for preparing diet tables.     

Plasma Phospholipid Fatty Acid Profile is Altered in Both Septic and Non-Septic Critically Ill: A Correlation with Inflammatory Markers and Albumin

This study analyzes fatty acid (FA) composition in plasma lipids and erythrocyte phospholipids while comparing septic and non‐septic critically ill patients. The aim was to describe impacts of infection and the inflammatory process. Patients with severe sepsis (SP, n = 13); age‐, sex‐ and APACHE II score‐matched non‐septic critically ill with systemic inflammatory response syndrome (NSP, n = 13); and age‐/sex‐matched healthy controls (HC, n = 13) were included in a prospective case–control study during the first 24 h after admission to the intensive care unit. In both SP and NSP, lower n‐6 polyunsaturated FA (PUFA) accompanied by higher proportions of monounsaturated FA (MUFA) in plasma phospholipids (PPL) was observed relative to HC. MUFA proportion was negatively correlated with n‐6 PUFA, high density lipoprotein cholesterol (HDL‐C), and albumin. MUFA was positively correlated with C‐reactive protein (CRP), procalcitonin (PCT), interleukins (IL‐6, IL‐10), oxidized low density lipoproteins (ox‐LDL), and conjugated dienes (CD). In both SP and NSP, inflammatory and lipid peroxidation markers were significantly higher—CRP (p < 0.001; p = 0.08), IL‐6, IL‐10, TNF‐α (p < 0.01, p = 0.06), ox‐LDL, and CD while total cholesterol, HDL‐C, LDL‐C albumin, and 20:4n‐6/22:6n‐3 and n‐6/n‐3 ratios were lower compared to HC. In conclusion, the changes in plasma lipid FA profile relate to the intensity of inflammatory and peroxidative response regardless of insult etiology. The lower MUFA and higher n‐6 PUFA proportions in PPL were inversely correlated with cholesterol and albumin levels.     

Effects of the flaxseed oil on the fatty acid composition of tilapia heads

The objective of this study was to evaluate the effects of adding flaxseed oil (FO) to feed on the incorporation of n‐3 PUFA in tilapia heads. Tilapia were given diets with increasing levels of FO (0.00, 1.25, 2.50, 3.75 and 5.00% for treatments A, B, C, D and E, respectively), as a source of LNA for 150 days. The proximate composition of the heads indicated high nutritional value and 40 FA (fatty acids) common to all treatments were identified in total lipids. Intake of LNA caused storage of LNA and sequential desaturation‐elongation to eicosapentaenoic acid (EPA) and DHA. With increasing levels of FO in the diet, the content of LNA in tilapia heads increased (1.7 and 14.0% for diets A and E, respectively), as well as the contents of EPA (0.1 and 0.9% for diets A and E, respectively) and DHA (0.5 and 1.8% for diets A and E, respectively). Adding FO to tilapia feed markedly increased the total content of n‐3 PUFA (3.0 and 21.1% for diets A and E, respectively), decreased the total content of n‐6 PUFA (41.3 and 24.9% for diets A and E, respectively), and consequently resulted in a decrease in the n‐6/n‐3 ratio (13.8 and 1.2 for diets A and E, respectively). Therefore, feeding tilapia with FO is a good way of valorizing this part of the fish by creating a valuable nutritional food source.     

Relationships between the fatty acid composition of muscle and erythrocyte membrane phospholipid in young children and the effect of type of infant feeding

Muscle membrane fatty acid (FA) composition is linked to insulin action. The aims of this study were to compare the FA composition of muscle and erythrocyte membrane phospholipid in young children; to investigate the effect of diet on these lipid compositions; and to investigate differential incorporation of FA into muscle, erythrocyte and adipose tissue membrane phospholipid, and adipose tissue triglyceride. Skeletal muscle biopsies and fasting blood samples were taken from 61 normally nourished children (15 males and 16 females), less than 2 yr old (means ±SE, 0.80±0.06 yr), undergoing elective surgery. Adipose tissue samples were taken from 15 children. There were significant positive correlations between muscle and erythrocyte docosahexaenoic acid (DHA) (r=0.44, P<0.0001), total n−3 polyunsaturated fatty acids (PUFA) (r=0.39, P=0.002), and the n−6/n−3 PUFA ratio (r=0.39, P=0.002). Adipose tissue triglyceride had lower levels of long-chain PUFA, especially DHA, than muscle and erythrocytes (0.46±0.18% vs. 2.44±0.26% and 3.17±0.27%). Breast-fed infants had higher levels of DHA than an age-matched group of formulafed infants in both muscle (3.91±0.21% vs. 1.94±0.18%) and erythrocytes (3.81±0.10% vs. 2.65±0.23%). The results of this study show that (i) erythrocyte FA composition is a reasonable index of muscle DHA, total n−3 PUFA, and the n−6/n−3 PUFA ratio; (ii) breast feeding has a potent effect on the FA composition of all these tissues; and (iii) there is a wide range in long-chain PUFA levels in muscle, erythrocytes, and adipose tissue.     

One-Step Extraction and Concentration of Polyunsaturated Fatty Acids from Fish Liver

The fatty acids (FA) eicosapentaenoic acid (20:5ω-3; EPA) and docosahexaenoic acid (22:6ω-3; DHA), which have several health benefits, have been concentrated from mako shark liver (Isurus oxyrinchus). The process was carried out in one single step, in which fish liver oil was simultaneously extracted, saponified and concentrated. Additionally, the polyunsaturated fatty acids (PUFA) concentrate was winterized to crystallize the remaining saturated FA, resulting in a further increase in the concentration of DHA and EPA. Two variables, temperature and water concentration in the saponification mixture, were optimized to increase the concentration of ω-3 PUFA. Best results were obtained at 12 °C and 0% water content in the mixture, obtaining 17.8% purity and 77.6% yield of EPA; DHA purity and yield were 33.3 and 82.2%, respectively.     

Fatty Acid Composition of Tropical Fish Depends on Reservoir Trophic Status and Fish Feeding Habit

Eutrophication results in a deficiency of n‐3 LC‐PUFA (long‐chain polyunsaturated fatty acids) in aquatic food chains, affecting fish nutrition and physiology. The trophic transfer of FA (fatty acids) to fish species of different feeding habits was investigated in two reservoirs in southeast Brazil—the mesotrophic Ponte Nova Reservoir (PN) and the hypereutrophic Billings Reservoir (Bil). Total FA profile of stomach contents and adipose tissue, triacylglycerols (TAG), and phospholipids (PL) from liver and muscle of the omnivorous Astyanax fasciatus and the carnivorous Hoplias malabaricus were analyzed by gas chromatography. A prevalence of n‐6PUFA, as 18:2n‐6 (linoleic acid) and 20:4n‐6 (arachidonic acid, ARA) was observed in the stomach contents and in the tissues of A. fasciatus from the PN reservoir. In contrast, n‐3 LC‐PUFA, as 20:5n‐3 (eicosapentaenoic acid, EPA) was accumulated in fish tissues from Bil, resulting in higher n3/n6 and EPA/ARA ratios, compared to fish from PN. This differential FA accumulation was also observed for H. malabaricus, but differences were slightly minor, and no changes were observed in the EPA/ARA ratios between fish from both reservoirs. Regardless reservoir, FA profiles of TAG resembled that of their diet, whereas FA profiles of PL were more conservative and mainly comprised by LC‐PUFA. We conclude that reservoir trophic status affected the FA composition of food resources available to these fish species, resulting in differential allocation of n‐3 and n‐6 FA. As expected, FA profile of the investigated fish species also reflected their feeding habit and physiological demands.     

Fatty acid composition of selected roes from some marine species

Fifteen roes from different marine fish species available in Spain were analyzed in order to determine their fatty acid (FA) composition, especially the eicosapentaenoic acid (20:5n‐3, EPA) and docosahexaenoic acid (22:6n‐3, DHA) contents. Roes from Atlantic bonito (Sarda sarda), European squid (Loligo vulgaris), cuttlefish (Sepia spp.), lumpfish (Cyclopterus lumpus), European hake (Merluccius merluccius), Atlantic salmon (Salmo salar) and gonads of male Atlantic mackerel (Scomber scombrus) reached EPA + DHA amounts higher than 30% of the total FA, and among them, roes from lumpfish, European hake and salmon provide different FA type ratios that could make them adequate as dietary sources of EPA and DHA.     

Production of PUFA Concentrates from Poultry and Fish Processing Waste

In fish and poultry processing, viscera are generally considered as a waste product and often discarded. Chicken and hilsa fish (Hilsa ilisa) viscera were used for the production of polyunsaturated fatty acids (PUFA) linoleic (18:2n-6), eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). Free fatty acids (FFA) were extracted by alkaline hydrolysis of chicken and fish viscera; yields were 5.2 and 5.9% (w/w) respectively. PUFA concentrates were obtained by a two step process—deduction of saturated fatty acids (FA) by low temperature crystallization in acetone followed by urea inclusion compound-based fractionation. Acetone treatment removed 90 and 96% of saturated FA in chicken and fish viscera respectively with FA to acetone ratio of 1:12 (w/v). Using an urea to FA ratio (w/w) of 4.0, chicken viscera produced a maximum of 84.1% of PUFA concentrates containing 82.1% of linoleic acid with a yield of 10% where as in the case of fish viscera the maximum PUFA concentrates were 91.3% containing 78.2% of EPA-DHA with the yield of 11%. Thus, the utilization of poultry and fish processing waste into the production of PUFA concentrates has been shown.