Fish Oil Research Articles

Longitudinal Changes in Dietary Supplement Use among United States Military Personnel: The US Military Dietary Supplement Use Study.

Previous studies investigating temporal changes in dietary supplement (DS) use have used representative samples but have not followed the same cohort over time. This study investigated longitudinal patterns of changes in DS use and factors associated with discontinuing DS use in a single group of active-duty United States military service members (SMs). SMs (n = 5778) completed two identical questionnaires on their DS use and demographic/lifestyle characteristics an average ± standard deviation 1.3 ± 0.2 years apart. Prevalences of reported DS use ≥1 times/week in the baseline (BL) and follow-up (FU) phases were: any DS, BL = 77%, FU = 78%; multivitamins/multiminerals (MVM), BL = 50%, FU = 48%; individual vitamins/minerals, BL = 33%, FU 35%; proteins/amino acids, BL = 43%, FU = 39%; combination products, BL = 44%, FU = 37%; prohormones, BL = 5%, FU = 4%; herbal products, BL = 23%, FU = 21%; joint health products, BL = 12%, FU = 12%; fish oils, BL = 25%, FU = 23%; other DSs, BL = 17%, FU = 17%. Among BL users, the proportions reporting use in the FU phase were: any DS 88%, MVM 74%, protein/amino acids 70%, individual vitamin/minerals 62%, combination products 62%, fish oils 61%, joint health products 57%, herbal products 50%, other DSs 50%, and prohormones 37%. Higher odds of discontinuing any DS use in the follow-up were associated with female gender, younger age, higher BMI, and less weekly resistance training. Overall, prevalence of DS use was relatively consistent in the two phases; however, the cohort changed their use patterns in the follow-up with some discontinuing use and others initiating use, thus maintaining use prevalence over the period. These findings have implications for repeated cross-sectional DS studies where different samples are followed over time.

Effects of dietary fish to rapeseed oil ratio on steatosis symptoms in Atlantic salmon (Salmo salar L) of different sizes

Choline is recognized as an essential nutrient for Atlantic salmon at all developmental stages. However, its dietary requirement is not well defined. Choline plays a critical role in lipid transport, and the clearest deficiency sign is intestinal steatosis. The present work, aiming to find whether lipid source and fish size may affect steatosis symptoms, was one of a series of studies conducted to identify which production-related conditions may influence choline requirement. Six choline-deficient diets were formulated varying in ratios of rapeseed oil to fish oil and fed to Atlantic salmon of 1.5 and 4.5 kg. After eight weeks, somatic characteristics were observed, and the severity of intestinal steatosis was assessed by histological, biochemical, and molecular analyses. Fatty acid composition in pyloric intestine, mesenteric tissue, and liver samples was also quantified. The increasing rapeseed oil level increased lipid digestibility markedly, enhancing lipid supply to the fish. Moreover, small fish consumed more feed, and consequently had a higher lipid intake. In conclusion, the results showed that choline requirement depends on dietary lipid load, which depends on the fatty acid profile as well as the fish size.

Impact of omega-3 fatty acids on hypertriglyceridemia, lipidomics, and gut microbiome in patients with type 2 diabetes.

Fish oil (FO), a mixture of omega-3 fatty acids mainly comprising docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been recommended for patients with type 2 diabetes (T2D) and hypertriglyceridemia. However, its effects on lipidomic profiles and gut microbiota and the factors influencing triglyceride (TG) reduction remain unclear. We conducted a 12-week, randomized, double-blind, placebo-controlled trial in 309 Chinese patients with T2D with hypertriglyceridemia (ClinicalTrials.gov: NCT03120299). Participants were randomly assigned (1:1) to receive either 4g FO or corn oil for 12weeks. The primary outcome was changes in serum TGs and the lipidomic profile, and the secondary outcome included changes in the gut microbiome and other metabolic variables. The FO group had significantly better TG reduction (mean [95% confidence interval (CI)]: -1.51 [-2.01, -1.01] mmol/L) compared to the corn oil group (-0.66 [-1.15, -0.16] mmol/L, p= 0.02). FO significantly altered the serum lipid profile by reducing low-unsaturated TG species and increasing those containing DHA or EPA. FO had minor effects on gut microbiota, while baseline microbial features predicted the TG response to FO better than phenotypic or lipidomic features, potentially mediated by specific lipid metabolites. A total of 9 lipid metabolites significantly mediated the link between 4 baseline microbial variables and the TG response to FO supplementation. Our findings demonstrate differential impacts of omega-3 fatty acids on lipidomic and microbial profiles in T2D and highlight the importance of baseline gut microbiota characteristics in predicting the TG-lowering efficacy of FO. This study was funded by the National Nature Science Foundation.

Immobilized Burkholderia cepacia lipase and its application in selective enrichment of EPA by hydrolysis of fish oil

Eicosapentaenoic acid (EPA), an orally active Omega-3 long-chain polyunsaturated fatty acid, has attracted much attention for its medical and healthcare value. Due to a large amount of polyunsaturated fatty acids (PUFA) including docosahexanoic acid (DHA) in fish oil, the highly specific enrichment of EPA from fish oil is difficult to achieve. In our study, we conducted immobilization studies on Burkholderia cepacia lipase (BCL) and its application in the selective enrichment of EPA in fish oil. BCL was immobilized on resin LX201A by covalent crosslinking, and immobilization conditions including glutaraldehyde concentration, pH, time were optimized. The optimal immobilization conditions were 0.5% glutaraldehyde, 4 h, and pH 8.0. The loading rate of BCL reached to 93.5%, and its activity was up to 68263 U/g under the optimal immobilization conditions. After hydrolysis reaction of fish oil for 15h catalyzed by immobilized BCL, EPA content showed a more increase by 33.2%, while a slight increase by 0.78% in DHA content. Moreover, after recycling use for 10 times, the catalytic efficiency of immobilized BCL remained at 93.0%. These indicated that immobilized BCL possessed good selectivity, reusability and stability, providing great application potential in EPA selective enrichment in fish oil industry.

Short-term dietary changes are reflected in the cerebral content of adult ring-billed gulls.

Omega-3 long-chain polyunsaturated fatty acids (n3-LCPUFAs) are produced primarily in aquatic ecosystems and are considered essential nutrients for predators given their structural role in vertebrates' cerebral tissues. Alarmingly, with urbanization, many aquatic animals now rely on anthropogenic foods lacking n3-LCPUFAs. In this study undertaken in Newfoundland (Canada), we tested whether recent or longer term diet explains the cerebral fatty acid composition of ring-billed gulls (Larus delawarensis), a seabird that now thrives in cities. During the breeding season, cerebral levels of n3-LCPUFAs were significantly higher for gulls nesting in a natural habitat and foraging on marine food (mean ± s.d.: 32 ± 1% of total identified fatty acids) than for urban nesters exploiting rubbish (27 ± 1%). Stable isotope analysis of blood and feathers showed that urban and natural nesters shared similar diets in autumn and winter, suggesting that the difference in cerebral n3-LCPUFAs during the breeding season was owing to concomitant and transient differences in diet. We also experimentally manipulated gulls' diets throughout incubation by supplementing them with fish oil rich in n3-LCPUFAs, a caloric control lacking n3-LCPUFAs, or nothing, and found evidence that fish oil increased urban nesters' cerebral n3-LCPUFAs. These complementary analyses provide evidence that the brain of this seabird remains plastic during adulthood and responds to short-term dietary changes.

Valorization of refined sardine oil in canned Sardina pilchardus

This study aimed to use refined sardine oil as a covering juice in canned Sardina pilchardus. The oil’s fatty acid profile, acidity, peroxide value, and p-anisidine value were analyzed. The biochemical composition, histamine content, and bacteriological stability of the canned sardines were determined. The results showed that canned sardines contained 51.40 g of moisture, 27.87 g of fat, 17.91 g of protein, and 1.03 g of salt per 100 g net weight. The fatty acid composition included 10.35% polyunsaturated fatty acids, 8.86% saturated fatty acids, and 6.27% monounsaturated fatty acids, with the most abundant fatty acids being eicosapentaenoic acid (EPA), palmitic acid, oleic acid, myristic acid, and docosahexaenoic acid (DHA). This recipe provided 8.88 g/100 g (net weight) of EPA and DHA. These findings support the interest in using refined fish oil to enrich foods with essential marine fatty acids, highly recommended for their health benefits and leading to encouraging prospects for sardine canneries to develop new and nutritious value products.

Evaluation of cottonseed oil as a substitute for fish oil in the commercial diet for juvenile swimming crab (Portunus trituberculatus)

A six-week feeding trial was carried out to determine the feasibility of cottonseed oil (CSO) as a viable substitute for fish oil (FO) in the commercial diet of swimming crab. Ninety healthy swimming crabs (initial body weight 34.28 ± 0.59 g) were randomly assigned to 90 plastic baskets. Three isonitrogenous and isolipidic diets (450 g/kg protein and 120 g/kg lipid) were formulated replacing FO with CSO at 0%, 50% and 100% (CSO-0, CSO-50, and CSO-100), respectively. Each diet was randomly allocated to three replicates, each consisting of 10 crabs. Results indicated that crabs fed with CSO-100 diet had the lowest the percent weight gain (PWG), specific growth rate (SGR) and survival among all treatments (P < 0.05). Albumin (ALB), alkaline phosphatase (ALP), glucose (GLU), triglyceride (TAG), total cholesterol (T-CHO), low-density lipoprotein cholesterol (LDL-C), non-esterified fatty acid (NEFA) contents and alanine amino transferase (ALT) activity in hemolymph were significantly affected by dietary substitution of FO with CSO (P < 0.05). The contents of total saturated fatty acids (SFA), total mono-unsaturated fatty acids (MUFA) and total long-chain polyunsaturated fatty acids (LC-PUFA) in the hepatopancreas and muscle were negatively correlated with the substitution level, whereas total n-6 polyunsaturated fatty acids (n-6 PUFA) and linoleic acid (18:2n-6) contents increased significantly with increasing levels of dietary substitution of FO with CSO (P < 0.05). Dietary substitution of FO with CSO resulted in changes in the composition of volatile substances in muscle, with 16 volatile substances in muscle significantly affected (P < 0.05). The relative expression of genes related to lipid synthesis such as fatty acid synthase (fas), acetyl-CoA carboxylase (acc) and glycerol-3-phosphate acyltransferase 1 (gpat1) in the hepatopancreas were significantly up-regulated in the CSO-50 group compared to other treatment groups (P < 0.05). The relative expression of fatty acid anabolism-related genes fatty acyl desaturase 2 (fads2) and elongase 4 (elovl4) were significantly down-regulated with the increase of dietary substitution of FO with CSO (P < 0.05). In conclusion, 50% substitution with CSO had no negative effects on growth performance, promoted lipid synthesis and metabolism, facilitated lipid accumulation. However, complete substitution of FO with CSO inhibited fatty acid synthesis and metabolism, resulting in a lower tissue LC-PUFA content and an altered composition of muscle volatiles.

Valorization of refined sardine oil in canned Sardina pilchardus

This study aimed to use refined sardine oil as a covering juice in canned Sardina pilchardus. The oil’s fatty acid profile, acidity, peroxide value, and p-anisidine value were analyzed. The biochemical composition, histamine content, and bacteriological stability of the canned sardines were determined. The results showed that canned sardines contained 51.40 g of moisture, 27.87 g of fat, 17.91 g of protein, and 1.03 g of salt per 100 g net weight. The fatty acid composition included 10.35% polyunsaturated fatty acids, 8.86% saturated fatty acids, and 6.27% monounsaturated fatty acids, with the most abundant fatty acids being eicosapentaenoic acid (EPA), palmitic acid, oleic acid, myristic acid, and docosahexaenoic acid (DHA). This recipe provided 8.88 g/100 g (net weight) of EPA and DHA. These findings support the interest in using refined fish oil to enrich foods with essential marine fatty acids, highly recommended for their health benefits and leading to encouraging prospects for sardine canneries to develop new and nutritious value products.

Optimization of inclusion level of lipid in larval diet of Labeo rohita (Hamilton, 1822).

Formulation and preparation of larval feed according to the requirement of Indian major carp is a prerequisite for improving the survival (%) and growth during early developmental stages. A feeding trial of 50days in a replicate of five was conducted to determine the optimal inclusion levels of fish oil (lipid) in the larval diet of Labeo rohita. Four isonitrogenous (50% CP) nanoparticulate diets with four lipid inclusion levels, L5 (5%), L7 (7%), L9 (9%), and L11 (11%) were prepared and fed to four groups of rohu (Labeo rohita) larvae. At the end of feeding trial, survival (%), growth performance, digestive enzyme activity, gut morphology, and expression of growth and feed intake genes were evaluated. All pairwise comparisons among groups indicated higher growth performance (weight gain, specific growth rate, and daily weight gain), survival (%), and IGF-1 gene expression of the L9 group followed by the L7 while the L11 showed poor performance even less than L5. All studied intestinal enzymes except amylase showed a similar trend. Amylase showed comparable results among L7, L9, and L5, while L11 showed the lowest value. The intestinal villi length also showed higher values in L9 followed by L7, and lowest in the L11 group. Feed intake regulating genes, leptin showed lipid inclusion level upregulation, while ghrelin showed the highest expression in the L9 group. Based on growth performance, gut morphology, intestinal enzyme activity, and gene expression analysis, 9% dietary lipid could be recommended to ensure the optimum growth and survival of L. rohita larvae.

Genetic Influence of Oily Fish Intake on Age-Related Macular Degeneration Risk: A Two-Sample Mendelian Randomization Analysis.

Emerging research indicates a link between the intake of fatty fish and age-related macular degeneration (AMD). However, observational studies fall short in establishing a direct causal link between oily fish intake and AMD. We wanted to determine whether causal association lies between oily fish intake and age-related macular degeneration (AMD) risk in human beings. This two-sample mendelian randomization (MR) study used the MR method to probe the genetic causality in the relationship between oily fish intake and AMD. The genome-wide association study (GWAS) data for AMD were acquired from a Finnish database, whereas the data on fish oil intake came from the UK Biobank. The analysis used several approaches such as inverse-variance weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode MR. In addition, the Cochran's Q test was used to evaluate heterogeneity in the MR data. The MR-Egger intercept and MR-pleiotropy residual sum and outlier (MR-PRESSO) tests were used to assess the presence of horizontal pleiotropy. A leave-one-out sensitivity analysis was conducted to determine the reliability of the association. The IVW method revealed that the intake of oily fish is an independent risk factor for AMD (P = 0.034). It also suggested a minimal likelihood of horizontal pleiotropy affecting the causality (P > 0.05), with no substantial heterogeneity detected in the genetic variants (P > 0.05). The leave-one-out analysis confirmed the reliability and stability of this correlation. This research used a two-sample MR analysis to provide evidence of a genetic causal relationship between the eating of oily fish and AMD. This discovery held potential significance in AMD prevention.

Effect of Garlic Paste Addition on the Fatty Acid Profile and Oxidative Stability of Shrimp Analogue Fortified with PUFA-rich Fish Oil During Frozen Storage at -20°C

Effect of Garlic Paste Addition on the Fatty Acid Profile and Oxidative Stability of Shrimp Analogue Fortified with PUFA-rich Fish Oil During Frozen Storage at -20°C

AMPK activation by dietary acadesine improves fillet texture in large yellow croaker (Larimichthys crocea) fed a linseed oil-based diet

The impacts of AMP-activated protein kinase (AMPK) activation by dietary acadesine (AICAR) on growth performance and muscle quality of large yellow croaker (Larimichthys crocea) fed a linseed oil-based diet (LO) were investigated by a 56-day feeding trial in this study. Fish (initial weight: 92.24 ± 0.30 g) were fed fish oil-based diet (FO), LO or LA (LO diet supplemented with 150 mg kg−1 AICAR) with three replicates of each treatment. Results indicated that weight gain rate and specific growth rate (SGR) were significantly decreased in the LO and LA groups than those of the fish fed FO, while the opposite was true for the feed conversion ratio. Moreover, the SGR of fish fed LA was significantly lower than that of the LO group. Dietary linseed oil and AICAR significantly lowered muscle eicosapentaenoic acid and docosahexaenoic acid contents. Furthermore, the LO group showed significantly lower fillet hardness, chewiness and pH, while higher lipid loss than those of the FO group. However, the FO and LA groups had similar fillet hardness, lipid loss and pH. Compared with the fish fed FO and LA, the LO group possessed significantly lower p-AMPK protein level and p-AMPK/AMPK ratio in muscle. The phosphorylation of TOR protein and the ratios of p-TOR/TOR and p-S6/S6 were significantly decreased in muscle of the LA group than those of the fish fed FO and LO. Meanwhile, totally replacing fish oil with linseed oil inhibited the AMPK/SIRT1/PGC-1α pathway, changed myofibre characteristics (e.g., density, diameter and type of myofibre) and raised the expression of genes or activity of enzyme related to anaerobic metabolism in fish muscle. Dietary AICAR activated AMPK/SIRT1/PGC-1α pathway, restored myofibre characteristics and promoted aerobic metabolism-related genes expression in muscle to some extent. In conclusion, total substitution of dietary fish oil with linseed oil reduced growth, feed utilization and nutritive value of large yellow croaker. And high level of dietary linseed oil induced softer texture and poorer liquid holding capacity (LHC) of muscle, which may be ascribed to the myofibre characteristics changed by linseed oil through depressing muscle AMPK/SIRT1/PGC-1α pathway. Inclusion of AICAR in a linseed oil-based diet improved fish muscle hardness and LHC, which may be relevant to the activated muscle AMPK/SIRT1/PGC-1α pathway and restored myofibre characteristics by AICAR. Notably, dietary AICAR could inhibit TOR pathway by activating AMPK in muscle, which may be responsible for the further decreased SGR of fish fed a linseed oil-based diet.

Diet and Nutraceuticals for treatment and prevention of primary and secondary stroke: Emphasis on nutritional antiplatelet and antithrombotic agents

Ischemic stroke is a devastating disease that causes morbidity and mortality. Malnutrition following ischemic stroke is common in stroke patients. During the rehabilitation, the death rates of stroke patients are significantly increased due to malnutrition. Nutritional supplements such as protein, vitamins, fish, fish oils, moderate wine or alcohol consumption, nuts, minerals, herbal products, food colorants, marine products, fiber, probiotics and Mediterranean diets have improved neurological functions in stroke patients as well as their quality of life. Platelets and their mediators contribute to the development of clots leading to stroke. Ischemic stroke patients are treated with thrombolytics, antiplatelets, and antithrombotic agents. Several systematic reviews, meta-analyses, and clinical trials recommended that consumption of these nutrients and diets mitigated the vascular, peripheral, and central complications associated with ischemic stroke (Fig. 2). Particularly, these nutraceuticals mitigated the platelet adhesion, activation, and aggregation that intended to reduce the risks of primary and secondary stroke. Although these nutraceuticals mitigate platelet dysfunction, there is a greater risk of bleeding if consumed excessively. Moreover, malnutrition must be evaluated and adequate amounts of nutrients must be provided to stroke patients during intensive care units and rehabilitation periods. In this review, we have summarized the importance of diet and nutraceuticals in ameliorating neurological complications and platelet dysfunction with an emphasis on primary and secondary prevention of ischemic stroke.

Eicosapentaenoic acid supplementation alleviates pruritus, enhances skin moisture, and mitigates depression in maintenance hemodialysis patients.

The objective of this study is to investigate the effects of oral supplementation with eicosapentaenoic acid (EPA) on circulating inflammatory factors, cardiometabolic parameters, skin moisturization, and the consequent symptoms of pruritus and depression in maintenance hemodialysis patients. A total of 60 maintenance hemodialysis patients with severe pruritus symptoms completed this randomized, placebo-controlled study. Subjects of treatment group (n = 30) were instructed to consume 1000 mg fish oil (>900 mg EPA) and subjects of placebo group (n = 30) were instructed to consume 1000 mg soybean oil twice daily for 3 months. 5-D pruritus scoring, the Beck Depression Inventory (BDI) scale, skin moisture, serum creatinine, inflammatory factors, and cardiometabolic parameters were examined at baseline, and at the first, second, and third month post-supplementation. A significantly decreased pruritus level was observed in the treatment group, whereas an opposite result was observed in the placebo group. Increased skin moisture levels on both the face and arms were observed in the treatment group, but not in the placebo group. Supplementation of EPA significantly decreased serum CRP and IL-6 levels. Significant decreases in total cholesterol (CHO), and triglycerides (TG) levels were observed; however, a decrease in high-density lipoprotein (HDL) level was observed in the treatment group. There was no change in plasma creatinine (CR) observed in both groups. A significantly decreased BDI score was observed, whereas the opposite result was observed in the placebo group. A correlational study showed that the severity of pruritus was significantly associated with skin moisture and serum CRP. The severity of pruritus was also positively correlated with the BDI score. Supplementation of EPA may provide multiple benefits including alleviating pruritus symptoms, addressing skin dryness, and mitigating depression in maintenance hemodialysis patients.

BENEFITS OF PHOSPHOLIPIDS IN AQUAFEED DEVELOPMENT: A REVIEW

Fish oil (FO) is the main source of lipids in aquafeed, but its use has become very unsustainable due to over-exploitation, scarcity and high cost. Plant oil has been proposed as an alternative to FO, but they are less digestible and not rich in fatty acids. In addition, larval and juvenile fish are unable to synthesise sufficient phospholipids (PLs) for their metabolic need. Hence, the necessity to supplement PLs in their diets. This review describes the application and beneficial impact of dietary PLs in aquafeed. PLs are an essential component of aquafeed as they supply energy for metabolic activities and enhance digestion and absorption of other dietary lipids. Plantbased PLs such as soy lecithin serve as an emulsifier that helps lipid catabolism by facilitating enzymatic hydrolysis in the fish’s digestive system, besides improving nutrient absorption, growth and health. Studies on farm animals have confirmed the positive effects of PLs. Although the literature on aquafeed application is limited, to growth and health of farmed fish and crustaceans. The use of PLs in aquaculture is set to increase as both feed producers and farmers seek to maximise production through efficient feed utilisation and ensure sustainability in delivering quality fish to consumers.

Efficient expression of OUC-Sb-lip2 in Yarrowia lipolytica and its comprehensive utilization in the enrichment of DHA and EPA from fish oil

Lipases are widely used in the modification of functional lipids, particularly in the enrichment of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In this study, a lipase named OUC-Sb-lip2 was expressed in Yarrowia lipolytica, achieving a promising enzyme activity of 472.6 U/mL by optimizing the culture medium, notably through olive oil supplementation. A significant proportion (58.8%) of the lipase activity was located in the cells, whereas 41.2% was secreted into the supernatant. Both whole-cell and immobilized OUC-Sb-lip2 were used to enrich DHA and EPA from fish oil. The whole-cell approach increased the DHA and EPA contents to 2.59 and 2.55 times that of the original oil, respectively. Similarly, the immobilized OUC-Sb-lip2 resulted in a 2.00-fold increase in DHA and an 1.99-fold increase in EPA after a 6-h hydrolysis period. Whole cell and the immobilized OUC-Sb-lip2 retained 48.7% and 52.7% of their activity after six cycles of reuse, respectively.

Developing fish oil emulsion gel enriched with Lentinula edodes single cell protein and its effect on controlling the growth of Acinetobacter baumannii

In this study, the characterization of fish oil (FO) emulsion gel (EGEL) containing single cell protein (SCP) produced from Lentinula edodes (L. edodes) and its potential inhibition against Acinetobacter baumannii (A. baumannii) were investigated. Oil extracted from the fish liver was emulsified with tween 80 and water, and then gelled using gelatin with the assistance of an ultrasonic homogenizer. The characteristics and surface analysis of SCP-EGEL were examined using FTIR (Fourier-transform infrared spectroscopy) and SEM (Scanning electron microscope). The particle size distribution and zeta potential of SCP-EGEL were measured using a Malvern Zetasizer. When SCP-EGEL was applied to the surface of the medium inoculated with A. baumannii, the inhibition zone (IZ) was 8.2 mm. An expansion of the IZ was observed (10.2 mm) when SCP-EGEL was applied to a fish skin (FS) surface prepared in the shape of a 6-mm diameter disc. In the SEM images, when SCP was added to lipo gel, the gel structure appeared flattened or swollen in some areas. The appearance of SCP cells being covered with gel gave the impression that they have a secondary wall. Therefore, the resulting complex can potentially be used as an additive in animal and human nutrition, in functional food coatings to suppress A. baumannii, and in fish feed to enrich it with protein.

Determination of Free Glycidol and Total Free Monochloropropanediol in Fish and Krill Oil with Simple Aqueous Derivatization and High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

This study introduces a novel method for detecting free glycidol and total free monochloropropanediol (MCPD) in fish and krill oil. Before analysis on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS), p-(dimethylamino)phenol was used for derivatization of these compounds, enabling the sensitive determination of these contaminants. The sample preparation procedure includes a simple, efficient pretreatment using NaCl aqueous solution extraction and C18 sorbent cleanup (for demulsification), distinguishing glycidol from MCPD under varied reaction conditions for derivatization (weak acidic and strong alkaline aqueous environments). This approach shows broad linearity from 1 to at least 256 ng·mL-1, improved sensitivity compared to standard GC-MS methods, with the limit of detection (LOD) and limit of quantification (LOQ) for MCPD and glycidol in both oil samples verified at 0.5 ng·mL-1 and 1 ng·mL-1, respectively. Different from previous HPLC-MS methods for direct detection of glycidol esters or MCPD esters, this is the first HPLC-MS method used for the detection of free glycidol and total free MCPD in edible oil. Furthermore, this method can be potentially developed for glycidol or monochloropropane diol esters, which is similar to the current official methods adopted for indirect detection of these contaminants in different food matrices. Application of this detection method to real dietary supplements (fish oil and krill oil) revealed MCPD residues in fish oil (maximum detected: 32.78 ng·mL-1) and both MCPD (maximum detected: 2767.3 ng·mL-1) and glycidol (maximum detected: 22.2 ng·mL-1) in krill oil, emphasizing its effectiveness and accuracy for assessing contamination in these supplements.

Effect of non-covalent binding of tannins to sodium caseinate on the stability of high-internal-phase fish oil emulsions

In this study, we designed the noncovalent binding of sodium caseinate (SC) to tannic acid (TA) to stabilize high internal phase emulsions (HIPEs) used as fish oil delivery systems. Hydrogen bonding was the dominant binding force, followed by weak hydrophobic interaction and weak van der Waals forces, as demonstrated by FTIR, fluorescence spectroscopy, and molecular docking experiments, with a binding constant of 3.25 × 106, a binding site of 1.2, and a static quenching of the binding. Increasing SC:TA from SC to 2:1 decreased the particle size from 107.37 ± 10.66 to 76.07 ± 2.77 nm and the zeta potential from −6.99 ± 2.71 to −22 ± 2.42 mV. TA increased the interfacial tension of SC, decreased the surface hydrophobicity from 1.3 × 104 to 1.6 × 103 and improved the oxidation resistance of SC. The particle size of high internal phase emulsions stabilized by complexes with different mass ratios (SC:TA from 1:0 to 2:1) increased from 4.9 ± 0.02 to 12.9 μm, the potential increased from −32.37 ± 2.7 to −35.07 ± 2.58 mV, and the instability index decreased from 0.75 to 0.02. Thicker interfacial layers could be observed by laser confocal microscopy, and an increase in the storage modulus indicated a formation of a stronger gel network. SC:TA of 1:0 showed emulsion breakage after 14 d of storage at room temperature. SC:TA of 2:1 showed the lowest degree of oil-water separation after freeze-thaw treatment. Especially, the most stable high endo-phase emulsion (at SC:TA of 2:1) prepared at each mass ratio was selected for further stability exploration. The emulsion particle size increased only from 15.63 ± 0.06 to 22.27 ± 0.35 μm at salt ion concentrations of 50–200 mM and to 249.33 ± 31.79 μm at 300 mM. The instability index and storage modulus of the high endo-phase emulsions increased gradually with increasing salt ion concentrations. At different heating temperatures (55–85 °C), the instability index of the high internal phase emulsion gradually decreased and the storage modulus gradually increased. Meanwhile, at 50 °C for 15 d of accelerated oxidation, the content of hydroperoxide decreased from 53.32 ± 0.18 to 37.48 ± 0.77 nmol/g, about 29.7 %, and the thiobarbituric acid value decreased from 1.06 × 103 to 0.8 × 103, about 24.5 %, in the high endo-phase emulsions prepared by 2:1 SC:TA compared to the fish oils, and the SC-stabilized high endo-phase only emulsion broke at the sixth day of oxidation. From the above findings, it was concluded that the high internal phase emulsion prepared with SC:TA of 2:1 can be used as a good delivery system for fish oil.

Unravelling the intricate language of fish guts: Impact of plant-based vs. plant-insect-poultry-based diets on intestinal pathways in European seabass

The long-term sustainability of aquaculture depends on finding economically viable and environmentally friendly feed ingredients to reduce the use of fishmeal and fish oil. An optimal strategy for the industry is not to identify substitutes or alternatives, but to find a combination of complementary raw materials that together meet the specific nutritional requirements for a given farmed fish species. The study aimed to examine the effects of different diets on the pyloric caeca and distal intestine of subadult European seabass (Dicentrarchus labrax) by applying transcriptomics and transmission electron microscopy. The study examined three dietary approaches: the classic fishmeal-based diet, a plant-based diet, and a plant-insect-poultry-based diet. The distal intestine was more sensitive to dietary changes than the pyloric caeca. The differentially expressed genes in both experimental diets were mainly involved in the digestion and absorption of proteins, fats, and vitamins. The overall transcriptomic changes were greater in the plant-based group than in the plant-insect-poultry-based group and included a greater number of overrepresented metabolic and signalling pathways. In contrast to the transcriptomic results, the ultrastructural findings showed decreased inflammation and/or evidence of tissue repair in the plant-based group, particularly in the pyloric caeca. Since the nutritional quality of all fish groups in this study was previously evaluated positively, the detected transcriptome-level changes can serve as evidence supporting the efficient nutrient utilisation and adaptability in European seabass. The study provides valuable insight into the potential benefits and implications of these dietary modifications on intestinal health and pathway regulation in European seabass. This can serve as a basis for further development of sustainable European seabass aquaculture practices and optimisation of diet formulations.