Tuna Oil Research Articles

Concentration of docosahexaenoic acid from tuna oil via a two lipase-catalyzed reaction

Docosahexaenoic acid (DHA) was concentrated successfully in the glyceride fractions from tuna oil via a two-step enzyme reaction involving hydrolysis and ethanolysis. In the first step, Candida rugosa lipase-catalyzed hydrolysis was carried out to concentrate DHA in the glyceride fractions. The DHA content in the glyceride fraction after hydrolysis increased from 30% in the initial tuna oil to 46%. In the second step, Lipozyme RM IM-catalyzed ethanolysis was conducted with the reaction mixture from the first step to further concentrate DHA in the glyceride fraction. In this step, the reaction mixture obtained from the first step was employed directly in Lipozyme RM IM-catalyzed ethanolysis without additional steps needed to remove free fatty acid. Finally, DHA was concentrated from an initial content of 30% in the tuna oil to 68.4% in the glyceride fractions via a novel two-step enzyme reaction strategy.

Lipase-catalyzed preparation, bioavailability and functional properties of a DHA-enriched tuna oil

Docosahexaenoic acid (DHA) in the form of triacylglycerols (TAG) are widely recognized for their health benefits. As naturally occurring DHA in the form of TAG are limited, this work developed and optimized a Candida rugosa lipase-catalyzed selective hydrolysis process to enrich DHA in tuna oil. The DHA-enriched tuna oil produced at optimal conditions (lipase concentration of 4 %, ratio of water to tuna oil of 1:3, reaction temperature of 55°C) contained 46.12 % of DHA, in which 55.24 % of DHA was located in sn-2 position of the glycerides. In-vitro bioavailability test shows, the DHA-enriched tuna oil (7.89 %) had significantly higher cellular uptake of DHA as compared to unprocessed oil. The DHA-enriched oil demonstrated increased intracellular oxidation and mitochondrial damage of Caco-2 cell.

Spray drying the Pickering emulsions stabilized by chitosan/ovalbumin polyelectrolyte complexes for the production of oxidation stable tuna oil microcapsules

The microencapsulation of polysaturated fatty acids by spray drying remains a challenge due to their susceptibility to oxidation. In this work, antioxidant Pickering emulsions were attempted as feeds to produce oxidation stable tuna oil microcapsules. The results indicated that the association between chitosan (CS) and ovalbumin (OVA) was a feasible way to fabricate antioxidant and wettable complexes and a high CS percentage favored these properties. The particles could yield tuna oil Pickering emulsions with enhanced oxidation stability through high-pressure homogenization, which were successfully spray dried to produce microcapsules with surface oil content of 8.84 % and microencapsulation efficiency of 76.65 %. The microcapsules exhibited significantly improved oxidation stability and their optimum peroxide values after storage at 50 °C, 85 % relative humidity, or natural light for 15 d were 48.67 %, 60.07 %, and 39.69 % respectively lower than the powder derived from the OVA-stabilized emulsion. Hence, Pickering emulsions stabilized by the CS/OVA polyelectrolyte complexes are potential in the production of oxidation stable polyunsaturated fatty acid microcapsules by spray drying.

Omega-3-Rich Tuna Oil Derived from By-Products of the Canned Tuna Industry Enhances Memory in an Ovariectomized Rat Model of Menopause.

To increase the value of the by-products of the canned tuna industry, the memory enhancement effect and the possible mechanisms of omega-3-rich tuna oil in bilateral ovariectomized (OVX) rats were assessed. Female rats were orally given tuna oil at doses of 140, 200, and 250 mg/kg of body weight (BW) for 28 days before OVX and for 21 days continually after OVX. Memory performance was assessed every week, whereas the parameters regarding mechanisms of action were assessed at the end of the study. All doses of tuna oil enhanced memory, docosahexaenoic acid (DHA) levels, and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities but decreased cortisol, acetylcholinesterase (AChE), malondialdehyde (MDA), and inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Medium and high doses of tuna oil suppressed monoamine oxidase (MAO) but increased eNOS activity. A high dose of tuna oil suppressed gamma-aminotransferase (GABA-T) but increased glutamic acid decarboxylase (GAD) and sirtuin-1. A medium dose of tuna oil decreased homocysteine (Hcys) and C-reactive protein. No change in telomere or estradiol was observed in this study. Our results suggest the memory-enhancing effect of tuna oil in an OVX rat model of menopause. The main mechanisms may involve a reduction in oxidative stress, inflammation, and neurotransmitter regulation.

Do different camera trap lures result in different detection rates of vertebrates because of their attractiveness to invertebrates?

SummaryThe type of attractant used in camera trap lures is recognised as an important methodological decision. We investigated whether the type of attractant in lures indirectly influences detectability of wildlife on cameras via differential attraction of invertebrates which themselves constitute prey of insectivorous animals. We indexed invertebrate abundance using pitfall and sticky‐traps at 36 camera stations deployed in a Latin Squares design for 5 days, with three lure options (peanut‐butter, tuna oil and control) in a coastal mosaic, at Cape Otway, Victoria, Australia. We classified vegetation types (habitat) as: low (no or sparse), medium (grass), and high (shrubs) from aerial imagery and estimated their percentage cover at each grid point (medium and high were uncorrelated and included as separate variables in models). We first examine if attractant types or the habitat influence invertebrate abundance and assemblage, and then examine whether invertebrate abundance influences vertebrate detectability on cameras. There was a trend for the composition of terrestrial invertebrate assemblages to be influenced by lure type (peanut‐butter, tuna oil and control attractants) and the proportional cover of medium height vegetation within 20 m; however, assemblage composition was clearly influenced by the proportional area of high vegetation cover within 20 m. The detection probability of insectivorous birds increased where medium‐sized (2.5–5 mm) flying invertebrates were present whereas insectivorous mammal detectability increased with terrestrial invertebrate species richness. Mammal detections are more likely associated with use of habitats that have more diverse invertebrate communities. This study provides some support to the hypothesis of the indirect mechanism whereby bird detections are influenced by invertebrate attraction to lures. Therefore, lure choice for camera traps is critical and the possibility of guild‐level biases in detection suggests that cautious interpretation of results is required.

Enzymatically produced acylglycerol and glycerin monostearate additives improved the characteristics of gelatin-stabilized omega-3 emulsions and microcapsules

The impacts of enzymatically produced acylglycerol and glycerin monostearate on the characteristics of gelatin-stabilized omega-3 emulsions and microcapsules were investigated. Tuna oil was enzymatically produced and the resulting acylglycerol was mixed with tuna oil at 12.5% (w/w) to prepare a novel oil phase. This oil phase was stabilized by gelatin to prepare oil-in-water emulsions and subsequent microcapsules via complex coacervation. The tuna oil with glycerin monostearate (GMS) at 1 and 2% (w/w) were used as controls. Results showed that both acylglycerol and GMS significantly reduced the emulsion droplet size and zeta potential, while increasing the viscoelasticity and stability. The diacylglycerol/monoacylglycerol were involved in the oil/water interfacial layer formation by lowering interfacial tension and increasing droplet surface hydrophobicity. Overall, the changed emulsion properties promoted the complex coacervation and contributed to the formation of microcapsules with improved oxidative stability. Therefore, enzymatically produced acylglycerol can develop high-quality stable omega-3 microencapsulated novel food ingredients.

Spot the difference: optimising camera trap use to detect and identify individuals of a medium-sized carnivorous marsupial

Camera trap model and setup choice can significantly affect data collection. This study investigated standard-angle Reconyx and wide-angle Swift camera traps in different setups and how the choice of equipment influenced detection and individual identification of the chuditch (Dasyurus geoffroii). Camera models were placed side-by-side in four setups: (i) single and (ii) paired camera traps 30 cm above ground; and single cameras (iii) 1 m and (iv) 2 m above ground, with a lure (tuna oil) in the centre of all setups. Swifts had a higher Detection probability than Reconyx, although the number of detections with identified individuals did not significantly differ between camera models. The 30 cm paired camera setups had the highest Detection and Identification probabilities for both camera models, with both probabilities decreasing as cameras were positioned higher. Camera model and setup choice are important in obtaining detection and identification data, and should be considered when planning studies and interpreting results.

Encapsulation of tuna oil by liquid and solid self‐emulsifying delivery system: in vitro digestion and oxidative stability assessment

SummaryTuna oil, one of the main sources of omega‐3 polyunsaturated fatty acids (omega‐3 or n‐3 PUFAs), is known to have limited bioavailability due to its hydrophobicity. Moreover, the main n‐3 PUFAs found in tuna oil, that is docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are prone to oxidation. To overcome these drawbacks, tuna oil encapsulation via liquid (LSEDS) and solid self‐emulsifying delivery system (SSEDS) was developed. Different LSEDS formulations were prepared and evaluated in terms of tuna oil droplet size and dispersibility. Accordingly, the formulation with small droplets size and narrow size distribution was selected and further developed into SSEDS by spray drying process. SSEDS was thereafter characterised concerning production yield, moisture content, size, size distribution and morphology. Furthermore, the in vitro simulated gastrointestinal model of LSEDS and SSEDS was carried out. The results showed that after intestinal digestion stage, 87% and 72% of DHA were released from LSEDS and SSEDS, respectively. Therefore, these formulations of LSEDS and SSEDS were proven their ability to enhance the bioaccessibility of DHA. Moreover, the oxidative stability of LSEDS and SSEDS formulation was investigated and compared to pure tuna oil using non‐isothermal differential scanning calorimetry (DSC) analysis under oxygen. The results showed that both LSEDS and SSEDS formulations exhibited a high oxidative resistance with a higher energy needed to induce tuna oil oxidation than pure tuna oil. The chemical and thermal stability given by LSEDS and SSEDS may be efficiently applied in food area to enhance the techno‐functional properties of hydrophobic compounds.

Concentration of docosahexsaenoic acid from tuna oil by a combination of solvent crystallization and lipase‐catalyzed ethanolysis

AbstractThe docosahexaenoic acid (DHA) was concentrated from tuna oil fatty acid using solvent crystallization combined with lipase‐catalyzed ethanolysis. In the first step, solvent crystallization was carried out to concentrate DHA from tuna oil fatty acid using acetonitrile as a solvent. The optimal conditions of solvent crystallization were the crystallization temperature of −40°C and the fatty acid to solvent ratio of 1:8 (w/v). This step increased the DHA content in the original tuna oil fatty acid from 22% up to 61%. In the second step, lipase‐catalyzed ethanolysis was conducted with DHA‐enriched fatty acid from the first step using Lipozyme RM IM (from Rhizomucor miehei) as a biocatalyst. The optimum conditions of this second step were the reaction temperature of 20°C and the molar ratio of 1:1 (fatty acid to ethanol). Overall, DHA enrichment with purity of 85% was obtained by the two step processes.

Trace metals in commercial seafood products (canned, pickled and smoked): Comparison, exposure and health risk assessment

This study used inductively coupled plasma and mass spectrometry, followed by microwave digestion, to assess the concentration of six trace metals (Cr, Ni, As, Cd, Hg, and Pb) in three canned products (tuna in oil [TIO], sardine in oil [SIO], and mackerel in oil [MIO]), two pickled products (prawn pickle [PP] and fish pickle [FP]), and one smoked product (masmin) collected from Tuticorin market, southern India. Trace metal (TM) levels in canned, pickled, and smoked fish varied from 0.01 to 1.48, 0.009 to 0.94, and 0.08 to 4.13 mg/kg, respectively. The concentration of TMs in the seafood was observed in the following order: As > Cr > Pb > Ni > Cd > Hg. Regarding their accumulation in the seafood products, masmin showed the highest levels followed by SIO, MIO, TIO, FP, and PP. The results revealed that smoked products showed higher TM concentrations, followed by canned and pickled products. The level of TMs in seafood products was below the maximum residue limit set by the European Commission (EC/1881/2006) and the Food Safety and Standards Authority of India (FSSAI). Risk assessment for consumer health implied that the evaluated target hazard quotient (THQ < 1), hazard index (HI < 1), and target cancer risk (TCR < 1.E−04) values did not exceed their guideline values and did not cause non-carcinogenic and carcinogenic health impacts through seafood product consumption. The pollution index (Pi) values of TMs in seafood products ranged from 0.01 to 0.7, with As and Cd showing the lowest and highest values, which were below 0.7, indicating their safety for consumption. The metal pollution index (MPI) for TMs in seafood ranged from 9.E−05 to 0.007, with the lowest and highest values associated with PP and TIO products. The MPI value for seafood products was below 1, signifying low TMs accumulation, suggesting the safety of seafood for consumption. The maximum seafood meal consumption limit (CRmm) was calculated, showing that adults can safely consume > 16 meals/month without chronic or acute toxicity. The results of this study suggest that the accumulation of TMs in the analyzed seafood product was below the health guidelines and pollution index values, making it suitable for smooth domestic and international export as well as safe consumption.

Effect of enzymatically produced tuna oil acylglycerol on the characteristics of gelatin O/W emulsion during microencapsulation using complex coacervation

Complex coacervation is an effective process to deliver ingredients for functional food applications. A stable oil-in-water (O/W) emulsion with desired characteristics significantly affects the complex coacervation and the quality of final microcapsules. In this study, tuna oil was partially hydrolyzed using TL100 and ADL lipases to produce acylglycerols TL100-AC and ADL-AC, respectively. These lipids were subsequently stabilized by gelatin in the O/W emulsion, followed by the complex coacervation with sodium hexametaphosphate. The effect of lipids on emulsion properties, such as interfacial properties, rheological properties, protein conformation and microcapsule formation during complex coacervation, was investigated. Compared with tuna oil-based emulsion, acylglycerol-based ones exhibited reduced droplet size (<600 nm), zeta-potential, interfacial tension (<8 mN/m) and interfacial protein concentration (about 80%). The gelatin in the acylglycerol-based emulsions had reduced β-sheet and slightly increased random coil contents. Compared with the one containing tuna oil, the ones containing acylglycerol possessed higher complex coacervation yields (>75%). These changes were beneficial to the formation of coagulant and flocculant so that gelatin-stabilized acylglycerol-based O/W emulsion resulted in improved complex coacervation between gelatin and sodium hexametaphosphate. This study provides a scientific basis for designing specific gelatin O/W emulsions and microencapsulation for the stabilization and delivery of omega-3 fatty acids.

Effects of endogenous lipid on the functional qualities of tuna protein during cold storage

The effects of endogenous lipid on the quality of tuna protein during storage was evaluated. Defatted tuna protein was prepared and co-stored with different contents of tuna oil or soybean oil, and the functional qualities, oxidation, protein structure and lipid oxidation were compared. During storage, a higher tuna oil content caused a greater attenuation in the functional qualities of protein, including emulsifying, foaming and water absorption abilities, and tuna oil could lead to more severe attenuation than soybean oil. Besides, the higher the oxidation degree of oil, the higher the oxidation degree and the more disordered of sarcoplasmic and myofibrillar proteins, which indicated that protein oxidation could be induced by lipid oxidation and cause greater structural damage. Finally, Pearson correlation revealed that variation in myofibrillar protein more strongly affects the functional qualities than sarcoplasmic protein. Therefore, the removal of endogenous lipid had a significant positive impact on the quality stability of protein products during storage, especially for marine protein products.

An optimisation study to reduce greenhouse gas emissions from adults’ current diet in Italy

Abstract Background Trade-offs between health and sustainability dimensions should be addressed since environmentally sustainable diets can require a substantial dietary shift and result in nutrient deficiencies. The study aimed at modelling the current dietary consumption of the adult population in Italy to reduce diet-related greenhouse gas emission (GHGe) while complying with the National Recommended Energy and Nutrient Intake Levels (LARN), food-based dietary guidelines, and preferences. Methods Food consumption data from the Italian Nutrition &amp; HEalth Survey (INHES) study (n = 8944, 53% females) have been used as reference diet. Through a non-linear programming model, two intermediate nutritionally adequate dietary scenarios, which alternatively minimised the impact on climate change or modifications in current food consumption, have been generated contextually to a final diet model combining both outcomes. Several constraints ranging from recommended dietary intakes to proper food associations and substitutions were applied to the model. Results The final modelled diet had an average energy content of 2100 kcal/d with carbohydrates, proteins, lipids, and fibers accounting respectively for 49%, 16%, 31%, and 4% of the total energy. The associated GHGe were 2.01 kg CO2 eq/d: 49% less than the current diet, 22% more than the balanced diet with the lowest GHGe, and 12% less than the balanced diet closest to actual food consumption. Wholegrain bread, peas, seasonal fruit and vegetables, chicken, tuna, whole milk and extra-virgin olive oil were the most represented products within each corresponding food group. Conclusions The study proposes a balanced and climate-friendly diet which simultaneously minimises changes in food preferences, reducing barriers towards more sustainable food choices. Diet optimisation can be a promising tool to support public health strategies by suggesting less environmentally impactful and culturally acceptable dietary shifts at the country level. Key messages • The present study provides a culturally acceptable and nutritionally balanced dietary scenario optimised for greenhouse gas emissions to be proposed as a model for the adult population in Italy. • The study contributes to the development of public health policies by supporting feasible dietary behavioural shifts towards healthy and sustainable dietary choices.

Therapeutic Benefits of Tuna Oil by In Vitro and In Vivo Studies Using a Rat Model of Acetic Acid-Induced Ulcerative Colitis.

Ulcerative colitis (UC), an inflammation of the colon lining, represents the main form of inflammatory bowel disease IBD. Nutritional therapy is extremely important in the management of ulcerative colitis. Fish oil contains long-chain omega-3 polyunsaturated fatty acids, which have beneficial effects on health, including anti-inflammatory effects. This study aims to investigate the benefits of bluefin tuna oil extracted by the Soxhlet method in vitro by determining the anti-radical and anti-inflammatory activities and in vivo by evaluating the preventive and curative effects. The experiments were carried out using two doses of oil (100 and 260 mg/kg) and glutamine (400 and 1000 mg/kg) on the acetic acid-induced UC model. UC has been induced in Wistar rats by intrarectal administration of a single dose of 1 mL acetic acid (5% v/v in distilled water). The obtained results indicate that tuna oil and glutamine have a significant anti-free radical effect. Tuna oil has a marked anti-inflammatory power based on membrane stabilization and inhibiting protein denaturation. The reduction of various UC parameters, such as weight loss, disease activity score DAS, and colonic ulceration in rats pre-treated with tuna oil and glutamine, demonstrate that these treatments have a significant effect on UC. Total glutathione GSH, superoxide dismutase SOD, and catalase activities are significantly restored in the tuna oil and glutamine groups, while lipid peroxidation has been markedly reduced.

Physicochemical evaluation of chitosan–xanthan gum nanoemulsions as polyunsaturated enriched lipid–carrier

Polyunsaturated enriched lipid–carriers have been drawn attention due to their health benefits. This work aimed to develop new delivery carriers based on chitosan–xanthan gum nanoemulsions with tuna oil, which is rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Therefore, it was intended to elucidate the physicochemical interactions within chitosan–xanthan gum–polyunsaturated fatty acids nanoemulsions. The droplets size, zeta potential, rheological and thermal characteristics, as well as the kinetic, thermodynamic and oxidative studies of the nanoemulsions were performed. All emulsions presented droplet sizes in the nanoscale range (around 224–289 nm) and a pseudoplastic rheological behavior. Thermodynamic parameters showed that the viscous flows of all nanoemulsions were nonspontaneous and exothermic, presenting a more orderly state. However, increased xanthan gum concentration resulted in endothermic viscous flow. Based on the results, protonated amino groups from chitosan improved electrostatic stability due to an increase in zeta potential values, while the enhanced viscosity led to by xanthan gum reduced the diffusivity of dissolved oxygen and increased oxidative stability. Moreover, electrostatic interactions between chitosan and xanthan gum increased the steric and oxidative stabilities of nanoemulsions.

Bisphenol a (BPA) emitted from food cans: an evaluation of the effects of dry heating, boiling, storage period, and food type on migration and its potential impact on human health

ABSTRACT Bisphenol A (BPA) is one of the main pollutants associated with food hygiene. This study evaluates the health risk of BPA migrated from the inner wall of canned food to its contents. For this purpose, a total of 120 samples of 5 different types of canned food, including tuna fish, oil, beans, tomato paste, and eggplant, were randomly selected from the market of Kermanshah. BPA was analysed using solid-phase microextraction (SPME) along with gas chromatography equipped with single quadrupole mass detection (GC-MS). Finally, the results were analysed statistically, and the estimated daily intake and hazard quotient for BPA from consuming 5 varieties of canned food among Iranian consumers were calculated using formulas and functions related to health risk assessment. The results showed a significant difference (p < 0.05) in the mean concentration of BPA in various canned foods. Generally, boiling and dry heating processes, as well as increasing the storage time above 6 months, cause a significant increase in BPA migration from the inner wall of the can into the canned food. Lastly, it can be concluded that the consumption of each canned food, both separately and simultaneously, is safe in creating non-carcinogenic health risks associated with BPA (HQ < 1). Furthermore, the amount of BPA released cannot harm Iranian consumers’ health since the initial amount of BPA in analysed canned food was low, even after boiling and heating processes for 20 minutes to destroy the botulinum toxin.

Preparation of glycerides enriched with n-3 long-chain polyunsaturated fatty acids by Thermomyces lanuginosus lipase-catalyzed hydrolysis of tuna oil

n-3 Long-chain polyunsaturated fatty acids (LC-PUFAs) in glyceride form have attracted much attention due to their nutritional value and high bioavailability. In this work, Thermomyces lanuginosus lipase (TL 100 L) was used to selectively hydrolyze tuna oil for preparing glycerides enriched with n-3 LC-PUFAs. Effects of reaction variables on the hydrolysis reaction were optimized by response surface methodology, and the optimal conditions were as follows: reaction temperature 54 °C, enzyme load 3%, reaction time 6 h, mass ratio of water to tuna oil 1.5:1. Under these conditions, the resulting degree of hydrolysis was 55.01%, and the total content of eicosapentaenoic acid and docosahexaenoic acid in the glyceride fraction was found to be 46.39%. The final product was mainly composed of diacylglycerols (53.93%) and triacylglycerols (34.58%) after removal of the free fatty acids. This paper provides a simple and suitable method for industrial production of glycerides enriched with n-3 LC-PUFAs.

Characteristics and functions of Limosilactobacillus reuteri (Lactobacillus reuteri) from the intestine of mice supplemented with three dietary components based on genome resequencing and metabolite analysis

Limosilactobacillus reuteri is a resident probiotic in the intestines of animals with strong environmental adaptability. In the current study, to elucidate the adaptation strategies of L. reuteri to the intestine of mice supplemented with three dietary components (oil, peptide and cellulose), whole genome resequencing and determination of intracellular metabolites were carried out. The resequencing results showed that L. reuteri TO60 (LR-TO) from the intestines of mice supplemented with high docosahexaenoic acid (DHA) tuna oil, or fermented Benincasa hispida culture (L. reuteri FB151, abbreviated as LR-FB) had relatively consistent single nucleotide polymorphisms (SNPs) and insertions and deletions (InDels), and those of L. reuteri from the intestines of mice supplemented with Rhopilema esculentum polypeptides (L. reuteri RE225, abbreviated as LR-RE) were quite different from them. The KEGG functional annotation of resequencing and the intracellular metabolites suggested that in all of the L. reuteri adapted to the intestinal environment mainly by regulating carbohydrate metabolism and membrane transport metabolic pathways. However, there were still some differences in their genes and metabolites, which may be related to the changes in the intestinal environment caused by three different types of dietary interventions. Our study analyzed the adaptation mechanism of L. reuteri to different isolated sources at the genetic level and metabolic level, which is helpful to clarify the adaptation strategies of probiotics to the intestinal environment, and provide supplementary information for the use of dietary nutritional supplements.

Chitosan-based nanocapsules by emulsification containing PUFA concentrates from tuna oil.

Chitosan nanocapsules containing polyunsaturated fatty acid (PUFA) concentrates from tuna oil, with EPA + DHA contents around 57% (w/w), were developed by emulsification process, using different chitosan concentration (1.0%, 1.5%, 2.0%, w/v) and stirring speed (10,000, 15,000, 20,000 rpm). The effects of these parameters on particle size and zeta potential were evaluated. The physical and oxidative stabilities were used to measure the product quality during storage. Chitosan concentration, stirring speed and its interaction significantly affected (p < 0.05) the particle size. In addition, chitosan concentration significantly affected (p < 0.05) the zeta potential of nanocapsules emulsion. Based on the results of physical and oxidative stabilities, the nanocapsules were stable for 30 days under refrigeration temperature (7 °C), and with 1.5-2% chitosan resulted in improved protection against oil oxidation. The nanocapsules produced with 2% chitosan and 10,000 rpm showed the lowest variations of polydispersity index and nanocapsules size after 30 days of storage (221.8 ± 3.0 nm). These conditions can be considered the most suitable to produce nanocapsules of PUFA concentrates from tuna oil using chitosan as wall material. These nanocapsules showed physical characteristics and oxidative stability, which could enable their application in the food industry, representing an important source of EPA and DHA fatty acids.

Omega-3 meat enrichment and L-FABP, PPARA, and LPL genes expression are modified by the level and period of tuna oil supplementation in slow-growing chickens.

This study proposes a strategy to manipulate the fatty acid (FA) content in slow-growing Korat chicken (KRC) meat using tuna oil (TO). To determine the optimal level and feeding period of TO supplementation, we conducted a study investigating the effects of dietary TO levels and feeding periods on meat quality, omega-3 polyunsaturated fatty acid (n-3 PUFA) composition, and gene expression related to FA metabolism in KRC breast meat. At 3 wk of age, 700 mixed-sex KRC were assigned to seven augmented factorial treatments with a completely randomized design, each consisting of four replicate pens containing 25 chickens per pen. The control group received a corn-soybean-based diet with 4.5% rice bran oil (RBO), while varying amounts of TO (1.5%, 3.0%, or 4.5%) replaced a portion of the RBO content in the experimental diets. The chickens were fed these diets for 3 and 6 wk, respectively, before being slaughtered at 9 wk. Our results indicated no significant interactions between TO levels and feeding periods on the growth performance or meat quality of KRC (P > 0.05). However, the liver fatty acid-binding protein gene (L-FABP, also known as FABP1), responsible for FA transport and accumulation, showed significantly higher expression in the chickens supplemented with 4.5% TO (P < 0.05). The chickens supplemented with 4.5% TO for a longer period (3 to 9 wk of age) exhibited the lowest levels of n-6 PUFA and n-6 to n-3 ratio, along with the highest levels of eicosapentaenoic acid, docosahexaenoic acid, and n-3 PUFA in the breast meat (P < 0.05). However, even a short period of supplementation with 4.5% TO (6 to 9 wk of age) was adequate to enrich slow-growing chicken meat with high levels of n-3 PUFA, as recommended previously. Our findings indicated that even a short period of tuna oil supplementation could lead to desirable levels of omega-3 enrichment in slow-growing chicken meat. This finding has practical implications for the poultry industry, providing insights into optimal supplementation strategies for achieving desired FA profiles without adversely affecting growth performance or meat quality.