Search Results (32)

Off-odor volatiles limit the acceptability of Atlantic salmon. This study investigated the effects of spatial distribution within the fillet, storage conditions, and cooking methods on the volatile profile of salmon and evaluated how pre-harvest rearing conditions, sex, and the presence of skin influence volatile compound formation during storage and cooking. Volatiles were classified as lipid-derived, protein-derived, and environmental contaminants. Spatial distribution within the fillet influenced volatile formation, with the head region exhibiting higher concentrations than the center and tail, reflecting differences in lipid distribution and precursor availability. During storage, fillets stored on ice generally exhibited higher volatile concentrations than samples frozen immediately, particularly for lipid-derived and environmental compounds, consistent with continued biochemical and microbial activity during chilled holding, whereas frozen storage preserved the biochemical state of the fillet. The magnitude of these differences depended on pre-harvest rearing conditions, the presence of skin, and harvest age. Cooking significantly increased volatile concentrations compared to raw fillets, with dry-heat methods, particularly baking, producing the highest levels, while boiling resulted in lower concentrations due to leaching into the cooking medium. Lower volatile formation was generally associated with cool-reared fish, male fillets, and muscle-only samples, while warm-reared, female, and skin-on samples exhibited greater volatile formation or retention, reflecting differences in precursor availability and tissue structure. These findings demonstrate that volatile formation in salmon is governed by the interaction between precursor accumulation during growth, spatial variability within the fillet, and transformation during post-harvest storage and cooking. Full article

Diet form is increasingly recognized as a welfare-relevant factor in intensive aquaculture, yet the effects of feed cooking on fish behavioral and physiological welfare remain poorly characterized. Juvenile southern catfish (Silurus meridionalis; 6.18 ± 0.52 g) were reared for 6 weeks in an indoor recirculating aquaculture system and fed either raw grass carp (Ctenopharyngodon idella) muscle (fish fed raw muscle, FR) or cooked grass carp muscle (fish fed cooked muscle, FC; 15 min ramp to ~100 °C followed by 2–3 min at ~100 °C). Locomotor activity and anxiety-like behavior were assessed using the open-field test and an annular light–dark preference assay, respectively. Flow-through respirometry further revealed a significantly lower standard metabolic rate (SMR) in FC fish than in FR fish, decreasing from 10.30 to 6.83, which represents a 33.7% reduction. Endocrine and biochemical analyses showed that cooking significantly decreased serum total triiodothyronine (T3) by 23.8%, whereas routine serum biochemical indices remained unchanged. In brain tissue, dopamine (DA) was significantly reduced by 7.2% in the FC group, and RT-qPCR analysis of dopamine-related genes further showed a significant downregulation of the rate-limiting synthesis gene th. These results indicate that cooking primarily downshifts the activity-energy axis in southern catfish and is accompanied by coordinated thyroid and dopaminergic changes. To our knowledge, this is the first integrated study to evaluate the behavioral, metabolic, and neuroendocrine effects of cooked feed in S. meridionalis, providing a short-term phenotypic baseline for assessing welfare-relevant feeding scenarios in aquaculture. Full article

The rapidly developing food industry necessitates the efficient use of raw materials, which can be achieved through the production of functional ingredients with high nutritional value. Secondary fish raw materials generated during the filleting of Atlantic cod (Gadus morhua), including vertebral bones with residual muscle tissue, skin, tails, and fins, represent a promising source of both biologically active compounds and highly digestible protein substances. The aim of this study was to evaluate the properties of protein hydrolysates obtained from secondary Atlantic cod raw materials by conventional enzymatic hydrolysis and combined enzymatic-ultrasonic treatment. The best results were achieved at a power of 320 W and a treatment duration of 3.5 min prior to the addition of the enzyme preparation (Protozyme C). The application of ultrasound enhanced the degree of hydrolysis by 4–5% while simultaneously reducing the amount of enzyme used. Electrophoretic analysis demonstrated a predominance of smaller peptides in the 10–15 kDa range compared to the control sample (43–95 kDa). Infrared spectroscopy confirmed structural changes in the samples under study, manifested in an increase in the number of terminal groups and partial disaggregation of the peptide mixture. Particle size distribution analysis revealed a more uniform distribution and a decrease in the median particle size in samples with ultrasonic pretreatment. The safety and antioxidant activity assessment did not show any toxic effects, but manifested a significant increase in antioxidant indicators (2.5–3.2 times) compared to the control sample. The results obtained show the enzymatic-ultrasonic treatment to be promising for the integrated processing of fish raw materials and the production of functional food ingredients with improved properties. Full article

Insect meal can be a valuable component of poultry diets, both during rearing and fattening, as well as for laying hens. Regarding protein feeds, the most commonly used are oil meals from soy and/or rapeseed, along with certain animal-derived feeds like fish meal. Recent years have seen considerable interest in the use of insect products in poultry nutrition. Insect meal has a high protein content with a favourable amino acid profile, similar to that of traditional animal-derived raw materials or soybean meal. The present study aimed to determine the effect of replacing 50% or 100% of soybean meal with black soldier fly (BSF) products, in the form of meal or whole dried larvae, on the performance and slaughter characteristics, blood lipid profile, sensory properties, and fatty acid composition of pheasant muscle, considering gender. The study showed that irrespective of the type of BSF products (e.g., meal or whole dried larvae), they can be successfully used to replace soybean meal, which is most commonly available commercially in the form containing GMOs. Further research is needed into optimising the proportion of BSF products in feed rations and their impact on the performance, as well as the quality of meat and eggs. Full article

Aquaculture advancement depends on alternative raw materials to reduce reliance on fishmeal (FM) and fish oil (FO) from extractive fisheries. Strategies like restricted feeding reduce costs and improve sustainability by minimizing feed waste and enhancing water quality, while selective breeding boosts growth and adapts fish to innovative diets. However, these measures may affect quality and shelf life. Gilthead seabream selected for high growth or non-selected were fed in 500 L tanks for 300 days until apparent satiety (AS) or with food restrictions (85AS or 65AS) using a control diet with low FM and FO balanced with vegetable ingredients, and an alternative diet (ALT) where FM was substantially replaced with insect, poultry by-product, feather, and porcine blood meals, while FO was completely replaced by microalgae, poultry, and salmon by-product oils. The ALT diet improved EPA + DHA levels, n-3/n-6 ratio, and fillet hardness. The selected fish outperformed the non-selected ones in growth and were more resilient to ALT diet and feeding restrictions. The 85AS feeding strategy optimized fillet quality by preventing lipid accumulation and muscle adaptations, as observed with the other feeding strategies. Combining sustainable feed formulations, genetic selection, and moderate feed restriction enables a viable, long-term strategy for high-quality, environmentally responsible seabream farming. Full article

The influence of algae in a final fattening diet for gilthead seabream, Sparus aurata, was studied in an 87 d feeding trial. Five groups were analysed (three tanks per group). In the first 38 days, one lot was fed with standard algae-free feed (C1) and four batches were fed with an algae-free diet low in fishmeal (FM) and fish oil (FO) and rich in terrestrial vegetables (C2). Subsequently, the C2 diet was changed in three out of the four groups, two of them being fed a diet with a microalgae blend (10%) plus 2% macroalgae (Alaria esculenta), either in raw (C2-R) or hydrolysed (C2-H) form, and a third batch with a diet lacking FM and FO but supplemented with 10% microalgae and 7% algae oil (C2-O) for 49 days. Body length and weight, muscle parameters, and conversion index were analysed after 38 and 87 days. At day 38, no significant differences were observed in any parameter between C1 and C2, but at the end of the trial (day 87), C2 displayed the lowest weight gain and the worst conversion rate, whereas C2-R showed higher body weight, fibrillar hypertrophy, and better conversion rates than the other groups, and C2-H displayed higher hyperplasia values than the other groups. Full article

Popular foods such as sushi and sashimi depend on the quality of raw fish meat to maintain consumer satisfaction. Recently, dietary insect meal and insect-derived substances have been extensively studied for application in aquaculture as a protein alternative or immunostimulant. However, the impact of insect functional substances on the fish meat quality of teleosts remains unclear. Here, we investigated the influence of dietary inclusion of silkrose-BM, a novel bioactive polysaccharide derived from the silkworm, Bombyx mori, on the meat quality of yellowtail (Seriola quinqueradiata). This study was conducted by comparing two groups given different feeds, commercial EP and feeds containing Silkrose-BM (0.1%), after a culture period of six months in separate floating-net cages. The yellowtail were specifically cut into loins and several meat quality parameters were observed, including proximate, meat color changes, total collagen, drip loss, muscle histology, and gene expression (qRT-PCR). The results of the color-change analysis showed that discoloration of red muscle in the EP feed group occurred faster than in the silkrose-BM group, indicating an antioxidant property of silkrose-BM. Dietary silkrose-BM also significantly reduced drip loss and increased the total collagen content of yellowtail meat. Furthermore, qRT-PCR analysis showed that genes related to lipid and protein degradation were downregulated in the muscles of fish fed on silkrose-BM. In contrast, proximate analysis indicated no significant change in the nutritional composition of the meat between the groups. Taken together, our results suggest that dietary silkrose-BM could improve fish meat quality by minimizing protein denaturation and inhibiting lipid oxidation during fish meat storage. Full article

The storage temperature is important for maintaining the quality of raw fish meat. The characteristics of ordinary muscle (OM) and dark muscle (DM) differ. This study aimed to clarify the effects of storage temperature (refrigeration, ice storage, and super-chilled (SC) storage) on the bacterial flora and quality (biochemical changes, volatile organic compounds (VOCs), and off-flavor development) of both muscles of yellowtail (Seriola quinqueradiata). SC storage effectively extended the shelf life of the dorsal part of ordinary muscle (OM) and DM by reducing bacterial proliferation, VOC changes, and off-flavor formation. However, their effects on the inhibition of trimethylamine (TMA) accumulation and lipid oxidation are limited. (E,E)-2,4-octadienal and (E,E)-3,5-octadien-2-one were identified as candidate markers of OM quality deterioration, whereas 1-hexanol was identified as a potential marker for DM. Alcohols, esters, and ketones are potential spoilage indicators of yellowtail muscles (OM and DM). Pseudomonas was the dominant spoilage bacterium in OM and DM across all storage conditions, with Acinetobacter, Brochothrix, and Shewanella appearing in later storage stages. These findings highlight the importance of storage at lower temperatures and understanding the dynamics of spoilage-causing bacteria and changes in VOCs in raw fish meat (OM and DM) to prevent spoilage and maintain meat quality. Full article

Fish provides a low-caloric content, polyunsaturated fatty acids, many essential trace elements and is also a rich source of protein, ranging from 10% to 25%. Therefore, the production of FPH (fish protein hydrolysates) is of great interest, as the resulting products exhibit a variety of important bioactive and technological properties, making them potential ingredients for new functional foods and supplements. The aim of this review was to compile and analyze information on enzymatic hydrolysates, with particular emphasis on those derived from fish by-products, as a potential ingredient in human nutrition. Their nutritional characteristics, food safety aspects, bioactive properties, technological attributes, key influencing factors, and applications in food products were evaluated. The findings revealed that these properties are influenced by several factors, such as the raw material, enzymes used, degree of hydrolysis, and the molecular weight of the peptides, which need to be considered as a whole. In conclusion, the gathered information suggests that it is possible to obtain high-value products through enzymatic hydrolysis, even when using fish by-products. However, although numerous studies focused on FPH derived from fish muscle, research on by-products remains limited. Further investigation is needed to determine whether the behavior of FPH from by-products differs from that of muscle-derived FPH. Full article

In the marine environment, fish parasites are present in most seafood species. The most common are nematodes of the genus Anisakis, which can parasitize human tissues, causing anisakiasis and allergies—in some cases with a strong reaction, such as anaphylactic shock. This happens when people ingest live or dead larvae present in the muscles or viscera of a wide range of fish and cephalopods. Consumer education has been positioned as one of the most effective alternatives for its prevention. This study, carried out in Asturias (northwest Spain), sought to identify the seafood products that present the greatest risk of anisakiasis for consumers, taking into account their consumption, the prevalence of Anisakis, and consumer knowledge about this parasitosis. In the results, hake (Merluccius merluccius) and cod (Gadus morhua), frequently consumed in the region and with high parasite prevalence, do not pose a great risk because they are consumed when well cooked. Instead, sardine (Sardina pilchardus), highly consumed and less parasitized, and anchovy (Engraulis encrasicolus), highly parasitized and less consumed, would exhibit a medium risk. Young participants know more about the risks of anisakiasis from raw seafood. The gaps detected in the knowledge about the ability of temperature treatments to eliminate parasites, especially in allergic people, must be addressed for better prevention. We suggest campaigns adapted to the population sectors. Full article

The aim of this research is to explore the potential effects of two microalgae-based additives included in finishing feeds on the quality and shelf-life of seabream fillets. In a 41-day feeding trial, seabream specimens were fed with experimental aquafeeds containing 10% of the bioactive supplements. These additives consisted of a blend of Nannochloropsis gaditana and Arthrospira platensis biomass, which was utilized as either raw (LB-CB) or enzymatically hydrolyzed (LB-CBplus). A control group received a microalgae-free diet. The results showed that the functional aquafeeds improved the nutritional profile of seabream fillets, increasing protein and PUFA-n3 contents while reducing the atherogenic index, especially for the LB-CBplus treatment. LB-CBplus also enhanced the texture parameters (hardness and chewiness) of fillets during the initial 5 days under cold storage. Regarding skin pigmentation, fillets showed increased greenish and yellowish coloration compared to control fish, mostly attributed to the inclusion of crude algal biomass (LB-CB). Moreover, diets enriched with microalgae additives effectively delayed muscle lipid oxidation processes under refrigeration for up to 12 days, with LB-CBplus exhibiting higher antioxidant effects. These findings highlight the potential of microalgae-based additives to enhance both the nutritional and organoleptic quality of seabream fillets. Full article

Low levels of docosahexaenoic acid (DHA) in the brain have been related to neurological disorders, like Alzheimer’s disease (AD). After ingestion, dietary DHA must cross the blood–brain barrier, where it is absorbed as lysophosphatidylcholine (LPC), due to its role as a preferential DHA carrier in the brain. This work aimed at the production of LPC-DHA extracts to be used in supplementation/food fortification intended neural enrichment in DHA. As it is rich in DHA, especially its phospholipids (PL), Atlantic mackerel (Scomber scombrus, caught in Spring/2022) was used as a raw material. The polar lipids fraction was separated and hydrolysed with Rhizomucor miehei lipase, to enzymatically convert phosphatidylcholine (PC) into LPC. The fish (muscle and by-products) lipids fraction was used for total lipids (TL) content, lipid classes (LC) and fatty acid (FA) profile evaluation, whilst polar lipids extracts were studied for LC production and FA analysis. Muscle TL ranged between 1.45 and 4.64 g/100 g (WW), while by-products accounted for 7.56-8.96 g/100 g, with the highest contents being found in March. However, PL were more abundant in muscle (22.46–32.20% of TL). For polar lipids extracts, PL represented 50.79% of TL, among which PC corresponded to 57.76% and phosphatidylethanolamine to 42.24%. After hydrolysis, nearly half of this PC was converted into LPC. When compared to the initial PC, DHA relative content (33.6% of total FA) was significantly higher after hydrolysis: 55.6% in PC and 73.6% in LPC. Such extract, obtained from this undervalued species, may represent a promising strategy to increase DHA uptake into brain cells while allowing this species to upgrade. Full article

Previous studies have shown that Nannochloropsis gaditana can partially replace fishmeal in the diet of gilthead seabream, Sparus aurata. However, its effect on muscle growth is hardly known. This experiment was carried out with gilthead seabream adults that were fed with N. gaditana at two inclusion levels (2.5 or 5%) either raw (R2.5 and R5 groups) or cellulose-hydrolyzed (H2.5 and H5 groups) for 45 days in the final fattening phase. The body length and body weight were measured in all fish at the beginning and end of the experiment. Also, the white muscle transverse area (WM), size, number and fibrillar density of the white fibers were measured in 9 fish group⁻¹. After 45 days, the body parameters and the WM did not show significant differences among the groups. However, muscle cellularity did show significant differences, such that the hypertrophy values were higher in the H2.5 and H5 than in the R2.5 and R5 groups. On the contrary, R2.5 and R5 showed the highest fibrillar density and hyperplasia values, which are often positively correlated with the fillet firmness and therefore could improve the final quality of the fish. No significant differences attributable to the inclusion levels of N. gaditana were observed. Full article

A total of 30 samples of Atlantic bluefin tuna were analysed for total mercury concentration. Relationships between total mercury content and age, Fulton’s condition index (K) and fat content were statistically evaluated. The effect of muscle status (raw, pre-canning, canned) on mercury content was also investigated. The average total mercury content was: 1.185 ± 0.662 mg/kg in raw, 1.481 ± 0.893 mg/kg in pre-canning and 1.393 ± 0.882 mg/kg in canned samples, respectively. Canning promotes a statistically significant increase in the concentration of mercury. The weight of fish, K and fat content are useful tools to estimate the mercury accumulation in Atlantic bluefin tuna. The results of the present study represent a contribution to the assessment of the EU mercury levels in Atlantic bluefin tuna. Full article

Currently, microalgae are used in fish diets, but their long-term growth effect is unknown. In this experiment, juvenile seabream specimens were fed with microalgae-enriched diets for three months, and then transferred to a microalgae-free diet for 10 months to assess long-term effects up to commercial size (≈27 cm and ≈300 g). The juvenile diets contained Nannochloropsis gaditana at 2.5 or 5% inclusion levels, either raw (R2.5 and R5 groups) or cellulose-hydrolyzed (H2.5 and H5 groups). The body length and weight were measured in 75 fish group⁻¹ at commercial stage. The size, number, and fibrillar density of white muscle fibers and the white muscle transverse area were measured in nine fish group⁻¹ at commercial stage. The results showed the highest body weight in H5 at commercial stage. The white muscle transverse area and the white fibres hyperplasia and density also showed the highest values in H5, followed by H2.5. In contrast, the highest hypertrophy was observed in C and R2.5, being associated with the lowest muscle growth in both groups. These results showed a microalgae concentration-dependent effect in hydrolyzed diets as well as an advantageous effect of the hydrolyzed versus raw diets on the long-term growth of Sparus aurata. Full article