Narcisa Maria Bandarra

The yellow mealworm ( Tenebrio molitor ) is increasingly recognised as a novel feed ingredient. During industrial processing, larvae are often defatted to improve storage, handling and extrusion properties. Full-fat (ffTM) and defatted (dTM) mealworm meals were compared as total fishmeal replacements for rainbow trout ( Oncorhynchus mykiss ) diets. Three experimental diets were formulated to be isoproteic and isolipidic: a fishmeal-based control (FM) and two diets containing 25% ffTM (FFTM25) or dTM (DTM25). Juvenile rainbow trout (11.4 ± 1.5 g) were fed to apparent satiation twice daily. After 56 days, no impact on growth performance was observed. Feed intake decreased in the DTM25 and FFTM25 groups, while the feed conversion ratio was reduced in the FFTM25 diet, compared to the FM diet. In the anterior intestine, the DTM25 diet increased villus width and enterocyte height. Fish fed the DTM25 diet had higher whole-body lipid content, whereas fillet lipid content was higher in the FFTM25 group. The FFTM25 diet also increased fillet saturated and n-6 polyunsaturated fatty acids (PUFA), the thrombogenicity index and reduced the hypocholesterolemic/hypercholesterolemic ratio, while the n-3/n-6 PUFA ratio was highest in the FM diet. Nevertheless, all experimental treatments showed similar absolute levels of n-3 PUFA. Fillet yellowness was higher in the control and FFTM25 groups. Overall, the complete dietary replacement of fishmeal with both dTM and ffTM supported growth and anterior intestine health of rainbow trout juveniles. Nevertheless, the ffTM dietary inclusion improved feed efficiency, but reduced fillet lipid quality, indicating a trade-off between mealworm lipid use and product quality.

Fish oil has traditionally been the primary source of n-3 long-chain polyunsaturated FA (n-3 LC-PUFA) in aquafeeds but is increasingly being replaced by alternative lipid sources. However, marine carnivorous fish require dietary n-3 LC-PUFA, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which these alternative sources lack. This study assessed the long-term impact of graded levels of dietary EPA+DHA from microalgal oil on European seabass growth, feed utilization, immunological and oxidative status, and muscle FA profile. Six isoproteic (47% protein) and isolipidic (17% lipid) diets containing 0.56%, 0.66%, 0.71%, 0.90%, 1.11%, and 1.27% EPA+DHA were fed to fish (107 g initial weight) for 180 days at 23 °C, followed by a 7-day thermal challenge at 30 °C. At the end of the feeding trial, growth performance, feed utilization, organosomatic indices, blood and innate immune parameters, and oxidative stress were unaffected. Muscle FA composition mirrored that of the diets, and linear correlations were observed between muscle and dietary n-3 LC-PUFA levels. In the thermal challenge, no mortalities occurred, but hematological parameters, immune responses, and oxidative stress were intensified. Muscle FA composition remained unchanged, indicating that a dietary EPA+DHA level of 0.56% appears sufficient to meet physiological needs during an acute temperature challenge.

Due to its high prevalence and significant impact on modern society, Alzheimer’s disease (AD) is one of the most important neurodegenerative disorders. It is more common among individuals over the age of 65, and its incidence has increased sharply as a result of rising life expectancy. Several factors have made it challenging to identify an effective treatment for AD. One major difficulty lies in its complexity, as the mechanisms involved in its progression are not yet fully understood. Nevertheless, the role of diet and lipids has been highlighted by numerous studies, underscoring their potential influence on this pathology. Due to the intricacy of its biochemical and metabolic interactions, this subject continues to be of particular interest, highlighting the need for further research. In this sense, this comprehensive and updated review aimed to elucidate these aspects, especially regarding marine-derived lipids, whose bioactive potential may become an irreplaceable tool in the management of AD, whether in terms of its treatment or prevention.

Extreme weather events, particularly marine heatwaves (MHWs), increasingly threaten aquaculture systems worldwide by impairing animal physiology and economical sustainability. This showcases the need to develop nutritional approaches that enhance animal performance under sub-optimal conditions. This study evaluated the effects of dietary supplementation with the brown macroalga Laminaria digitata (whole dried powder or extract) on the antioxidant status, digestive activity, and lipid metabolism of juvenile Sparus aurata exposed to a simulated MHW. Fish were fed four diets (control, 0.3% extract, and 0.3% or 1.5% powder) for 30 days before being exposed to a category III Mediterranean MHW. Under optimal temperature, macroalgae supplementation reduced oxidative status (lower catalase activity). The powder-feeds decreased lipid peroxidation, while the extract-feed elicited the opposite. All supplemented diets reduced proteolytic activity, and the extract-feed also decreased amylase activity. The MHW impaired gastrointestinal antioxidant defenses and liver lipid metabolism, decreasing catalase and glutathione S-transferase activities, as well as ΣPUFA n-6, 16:1 n-7, and 18:2 n-6 levels. The 0.3% powder-feed mitigated MHW-induced reductions in antioxidant activity, while both 0.3%-diets prevented thermal stress-related alterations on fatty acid profile. Overall, L. digitata powder at 0.3% was most effective at enhancing thermal stress resilience, supporting its value as a functional aquafeed ingredient.

Growing pressure to build sustainable food systems is steering interest toward edible insects as efficient, nutrient-rich alternatives. In this work, it was evaluated whether adding DHA extracted from microalgal biomass to the standard diet of Acheta domesticus can enrich the crickets’ lipid quality. Diets containing 0, 5, and 10% DHA were fed under controlled rearing. Subadult crickets were milled and analyzed. Compared with controls, supplemented groups showed higher total lipids and a healthier fatty-acid profile, with clear increases in omega-3 and the appearance of DHA. This minor dietary change is simple, scalable, and compatible with low-impact rearing, supporting the development of higher-value insect-based ingredients for human nutrition.

Alzheimer’s disease (AD) is marked by cognitive decline, and also by retinal degeneration. Having in mind that docosahexaenoic acid (DHA, 22:6n − 3) is a safe, low-cost, and pivotal fatty acid for brain health and sustained cognitive function, this study exploits environmentally friendly non-fish sources as potential dietary supplements enriched with DHA to prevent or reverse AD. Forty 5xFAD transgenic male mice, aged five weeks old, were randomly distributed by five body weight-matched dietary groups (with eight animals each) and fed isocaloric diets based on the AIN-93M standard formulation for rodents for 6 months. Except for the control feed (without supplementation), each diet contained a modified lipidic fraction supplemented with 2% of the following: (1) linseed oil (LSO, rich in alpha-linolenic acid (ALA, 18:3n − 3)); (2) cod liver oil (fish oil, FO, rich in both DHA and eicosapentaenoic acid (EPA, 20:5n − 3)); (3) Schizochytrium sp. microalga oil (Schizo, with 40% of DHA); and (4) commercial DHASCO (DHASCO, with 70% of DHA). The aim of this study was to measure retinal neural layer thickness, calculate ganglion cell layer (GCL) density, and assess retinal injury by means of immunohistochemical staining for β-amyloid plaques deposition, TAU protein levels, and IBA1, as hallmark features of AD progression, in order to elucidate the effects of different dietary DHA treatments in Alzheimer’s retinas. Although no statistical differences were observed across retinal layer thicknesses depending on the diet (p > 0.05), there was a consistent pattern for slightly increased retinal thickness in 5xFAD mice fed fish oil relative to the others for the measurement of total layers, in general and for the inner segment/outer segment layer, the outer nuclear layer, the outer plexiform layer, the inner nuclear layer, and the inner plexiform layer, in particular. The ganglion cell layer (GCL) density was increased in 5xFAD mice fed the DHASCO oil diet relative to the control (p < 0.05), suggesting a benefit of DHA supplementation on the number of viable ganglion cells. No positive staining was observed for β-amyloid plaques deposition or the neuroinflammatory marker, IBA1, corroborating previous findings in human AD retinas. Conversely, the internal retinal layers showed intense TAU immunostaining. Immnunostained TAU area was significantly reduced in 5xFAD mice fed a fish oil diet compared to control (p < 0.05), although the number of TAU-positive cells did not differ across diets (p > 0.05). The retinal protected integrity derived from the benefits of DHA supplementation found, either from fish oil or DHASCO oil, underscores the potential of retinal biomarkers as non-invasive indicators of cognitive decline and overall brain health, opening new avenues for investigating AD pathophysiology in the retina.

Alzheimer’s disease (AD) is the most common form of dementia, affecting over 50 million people globally. Since 1906, efforts to understand this neurodegenerative disease and to develop effective treatments have continued to this day. Recognizing docosahexaenoic acid (DHA, 22:6n-3) as a safe, inexpensive and vital nutrient for brain health and cognitive protection due to its key role in brain development and function, this study explores novel, sustainable non-fish sources as potential dietary supplements to prevent or mitigate AD, within a blue biotechnology framework. Forty 5×FAD male mice, five weeks old, were allocated to five body weight-matched dietary groups (n = 8) and fed isocaloric diets based on AIN-93M standard chow for 6 months. Each diet, except the control feed (non-supplemented group), enclosed a modified lipid fraction supplemented with 2% of the following: (1) linseed oil (LSO, rich in alpha-linolenic acid (ALA,18:3n-3)); (2) cod liver oil (fish oil, FO, rich in both DHA and eicosapentaenoic acid (EPA, 20:5n-3)); (3) Schizochytrium sp. microalga oil (Schizo) with 40% of DHA; and (4) commercial DHASCO oil (DHASCO) with 70% of DHA. The different diets did not affect (p > 0.05) growth performance criteria (e.g., final body weight, daily feed intake, and body weight gain) suggesting no effect on the overall caloric balance or mice growth, but n-3 long-chain polyunsaturated-fatty acid (n-3 LCPUFA) supplementation significantly reduced total cholesterol (p < 0.001) and total lipids (p < 0.001). No systemic inflammation was detected in 5×FAD mice. In parallel, a beneficial modulation of lipid metabolism by DHA-enriched diets was observed, with polyunsaturated fatty acid incorporation, particularly DHA, across key metabolic tissues, such as the liver (p < 0.001) and the brain (p < 0.001). No behavioural variations were detected using an open-field test after 6 months of diet (p > 0.05). While mice fed a standard diet or LSO diet showed cognitive deficit, the incorporation of FO, Schizo or DHASCO oils into dietary routine showed promising protective effects on the working memory (p < 0.05) and the last two diets also on the recognition memory (p < 0.05) Increased neuronal count (p < 0.05), reflecting neuronal survival, was clearly observed with the fish oil diet. In turn, the number of TAU-positive cells (p < 0.05) was reduced in the Schizo diet, while β-amyloid deposition (p < 0.01) and the neuroinflammatory marker, IBA1 (p < 0.05), were decreased across all DHA-enriched diets. These promising findings open new avenues for further studies focused on the protective effects of DHA derived from sustainable and underexploited Schizochytrium sp. microalga in the prevention of AD.

The omega-3 index (O3I) is used as a biomarker for cardiovascular disease risk. The factors affecting O3I are not fully understood. A study was conducted in a representative sample of the Portuguese population (1,126 individuals) involving blood sampling for the determination of O3I and answering a questionnaire. Participants were asked to indicate their consumption frequencies and other relevant data. The average O3I of the population was 4.82±2.30%. There was a clear increasing trend of the O3I with higher amounts of consumed seafood, achieving an O3I of ~6% with three or more weekly meals. Age was a major determinant, presenting 50-79 year old males higher O3I values than 18-49. Physical activity led to higher O3I, 5.05±2.39% vs 4.64±2.21%. Smoking caused a lower O3I, 4.38±1.97% vs 4.89±2.34%. Physical activity had a larger effect upon O3I in consumers with high seafood consumption. In elderly (>70 year old), there was an inverse relation between O3I levels and high blood pressure. This study’s findings point to the importance of changing dietary habits in the direction of increasing seafood consumption and combining these nutritional changes with a healthier lifestyle (with more physical activity and no smoking) for a higher O3I and a lower cardiovascular disease incidence.

This study investigated a sustainable alternative to squalene production utilizing Thraustochytrium sp. and Aurantiochytrium sp., thereby reducing dependence on critically endangered sharks exploited for this compound. By optimizing fed-batch cultivation, a technique prevalent in industrial biotechnology, we have enhanced squalene yields and have demonstrated, through sensitivity analysis, the significance of this shift in preserving species at risk of extinction. Optimization of culture conditions led to the highest biomass concentrations for Thraustochytrium sp. being achieved at lower C–N ratios (Aurantiochytrium sp. occurred in culture media with a high C–N ratio of 54:50. Regarding squalene production, Thraustochytrium sp. produced 26.13 mg/L in the fed-batch system after 72 h, and Aurantiochytrium sp. produced 54.97 mg/L in a batch system with 30 g/L glucose and 0.22 g/L nitrogen after 96 h, showcasing their potential for industrial applications. Moreover, the sensitivity analysis revealed that, on an industrial scale, both strains could produce up to 59.50 t of squalene annually in large-scale facilities, presenting a valuable and sustainable alternative for the biotechnological industry and significantly reducing the reliance on non-renewable and endangered sources such as shark liver oil and preventing the annual capture of over 156,661 sharks.