The authors studied a 47-year-old patient who presented with an association of deafness, acute cerebral stroke-like episode, leukoencephalopathy, and extensive basal ganglia calcifications. Late onset and neuroradiologic findings were atypical for MELAS syndrome (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Strokelike episodes). A heteroplasmic G to A transition at nucleotide 4332 in the tRNA glutamine gene was identified in the patient’s muscle mitochondrial DNA. The pathogenicity of the mutation was shown in single muscle fibers by the correlation between high mutation load and cytochrome c oxidase defect.

This study aimed to evaluate the efficiency of an integrated multi-trophic aquaculture (IMTA) system comprising co-cultured fed fish and organic extractive species representing three distinct trophic levels as well as the impact and potential utilization of two commercially available fish feeds made up of 35% fish meal (FM) and 20% fish meal (LFM) ingredients, using a multi-indicator assessment approach. Significant alterations were observed in growth performance indicators (GPIs), water and sediment quality indices, toxicity tests and biomarkers within the IMTA system. The fish survival, weight gain (WG), and specific growth rate (SGR) were higher in the IMTA system with significantly lower feed conversion ratios (FCRs) and higher feed efficiency (FE) in comparison to the fed fish monoculture system. Yet, organic filter feeders displayed 100% survival, and increased shell growth, while deposit feeders exhibited successful survival and significant weight gain. In the comparison between FM-IMTA and LFM-IMTA, fed fish in FM-IMTA showed higher WG, SGR, and FE with lower FCR. Environmental parameters like temperature, oxygen, and nutrient concentrations fluctuated but generally improved in the IMTA system, indicating lower mesotrophic conditions. Sediment fatty acid profiles differed between systems and toxicity assessments, which suggested a lower impact in IMTA and FM-IMTA systems. The sediment microbial community displayed high similarity within IMTA systems and between FM-IMTA and LFM-IMTA. These findings underscore the potential of IMTA systems for sustainable aquaculture, emphasizing improved growth performance and reduced environmental impact, particularly when using fish meal feeds.

The present study was applied to evaluate the effects of alternate feeding and feed restriction on gene expression, growth, proximate composition and biochemical indices in European seabass, Dicentrarchus labrax. Fish were randomly divided into six indoor tanks with 90 fish per tank in a recirculating aquaculture system. Two feeding strategies were applied, in which the first group was fed daily to satiation and the second was intermittently fed (8 days feeding to satiation–2 days starvation) for 40 days. At the end of the experiment, outlier fish were sorted as fast growers (FG) and slow growers (SG) according to their final body weight. The differential gene expression tested was related to glycolysis (pk, ldha, hk, g3pdh, eno1 and alda), fatty acid metabolism (lpl and acc) and cholesterol synthesis (7dhcr and sqle). In addition, muscle ldha and gpi expressions were positively correlated with fish weight. The concentrations of glucose, triglycerides, cholesterol and non-esterified fatty acids (NEFA) were not affected by the dietary treatments. Glucose and NEFA differed significantly between SG and FG fed groups. Overall, the physiological responses of glucose and fatty acid metabolism in fish, as recorded by gene expression assays, were triggered by minor interventions in feeding rather than the different growth rates. Expression of specific genes and biochemical parameters could be used as potential biomarkers to improve aquaculture practices and benefit fish husbandry through selective breeding, feeding strategies and farm management. The study provides new insights on the impact of intermittent feeding of European seabass, with gene markers and their potential effects, for European seabass aquaculture.

European sea bass andUlvasp. were co-cultured in different tanks of an indoor Recirculating Aquaculture System (Ulva-RAS) with bacterial biofilter, in an effort to optimize the efficiency of the system and to further decrease the waste effluent. A system with similar culture conditions, withoutUlva,was used as a control-RAS to elucidate integration effects on growth performance and chemical composition of sea bass. The role ofUlvaon N and P concentrations, gas (O₂, CO₂) and pH in water was also investigated. Fish were fed a diet of fish oil replacement (55%) with a mixture of rapeseed oil and palm oil (1:1). Our data showed thatUlvacould uptake N and P nutrients, but could also enrich sea water with phosphates. Sea bass reared inUlva-RAS exhibited isometric growth, while fish in control-RAS showed a positive allometric growth and an increased variance of body weight and length. In addition, sea bass inUlva-RAS demonstrated significantly higher levels of condition factor (K), feed intake, protein, lipid, P, EPA and DHA content (% wet weight of total body) and lipid productive value, compared to fish in control-RAS.Ulva,after bi-weekly culture, showed increased protein content (60%) compared to wild seaweed collected nearshore. CultivatedUlvaobtained dark green color, doubled chlorophyll concentrations, and exhibited lower levels of saturated and higher levels of certain monounsaturated and n-3 polyunsaturated fatty acids, indicating increased photosynthetic activity. Present results revealed the beneficial effects ofUlvaon sea bass growth and quality, which led to an improved response to the nutritional stress imposed by the fish oil replacement with vegetable oils, thus contributing to a sustainable aquaculture. Moreover, it was concluded thatUlvacould improve water quality by increasing pH and O₂, reducing CO₂and contribute to bioremediation of ammonia and nitrates from water in integrated aquaculture.

The authentication of food products and the verification of their identity are of major importance for consumers. Food fraud through mislabeling is an illegal practice consisting of the substitution of an expensive food product by a relatively cheaper one, misleading false labelling of their origin and adulteration in processed or frozen products. This issue is particularly of high importance concerning fish and seafood, which are easily adulterated primarily due to difficult morphological identification. Fish species of the Mullidae family are considered among the most high-valued seafood products traded in Greece and Eastern Mediterranean in general, in terms of the price and demand. Specifically, the red mullet (Mullus barbatus) and the striped red mullet (Mullus surmuletus) are both indigenous in the Aegean (FAO Division 37.3.1) and the Ionian (FAO Division 37.2.2) Seas, with high levels of consumers’ preferences. However, they could be easily adulterated or misidentified by the invasive Aegean Sea Lessepsian migrator goldband goatfish (Upeneus moluccensis) as well as by the imported West African goatfish (Pseudupeneus prayensis). Keeping this in mind, we designed two novel, time-saving and easy-to-apply multiplex PCR assays and one multiple Melt–Curve analysis real-time PCR for the identification of these four species. These methodologies are based on species-specific primers targeting single nucleotide polymorphisms (SNPs) detected via sequencing analysis of the mitochondrial cytochrome C oxidase subunit I (CO1) and of the cytochrome b (CYTB) genes in newly collected individuals, with additional comparison with congeneric and conspecific haplotypes obtained from the GenBank database. Both methodologies, targeting CO1 or CYTB, utilize one common and four diagnostic primers, producing amplicons of different length that are easily and reliably separated on agarose gel electrophoresis, yielding a single clear band of diagnostic size for each species or a certain Melt–Curve profile. The applicability of this cost-effective and fast methodology was tested in 328 collected specimens, including 10 cooked samples obtained from restaurants. In the vast majority (327 out of the 328) of the specimens tested, one single band was produced, in agreement with the expected products with a single exception a M. barbatus sample that was identified as M. surmuletus, the identity of which was confirmed using sequencing, indicating erroneous morphological identification. The developed methodologies are expected to contribute to the detection of commercial fraud in fish authentication.