By analyzing three multigene families, two closely related and commercially important species, Dicentrarchus labrax and Dicentrarchus punctatus, were characterized by cytogenetic and molecular methods. The interspecies hybrid Dicentrarchus labrax (♀) × Dicentrarchus punctatus (♂) was also analyzed. The multigene families studied were the 5S rDNA, 45S rDNA and the U2 snRNA. A microsatellite GTT motif was found within the non transcribed spacers (NTS) of the 5S rDNA from the two species. However, hexanucleotide duplication next to this microsatellite was observed in the D. labrax and hybrid clones, but not in D. punctatus. The U2 snRNA appeared to be linked to the U5 gene and showed two variant sequences, in both D. labrax and D. punctatus. They differed in one insertion/deletion of 7 nucleotides. The first internal transcribed spacer (ITS-1) region showed higher nucleotide variability in D. punctatus than in D. labrax. Nucleotide polymorphism within species and also nucleotide divergence between species were determined in the different gene regions. In a FISH analysis we obtained three chromosomal markers, because the 5S rDNA, 18S rDNA and U2 snRNA probes hybridized each in three different chromosome pairs. Hence none of them was co-localized. The 5S rDNA cluster and U2 snRNA were localized in acrocentric chromosome pairs, while the 18S rRNA gene probe hybridized in a subtelocentric pair. Finally, the usefulness of the results in developing tools for phylogenetic analysis and species identification are discussed in relation to other fish species.

The effect of gelatin-based edible coating incorporated with Mentha pulegium essential oil (MEO) on physicochemical (pH, titratable acidity (TA), weight loss, total soluble solids (TSS), and total phenolic content (TPC)), microbiological (total aerobic mesophilic flora (TAMF) and yeasts and moulds (YM)), and sensorial (color and firmness) characteristics of strawberries stored under refrigeration was studied. Strawberries were coated with gelatin alone (4%) and/or gelatin combined with two concentrations (0.5 and 1%) of MEO and stored at 4°C for 13 days. Gelatin coating and MEO combination significantly inhibited total flora and moulds and yeasts with comparison to control (uncoated strawberries) and had better hygienic quality at the end of storage. The effect was MEO concentration dependent. Our results also showed that the bioactive coating used in this investigation slowed down changes in pH, TA, weight loss, TSS, firmness, TPC, and color of strawberries. Gelatin coating incorporated with MEO at 1% protected at least 60% of strawberries from deterioration after 13 days of storage and could be used as bioactive packaging to prolong the shelf life and an alternative of pesticides use.

Globally, aquaculture contributes to sustainable food and nutritional stability. However, stress conditions constitute a major threat affecting farmed-fish welfare and fish farms’ performances. In this regard, the present study was aimed at measuring and comparing in-situ (offshore) the physiological stress responses caused by recurrent sampling operations for length–weight measurement. Studied fish were European sea bass Dicentrarchus labrax sub-adults and adults reared in intensive farming conditions in M’diq Bay, on the Moroccan Mediterranean coast. The physiological stress response was evaluated by measuring blood biomarkers, including cortisol, glucose, lactate, total cholesterol and total proteins levels, and hematocrit percentage. The hypercortisolemia, hyperglycemia, hyperlactatemia and hypoproteinemia detected in the post-sampling state in both age groups of D. labrax indicated stress tendencies and a high sensitivity to aquaculture practice-related stress factors, with major and minor responses detected in the same age and same stress conditions. It is also interesting to note that the fish age and the time-course of the sampling operation had a statistically significant effect in terms of the physiological response (with p < 0.01 and p < 0.001, respectively). In conclusion, the present study showed that sea bass subjected to various stressful situations in intensive farming conditions displayed a physiological stress response specific to its age, to the individual status, as well as to the duration of stressor.

-It is commonly presumed that the Portuguese oyster Crassostrea angulata was introduced into the North East (NE) Atlantic from Asia. The analysis of the nucleotide sequence of a highly polymorphic non-coding mitochondrial region (major noncoding region -MNR) of C. angulata samples collected in Europe (Portugal), Africa (Morocco) and Asia (Shantou and Taiwan) provided new insight into the introduction of this species into the NE Atlantic. Sixty haplotypes and a nucleotide diversity of 0.0077 were observed in 130 analyzed sequences. Higher nucleotide diversity levels were observed in NE Atlantic sites than in Asian sites and significant genetic differentiation was found between the two. Our results suggest that C. angulata might have been introduced to the NE Atlantic by multiple introductory events, though the exact origins remain unknown since none of the analyzed Asian sites seemed to have been a source of introduction. The nucleotide diversity of C. angulata was higher than that previously reported for Pacific oyster C. gigas in Europe and Asia for the same mitochondrial region. The results obtained in the present study suggest that NE Atlantic C. angulata stocks are a unique genetic resource, which highlights the importance of their conservation.

Fish gelatin‐pectin (GelExt/Pec) composite films incorporated with Mentha pulegium essential oil (MEO) and Lavandula angustifolia essential oil (LEO) at two concentrations (0.5% and 1.5%) were developed and their physicochemical, mechanical, and antimicrobial properties were determined. GelExt/Pec‐based film incorporated with 1.5% MEO (GelExt/Pec + 1.5% MEO) showed the highest antimicrobial activity against all bacterial strains tested. Incorporation of essential oils decreased significantly the tensile strength of all the films investigated. The film showing the best functional and antimicrobial properties (Gelext/Pec + 1.5% MEO) was used to prolong the shelf life of tilapia fillets under refrigeration. Control (unwrapped) and wrapped fillets were analyzed every 3 days in terms of microbiological (total viable count (TVC), psychrotrophic bacteria count (PC), lactic acid bacteria (LAB) and Enterobacteriaceae (ENT), and physicochemical parameters (total volatile base nitrogen [TVB‐N] and pH). Gelext/Pec + 1.5% MEO antimicrobial film retarded significantly (p < .05) the growth of TVC, LAB, PC, and ENT, throughout 12 days of storage compared with the control. Gelext/Pec + 1.5% MEO could be considered as an effective packaging to maintain the quality and extend the shelf life of tilapia fillets under refrigeration.

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The four species of the Engraulidae family: European anchovy (Engraulis encrasicolus), Californian anchovy (Engraulis mordax), Peruvian anchoveta (Engraulis ringens), and Japanese anchovy (Engraulis japonicus) studied in this work are very similar morphologically, and it is very difficult to distinguish between them, especially when frozen or processed. We have used the 5S rDNA as a molecular marker to discriminate these four species and used specific primers designed for each species in the nontranscribed spacers (NTS) of these genes. Multiplex PCR was performed with three pairs of primers, and three different sizes were obtained: 597 bp E. encrasicolus, 598 bp E. japonicus, 380 bp E. mordax, and 250 bp E. ringens. For the species E. encrasicolus and E. japonicus, PCR-RFLP was used as an additional technique to distinguish between them because their NTS sequences showed considerable similarity.