SummaryThe embryogenesis of Brycon cephalus was established in seven stages: zygote, cleavage, blastula, gastrula, segmentation, larval and hatching, in an incubation period of 11 h (26 • C). The zygote phase was observed directly after fertilization and egg hydration. Cleavage began at 0.5 h of incubation and extended up to the morula phase (1.5 h; +100 blastomeres). Cleavage was meroblastic and underwent the following division pattern: the first five divisions were vertical and perpendicular to each other, following the model 2 × 2, 4 × 2, 4 × 4 and 4 × 8. The sixth division was horizontal and occurred at 1.25 h after fertilization, giving rise to two cell layers (4 × 8 × 2) with 64 blastomeres. At the blastula stage (1.25-1.5 h), an irregular space between the blastomeres, the blastocoele, could be detected and the periblast structure initiated. The gastrula (1.75-6.0 h) was characterized by the morphogenetic movements of epiboly, convergence and cell involution, and formation of the embryonic axis. The segmentation stage (7-9 h) comprised the development of somites, the notochord, optic, otic and Kupffer's vesicles, neural tube, primitive intestine and ended with the release of the tail. The larval stage (up to 10 h) was characterized by the presence of 30 somites and growth and elongation of the larvae. At the hatching stage, the embryos presented more than 30 somites and exhibited swimming movements and a soft chorion. The blastomeres presented euchromatic nuclei, indicating a high mitotic activity and many yolk globules in the cytoplasm. The periblast was constituted of a layer with several nuclei and many vesicles, which grew during the epiboly movement.
17The aim of this study was to use proximate chemical composition, amcro and trace 18 elements, fatty acid profile and stable isotopes as traceability tools to assess geographic 19 origin and seasonality of croaker (Micropogonias furnieri). Croaker from Parnaíba 20 contained higher ash in July and lower fat content than croaker from Santos. In contrast, 21 croaker from Santos had statistically higher proportion of 16:1n-9+16:1n-7, 20:1n-11, 22 20:1n-9, MUFA and n-3/n-6 ratio than croaker from Parnaíba. Concerning seasonality, 23 croaker caught in July had significantly higher amounts of 14:0, 15:0, 16:1n-9+16:1n-7 24 and saturated fatty acids than fish caught in December. Concerning elements, significant 25 differences were also detected between seasons for Cl, Ca, Fe, Sr and S, whereas 26 differences between geographic origins were only observed with K. δ 13 C and δ 15 N were 27 statistically different between geographic origins, whereas differences between seasons 28 were only detected in δ 15 N ratio of croaker from Santos. Fatty acids, minerals and stable 29 isotope are effective methods to trace geographic origin and seasonality of croaker. 30Nonetheless, further investigation is still required with larger samples of croaker to 31 enable the implementation of fatty acids, elements or stable isotope as authenticity tools 32 by food control agencies. 33 34
Techniques to trace geographical origins and production methods are still scarce and not routinely applied by food safety authorities. The aim of this study was to assess the effectiveness of proximate chemical composition, fatty acid profile, macro and trace element content, and stable isotope ratios to distinguish wild (WM) and farmed (FM) meagre. There were differences in total lipids, some fatty acids (C16:2n‐4, C16:4n‐3, C18:0, C18:1n‐9, C18:2n‐6, C18:3n‐3, C20:1n‐9, C22:1n‐11, C20:4n‐6, C22:5n‐6, and DHA), some macro and trace elements (Cl, S, Fe, Zn, Se, and Br), and δ13C and δ15N stable isotopes contents between FM and WM. Additionally, some fatty acids (e.g., linoleic) and elements (e.g., Cl, Fe, Br, and Rb) significantly differed between large and small FM. Therefore, it is possible to differentiate between FM (large and small specimens) and WM based on these compounds. The results of this study emphasize effectiveness of chemometrics tools for seafood traceability purposes. Practical applications In recent years consumers are seeking healthy foods and increasingly discerning regarding food they will consume, however, consumers often do not find the information they seek. Thus, the fish authenticity is important requirements to ensure quality, provide adequate security controls and develop effective regulations. Food traceability includes food components identification to verify the compliance with labeling to prevent fraud. Fish industry must be providing information in the label about species, origin, age, and production systems. Therefore, there is an urgent need to develop methods to rapidly and accurately identify food that can help the authorities and fish industries to comply with the requirements for labeling and traceability, and to ensure product quality and consumer protection. This work was developed due to the need to establish functional techniques for fish discrimination. Techniques used in this study were effective in differentiation of meagre, which is one of the best candidates for large‐scale aquaculture in Europe. Other works such as species determination of high commercial value, seasonality, and capture sites differentiation are being developed by our group.
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