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The vitrification of ovarian follicles is a strategic tool that may contribute to advances in aquaculture and the conservation of many important species. Despite the difficulties inherent to the cryopreservation of oocytes, some successful protocols have been developed for different species, but little is known about the capacity of oocytes to develop after thawing. Therefore, the profiles of the reproductive pathway genes and fatty acid membrane composition during the initial stages of development were analyzed in fresh ovarian follicles and follicles after the vitrification process. There were differences in the expression of the hypothalamic-pituitary-gonad axis genes during the follicular development in the control group as well as in the vitrified group. Similarly, alterations in the composition of fatty acids were observed after vitrification. Despite this, many alterations were observed in the vitrified group; more than half of the stage III ovarian follicles were able to grow and mature in vitro. Therefore, the vitrification of ovarian follicles may impact them at molecular and membrane levels, but it does not compromise their capability for in vitro maturation, which indicates that the technique can be a strategic tool for aquaculture.

An 8-week trial was performed to evaluate the influence of docosahexaenoic (DHA) and eicosapentaenoic acid (EPA) ratios and temperature on the fatty acid (FA) metabolism and liver morphology of Epinephelus marginatus . A basal diet was manufactured, and DHA (D1:0.5%; D2:0.75%; D3:1%; and D4:1.5%) and EPA (D1:1.0%; D2:0.75%; D3:0.5%; and D4:0%) levels were added. E. marginatus were kept in twelve tanks with a lower temperature (LT, 23.17 ± 0.12 °C) and twelve with a higher temperature (HT, 28.63 ± 0.06 °C). The DHA/EPA ratio did not affect performance, regardless of the temperature, but the animals fed with the D4 diet showed better growth at HT. A higher lipid deposition and a large lipid vacuole area in the hepatocytes at HT were observed, regardless of the diet. Triacylglycerol (TG) in reflected the diet FA profile mainly in the muscle and liver, whereas the phospholipid (PL) was less influenced by the diet. The same DHA content in the TG fraction of muscle (D3 and D4) were observed at LT; however, only the DHA/EPA ratio of D4 could be differentially stored in the TG fraction of muscle (HT). Monounsaturated and polyunsaturated FA increased in the PL of the eyes at HT, whereas saturated FA was reduced in the TG and PL fractions at LT. These results evidence the importance of temperature and a balanced DHA/EPA ratio in the diet of marine fish.

A survey evaluated 2,300 healthcare workers following the first dose of a coronavirus disease 2019 (COVID-19) vaccine in a tertiary-quaternary hospital in São Paulo, Brazil. Adherence to protective measures following vaccination was compared to previous non-work-related behaviors. Younger age, previous COVID-19, and burnout symptoms were associated with reduced adherence to mitigation measures.

We used transcriptome sequencing to investigate the hepatic postprandial responses of Rachycentron canadum (cobia), an important commercial fish species. In total, 150 cobia juveniles (50 per tank, triplicate) were fed ad libitum with a commercial diet for 7 days, fasted for 24 h, and fed for 10 min. The liver was sampled 10 min prior to feeding and 30 min, 1, 2, 4, 8, 12, and 24 h after the feeding event. Each sample was evaluated in terms of liver fatty acid profile and gene expression. Differential gene expressions were evaluated, focusing on fatty acid synthesis and oxidation pathways. In general, the liver fatty acid profile reflected diet composition. Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) levels increased at 8 to 12 h but decreased at 24 h after the feeding event. A high number of differentially expressed genes (DEGs) were observed comparing fish that fasted for 8 h with those fasted for 30 min and 24 h, while a reduced number of DEGs was observed comparing individuals who fasted for 30 min compared with those who fasted for 24 h. Similarly, the main differences in the expression of genes related to the fatty acid biosynthesis and oxidation pathways were noticed in individuals who fasted for 8 h compared with those who fasted for 30 min and 24 h. The results suggested that the adequate time to sample the individuals ranged between 8 and 12 h after the meal since, apparently, after 24 h, differential gene expression was not necessarily influenced by food intake., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Phospholipids (PL) are membrane components composed of fatty acids (FA), while triglycerides (TG) are a main source of energy and essential FA. Polyunsaturated FA (PUFA), such as docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), are essential for marine carnivorous fish; thus, an 8-week experiment was performed to evaluate the influence of DHA and EPA, provided as PL and TG, on the morphophysiology of Epinephelus marginatus juveniles. A basal diet was manufactured, and DHA and EPA in PL form (PL1-low amount PL2-high amount) and TG form (TG1-low amount; TG2-high amount) were added. Dusky grouper juveniles were equally distributed in 12 tanks of 20 animals each, and liver and muscle were sampled for metabolic analysis. The total hepatic lipids in PL1 and PL2 were higher when compared to the initial, TG1 and TG2 groups. Total lipids in muscle were higher in PL2 and TG1 than PL1 and TG2, respectively. Diets rich in DHA and EPA in PL and TG resulted in higher deposition of these FA in the muscle polar fraction. However, fish fed diets containing lower amounts of DHA and EPA in PL and TG stored those in the muscle neutral fraction and liver, centralizing the storage of DHA and EPA.

It has been postulated that eutrophication causes replacement of n3 highly unsaturated fatty acids (n3 HUFA) rich taxa, such as Bacillariophyta, Cryptophyta and Dinophyta, with taxa poor in these fatty acids (FA), such as Chlorophyta and Cyanobacteria. Such a change in community composition at the basis of the food web may alter the FA composition of consumer tissues. Here, we investigated the effects of eutrophication on phytoplankton composition and FA profiles of seston and muscle of two omnivorous fish species (Astyanax fasciatus and Astyanax altiparanae) from reservoirs of different trophic status in Southeast Brazil. The phytoplankton composition and seston FA profiles reflected the degree of eutrophication at most of the studied sites. Three of the five most eutrophic sites were dominated by cyanobacteria and had the highest saturated fatty acid (SFA) and lowest polyunsaturated fatty acid (PUFA) relative contents among all sites. In contrast, the remaining two sites presented a higher phytoplankton diversity and higher relative contribution of sestonic PUFAs with 18 carbons (C18) and HUFAs than less eutrophic systems. However, there were no clear effects of sestonic FA profiles on the FA profiles of muscle of both fish species. A higher percentage of n3 HUFAs was found in the fish samples from a hypereutrophic and cyanobacteria dominated reservoir than in those from sites with a more diverse phytoplankton community in which fish mainly showed higher percentages of C18 PUFA. These results suggest a lack of a direct relationship between the degree of eutrophication and the percentage of n3 HUFAs in both fish species, which can be caused by specific characteristics of the reservoirs that may modulate eutrophication effects. Therefore, consumer FA biochemistry seemed to be dictated by their ability to select, accumulate, and modify dietary FAs, rather than by the eutrophication degree of the studied tropical reservoirs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The eutrophication increases the quantity of algae that are deficient in highly unsaturated fatty acids (HUFA) n3, as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), altering the bottom-up transfer of the entire food chain. Due to the importance of the fatty acids (FA) in physiological processes related to the main role of the membrane phospholipids (PL) and precursors of eicosanoids, and also the little knowledge about the influence of eutrophication in tropical ecosystems, it is important to understand how anthropogenic changes in the aquatic ecosystem affect the lipid quality, specifically n3 HUFAs. This study aimed to investigate the influence of eutrophication on the FA profile of the hepatic PL, as well as prostaglandin (PG) levels in Astyanax altiparanae females. Fish were collected in reservoirs with different eutrophication degrees: Jundiaí (Ju) reservoir and Embu-Guaçu (EG) branch, considered as mesotrophic points, and Barragem (Ba) and Aracati (Ar), branches from Guarapiranga reservoir, considered as supereutrophic and hypereutrophic points, respectively. The FA profile of the liver PL was analyzed by gas chromatography, and the concentration of liver PGE2 was analyzed using ELISA immunoassay kits. The degree of eutrophication did not alter the PG concentration and produced few modifications in the FA profile of hepatic PL. Fish collected at Ba and EG presented similar FA profiles, both with high percentages of n3 HUFA, especially DHA, in comparison to fish from Ju. However, no change was observed in the n3 HUFA profile of the fish from Ar. These data demonstrated that the FA profile in A. altiparanae seems to be more related to different physiological requirements of n3 HUFA of the species than eutrophication. So, this study contributed to findings on the trophic transfer dynamics in tropical freshwater reservoirs, where a direct effect of eutrophication on the availability of HUFA n3 to animals is not suggested., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The present study aimed to evaluate two different methods of artificial reproduction induction, and characterize the embryonic development of Salminus hilarii. Different than observed for other tropical fish species, artificial reproduction induction followed by hand-stripping of gametes was considered unfeasible for S. hilarii, as no gamete fertilization was observed. However, females that were induced and spawned naturally presented a fertilization rate of 65.64 ± 0.54%. With a mean temperature of 26.20 ± 0.90ºC it was possible to clearly distinguish a large perivitelline space at 14 min after fertilization (AF) and at 49 min AF more than 50% of the embryos presented two blastomeres, and these cleavages occurred until 1 h 54 min AF. The gastrula phase was characterized at 3 h 56 min AF, and blastopore closure was observed at 8 h 31 min AF. At 9 h 1 min, organogenesis started, with a clear distinction of the yolk mass, embryonic axis, cephalic and caudal regions; at 11 h 51 min AF the embryos already had advanced segmentation and a free tail. Total hatching occurred at 21 h 17 min and after opening the mouth, which occurred at 33 h 9 min, the larvae of S. hilarii presented a strong and characteristic cannibalism. This information can be considered fundamental to improving S. hilarii production in captivity and for collaboration with a conservation programme in the upper Tietê river basin.

This paper describes a simple, portable and environmentally friendly procedure for the determination of nitrite by combined spot test/diffuse reflectance spectroscopy on filter-paper. The method is based on the diazotization reaction of dapsone (4,4'-diamino-diphenyl sulphone, DAP) and (naphthyl)ethylenediamine hydrochloride (NED) with nitrite in acidic medium, yielding a coloured compound on the surface of a filter paper. Experimental design methodologies were used to optimise the measurement conditions. The reflectometric measurements were carried out at 545 nm and the linear range obtained was 0.29-5.0 mg L(-1) of nitrite (R=0.997), with detection and quantification limits of 0.09 and 0.29 mg L(-1), respectively. The proposed method was applied successfully to the analysis of nitrite in meat products and well water samples., (Copyright © 2012 Elsevier Ltd. All rights reserved.)