No abstract

The process of cooling and cryopreservation of prawn embryos is a viable alternative for a continuous supply of larvae for freshwater prawn farming ponds. However, studies involving the application of those techniques as well as on toxicity of cryoprotectants in freshwater prawn embryos are scarce. Thus, this study aims to test the toxicity of methylic alcohol (MET), dimethyl sulfoxide (DMSO) and ethylene glycol (EG) on Macrobrachium amazonicum embryos. For the present experiment, pools of embryos were taken from 15 M. amazonicum females and were divided into three groups and tested in duplicate at concentrations of 10, 5, 3; 1, 0.5 or 0.1%. Toxicity tests were conducted for 24 h in Falcon® pipes to obtain the lethal concentration for 50% of the larvae (LC50). After the set period for testing, random samples of embryos were removed for morphological analysis under stereoscopic microscopes. Results were analysed using analysis of variance (ANOVA) and Tukey's test at a 5% significance level and Trimmed Spearman-Karber Analysis to determine LC50-24 h. DMSO toxicity tests revealed that 5% and 10% concentrations showed the highest toxicity and differed from the control (P ≤ 0.05), 24h-LC50 was 437.4 ± 14.4 µL. MET was less toxic among the tested cryoprotectants and concentrations did not allow the determination of its LC50-24h. For tests with EG, concentrations of 3, 5 or 10% solutions resulted in a 100% mortality to tested embryos; EG was the tested cryoprotectant with the highest toxicity, with an LC50-24h average of 81.91 ± 35.3 µl.

Cooling techniques have several applications for reproduction in aquaculture. However, few studies have sought to create protocols for cooling and cryopreservation of Macrobrachium amazonicum embryos. Thus, the objective of this work was to verify the survival of M. amazonicum embryos and the correlation between embryonic volume and mortality of M. amazonicum embryos after cooling. Embryo pools were collected from three females and divided into two treatment groups: dimethyl sulfoxide (DMSO) 3% and ethylene glycol (EG) 0.5%, both of them associated with 2 M sucrose. Positive and negative control groups consisted of seawater 10%. Aliquots of 10 µg of embryos were placed in Falcon® tubes containing a cryoprotectant solution and submitted directly to the test temperature of 2°C for 2 and 6 h of cooling. Further analysis of survival and embryonic volume were performed under a stereoscopic microscope. Data were subjected to analysis of variance (ANOVA), and means were compared using the Tukey test at 5%. The highest embryonic survival rate was observed after the shortest storage time for both the DMSO 3% and the 0.5% EG groups, with survival rates of 84.8 ± 3.9 and 79.7 ± 2.8%, respectively. There was a reduction in survival after 24 h, with the DMSO 3% group presenting a survival rate of 71.7 ± 6.6%, and the EG 0.5% group, 66 ± 6.9%. Survival showed a statistically significant difference when compared with the positive controls after 2 h and 24 h of cooling, with 99 ± 0.5% and 95.8 ± 1.5% survival rates, respectively. There was no significant statistical difference in the embryonic volume, but it was possible to observe a change in the appearance of the embryos, from a translucent coloration to an opaque white or brownish coloration, after 24 h in incubators. Thus, it can be concluded that survival is inversely proportional to storage time and that, although there was no change in the embryonic volume after cooling, a change in the appearance of embryos could be observed.

Cryopreservation has not been successfully used to preserve fish embryos, although chilling techniques have been used with good results. The aim of this study was to chill Piaractus brachypomus embryos at different stages of development in some cryoprotectants and for various periods of chilling. Embryos at the following ontogenetic stages were used: blastoderm-1.2 hours post-fertilization (hpf); epiboly-5 hpf; blastopore closure-8 hpf; and appearance of optic vesicle-13 hpf. One hundred embryos were selected from each of the four stages and chilled in methanol, methylglycol or dimethylsulfoxide (DMSO) for 6, 8, 10 or 12 hours, at 2ºC. The total number of treatments was 4 stages x 3 cryoprotectants x 4 periods of chilling. The highest percentage of normal and live larvae (30.6%) was observed when embryos were chilled at 13-hpf in methanol for 6 hours. In general, larvae chilled at a more developed stages (8 and 13 hpf), in methanol and for shorter periods could survive chilling and develop normally, compared to the other treatments. Therefore, P. brachypomus embryos at the optical vesicle appearance stage (13 hpf) should be chilled in a solution containing 17.5% glucose and 10% methanol for up to eight six at 2°C.

No abstract

The cultivation of microalgae presents a great biotechnological potential, mainly to produce natural bioactive substances, which can be used in the pharmaceutical industry and especially in the development of functional foods, thanks to its nutritional properties. Among the commercially important microalgae, Haematococcus pluvialis is considered the main source of natural astaxanthin, a carotenoid of high antioxidant action and with wide applications in the nutraceuticals, cosmetics, food and aquaculture industries. This review aimed to cover the most important aspects of biology, biochemical composition, biosynthesis and astaxanthin accumulation in the cells of H. pluvialis, in addition to its broad application to humans and animals. The methodology used in this work was a systematic review of the literature, presenting the gaps and opportunities for research. This work provided a broader view of the technologies and methodologies used to produce H. pluvialis, providing a direction for future work to be undertaken. During the bibliographic survey, it was observed that information regarding the cultivation of H. pluvialis, aiming at the production of astaxanthin, is still very incipient in Brazil, with results observed only on a laboratory scale, making it difficult to really understand the implementation costs for a possible commercial production. This work has started a larger research and will serve as a basis for future activities, mainly to solve possible doubts.

RESUMOLocalizado a 48 km da cidade de Fortaleza, o distrito de Iguape possui uma pequena praia frequentada por moradores da região, sendo reduto de pescadores que trabalham de forma artesanal e tiram da pesca o seu sustento. Visto a importância que essa atividade econômica tem para a população local, o objetivo desta pesquisa foi caracterizar a pesca artesanal, analisar a biodiversidade da ictiofauna e saber quais aquelas que são de importância econômica para a comunidade. Os resultados mostraram que são utilizadas embarcações do tipo jangadas e paquetes a vela e botes a remo em pescarias de "ir e vir" e de "dormir". As pescarias são realizadas com linha de mão, tarrafas e redes de espera. Foram capturados 2.655 espécimens, inseridos em duas classes, sete ordens, 18 famílias e 32 espécies, revelando uma elevada diversidade e riqueza de espécies, com destaque para Harengula clupeola, Opisthonema oglinum, Haemulon parra e Haemulon plumierii, que contribuem acentuadamente para a renda da comunidade pesqueira.Palavras-chave: atividade econômica, peixe marinho, embarcações. ABSTRACTLocated at 48 km from Fortaleza, the district of Iguape has a small beach frequented by residents of the region, it is a redoubt of artisanal fishermen that have the fishing as the main income. Considering the importance of this economic activity to the local population, the objective of this research was to characterize the artisanal fishery, to analyze the biodiversity of the fish fauna and to know which ones are of economic importance to the community. The fleet is composed by small wooden rafts that are hollow or filled with Styrofoam and driven by sail or paddle. The fishing activities last from some hours to 2 days. The fisheries are carried out with handlines, casting nets and gillnets. A total of 2.655 specimens were caught, belonging to 2 classes, 7 orders, 18 families and 32 species, revealing a high diversity and species richness, mainly from Harengula clupeola, Opisthonema oglinum, Haemulon parra and Haemulon plumieri, contributing significantly to the fishing community income.

Aiming at analyzing the water quality at Iracema Beach, in Fortaleza/CE, as well as characterizing the planktonic community, monthly collections were carried out between February and November 2019, with 100 liters of water being filtered, concentrated to 10 mL and preserved in 4% formalin. In the laboratory, via microscopy, the plankton species were identified and then classified based on references relevant to the subject, as well as consultations with specialists and electronic addresses. Furthermore, data on water temperature, transparency, salinity, dissolved oxygen and pH were obtained in situ. Bimonthly, one liter of water was collected for microbiological analysis, in the laboratory. The parameters analyzed showed good quality water, with 17 phytoplankton species being recorded, distributed among the Classes Cyanophyceae, Bacillariophyceae, Euglenophyceae, Chlorophyceae, Mediophyceae, Coscinodiscophyceae and Zygnematophyceae. For zooplankton, there were five species included in the Rotifera, Cladocera and Crustacea Classes. Phytoplanktonic species diversity was high, the zooplanktonic was low; very high equability and low species richness in both communities. No species was considered a bioindicator of eutrophication or pollution, and the microbiological analysis showed minimum values ​​of thermotolerant coliforms, and the waters of Iracema Beach can be classified as class one saline, intended for recreation and with a very good quality.