Metodologia não destrutiva na extração de gametas de Arbacia lixula Linnaeus, 1758 (Echinoidea: Arbaciidae) para a utilização de embriões em bioensaios

• Autor(a) principal: Alcantara, Alessandra Araujo de
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/20635
• topic: ABNT; Bioindicadores; Ecotoxicologia; Método não destrutivo; Ouriço-do-mar; Reprodução in vitro; Bioindicators; Ecotoxicology; Non-destructive method; Sea urchin; In vitro reproduction; CIENCIAS EXATAS E DA TERRA::OCEANOGRAFIA::OCEANOGRAFIA BIOLOGICA

Sea urchin embryos act as tools for detecting the effects of chemical pollutants, mainly in water, and the ABNT NBR 15350 standards recommend returning organisms to the sea after obtaining gametes, making it important to obtain procedures of induction and extraction of gametes from adult sea urchins that reduce the mortality rate, or that are completely non-destructive. Observing, therefore, it was necessary to obtain less invasive methods, or that are totally non-destructive, reducing the mortality rates of the animals. Therefore, the objectives of the present study were to develop a non-destructive methodology for gamete extraction using the unconventional species Arbacia lixula, in addition to validating the technique of in vitro reproduction and development up to the pluteus phase, and with this, to contribute to the improvement of standards and the legislation regarding bioassays with sea urchins (ABNT Norms, IBAMA Deliberation). 386 sea urchins were collected from two beaches in Rio de Janeiro, the analyzes were performed through chemical induction for the emission of gametes with injection of 150 μL of 0.5 M KCl solution in the gonads of the animals. After fertilization of the animals, the cells were observed by optical microscope for analysis of the stages of embryonic development. For 15 months, between February 2022 and April 2023, monthly trials of the non-destructive method for A. lixula were carried out, using a minimum of 20 animals, respecting the period of the first fortnight of each month. 386 sea urchins received the optimized chemical method. Of this amount, only two animals did not survive after the tests, while 384 of the total specimens tested remained healthy and returned to their natural habitat after the tests. The animals used in the experiment spawned between the months of February 2022 and September of the same year, however, the experiment with fertilization was only carried out from March 2022 onwards. The highest number of ovate animals was observed the month of June, the percentage of development to pluteus reached only 30% after incubation, with 3% of prism (pre-pluteus embryonic stage), 40% for fertilized eggs, and a percentage of 27% in eggs that are not fertilized. While for the month of July, the percentage of pluteus development reached the value of 80%, considering this the minimum value for use in ecotoxicological tests and the highest value reached during the entire experiment. The percentage in prism stage was also observed in 12%, 4% for embryonic development, 3% for fertilized eggs and only 1% in non-fertilized eggs. The proposed non-destructive method applied to the A. lixula is effective in terms of the preservation of the animals, being returned healthy to the natural habitat after the tests, with atypical spawning for the period, compared to previous studies, A. lixula proved to be unfeasible for this reproduction study, therefore, further studies are needed to evaluate the reproductive periodicity of the species with a longer duration of time than those carried out in this work.