Genética molecular na identificação de espécies de raias exploradas comercialmente no estado de São Paulo
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Data
2020-02-24
Autores
Oliveira, Raul Barrera Camacho
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As raias são elasmobrânquios que apresentam o corpo achatado dorso-ventralmente, além de cinco a sete pares de fendas branquiais que se encontram na região ventral do corpo e nadadeiras peitorais desenvolvidas e fundidas à cabeça. No Brasil, existem 29 espécies de raias em perigo de extinção de acordo com a Lista Vermelha da IUCN. As espécies de raias comercializadas muitas vezes são de difícil identificação devido à descaracterização, o que pode ser solucionado com o uso da técnica DNA Barcode, a qual é um sistema de identificação molecular baseado em uma sequência de DNA mitocondrial Citocromo Oxidase subunidade I (COI), atuando como código de barras de DNA de cada espécie. Esse sistema tem sido utilizado com êxito para identificar amostras que são comercializadas descaracterizadas e de forma ilegal. Desta forma, a técnica de DNA Barcode foi utilizada para a identificação de amostras de raias comercializadas em peixarias no estado de São Paulo e na CEAGESP, com o intuito de identificar quais são as espécies utilizadas no comércio e se atualmente ocorre a venda de espécies ameaçadas de extinção, assim como validar a técnica como ferramenta de rotina para controle de qualidade relacionado ao mercado de raias. Foram coletados 239 amostras, das quais 82 foram identificadas como espécies de raias, sendo elas Paratrygon aiereba (40,24%), Gymnura altavela (14,63%), Potamotrygon motoro (13,41%), Hypanus dipterurus (10,98%), Atlantoraja castelnaui (9,76%), Hypanus americanus (4,88%), Atlantoraja platana (2,44%) e Bathytoshia centroura (2,44%), das quais B. centroura, P. aiereba, G. altavela e A. castelnaui possuem o comércio proibido pela Portaria Portaria 445/2014 por estarem em risco de extinção no país. Das 157 amostras restantes, 151 não apresentaram uma extração de DNA de qualidade, provavelmente devido ao uso de aditivos alimentares com o uso comercial proibido ou restrito, além de 6 amostras identificadas como as espécies de bactérias Shewanella putrefaciens ou Shewanella baltica, as quais estão relacionadas ao estado de putrefação do pescado. A técnica de DNA Barcode se mostrou eficiente para a identificação para espécies de raias, sendo uma alternativa para substituir a identificação morfológica, usada atualmente pelos órgãos competentes responsáveis pela fiscalização desses produtos.
Skates and stingrays are elasmobranch fish that display the body dormant ventrally, as well as five to seven pairs of branchial staves that separate into the ventral region of the body and pectoral fins that are fused to the head. There are currently 29 endangered species of skates and stingrays in Brazil according to the IUCN Red List. The marketed species of the group are often difficult to identify due to decharacterization, which can be solved using the DNA Barcode analysis, a molecular identification system based on a mitochondrial Cytochrome Oxidase subunit I (COI) DNA sequence that acts as a barcode of the DNA of each species. This system has been successfully used to identify illegally uncharacterised types of products. Thus, the DNA Barcode technique was used to identify species of stingrays and skates that are traded in fishmongers in the state of São Paulo and CEAGESP, in order to identify which species are marketed and if the sale of endangered species currently occurs, as well as validate a technique as a routine tool for quality control related to the group species. 239 specimens were collected, of which 82 were identified as species of stingrays and rays, which were Paratrygon aiereba (40,24%), Gymnura altavela (14,63%), Potamotrygon motoro (13,41%), Hypanus dipterurus (10,98%), Atlantoraja castelnaui (9,76%), Hypanus americanus (4,88%), Atlantoraja platana (2,44%) and Bathytoshia centroura (2,44%), of which B. centroura and P. aiereba, G altavela and A. castelnaui have their commercializations prohibited by Ordinance 445/2014 once they are in risk of extinction in the country. Of the 157 remaining samples, 151 did not show quality DNA extraction, probably due to the use of food additives with prohibited or restricted commercial use, in addition to 6 samples identified as the species of bacteria Shewanella putrefaciens or Shewanella baltica, which are related to the state of putrefaction of the fish. The DNA Barcode technique proved to be efficient for the identification of streak species, being an alternative to replace the morphological identification, currently used by the competent bodies responsible for the inspection of these products.
Skates and stingrays are elasmobranch fish that display the body dormant ventrally, as well as five to seven pairs of branchial staves that separate into the ventral region of the body and pectoral fins that are fused to the head. There are currently 29 endangered species of skates and stingrays in Brazil according to the IUCN Red List. The marketed species of the group are often difficult to identify due to decharacterization, which can be solved using the DNA Barcode analysis, a molecular identification system based on a mitochondrial Cytochrome Oxidase subunit I (COI) DNA sequence that acts as a barcode of the DNA of each species. This system has been successfully used to identify illegally uncharacterised types of products. Thus, the DNA Barcode technique was used to identify species of stingrays and skates that are traded in fishmongers in the state of São Paulo and CEAGESP, in order to identify which species are marketed and if the sale of endangered species currently occurs, as well as validate a technique as a routine tool for quality control related to the group species. 239 specimens were collected, of which 82 were identified as species of stingrays and rays, which were Paratrygon aiereba (40,24%), Gymnura altavela (14,63%), Potamotrygon motoro (13,41%), Hypanus dipterurus (10,98%), Atlantoraja castelnaui (9,76%), Hypanus americanus (4,88%), Atlantoraja platana (2,44%) and Bathytoshia centroura (2,44%), of which B. centroura and P. aiereba, G altavela and A. castelnaui have their commercializations prohibited by Ordinance 445/2014 once they are in risk of extinction in the country. Of the 157 remaining samples, 151 did not show quality DNA extraction, probably due to the use of food additives with prohibited or restricted commercial use, in addition to 6 samples identified as the species of bacteria Shewanella putrefaciens or Shewanella baltica, which are related to the state of putrefaction of the fish. The DNA Barcode technique proved to be efficient for the identification of streak species, being an alternative to replace the morphological identification, currently used by the competent bodies responsible for the inspection of these products.
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Palavras-chave
Chondrichthyes, Comércio ilegal, DNA barcoding