Uso do DNA barcoding na identificação do pescado comercial como forma de prevenção da adulteração

Abstract

Many cases of species substitution in trade involve the exchange of a species indicated on the packaging by others of inferior quality. Morphological analyzes are usually sufficient to identify fresh fish, but it is impossible in the case of fish fillets, processed and canned products, which today represent a high proportion of commercialization in the seafood market. Misidentification of the fish may be related to misconduct, whether voluntary or not, when labeling fish in relation to their origin and species. This type of error can happen at any stage of the supply chain, from the producer to the retailer. Illegal and undeclared fishing undermines the conservation of the oceans, the consumer, the trader and the economy. In the field of fish production, due to globalized production chains, it is becoming increasingly difficult to carry out this control adequately. The objective of this project was to carry out the genetic identification of industrialized fish acquired in supermarkets in Rio de Janeiro, in order to compare the species found by the DNA barcoding method to that reported on the product packaging by the manufacturer. The option for tilapia analysis considered the importance of this fish in the aquaculture sector in our country, and also its great production worldwide. The DNA barcoding technique is fast, efficient and allows the identification of species from different biological samples. In this work, a total of 41 different samples of 9 brands of fish marketed under the common name of tilapia were obtained. All of them belong to the genus Oreochromis, being the majority of the samples (78%) of the species Oreochromis niloticus. Samples of the species Oreochromis aureus (17%) and Oreochromis mossambicus (5%) were also found. The greater representation of the species O. niloticus in the samples agrees with data of the literature, which affirms that this species is the dominant tilapia in the world aquaculture because of its lighter colored flesh and its faster growth, which satisfies both consumers and producers. These results are important and positive in the face of the growing tilapia market existing in our country and in the world. The cases of fraud associated with the sale of food are recurrent and various measures have been taken around the world trying to curb these practices. The use of a technique capable of performing species identification efficiently and the existence of a database with the information that is obtained by researchers from different countries helps in a very significant way the quality control of marketed products, to protect consumers, merchants and species that may suffer from illegal trade.