Authentication of commercially available frozen shrimp meats using dna barcoding

Abstract

Shrimps and prawns are quite nutritious and provide quality protein, omega-3 fatty acids, certain antioxidants, vitamins, and minerals like iodine. Therefore, they are healthy food for human consumption. In order to find out fish fraud in value-added products, in this study, six frozen shrimp species packed and sold by different commercial companies were purchased, correctly identified using DNA barcoding of mt-COI gene, and the sequences were authenticated properly with the GenBank. The genomic DNA isolated from frozen shrimp samples showed greater than 10 kb. Their amplified products showed 564–770 bp of mt-COI gene. The BLAST results for the labeled frozen shrimp sample Litopenaeus vannamei showed maximum similarity (99%–100%) with the same species sequences available with NCBI database. Five unlabeled sample sequences (two samples taken from two independent packets, and three samples taken from one mixed shrimp packet) showed maximum similarity with the sequences available in the NCBI database and exactly identified as Fenneropenaeus merguiensis, Penaeus monodon, Fenneropenaeus indicus, Penaeus semisulcatus, and P. monodon, respectively. These six sequences showed more variable amino acid sites than the identical and similar amino acid residues within themselves. The AT biases (61.5%–67.51%, P. semisulcatus and P. monodon taken from unlabeled mixed packet) and GC biases (32.9%–38.6%, P. monodon and P. semisulcatus) varied among these six species sequences, which indicated less NUMTs gene. The interspecies divergence rate calculated for these six species ranged between 0.434 and 3.401 (L. vennamei vs. F. indicus, and F. merguiensis vs. P. monodon, taken from unlabeled independent packet). Thus, it is recommended that DNA barcoding of mt-COI gene can be used to identify any unlabeled or labeled shrimp/prawn/seafood available in the market to avoid fish fraud.