Identification and differentiation of Asian seabass and mangrove red snapper fillets by CYTB sequence-based PCR analysis

Overall quality attributes between deskinned Asian seabass and mangrove red snapper fillet are similar. This may lead to the substitution of Asian seabass, a cheaper species, with the latter. Therefore, the authentication method for distinguishing these two species could conquer adulteration. Four primers were designed, based on mitochondrial cytb gene alignment. Polymerase chain reaction (PCR) was performed using the DNA of both species with 35 cycles of amplification. The primers provided the amplicons with the size of 480, 396, 185, and 268 for primers 1, 2, 3, and 4, respectively. All primers successfully differentiated Asian seabass from mangrove red snapper both raw and cooked fillets from at least 30 mg of the sample weight. Moreover, primer 4 showed the highest specificity when tested with other 5 species of fish generally sold in the Thai market. The limit of detection was around 6 ng of Asian seabass DNA in a total of 120 ng mangrove red snapper DNA. Therefore, the PCR-based method using primer 4 was a useful tool for the identification of Asian seabass adulterated in mangrove red snapper fillets or slices. This primer could be implemented for authentication of fish and fish products to prevent mislabeling for customers.