Sarcoplasmic protein separation by agarose gel electrophoresis as a method for some fish species identification

Fish species identification has not been exclusively of taxonomists interest, but also for people in charge of sea food industry quality control. For that porpoise, some biochemical methods have been developed, and they go from isoenzymes determination to polimerase chain reaction (PCR) techniques and nucleic acids electrophoresis. Economical reasons and complexity level of some of these techniques, made necessary the utilization of simpler biochemical methods. Starch gel electrophoresis and poliacrilamide gel electrophoresis of sarcoplasmic proteins for fish species identification have been reported. Agarose gel electrophoresis presents itself as an alternative to previous methods, because of its good resolution and poor toxicity. For method testing, muscles of Corvina (Cysnoscion virescens), Lisa (Mugil curema), Mere (Epinephelus striatus) and Robalo (Centropomus undecimalis) were homogenized. Extracts were centrifuged and filtered before electrophoretic analysis. Electrophoresis was performed at 95 Volts, for 35 min using barbital buffer pH 8,6. All samples were analyzed in a densitometer using a wavelength of 520 nm. Differences were found in electrophoretic patterns and densitograms for all studied species; and identification test had a 95% of accuracy. Completely different patterns were observed for each species in all samples. Due to method efficiency, agarose gel electrophoresis of fish sarcoplasmic proteins for species identification is recommended.