Electronarcosis of Nile tilapia (Oreochromis niloticus): Effects on Dynamic Physiological Balance and Meat Quality

Electronarcosis is the most commonly used stunning method for large animals, but its consequences in tilapia still need to be evaluated. The aim of the study was to evaluate the application of electronarcosis in the pre-slaughter stunning of Nile tilapia (Oreochromis niloticus) and verify its effects on dynamic physiological balance and meat quality.

Nile tilapia specimens, totaling 184, with an average weight of 247.08 37.04 g, were randomly distributed. Each fish was individually placed in a rectangular tank constituted by a voltage regulator and aluminum electrode. The behavior of the fish subjected to different exposure times (5, 10, 20, and 30 seconds) and electric currents (1.50, 3.00, 4.50, and 6.00 amperes) with alternating and continuous currents was evaluated. Subsequently, the quality of the chilled fillets was checked after slaughter over a period of 35 days. The longest stun time was achieved using an alternating current of 3.00, 4.50, and 6.00A for 30 seconds.

The fillet quality index (FQI) showed a high correlation with the storage time. In the first 15 days of storage, the fish stunned with different alternating currents maintained a higher MQI, meeting the meat quality standard when compared to fish slaughtered by ice stunning. The fish fillets obtained using different electrical currents showed a pH similar to the fish fillets stunned with ice.

Therefore, electronarcosis can be applied in the slaughter of tilapia using alternating current between three and six amps for 30 seconds, with euthanasia time of 37 and 46 seconds, ensuring safety in the slaughter procedures in the industry, the quality of the meat, and the well-being of the animal.