<b>Impact of electrical stunning on fish behavior and meat quality of pacu (<i>Piaractus mesopotamicus</i>)

Abstract

ABSTRACT. Electrical stunning is considered one of less stressful fish stunning method. However, for its efficiency, it is important to determine the best way of application of the electrical variables. The aim of this study was to evaluate the effect of different voltages (100, 150, and 200 V) of alternating current (AC) or direct current (DC), frequency of 50 Hz, for 180 s exposure, concerning the aspects of behavior and meat quality of pacu (Piaractus mesopotamicus). Fish subjected to AC remained unconscious longer, evaluated by behavior analysis, when compared to DC. The pacu subjected to 100 AC, 200 AC and 100 DC showed less bleeding in the fillets. The lightness (L*) of the fillets were higher in 150 AC, 150 DC and 100 DC, followed by 200 and 100 AC. The redness (a*) in pacu fillets were moderate in treatments 200 and 150 AC and less intense in treatments 100 DC and 100 AC. The yellowness (b*) was higher in fish fillets treatment 150 DC and lower in 100 AC. Therefore, the 200 V alternating current (AC) used in water stunning caused apparent unconsciousness of up to 4 min. after exposure and less bleeding in fillets, thus it is a suitable stunning method to be recommended for the pacu processing industry.

Physiological stress and meat quality of pacu (Piaractus mesopotamicus) submitted to CO2narcosis, hypothermia and electrical stunning

“…For electrical stunning (ES), although an apparent loss of consciousness was observed after 30 s of exposure, visualized by the absence of movement, the electrical current was maintained for 180 s (3 min) to ensure the unconsciousness during bleeding. This protocol was used by Oliveira Filho et al (2016), who reported a recovery of consciousness of pacu after 4 min, which is enough time to be used by the fish processing industries.…”

“…On the other hand, very strong electrical current or long exposure times can result in blood spots in fillets, decreasing the commercial value (Zampacavallo et al, 2015). Therefore, for this stunning method to be effective, all technical parameters, such as intensity, type of current and frequency must be well adjusted for each fish species (Oliveira Filho et al, 2016; Venturini et al, 2018).…”

Evaluation of antioxidant level and protein oxidation of rainbow trout (Oncorhynchus mykiss) fillets during rigor and post‐rigor

“…Lactic acid accumulation in fish muscle may be considered in response to over‐activity, particularly in T3 group (Wendelaar Bonga, ). Fish material of the experiment being a white muscle fish shows that the anaerobic glycolysis is used to meet the energy needs (Oliveira Filho et al, ). As a known condition, the salmon white muscles affected by a stress agent are transformed from the aerobic ATP production to the anaerobic glycolytic pathway.…”

“…On the other hand, stunning stress can induce anaerobic metabolism, and increased lactate level can trigger this condition. (Oliveira Filho et al, ).…”

Slaughtering procedures on the flesh quality of frozen stored pacu

“…This technique keeps the flesh quality, but causing rapid and violent reaction and an attempt to escape (POLI et al, 2005). Electrical stunning, which consists of passing electric current in water or directly through fish until complete loss of consciousness, is also an alternative for fish stunning (GASCO et al, 2014;MORZEL;SOHIER;VA N DE VIS, 2002;OLIVEIRA FILHO et al, 2016). This technique leads to unconsciousness almost instantaneously.…”