Influence of Electronarcosis on Behavioral Responses, Blood Markers, and Fillet Properties of Silver Catfish (Rhamdia quelen)

Abstract

Behavioral responses, blood markers, and fillet properties were investigated after silver catfish exposure to different electric field strengths, frequency, and duration of electric current in the pre-slaughter stunning. All combinations of electric fields and frequencies were able to stun fish. Longer apparent stun was obtained at the intermediate electrical frequencies.High electric field strength detracted the texture of fillets. At least 5 s were required to stun fish, and longer exposure to electrical current did not prolong the apparent stun or damage fillet properties. Results indicate that silver catfish are relatively resistant to electronarcosis.

Electrical stunning in South American catfish (Rhamdia quelen) using direct current waveform: welfare and meat quality

“…The behaviours observed in this study were also reported by VEIT et al (2017) using sinusoidal waveform, different frequencies (50, 100, 300, 500 and 1000 Hz) and two electrical fields (128 or 256 V) in a tank (66 × 43 × 19 cm, L × W × H) with fresh water during 5 s, also in Rhamdia quelem. Fish remained electro-immobilized and showed a tonic phase of epileptiform insult, with open mouth and opercula and fins away from the body.…”

“…Immediately after slaughter the pH values (median, min-max) were 6.65 (6.20-6.90) for 125 and 6.70 (6.40-7.10) for 400 (Figure 5) (P = 0.236). Similar values (6.50 to 6.75) were observed in (Rhamdia quelem) submitted to electrical stunning (VEIT et al, 2017). Higher values were observed in African catfish slaughtered by cranial spiking, the initial pH of the muscle immediately after death was 7.10.…”

“…Probably, the current peak has an important role because it was equal to 3.3 A in 400, coinciding with longer unconsciousness (87.7 ± 21.6 s), different from 1.3 A in 125 (62.6 ± 15.4 s) (Figure 4). In South American catfish stunned through different currents and frequencies, VEIT et al (2017) observed a significant effect of frequency on the apparent stun duration. dASKALOVA & PAVLOV (2015) studied the effectiveness of tail-first dry electrical stunning for turbot (Scophthalmus maximus) and common sole (Solea solea).…”

“…The unconsciousness duration time was higher in 400, possibly due to higher voltage (400 V) in contrast with 125 (125 V). In a study on South American catfish (Rhamdia quelen) submitted to electrical stunning VEIT et al (2017) observed that all fish recovered responses to painful stimulation and VOR after 8.5 to 57.3 s, LAMBOOIJ et al ( 2006) reported 28 ± 8 s of unconsciousness in African catfish stunned through a voltage of 291 ± 5 V, 1.60 ± 0.11 A during 1 s. LAMBOOIJ ( 2014) reported that 40 s may be a suitable period of unconsciousness to facilitate exsanguination and onset of death in unconscious animals. In broiler chickens, the minimum duration of 60 s of unconsciousness is required for effective stunning, assuming that a neck cut is performed within 30 s after stunning (HINdLE et al, 2010).…”

Transporting live silver catfish (Rhamdia quelen) with salt addition does not mitigate fish stress and negatively affects meat quality

“…However, storage time showed influence on the lightness of meat which became paler over storage time in all treatments (P<0.05). The increase in meat lightness during storage was also reported by Veit et al (2016) in catfish fillets, by Vargas et al (2013) in matrinxã (Brycon cephalus) and by Santos (2013) in Nile tilapia (Oreochromis niloticus).…”