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

Abstract

One of the most critical steps in fish welfare occurs in the slaughter phase, with hormonal, biochemical, osmoregulatory and energetic alterations. These changes can affect the meat quality, with changes in colour and texture of the fillets, protein degradation, and lipid and metabolic oxidation (Daskalova et al.,2016;Zampacavallo et al., 2015).Various methods for stunning and killing fish have been studied, such as electrical current application, cranial percussion, hypothermia, asphyxiation, CO 2 narcosis, anaesthesia, and spiking. Among these methods, stunning by hypothermia has been one of the most used by the fish industry (Zampacavallo et al., 2015; Oliveira Filho, Oliveira, et al., 2015a; Oliveira Filho, 2015b). However, the rapid decline in the body temperature of fish can result in animal discomfort and delayed loss of consciousness Zampacavallo et al., 2015), increasing the plasma cortisol and catecholamines levels (Seth et al., 2013).CO 2 narcosis has various advantages, including the use of watersoluble gas, ease to apply and safe to handle (Rahmanifarah et al.,

Efeitos do estresse pré-abate na qualidade da carne do tambaqui armazenado no gelo

“…In the present study, a slower pH decrease was observed in meat samples from fish submitted to recovery periods after transport, while samples from fish collected right after harvesting and after transport presented lower pH values at time 0, confirming that the postmortem biochemical changes occurred more accelerated for these treatments according to reported by Oliveira-Filho (2021), who observed low pH levels after 5 hours of pacu slaughter using different slaughter methods. Melo et al (2018) also observed a decrease in muscle pH in tilapia slaughtered by different electronarcosis voltages after 5 hours of slaughter.…”

“…Front the current scenario of aquaculture market, it is essential to seek improvements in all points of the production chain, especially related to fish quality. Studies related to fish preslaughter practices since from the farm to the processing industry have very importance due to the negative effects that may occur in the fish meat quality at this stage, which also may provide many economic damages (Rahmanifarah et al, 2011;Mendes et al, 2015;Mendes et al, 2017, Oliveira Filho et al, 2021.…”

Stunning methods before slaughter induce oxidation changes of large yellow croaker during cold storage: the role of mitochondria and underlying mechanisms

“…Zhang et al 4 found that severe stress responses (gill cutting and hypothermia) promoted the high sensitivity of fillets to oxidation. Similarly, Oliveira Filho et al 6 found that CO 2 asphyxiation of Piaractus mesopotamicus caused less physiological stress.…”

“…5 Carbon dioxide (CO 2 ) anesthesia has the advantages of lower residual toxicity compared with other anesthetic methods. 6 Oliveira Filho et al 7 found that CO 2 anesthesia caused less damage to stress levels, such as antioxidant enzymes and plasma cortisol in Nile tilapia (Oreochromis Niloticus). Plasma cortisol levels under CO 2 anesthesia were halved compared with those of electrically stimulated Arctic char (Salvelinus alpinus).…”

“…Previous studies have shown that low temperatures can make a fish struggle, leading to rapid and early depletion of glycogen and adenosine triphosphate (ATP), thus increasing the content of inosine 5 . Carbon dioxide (CO 2 ) anesthesia has the advantages of lower residual toxicity compared with other anesthetic methods 6 . Oliveira Filho et al 7 .…”