Pre-Slaughter Stunning Methods Influence the Meat Quality of Arapaima gigas Fillets

Abstract

The aim of this study was to evaluate the influence of different stunning methods on the meat quality of Arapaima gigas fillets from fish farming. A total of 48 specimens of A. gigas in the weight class 11.1 to 14.0 kg were investigated; these fish were subjected to different stunning methods for slaughter: ice asphyxia (IA), air asphyxia (AA), electronarcosis (EE) and hypothermia followed by bleeding (HB). Then, data were obtained from the analysis of pH, rigor mortis index (RI), water activity (Aw), instrumental texture (compression strength, firmness and adhesiveness) and blood glucose and via instrumental colourimetry. During the study, for up to 15 days of refrigerated storage, the methods provided pH values below 6.0. A. gigas submitted to EE and HB remained longer in the pre-rigor status. In addition, they expressed lower percentages of Aw. The EE method resulted in better texture assignments in the fillets. The blood glucose values indicated that the fish subjected to EE were less stressed. Concerning instrumental colourimetry, the fillets submitted to EE and HB showed greater luminosity; the fillets subjected to AA showed greater red-green colour intensity, while the fillets subjected to EE showed greater yellow-blue colour intensity. Therefore, the fish did not suffer stress with electronarcosis, and the fillets showed better preservation, juiciness, and tenderness.

Evaluation of non-penetrative captive bolt stunning as a method of slaughter for white sturgeon (Acipenser transmontanus)

“…Pre-harvest factors, such as stress and handling, can profoundly impact fish quality and shelf life by increasing muscle activity (Green, 2010). Reducing stress during harvesting can delay the onset of rigor development, thereby extending the shelf life and maintaining the quality of fresh fish (Poli et al, 2005;Buzby et al, 2014;Braitenbach Cavali et al, 2024) and ultimately reducing food waste. The onset of rigor mortis can have detrimental effects on fish muscle, causing texture deterioration, gaping, discoloration, dehydration, and reduced shelf life (Boggess et al, 1973;Azam et al, 1990;Marx et al, 1997;Robb et al, 2000;Skjervold et al, 2001;Roth et al, 2002;Kiessling et al, 2004;Daskalova, 2019).…”