Advantages of recovery from pre-slaughter stress in tambaqui Colossoma macropomum (Cuvier 1816) agroindustry in the Amazon

Abstract Tambaqui is the main fish species farmed in the Amazon. It is produced on industrial scale, slaughtered in the field, primarily by post-harvest asphyxia. This procedure, however, is stressful because it depletes energy reserves that should be used in postmortem metabolism, which may compromise fish meat freshness and quality. The present study compared the quality of tambaquis slaughtered by asphyxia, the conventional industrial method, and hypothermia. Tambaquis weighing around 1.6 kg were harvested from dugout ponds, transported to experimental tanks and allowed to recover from transport stress for 48h. Biological parameters of fish were evaluated alive post- harvest (Harv), transport (Tr) and recovery (Rc), and postmortem analysis was performed in fish slaughtered by asphyxia (Asph) or hypothermia (Hyp) after transport and recovery. Initial observations showed that the content of total volatile nitrogen bases (TVB-N) and pH were higher in fish killed by asphyxia. Sensory analysis indicated that the quality of fish slaughtered immediately after transport was lower than in fish allowed to recover from pre-slaughter stress. The results suggest that recovery from pre-slaughter stress contributes to preserving meat freshness and quality in tambaquis slaughtered on an industrial scale, but other studies are required to determine the feasibility of this recommendation.