Influence of transport stress and slaughter method on rigor mortis of tambaqui (Colossoma macropomum)

Summary

The present work evaluated physiological stress responses of tambaqui to transport and their consequences to rigor mortis of fish slaughtered by hypothermia or by carbon dioxide asphyxia. Fishes were submitted to experimental transport to evaluate four fish stress stages before slaughter: post-harvest, after transport, after 24 h and 48 h recoveries. Fish stress after transport was the most acute, and fish slaughtered after that by hypothermia had the quickest rigor mortis onset: 60 min, while fish slaughtered by asphyxia had rigor mortis onset in 120 min. Fish slaughtered just after harvest had rigor mortis onset in 135 min for both slaughter methods (hypothermia or asphyxia). Fishes recovered from transport stress had slower rigor mortis onset: 225 min and 255 min after 24 h and 48 h recovery, respectively, for both slaughter method. No influence from slaughter method was observed on rigor mortis resolution in all the fish. Rigor mortis of fish slaughtered after transport ended in 12 days. Rigor mortis of fish slaughtered after harvest ended in 16 days. Fish recovered from transport stress had rigor mortis end at 20 days and 24 days after 24h and 48h recovery, respectively. Slaughter of tambaqui for industry is rather recommended after stress recovery, in order to extend the rigor mortis period.

Key words:
Colossoma macropomum ; Management; Metabolism; Processing