Rigor Mortis in Farmed Common Carp Cyprinus carpio: The Effects of Handling Temperature

The study was conducted to determine the rigor mortis in common carp Cyprinus carpio, weighing 1100 ± 163 g and measuring 37.5 ± 1.87 cm in total length. Immediately after catching, the fish were killed by a blow to the head, followed by washing with tap water, before being placed in six insulated boxes, either at the ambient temperature (25 ± 3°C) or at a chilled temperature of (0°C). The rigor mortis and biochemical changes were monitored at regular times to measure the rigor mortis index (%), pH, and chemical composition. The rate of rigor mortis index in fish kept at ambient temperature was 100% within 10 h after fishing, while it was 100% after 20 h in fish kept at a chilled temperature. During the later postmortem changes, pH slightly increased to reach a value of 7.2 for fish kept at ambient temperature and 7 for fish kept at a chilled temperature. The results also showed nonsignificant differences (p > 0.05) in the chemical composition of fish before and after rigor mortis. Therefore, it was considered that the development of rigor mortis in common carp occurring more rapidly at ambient temperature than at chilled temperature.