Ventilation of seawater during bleeding suppresses the occurrence of burnt meat in yellowtail Seriola quinqueradiata

Fifteen farmed yellowtail Seriola quinqueradiata were randomly selected from sea cages. Five fish were slaughtered instantly by cutting the spinal bulb (control group). The remaining ten fish were left for 20 min in a narrow net and then they were slaughtered by cutting the spinal bulb instantly. These ten fish were bled in two water tanks. In one tank, the water was aerated (ventilation group), while the other tank was not aerated (burnt group). The ATP ratio in the control group (83.8 ± 4.1%) was higher than the ventilation group (37.2 ± 22.1%) and the burnt group (5.8 ± 6.0%) at 3 h after slaughter. The K value of the burnt group increased remarkably at 3 h after slaughter, and was significantly higher than those for the other groups. The ventilation group showed a recovery in available energy for physiological maintenance to the same level as the control group during bleeding, as well as a significantly slowed loss of muscular firmness compared to the burnt group. This study shows that the yellowtail continued to respire and take up oxygen until complete physiological death, and elevated oxygen levels during bleeding slowed the postmortem changes and suppressed the occurrence of burnt meat.