EFFECTS OF DIFFERENT SLAUGHTERING METHODS ON MUSCLE PH AND BLOOD VARIABLES OF HETEROCLARIAS HYBRID FISH

The effect of different slaughtering methods on muscle pH and blood variables of heteroclarias (Heterobranchus bidorsalis × Clarias gariepinus ) was studied. The experiment was a completely randomized design comprising four slaughtering methods: percussive stunning, salt stunning, ice asphyxia, and electroshock. Eight (8) kg of live catfish, C. gariepinus, with an average weight of 500 ± 21g were collected from the concrete, they were divided into four groups and each group was slaughtered using various slaughtering methods including percussive stunning, salt stunning, ice slurry asphyxia and electroshock. The stress indicators (urea, glucose, sodium, chloride, potassium, osmolality, lactate and cortisol) were checked in the fish blood that was collected immediately after slaughter following standard experimental procedures. The muscle pH and rigor mortis were also measured. Fish stunned using percussive stunning had the highest pH (7.15) while that stunned with salt had a pH of 6.9. Glucose, cortisol and urea of heteroclarias slaughtered using ice slurry asphyxia was significantly (p < 0.05) higher than when other slaughtering methods were adopted. It is concluded that the various slaughtering methods impacted some stress on heteroclarias but ice slurry asphyxia impacted the most severe stress. However, the values obtained for the pH and blood variables in this study indicate that the fish is good for consumption irrespective of the slaughtering method employed.