Effect Of Pre-Slaughter Carbon Dioxide Anesthesia On Tilapia And Golden Pompano Flesh Quality And Stress Responses

This work evaluated the effect of pre-slaughter carbon dioxide (CO2) anesthesia on Tilapia and golden pompano flesh quality and stress responses. The different pre-slaughter handling of two fish is Tilapia at23±1℃, directly percussive blow to the head is control group, Golden Pompano at0.25±0.25℃, comparing with hypothermia, the directly percussive blow to the head also is control group. The results were as follows:CO2narcosis can prolong the pre-rigor period of the fillet, having a dramatically higher initial pH and not significantly lower final pH value. Weight loss of both methods do not have a significant difference in post-mortem3d, but weight losses of CO2anesthesia group were significantly lower than percussive stunning from post-mortem4to7d. Excepting for post-mortem0d and4to5d, TVB-N values of CO2anesthesia group were significantly lower than percussive stunning. Moreover, the textural deterioration and sensorial evaluation were not significant between two groups, but the texture hardness, shear force and sensorial evaluation were dramatically inferior at post-mortem7d to0d. CO2narcosis can markedly reduce stress. The pre-slaughter method of CO2anesthesia, combined with all quality indicators, is better suitable to process tilapia flesh than percussive stunning.Comparing with hypothermia, The CO2-saturated water combine with live-chilling handle Golden Pompano can shorten narcosis time, had a dramatically lower initial pH6.63. Moreover, it was significant severe stress responses than hypothermia and percussion at post-mortem0and4h. The plasma cortisol of CO2anesthesia group is7-fold and5-fold than other groups, respectively. The blood lactate level were not dramatically different among groups, CO2anesthesia group and hypothermia group had a higher blood glucose level. Moreover, the CO2anesthesia group had a lower blood K+, Cl-level and a higher blood Na+, Ca2+level. During4h post-mortem, Weight loss had a significant increase and TVB-N was increased, but there was no significant difference among groups. White flesh of CO2anesthesia group were lighter and more white (higher L*and lower a*). CO2anesthesia and hypothermia were not dramatically difference on texture, but they were softer than percussion.