Effects of crowding and two slaughtering procedures on blood physiology and some muscle physicochemical factors in common carp

In this study effects of two slaughtering procedures that were asphyxia and percussion onphysiological blood factors and physicochemical muscle attributes, determined in order toevaluate imposed stress and meat quality in common carp. Results showed crowding and two different slaughtering methods significantly affected on plasma cortisol, glucose, lactate, calcium and magnesium (P<0.05). Asphyxia decreased chloride but did not affect total protein plasma levels (P>0.05). pH in percussion groups was higher than asphyxia groups immediately after death. Percussion fish had the highest and asphyxia groups had the lowest level of water holding capacity than other groups. Crowding and asphyxia killing method significantly increased drip loss as compared to uncrowding and percussion killing methods (P<0.05). Fishs in asphyxia group exhibited a faster onset of rigor mortis than other groups.Although two slaughtering procedures did not affect on fillet color (P>0.05), howevercolorimetric results showed significant differences in the skin color parameters amongdifferent groups during post mortem time (P<0.05). In conclusion, the results revealed that over crowding and asphyxia slaughtering procedures impose maximum stress to fish and reduce meat quality and on the hand, uncrowding and percussion had no imposed stress fish and their meat quality was better than other groups.