engleski

Influence of leverage time on meat quality of pigs

This study comprised of 90 barrows divided into three groups of 30 pigs. Pigs were fattened on family farms in the Brodsko-Posavska county. All fattening farms were located approximately 100 kilometers away from the slaughterhouse. In the first group, pigs were slaughtered after resting for 24 hours. The second group consisted of pigs that were slaughtered immediately after loading without resting. In the third group, pigs were transported to the slaughterhouse and rested for 6 hours before slaughter. Blood was taken by venous puncture after sedation with carbon dioxide before the bleeding and analysed for the stress indicators (metabolite concentrations of glucose and lactate, the activity of creatine kinase enzyme and adrenal hormone cortisol). Pig carcasses were analysed after slaughter for meat quality traits. pH values in ham and longissimus dorsi muscle were taken 45 minutes and 24 hours after slaughter. Meat colour (CIE-values L *, a *, b *) was measured 24 hours after slaughter while the samples for drip loss measurement were taken. At the same time samples for measurement of instrumental tenderness of meat and cook loss were taken. Statistical analysis showed a significant effect of resting before slaughter on final pH values measured 24 hours after slaughter in ham and longissimus dorsi muscle (MLD). Differences were determined between the pigs that had rest for 24 hours, with the highest values recorded, while the other two groups with six hours of rest and without rest values were lower. Resting time had a significant effect on CIE-L * values. Results of CIE-a * values also showed that the rest before slaughter had a significant effect indicating that a group of pigs with a rest of 24 hours differed from the other two groups. Results of drip loss values obtained with bag method did not find significant effect of rest before slaughter, while EZ drip method determined significant differences. The concentration of cortisol level in blood was highest in the group of pigs that had no rest, and lowest in the group of pigs with rest of 24 hours. Creatine kinase (CK) in our research showed highest obtained differences between the groups. The highest value was determined in a group of pigs that were slaughtered without prior rest, while the lowest value was determined in the group with rest of 24 hours. Our study showed that lactate concentrations in blood were higher in the group of pigs without rest, than in groups with 6 and 24 hours rest before slaughter. Correlation between blood parameters and meat quality have demonstrated an association between CK and pH45 values measured in the MLD (r = -0.24), pH24 measured in ham (r = 0.55) and in MLD (r = 0 , 45) and meat tenderness (r = 0.28). Also, the association was found between cortisol and pH45 (r = -0.2) and drip loss obtained by bag method (r = 0.27) and EZ drip method (r =0.22). Consequently, it can be stated that pigs slaughtered under stress conditions tend to have PSE meat so the recommendation is to rest pigs before slaughter in order to avoid stress resulted by manipulation and transport to slaughterhouses and afterwards to perform slaughtering of animals.

transport of pigs ; stress ; quality of pig meat

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