Abstract: Pre-slaughter shackling is essential for meat ducks because it can improve the slaughter efficiency. However, pre-slaughter shackling can often aggravate stress in meat ducks and affect post-harvest blood quality, which has become an urgent problem to be solved in slaughterhouses. Herein, the effect of pre-slaughter shackling stress on the gel characteristics of duck blood was investigated by measuring hematological and blood coagulation indicators. Before slaughter, 40 Cherry Valley ducks were randomly divided into two groups: one group was the control group not receiving pre-slaughter shackling, and the other was the experimental group receiving pre-slaughter shackling for 2.5 min. After slaughter, blood samples were collected and used to prepare curds for determination of stress, hematological and blood coagulation indicators as well as gel properties. The results showed that the plasma levels of corticosterone and adrenocorticotropic hormone in the experimental group were higher than those in the control group C, indicating that pre-slaughter shackling induced stress in ducks. This was accompanied by an increase in the numbers of red blood cells and platelets, the concentration of hemoglobin, hematocrit, mean corpuscular volume (MCV) and mean platelet volume (MPV), and a significant increase in the levels of prothrombin (P < 0.01) and tissue factor (P < 0.05). Pre-slaughter shackling eventually accelerated the gelation of duck blood, increased the mobility of water in the gel system, reduced the percentages of bound and free water, increased the percentage of immobilized water, and weakened the texture properties and water-holding capacity of duck blood curds. This research revealed that pre-slaughter shackling stress could affect duck blood hematology and coagulation, thereby changing its gel behavior and gel properties. This finding will provide a theoretical basis for improving the gel quality of duck blood.

Key words: pre-slaughter shackling; duck blood; blood coagulation system; gel properties