The influence of current parameters during the water-bath stunning of overfed geese (Anser anser) on blood loss and on fatty liver and meat downgrading

Abstract

Three experiments were carried out to study the effect of current intensity, stunning duration and current frequency during the water-bath stunning of overfed geese, on blood loss and fatty liver downgrading. In experiment 1,259 geese and ganders were stunned for 5 s with a sinusoidal alternating current (AC) of 50 Hz at 30, 50 or 70 mA. In experiment 2, a sinusoidal AC (50 Hz, 50 mA) was applied for 2, 5 or 13 s on 223 geese and ganders. In experiment 3, 180 geese and ganders were stunned with a sinusoidal AC (50 mA, 5 s) at 50, 300, 600 or 1200 Hz. In each experiment, a control group was slaughtered without stunning. In experiment 1, the stunned birds showed less blood loss than the control ones. Stunning increased the incidence of pink/red coloration of liver lobe tips and the incidence of petechial hemorrhages on breast muscle. Geese showed an increased incidence of petechial hemorrhages on fatty liver with increased current intensity. In experiment 2, the control birds showed higher blood loss than stunned birds. Increasing stunning duration decreased the paleness (L*) of the liver, enhanced its redness (a*) and increased the incidence of petechial hemorrhages in the breast muscle of the ganders. Stunning at high frequency (1200 Hz, experiment 3) decreased the pink/red coloration of liver lobe tips in the ganders and the incidence of petechial hemorrhages on the breast muscle in both sexes. Overall, the present data showed a detrimental effect of stunning on blood loss and fatty liver downgrading, regardless of stunning conditions.