Preliminary study on physicochemical and biochemical stress markers at poultry slaughterhouse

Pre-slaughter stress can result in variations in the glycogen storage and metabolic changes of muscle, responsible for quality poultry meat. Aim of this study was to investigate, as pre-slaughter stress markers and quality meat, physicochemical (pH), biochemical (muscle glycogen content), and chemical (super oxides free radicals) parameters. The carcass quality, as incidence of individual carcass defects, was also evaluated. Twenty broilers were processed with two different electrical stunning: high (250 Hz; 640 mA; 60V) (Lot C or control) and low (150 Hz; 360 mA; 60 V) (Lot A) frequency and intensity, using sinusoidal alternating current. As preliminary results, the use of low frequency and intensity induced faster pH decline post mortem and adequate acidification of pH at 3 hours (6.49 Lot C; 6.37 Lot A), better muscle glycogen reserve (0.770 μL/50 mL Lot C; 1.497 μL/50mL Lot A), and lightly more rapid muscle oxidation (IDF: 0.109 Lot C; 0.122 Lot A), (FOX: 0.131 MeqO₂/kg Lot C; 0.140 MeqO₂/kg Lot A). The incidence of individual carcass defects sufficient to cause downgrading or rejection, both in Lot C and Lot A, was generally low. In a multidisciplinary approach, to assess animal welfare and quality poultry meat, additional and feasible parameters should be implemented. Monitoring of pH, muscle glycogen reserve and superoxide free radical production measurements might be markers easier to use, routinely, in practice at abattoir. Further studies are needed to evaluate the usefulness of these parameters.