Pa. Papinaho et al., EFFECT OF ELECTRICAL STUNNING AMPERAGE AND PERI-MORTEM STRUGGLE ON BROILER BREAST RIGOR DEVELOPMENT AND MEAT QUALITY, Poultry science, 74(9), 1995, pp. 1533-1539
Two experiments were conducted to determine the effects of electrical
stunning and peri-mortem muscle activity (struggle in and around the t
ime of slaughter) on post-mortem biochemical reactions in broiler brea
st muscle (Pectoralis major). Broilers were stunned with either 50 or
125 mA or were killed without stunning. In Experiment 1 (n = 273), bro
ilers were either physically restrained to reduce struggling during sl
aughter or were unrestrained and allowed to struggle freely. Breast me
at pH and R-value (ratio of adenosine to inosine nucleotides) were det
ermined at 15 min and 24 h postmortem, and Allo-Kramer shear was deter
mined on 48 h post-mortem cooked meat samples from muscles excised at
15 min or 24 h. Ln Experiment 2 (n = 65), the breast muscle was unilat
erally denervated by surgically severing the Pectoralis nerve on one s
ide and performing a sham operation on the contralateral side. Results
indicated that physical restraint resulted in higher muscle pH and lo
wer R-values at 15 min post-mortem in the unstunned birds and birds st
unned at 50 mA, but had no effect on breast meat from birds stunned at
125 mA. There were no treatment effects on meat tenderness or 24-h po
st-mortem pH or R-values. Stunning amperage had no effect on denervate
d muscle pH at 15 min post-mortem but did affect the sham-operated mus
cle pH and R-values as in Experiment 1, These results indicate that th
e main effect of electrical stunning on early rigor development may be
due primarily to inhibition of peri-mortem struggle.