Abstract:

Objective: The objective of this study was to investigate the postmortem changes in protein phosphorylation of
sarcoplasmic proteins and myofibrillar proteins in three chicken groups with different fasting time and different postmortem
time (0, 3 h and 10 h). Methods: Thirty three yellow chickens were randomly divided into three groups: no feed deprivation,
feed deprivation for 12 h and feed deprivation for 24 h. Immediately after slaughter, breast muscles were rapidly removed
and cut into three pieces. One piece was designated as postmortem 0 h sample. The others were placed at 0 ℃ for 3 h and
10 h, respectively as postmortem 3 h and 10 h samples. One dimensional electrophoresis combined with Pro-Q Diamond
staining was employed to analyze protein phosphorylation of sarcoplasmic and myofibrillar proteins. Results: The protein
phosphorylation level of sarcoplasmic proteins in fasting 12 h samples was the highest level, while myofibrillar proteins
became higher with increased fasting time (P ＜ 0.05). Besides, the protein phosphorylation level of most proteins in
fasting and control muscles became the highest at 3 h postmortem. Conclusion: Protein phosphorylation of sarcoplasmic
and myofibrillar proteins is significantly affected by fasting and postmortem time. Therefore, meat rigor mortis and meat
tenderness may be affected by fasting as a result of regulating protein phosphorylation in muscles.

Key words: protein phosphorylation, sarcoplasmic proteins, myofibrillar proteins, fasting, postmortem time