Effects of acute heat stress on indices of meat quality in different skeletal muscle types in broiler chickens.

DA Sandercock*, Nicholas A Gonet, Richard R Hunter, Paul Hocking, MA Mitchell

*Corresponding author for this work

Research output: Contribution to journalMeeting Abstractpeer-review


Previous studies have demonstrated decrements in post-mortem breast meat quality in broiler chickens exposed to acute heat stress (AHS). These changes included lowered muscle pH immediately post-slaughter (pHi) and elevated meat drip loss associated with increased rates of pre and post-mortem glycolytic metabolism. It is not known if AHS affects skeletal muscle types in the same manner. This study therefore examined the effect of AHS on indices of meat quality in broiler muscles of differing metabolic characteristics (glycolytic vs. oxidative) in the breast (BM), thigh (TM) and drumstick (DM). Two groups of 12 male broilers (8 weeks) were exposed to AHS (31°C/75%RH) or control conditions (21°C/50%RH) for 2h in controlled climate chambers. Indices of thermoregulatory effort and success were measured to quantify the extent of the effect of the imposed heat load. Muscle pH, drip loss and colour were measured as indices of meat quality. Exposure to AHS produced a lower pHi in all muscles (P<0.05), this effect was greatest in BM. Muscle pH after 24 h (pHu) was lower in BM than in the other muscle types (P<0.01). Values for pHu were not affected by AHS in any of the muscle types. Drip losses were greatest in BM and were further elevated in this muscle by AHS exposure (P<0.001). AHS did not affect drip losses from TM and DM. Muscle lightness (L*) values increased in BM (P<0.001) and decreased in TM (P<0.01) after AHS but did not alter in DM. Both BM and TM exhibited increases in redness (a*) values (P<0.05) the extent of the increase being greater in the TM (P<0.02). Muscle yellowness (b*) values decreased in BM and TM to a similar extent following AHS exposure (P<0.05). It is clear from this study that alterations in meat quality attributes induced by AHS are dependent upon muscle fibre type. Changes in meat pH, drip loss and colour appear to be greater in muscles which predominantly function via glycolytic metabolism.
Original languageEnglish
Article numberabstract 150
Pages (from-to)35
Number of pages1
JournalPoultry Science
Issue numberSupplement 1
Publication statusPrint publication - 2000
Externally publishedYes
EventWPSA XXI World's Poultry Congress 2000 - Montreal, Canada
Duration: 20 Aug 200024 Aug 2000


  • Acute heat stress
  • Broiler chicken
  • Glycolytic muscle metabolism
  • Oxidative muscle metabolism
  • Meat appearance
  • Muscle pH
  • Drip loss
  • Meat colour
  • Muscle fibre type
  • Glycolytic fibre susceptibility


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