Acute Heat Stress-Induced Alterations in Blood Acid-Base Status and Skeletal Muscle Membrane Integrity in Broiler Chickens at Two Ages: Implications for Meat Quality

Abstract

The effects of acute heat stress (AHS) on indices of respiratory thermoregulation and skeletal muscle damage (myopathy) were examined in broiler chickens at two ages (35 and 63 d of age); the relationships of these responses with changes in meat quality were assessed. Exposure to AHS significantly increased deep-body temperatures, panting-induced acid/base disturbances, and plasma creatine kinase (CK) activities, reflecting heat stress-induced myopathy (HSIM). The extent of the hyperthermia and disturbances in acid/base status and myopathy was significantly (P < 0.05) higher in the older birds. Consistent with AHS-induced alterations in thermoregulatory indices and muscle membrane integrity were changes in breast muscle glycolytic metabolism as indicated by lower muscle pH immediately postslaughter (pHi), increased water loss, and increased incidence of breast muscle hemorrhages. Values of pHi were lower and hemorrhage scores greater in the AHS birds at 63 d; drip losses were significantly higher in the 35-d-old birds. Exposure to AHS did not affect breast meat eating quality, although overall reductions in flavor attributes were observed in the older birds. We concluded that exposure to AHS induced disturbances in blood acid/base status and had a detrimental effect upon skeletal muscle membrane integrity. Muscle from broilers exhibited an increased sensitivity to AHS exposure with age. Alterations in antemortem blood acid/base status and muscle membrane integrity induced by AHS were associated (though not necessarily causally) with adverse effects upon breast meat quality. It is recommended that preslaughter exposure of broiler chickens to AHS should be avoided in order to reduce alterations in muscle metabolism and membrane integrity and undesirable meat characteristics.

Increasing the incubation temperature between embryonic day 7 and 10 has no influence on the growth and slaughter characteristics as well as meat quality of broilers

“…Santiago et al (2005) compared commercial broilers slaughtered at 42 days and 53 days and also found higher water-holding properties in the MPS of the older birds but comparable pH and lightness values. Sandercock et al (2001) compared broilers with ages of 35 and 69 days and the authors foundcontrary to this study -no differences of the drip loss and colour score but a reduced pH 24 h p.m. in the older broiler.…”

Evaluation of cold water and vitamin C on broiler growth during hot-dry season in sw Nigeria

“…This in agreement with the report of Mbajiorgu et al (2007) that increasing ascorbic acid supplementation increased dressing percentage and breast meat yield at 42 days old Ross 308 broilers. Hot conditions negatively affect yield and quality of broiler breast meat (Leenstra and Cahaner, 1992;Sandercock et al, 2001). This finding shows that with addition of vitamin C to drinking water of broilers, this effect of heat stress could be ameliorated.…”

Expression of heat shock protein 70 in transport-stressed broiler pectoralis major muscle and its relationship with meat quality

“…These elevations indicate muscle cell membrane disruption and permeability, which led to subsequent skeletal muscle damage and fatigue (Sandercock et al, 2001). Scheffler and Gerrard (2007) indicated that damage on muscle membranes is an important factor that leads to a reduction in meat quality, as shown in Table 1.…”