The objective of this work was to investigate the occurrence of pale, soft, exudative meat (PSE) in chicken by submitting birds to physical stress. Dietary supplementation of vitamin E was undertaken to overcome this syndrome. Postmortem muscle biochemical events and their consequence on meat properties were evaluated in samples with and without supplemented vitamin E. Our studies showed chickens were susceptible to heat stress which promoted changes in the glycolytic parameters causing the development of chicken PSE. Dietary vitamin E was capable of inhibiting the development of the syndrome hence improving meat functional properties.

The objective of this work was to investigate the influence of water spray treatment before broiler slaughtering on the quality of breast meat (Pectoralis major) and to observe ultrastructural changes promoted by the biochemical/physiological events during rigor mortis onset. Commercial Ross chickens were divided into two groups: Untreated Group (UG) (n = 608) and Treated Group (TG) (n = 611), without and with water shower treatment, respectively. Drip and cook losses, pH and color measured after 24 h postmortem demonstrated that antemortem water shower treatment inhibited PSE development in chicken breast meat. Histological studies of the PSE samples from UG birds after 72 h postmortem revealed under light microscopy a shrinking of muscle cell diameter by approximately 10% in relation to TG samples and an extracellular enlargement of endomysium and perimysium sheaths. By electron microscopy of PSE meat, Z‐lines appeared fragmented, A‐bands including the M‐line disappeared and a super‐contraction of sarcomeres was observed, indicating that proteins were adversely affected by heat stress.

The interrelationship between phospholipase A2 activity (PLA (2)) and the development of pale, soft, exudative meat (PSE) in chicken was evaluated. Pectoralis major m. from female birds of 45 days of age after hatch was studied and determination of the enzyme activity was estimated by the formation of long‐chain fatty acids. The occurrence of PSE was evaluated by measuring pH, L* values, water holding capacity and sarcoplasmic Ca2+ concentration from both heat‐stressed and nonstressed birds. In addition, the occurrence of the syndrome was monitored with birds advancing in age. Our studies revealed that PLA(2) plays an important role towards the occurrence of PSE symptoms and its activity increased as the birds became older. The enzyme activity was detected from the beginning of our experiment at 36 days and increased up to 70 days after hatch. The overall average activity was 1.25 times more pronounced in PSE samples from heat‐treated birds when compared to control animals (P ≤ 0.05).

The effect of α-tocopheryl acetate (AT) supplementation and exogenous application of this vitamin E associated with phytic acid (PA) on chicken breast meat WOF development was assessed. C ontrol group was fed with 7.7IU of AT/kg of ration and supplemented group was fed with 200.0IU of AT/kg of ration. Dietary vitamin E as measured by TBARS inhibited WOF development by 78.9; 69.0; 60.7 and 46.5% (p<0.05)

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