FIGURE 4.

Hypothetical oxidative mechanism occurring in meat of broiler chickens raised in thermoneutral (TNT) or chronic heat stress (HS) conditions from 35 to 41 days of age. Antioxidants and lipids content as well as fatty acids profile are similar in the two groups. In both TNT and HS conditions, lipid oxidation occurs to the same extent, with the production of MDA (malondialdehyde). In TNT, MDA reacts with the TBA (thiobarbituric acid) to detect the TBARS level (thiobarbituric acid reactive substances). In HS, MDA reacts with the N-terminal group of free amino acids and polypeptides derived from protein mobilization. Carbonyls level increase while the reaction between MDA and TBA occurs to a lesser extent, thus resulting in a reduced TBARS detection.