Impact de la congélation sur la qualité de la viande de poulet fermier et poulet de chair

Abstract

The evaluation of the incorporation of phytobiotics—in the form of eucalyptus leaf powder, turmeric rhizome powder, and pomegranate peel powder—at inclusion levels of 1%, 3%, and 5% in the diets of free-range broilers (poulet fermier) and commercial broilers (poulet de chair) reveals contrasting response profiles depending on the anatomical, visceral, and physicochemical parameters studied. Regarding skeletal and muscular development, analysis of variance (ANOVA) demonstrates high overall stability: the muscle masses of the thighs and pectoralis major, as well as the weights of the neck and right wing, show no statistically significant changes compared to the control group, reflecting the safety of these feed additives on thigh and breast musculature, although a slight variation was recorded for the left wing. At the visceral level, the absolute weights of the liver, intestine, and heart remain homogeneous, confirming the absence of toxicity or metabolic overload, whereas a highly significant modification is observed in abdominal fat deposition and gizzard weight, witnessing a mechanical adaptation to the fibrous texture of the plant powders. Furthermore, the post-freezing physicochemical study shows that the bioactive compounds markedly influence the acid-base profile, dry matter content (DM %), and water-holding capacity (WHC). In free-range broilers, eucalyptus induces a dose-dependent increase in dry matter, reflecting a protective effect of polyphenols on myofibrillar proteins, while turmeric exhibits a stabilizing threshold effect at 5%. Conversely, in commercial broilers, high concentrations of turmeric and eucalyptus cause a sharp drop in dry matter and profoundly alter the protein matrix. Pomegranate peel ensures relative stability in dry matter and water retention across both strains through the action of its tannins. Finally, the analysis of thaw drip loss (exudate) underscores that unadjusted doses disrupt tissue integrity and water balance, thereby confirming the imperative of rigorously controlled phytogenic dosing to optimize the preservation and technological quality of poultry meat.