The evolution of parameters known to be relevant indicators of energy status, oxidative stress, and antioxidant defense in chickens was followed. These parameters were measured weekly from 1 to 42 days in plasma and/or muscles and liver of two strains differing in growth rate. At 1-day old, in plasma, slow-growing (SG) chicks were characterized by a high total antioxidant status (TAS), probably related to higher superoxide dismutase (SOD) activity and uric acid levels compared to fast-growing (FG) chicks whereas the lipid peroxidation levels were higher in the liver and muscles of SG day-old chicks. Irrespective of the genotype, the plasma glutathione reductase (GR) and peroxidase (GPx) activities and levels of hydroperoxides and α- and γ-tocopherols decreased rapidly post-hatch. In the muscles, lipid peroxidation also decreased rapidly after hatching as well as catalase, GR, and GPx activities, while the SOD activity increased. In the liver, the TAS was relatively stable the first week after hatching while the value of thio-barbituric acid reactive substances (TBARS) and GR activity increased and GPx and catalase activities decreased. Our study revealed the strain specificities regarding the antioxidant systems used to maintain their redox balance over the life course. Nevertheless, the age had a much higher impact than strain on the antioxidant ability of the chickens.

Phosphorus (P) is an essential mineral in poultry nutrition, but its low bioavailability from conventional feed ingredients presents a significant challenge for efficient utilization. This study investigated the effects of different P sources (monocalcium phosphate (MCP) and calcium humophosphate (CHP)) and three phytase concentrations (0, 1000, or 2000 FTU/kg of feed) on broiler performance and ileal nutrient digestibility. A total of 600 Cobb 500 male broilers were fed one of six different dietary treatments with 10 replicates per treatment from 11 to 21 d of age. The birds and feed were weighed at 1, 10, and 21 d of age to determine growth performance. At 21 d of age, ileal digesta was collected from all the birds to determine dry matter, organic matter, Ca, P, and ash digestibility. The results indicated that phytase supplementation at 1000 and 2000 FTU/kg improved the feed conversion ratio and P digestibility compared with the non-supplemented group. The broilers fed CHP showed superior P digestibility compared to those fed MCP, regardless of phytase concentration. The results also indicated interactive effects between P source and phytase concentration on the digestibility of dry matter, organic matter, and ash. The findings suggest that CHP enhances nutrient digestibility and could optimize P utilization in broiler diets with phytase inclusion. This report reveals a better understanding of the effects of P sources and phytase concentration on feed digestibility. Further studies are needed to confirm these findings and support improvements in broiler performance under commercial production conditions.

Le métabolisme glucidique de l’oiseau est important pour maitriser la croissance de l’animal et la qualité de la viande. Nous avons étudié l’utilisation périphérique du glucose chez le poulet au niveau musculaire en identifiant et en caractérisant les principaux acteurs impliqués. Nous avons identifié et caractérisé un nouveau transporteur de glucose chez les oiseaux, GLUT12. Il est exprimé dans les muscles, son expression est régulée in vivo par l’insuline et il peut être enrichi dans les membranes plasmiques des cellules suite à une stimulation insulinique. In vitro, une augmentation du transport de glucose est mesurée sur le même pas de temps que la translocation de GLUT12. Comme pour GLUT4 chez les mammifères, la PI3K est impliquée dans la translocation de GLUT12. L’expression des GLUTs musculaires varie avec l’âge des animaux mais aussi avec leur état physiologique, le type métabolique et/ou la fonction du muscle. L’ensemble de nos résultats explique en partie le métabolisme glucidique atypique des oiseaux et laisse entrevoir le développement de nouvelles stratégies d’élevage pour répondre à une demande croissante de produits avicoles de qualité.