title: Adaptive response of broilers to dietary phosphorus and calcium restrictions.
abstract: The aim of this study was to evaluate the capacity of chickens to adapt to and compensate for early dietary restriction of non-phytate P ( NPP: ) and/or Ca (10 to 21 d) in a later phase (22 to 35 d), and to determine whether compensatory processes depend on the P and Ca concentrations in the finisher diet. Four diets were formulated and fed to broilers from 10 to 21 d in order to generate birds with different mineral status: L1(0.6% Ca, 0.30% NPP), L2(0.6% Ca, 0.45% NPP), H1(1.0% Ca, 0.30% NPP), and H2(1.0% Ca, 0.45% NPP). On d 22, each group was divided into three groups which received a low (L, 0.48% Ca, 0.24% NPP), moderate (M, 0.70% Ca, 0.35% NPP), or high (H, 0.90% Ca, 0.35% NPP) finisher diet until 35 d, resulting in a total of 12 treatments. Lowering the Ca level enhanced apparent ileal digestibility of P (P AID) at 21 d especially with the high NPP level (Ca × NPP, P < 0.01). The lower bone mineralization observed at 21 d in broilers fed the L1diet compared to those fed the H2diet had disappeared by 35 d with long-term stimulation of the P AID with the low NPP level (P < 0.001). Although P AID and growth performance were improved in birds fed the L1L compared to the L1H and H2H treatments, tibia characteristics tended to be lower in birds fed the L1L compared to those fed the L1H treatment. Birds fed the H1M treatment had higher P AID, growth performance and tibia ash content than those fed the H1H treatment. A significant increase in the mRNA levels of several genes encoding Ca and P transporters was observed at 35 d in birds fed the L1followed by the L diet compared to birds fed the L1followed by the M diet. In conclusion, chickens are able to adapt to early dietary changes in P and Ca through improvement of digestive efficiency in a later phase, and the extent of the compensation in terms of growth performance and bone mineralization depends on the P and Ca levels in the subsequent diet.
authors.affiliation: INRA-UR0083, Recherches Avicoles, F-37380 Nouzilly, France.|MixScience, F-35172 Bruz cedex, France.
authors.forename: Xavière
authors.initials: X
authors.lastname: Rousseau
authors.affiliation: INRA-UR0083, Recherches Avicoles, F-37380 Nouzilly, France.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Valable
authors.affiliation: Université Laval, Faculté des sciences de l'agriculture et de l'alimentation, Département des Sciences Animales, Québec, J1M 1Z3, Québec, Canada.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Létourneau-Montminy
authors.affiliation: INRA-UR0083, Recherches Avicoles, F-37380 Nouzilly, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Même
authors.affiliation: INRA-UR0083, Recherches Avicoles, F-37380 Nouzilly, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Godet
authors.affiliation: MixScience, F-35172 Bruz cedex, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Magnin
authors.affiliation: INRA-UR0083, Recherches Avicoles, F-37380 Nouzilly, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Nys
authors.affiliation: INRA-UR0083, Recherches Avicoles, F-37380 Nouzilly, France.
authors.forename: Michel J
authors.initials: MJ
authors.lastname: Duclos
authors.affiliation: INRA-UR0083, Recherches Avicoles, F-37380 Nouzilly, France agnes.narcy@tours.inra.fr.
authors.forename: Agnès
authors.initials: A
authors.lastname: Narcy
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000172:deficiency*; D002645:Chickens / Q000378:metabolism / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D008297:Male; D010758:Phosphorus / Q000172:deficiency*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D010758:Phosphorus; D002118:Calcium
keywords: adaptation; broiler; calcium; phosphorus