Modulation de l'utilisation digestive du phosphore chez le porcelet sevré: influence de l'apport de calcium et de phytase sur le pH et la solubilité des minéraux au niveau gastro-intestinal

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Modulation of phosphorus digestive utilization in weanling pigs : influence of dietary calcium and phytase on gastro-intestinal digesta pH and mineral solubility

Egalement publié dans J. Dairy Sci. 95(Suppl. 2)Egalement publié dans J. Dairy Sci. 95(Suppl. 2)The study was conducted to evaluate the impact of dietary calcium (Ca) concentration, added in the form of calcium carbonate (CaCO3), on phosphorus (P) digestibility and gastro-intestinal digesta pH and soluble mineral concentration in weanling pigs fed diets with or without microbial phytase. A 3 × 2 factorial arrangement was used with maize-soybean meal based diets formulated to contain combinations of 3 concentrations of Ca: 0.50, 0.75 and 1.00% with or without the addition of 1000 FTU of microbial phytase/kg. After a 5-d adaptation period under a standard diet, 40 male weanling pigs were blocked by weight and allotted to one of the 6 dietary treatments in a 29 d experiment. The addition of microbial phytase improved (P < 0.001, +20.1 points) P digestibility regardless of dietary Ca concentration. In addition, P digestibility was linearly decreased (P < 0.001, −4.30 points) when increasing dietary Ca. Dietary Ca concentration and microbial phytase did not affect the pH of the different digestive compartments. Nevertheless, the pH of the different segments followed an increasing proximo-distal gradient (segment, P < 0.001): 4.69, 5.62, 6.66 and 7.10 pH units respectively for the stomach, the duodenum, the jejunum and the ileum. A negative quadratic relation was observed between the gastric pH and the proportion of soluble inorganic P (iP) and Ca. In the same segment, phytase improved the solubility of iP depending on dietary Ca concentration (Ca x phytase, P < 0,001). Indeed, the addition of microbial phytase increased the proportion of soluble iP (% total P) by 20.2, 9.30 and 8.90 points in diets containing 0.50, 0.75 and 1.00% of dietary Ca respectively. The present results suggest that the increase of dietary Ca concentration may affect the solubility of phytates in the stomach reducing in this way their hydrolysis by phytase. Nevertheless, this step did not appear to be limiting regarding the enzyme efficacy in ameliorating P digestibility

Modulation de l'utilisation digestive du phosphore chez le porcelet sevré: influence de l'apport de calcium et de phytase sur le pH et la solubilité des minéraux au niveau gastro-intestinal

Session : AlimentationNational audienc

Effect of dietary non-phytate phosphorus and calcium concentrations on growth performance, bone mineralisation and mineral retention of chicks fed diets supplemented with microbial phytase

Texte intégral de 5 pages sur CD-RomNational audienc

Effect of dietary non-phytate phosphorus and calcium concentrations on growth performance, bone mineralisation and mineral retention of chicks fed diets supplemented with microbial phytase

Texte intégral de 5 pages sur CD-RomNational audienc