Bioavailability of minerals : pigs are different from broilers !
Dr Daniel Brugger, from Technical University of Münich (Germany), reviewed differences between digestibility of macro-minerals and bioavailability of micro-minerals. The following terms should not be confused : bioaccessibility (access to intestinal mucosa), digestibility, and bioavailability. Digestibility studies can be apparent, or true when they take into account endogenous losses from organs or from sloughed off intestinal cells. In pigs, there are no differences between total tract and ileal digestiblity of Ca and P, which is not the case in poultry where feces and urine are mixed. With macro-minerals, urinary losses can be relevant, which is different with cationic trace minerals. Apparent digestibility of zinc seems to be a good criteria if measured in well controlled dose-response studies. Appropriate and sensitive biomarkers to determine the bioavailability of trace minerals and the status of animals are still under discussion.