Low Phytic Acid Barley Improves Performance, Bone Mineralization, and Phosphorus Retention in Turkey Poults

A study was conducted to determine whether P in a low phytic acid mutant barley (Hordeum vulgare L.; MB) containing the lpa 1-1 allele is more available than P in a near-isogenic, wild-type barley (NB). The MB contained 0.21% non-phytate P (nP) (estimated available P; aP) and 0.35% total P (tP), whereas NB contained 0.11% aP and 0.35% tP. A completely randomized design was used with 150 1-d-old male poults randomly assigned to five treatments (six pens of five poults per treatment) for 21 d. The five treatments were 1) a NB diet containing 0.30% aP, 0.41% tP, and 1.0% Ca; 2) a MB diet containing 0.36% aP, 0.41% tP, and 1.0% Ca; 3) a NB diet similar to Diet 1 but with KH2PO4 added to increase the aP to 0.36% (0.47% tP) to match the aP in Diet 2; 4) a MB diet containing 0.60% aP, 0.86% tP, and 1.2% Ca; and 5) a NB diet containing 0.60% aP, 0.92% tP, and 1.20% Ca. Performance and bone ash were significantly lower (P < 0.05) in poults fed Diet 1 compared with those in poults fed Diet 2. Performance and bone ash were similar (P > 0.05) in poults fed Diets 2 and 3 and in poults fed Diets 4 and 5. Poults fed Diet 1 retained 13.9% more P than did poults fed Diet 2 (P < 0.05). Poults fed Diets 2 and 4 retained 11.9 and 4.9% more P than poults fed Diets 3 and 5, respectively (P < 0.05). Poults fed MB diets excreted 41% less P than did poults fed NB diets when barley was the sole source of phytic acid in the diet. Results of the current study indicate that P in MB is more available than P in NB, and decreasing the phytate content did not compromise the nutritional value of MB.