Submitted to: British Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2008
Publication Date: 5/1/2008
Citation: Salarmoini, M., Campbell, G.L., Rossnagel, B.G., Raboy, V. 2008. Retention and growth performance of chicks given low-phytate conventional or hull-less barleys. British Poultry Science. 49:321-328 Interpretive Summary: Phosphorus is an important nutrient for plants and animals. Most of the phosphorus in seeds is found in one chemical form called "phytic acid". Monogastric animals such as chickens and pigs do not digest and utilize the phosphorus found in phytic acid. Therefore grains and legumes used in poultry and swine feeds are deficient in "available phosphorus". In "low phytic acid" grains, seed phytic acid phosphorus is reduced and seed "available phosphorus" is increased. In this study, chicks were fed diets prepared with five experimental, low-phytic acid barley lines, or normal phytic acid lines used as controls. Chicks consuming diets prepared with low-phytic acid barley lines gained more weight, had healthier bones, and required less supplemental phosphorus, than did chicks consuming normal phytic acid barley lines. In addition, since chicks utilized more of the phosphorus in low-phytic acid barley lines than they did when consuming normal phytic acid lines, they excreted less phosphorus. Thus use of low phytic acid lines in chick feeds allowed for better animal productivity while at the same time resulted in reduced production of waste.
Technical Abstract: Four low-phytate, hulled lines, M2 422 (now referred to as barley lpa1-1), M2 635 (now referred to as barley lpa3-1), M2 955 and M2 1070 (now referred to as barley lpa2-1), and a "hulless" version of M2 422, were evaluated in a chick feeding experiment. The diets were provided in meal form, with the experimental barleys constituting the cereal source. Two additional treatments were added for each of the control barleys in which intermediate and recommended phosphorus were provided. A completely randomized design was used with 5 replicates of 5 chicks per treatment. The chicks were grown from 2 to 14 days of age with subsequent 3 days total collection. Although total phosphorus levels were similar for all barley samples, there were striking differences in phytic acid content, ranging from zero to 13.8 g Kg-1. M2 955 hulled barley exhibited the lowest phytic acid and the highest phosphorus solubility. Weight gain was significantly higher in chicks consumign M2 995, as compared with the control, and feed conversion was significantly higher in both M2 955 and M2 1070(p<0.001). Tibia ash was only significantly higher than in the control for M2 635 and M2 955 (p<0.0001). The low phytic acid hulless barley (M2 H 422) gave better feed conversion than the control hulless barley. The hulless low phytate barley gave significantly higher total phosphorus retention coefficient and soluble phosphorus retention than the hulless control (p<0.001).The low phytate varieties tended to give lower excreta phosphorus (total and soluble). Amino acid retention was significantly higher for the low phytic acid hulless barley than control. Overall, the results suggest that feeding low-phytate barleys can reduce the need for supplemental P.