Efficacy of phytase in enhancing nutrient utilisation in broilers is dependent on dietary ions content
A total of 336 Ross 308 male day old broiler chicks were allocated to 7 treatments in a randomized complete block design. Each treatment had 6 replicates with 8 birds each. A 3×2 factorial arrangement (plus a positive control diet) was used with 3 levels of dietary undetermined anions, dUA (230, 290 and 370 mEq/kg) and 2 phytase levels (0 and 1500 FTU/kg). Birds and feed were weighed on days 0 and 21, excreta were collected on days 19 and 20 and digesta from the terminal ileum collected on day 21. There were dUA × phytase interactions (P < 0.05) for ileal digestibility and total tract retention for most of the nutrients. When dUA was 230 mEq/kg nutrient utilization was generally lower (P < 0.05) in phytase-supplemented compared with non-supplemented diets, in contrast to the substantial performance gains seen in the phytase fed birds. Utilization of DM, Ca, K, and P was greater (P < 0.05) in phytase-supplemented diets when dUA was 290 mEq/kg and, for P and K was greater in phytase-supplemented diets when dUA was 370 mEq/kg. Ileal and total tract P utilization were greater (P < 0.05) in birds fed NC and phytase-supplemented diets than in PC birds. It is concluded that the extent of phytase effect differs depending on the mineral (dUA) content of the diets. Comparison of the effects of phytase and dUA on nutrient utilization and growth performance indicates that treatments effects seen in nutrient utilization do not always reflect effects observed in growth performance.
Other Titles/Title of Conference
XIVth European Poultry Conference, Stavanger, Norway
World's Poultry Science Association
Journal Title/Title of Proceedings
Proceedings of the XIVth European Poultry Conference