نعمت ضیائی

A ten-week experiment was conducted to study the effect of a nanostructure of phytic acid absorber (NPAA) on the performance and protein digestibility in laying hens. A total of 100 Bovans laying hens were randomly assigned to 5 treatments, with 4 replicates, 5 hens each. The experiment was a completely randomized design with 5 levels of NPAA; including zero (T1, as a basal diet (BD)); T2 (BD+ 0.5% NPAA); T3 (BD + 0.25% NPAA); T4 (BD + 0.0625% NPAA) and T5 (BD + 0.03125% NPAA of total P) in diet. Water and feed were offered ad libitum. Inclusion of NPAA to the diet had significant effects (P<0.05) on egg production (%) at 25 weeks of age and over the whole experiment. Dietary treatments significantly affected the egg weight (P<0.001) at 29th weeks of age, and hens receiving T5 produced heavier eggs compared to T1, T2 and T3 treatments. NPAA also affected (P<0.05) the egg mass and feed conversion ratio (FCR) at weeks 29 and 30. Egg shell weight was significantly (P<0.05) affected at 29th week of age; however, dietary treatments had no effect on the relative egg shell thickness. Egg shell phosphorus and calcium contents were in-creased by 14.6 and 14.2% respectively at 29th week of age in T5 compared to the control. At 33rd week of age, hens in T4 group had significantly higher protein digestibility than T1 birds (P<0.05). It was concluded that inclusion of NPAA to the diet at the level of 0.0625%, may reduce the anti-nutritional effects of phytic acid and improve production performance and protein digestibility in laying hens.