Effects of Phytase Supplementation of Low Phosphorous Diets Included Olive Pulp and Date Pits on Productive Performance of Laying Hens, Egg Quality Traits and Some Blood Parameters

Aims: This study was conducted to evaluate effects of phytase (E) supplementation of low phosphorous diets (NPP) included olive pulp (OP) and date pits (DP) on performance of laying hens, egg quality traits, blood parameters and excreta pH of laying hens.
Study Design: Data were analyzed based on 2×2×2 factorial arrangements in completely randomized design using GLM procedure of SAS.
Place and Duration of Study: The present experiment was done in Animal Science Department of Razi University, Kermanshah, Iran. All procedures used in this study were approved by the Animal Ethics Committee of Razi University and complied with the "Guidelines for the Care and Use of Animals in Research".
Methodology: A total number of 288 Lohmann LSL-Lite laying hens was randomly divided in 48 cages (n=6). Based on a 2×2×2 factorial arrangement of treatments, 8 iso-caloric and iso-nitrogenous experimental diets (ME =2720 Kcal/Kg and CP=150 g/Kg) consisting of two levels of date pits and olive pulp (0, and 90 g/kg), two levels of dietary non-phytate phosphorus (NPP: 2.6 and 3.3 g/kg diet) and phytase (0 and 150 FTU/kg) were formulated. Hens in every randomly-selected six cages (replicates) allotted to feed on each of 8 experimental diets.
Results: Dietary treatment did not have significant effect on egg production (EP) and feed intake (FI). Phytase numerically increased egg mass (EM) compared to control diets. Dietary inclusion of date pits and olive pulp significantly affected feed conversion ratio (FCR). Yolk index and Haugh unit were not significantly affected by dietary treatment (P>0.05). Diet inclusion of olive pulp and date pits numerically decreased eggshell weight and thickness in the first egg sampling (wk 3) in compared to control diet (P=.05). In the second egg sampling (wk 7), egg index, yolk index, Haugh unit, egg gravity and eggshell thickness were not significantly affected by dietary treatment. Dietary treatment did not have significant effect on blood parameters except for monocyte, so that a significant interaction between DO, P and E (p=0.01) was detected. Dietary treatment did not have significant effect on body weight changes (BWC) and excreta pH.
Conclusion: From the results of the present study, it can be concluded that DP and OP can be included in diet of laying hens up to 9% with no adverse effect on birds' performance. However, diet inclusion of DP and OP has some adverse effects on egg yolk color and eggshell weight.