The effect of enzyme and protein source on laying hens performance, eggshell and bone traits

Abstract

The aim of the study was to investigate the interaction between exogenous phytase with protease and protein source in laying hens diet. A completely randomised design study with a 2 × 4 factorial arrangement was conducted to observe effects of protein source (soybean vs. yellow lupine seeds diet) and enzyme addition (no enzyme vs. phytase or protease or both) on laying hens performance, bone mineralization and some egg traits. One hundred sixty Hy-Line Brown hens at the age of 18 weeks were weighed and randomly assigned to 10 treatments, each with 16 birds. According to the producer recommendation in diets containing enzymes reduced the level of available phosphorus (50% reduction) and digestible amino acids - 5% reduction. The egg production during the entire experiment was similar in all groups without significant differences. The egg weight was also on an equal level in all treatments and it was about 58 g. Birds fed different protein source were characterized by similar feed intake and feed conversion ratio during the whole experiment. The feed conversion ratio (FCR) was about 1.9-2.0 in all groups. Tibia ash was affected by enzymes supplementation. There was an interaction between protein source and enzymes addition. Birds from treatments fed with yellow lupine meal (YLM) diets reached highest tibia ash level in a group with phytase addition and in groups with SMB in a group with phytase and protease mix. The inclusion of enzymes improved the thickness of the shell. There was an interaction between protein source and enzyme inclusion. It was an interaction between experimental factors in shell breaking strength. Stronger eggshell was laid by hens from groups fed with the inclusion of yellow lupine meal. Addition of phytase had a positive impact on increasing the strength of eggshell. Only inclusion of enzymes affected significantly on shell elastic deformation in part I of eggs. Eggs from hens fed diets with inclusion of protease and phytase mix were most resistant to elastic deformation.