Project 2.5

The following objectives were mainly created on the basis of the findings of the first funding period of projects 1.5 and 1.1:
• Optimising metabolic performance in laying hens by myo-inositol
• Understanding of underlying pathways and metabolic networks
• Identification of metabolic markers of phytase-efficient hens

The experimental design of trials in the second funding period is suitable to broaden the knowledge about the impact of myo-inositol in laying hens further by challenges, which increase myo-inositol availability for the hen. Providing dietary myo-inositol supplementation at different amounts will lead to dose-dependent changes of metabolic responses in both, LSL and LB hens. Reducing dietary P availability will force LSL and LB hens to efficiently use their endogenous phytase capacity to obtain sufficient inorganic P for their metabolism. Higher phytase activity will also provide higher myo-inositol amounts in the intestine as an end product of complete phytate dephosphorylation. A large number of LSL and LB hens supplied with low dietary P level will help to study relationship of potential metabolic markers with genetic traits (project 2.2). The already identified strain-specific differences in metabolism, especially at onset of egg laying, will create a wide range of physiological conditions helping to characterise the optimal metabolic setting for laying performance of hens.