Project 2.8

The overall objective is to generate and integrate data of genetic/epigenetic variation and nongenetic variation based on dietary changes during the production period and the physiological relevance across the hen lifespan. In consistent follow-up to the previous work and based on prior results we aim to provide more information about host-microbiota interactions by considering an additional level of the genotype-phenotype map here - the epigenetic regulation - and by addressing the role of different gut cell types. In view of the findings of the first funding period, the new project will in particular investigate the influence of epigenetic modifications in the transition period before and after the start of laying - also with the help of a new animal experiment. Narrowing the window of the transition period from pullet to laying hen of different strains of laying hens will provide deeper molecular insights into the inositol phosphate metabolic system. In addition, complete removal of mineral P from the feed and MI-supplements may promote changes not only at physiological but also at molecular levels. Single-cell transcript levels which provide a clearer picture to identify intestinal cell types in complex populations of heterogeneous intestinal tissues will be added.

The objective of this project is not only to provide a methodological platform for integrating data from other projects of the proposed Research Unit but also adding additional levels of regulation as well as deeper insight into cell levels for analysing host genome–microbiome network associations in hens. Integration of these data will enable us to test the following three hypotheses:
1. Epigenetic mechanisms mediate much of the interplay between the host and the gut microbiota at the background of different strains, diets and production periods. Systems biology and innovative data integration can provide insights into the molecular changes of host- microbiota interaction based on dietary change during the production period and their physiological relevance across the hen lifespan.
2. The cell composition of the gut differs between laying strains, reflecting the different cell subpopulations and their various functions, including nutrient uptake, microbial defense, and endocrine function. Single-cell expression survey of gut cells reflects the specific cellular activity affecting P utilization and metabolism between the laying strains.
3. The host-microbiome biological networks are modified due to the diet (myo-inositol supplementation and avoidance of mineral P supplementation) and genetic/epigenetic background of the laying hens.