The present invention relates to a method for providing an animal populationhaving an essentially identical metabolome comprising compiling an animalpopulation being of essentially the same age, keeping said animal populationfor a time period sufficient for acclimatization under the following housingconditions: (i) constant temperature, (ii) constant humidity, (iii) physicalseparation of the animals of the animal population, (iv) feeding ad libitum,wherein the food to be fed is essentially free of chemical or micro- bialcontaminance, (v) drinking libitum, wherein the drinking liquid is essentiallyfree of chemical or microbial contaminance, (vi) constant illumination period,and providing the animal population after said time period. Further, thepresent invention relates to methods for the identification of a compoundwhich effects the metabolome of an animal, or methods for the identificationof a marker for such compounds. Moreover, the present invention encompassesmethods for the identification of such compounds or markers thereof comprisingmetabolically analyzing a sample from at least one animal of an animalpopulation.
