The group “animal physiology” is dealing with neuro-ethological and neuro-endocrinological mechanisms underlying the interactions between animals and their respective environment. Therefore we focus on neuro-ethological and neuro-endocrinological control mechanisms, e.g. the HPA-axis.
These interactions are investigated, for example, using specific learning tests such as the “Step-Down-Avoidance Test” and the “Fear Conditioning Test” combined with subsequent analysis of different stress physiological and neuro-endocrinological parameters. We have established methods to analyze stress hormones (Cortisol and Corticosterone, not their metabolites) in all body fluids (e.g. urine, milk, saliva) and in faeces. The adrenals, which are secreting these stress hormones, often show morphological changes after chronic stress. These changes can be measured using histological methods.
Another topic of our research deals with a brain region of the limbic system, the hippocampus, in which even during adulthood neurogenesis has been observed. This growth of new neurons seems to play an important role for consolidation of long term memory and, additionally, can positively or negatively be influenced by the interaction between organism and environment. In order to test these interactions we investigate the learning performance of layers kept either in enriched or in barren environments. In addition, we test relationships between stress hormones and both learning performance and long term memory.
The group is further investigating the development of bone diseases in laying hens. Reduced bone stability in laying hens is associated with a high prevalence of keel bone damage and fractures, which are painful conditions and important animal welfare problems. In addition, reduced mobility of affected animals can have negative economic consequences. Although no causal links have been established to date, potential associations between keel bone damage and high laying performance are increasingly discussed. To assess whether the high demand of calcium that is needed during eggshell formation affects the formation of the so-called medullary bone and other osseous structures, is one aspect that is investigated within the comprehensive cooperative project AdaptHuhn. To do so, we perform digital radiography in living animals and conduct histological and immunohistological analysis in decalcified and native bones. These analyses are done in cooperation with the Department of Experimental Animal Facilities and Biorisk Management (ATB). Since immune status is influenced by the various endocrine systems, we determine hormone titers using different enzyme-assays and collaborate with the Institute of Immunology (IfI) to assess the immune status of laying hens.