The ingestion, digestion and absorption of food serves to supply the body with nutrients that drive vital processes in the body as a source of energy and serve as building materials for body substance. Furthermore, the composition of the ingested food influences the intermediary metabolism and hormone balance, as well as the environment via the excretion of metabolic end products.
In our working group “Gastrointestinal Physiology” we deal with the influences of the diet on growth, health and metabolism of animals, the mechanisms of digestion and absorption, as well as the excretion of nutrients and their effects on metabolic processes.
We especially focus on the microbial digestion of food in the forestomach system, the reduction of nitrogen and methane emissions by ruminants as well as the influence of dietary factors (nitrogen, calcium or phosphorus) on the growth of young ruminants.
Melanie Brede, PhD
Main focus: Microbial fermentation in the forestomach of ruminants
Ruminants are characterized by a forestomach system, in which plant food can be efficiently degraded with the help of bacteria, protozoa and fungi and thus broken down into substrates usable by the ruminant. The community of microorganisms in the rumen is a highly complex system that is influenced by both diet and genetics of the host animal and is also related to its productivity. Using the so-called Rumen Simulation Technique, an in vitro apparatus for investigations on rumen metabolism, we investigate the influence of different feeds or feed additives on rumen fermentation and the composition of the rumen microbiota. In addition, the effects of different physiological and pathological conditions on classical fermentation parameters and the microbial community are investigated. For this purpose, for example, a model for the generation of subacute ruminal acidosis was established and characterized in the RUSITEC system. Furthermore, we study e.g. approaches to reduce methane emissions and to improve fiber degradation in biogas plants. For detailed analysis of the rumen microbiome and metabolome, we collaborate with research groups with sequencing facilities and with metabolomics facilities.
Link Article TiHo Anzeiger (02/2019): Die klimafreundliche Kuh?
Dr. rer. nat. Alexandra Muscher-Banse
Main focus: Effect of nitrogen reduction on vitamin D metabolism in growing goats
Nitrogen (N)-reduced feeding of ruminants is desirable in terms of resource conservation as well as environmental and climate protection. Due to the ruminohepatic cycle, ruminants can adapt metabolism and maintain growth and metabolism in times of reduced N supply. From our own studies on growing goats fed a N-reduced diet, it has been shown that there is a disruption of the somatotropic axis and thus decreased insulin-like growth factor 1 (IGF1) levels. The reason for this disruption is thought to be decreased insulin levels, which inhibit growth hormone receptor expression in the liver. Decreased IGF1 levels modulate, among other things, vitamin D metabolism, in which the central enzyme, 1-α-hydroxylase, is decreased in expression and thus many vitamin D-dependent metabolic processes are inhibited such as intestinal absorption of calcium. The 1-α-hydroxylase ensures the formation of active vitamin D3, calcitriol. Thus, the modulation of calcitriol synthesis in the kidney by an N-reduced diet in growing goats will be characterized. The results of this work will contribute to a better understanding of possible interaction partners as well as their dietary regulability by N in growing ruminants. In addition, these metabolic data will provide information to assess animal health.
Link Article BJN (03/2020): https://pubmed.ncbi.nlm.nih.gov/31775916/