Cows get through on average 18 kilograms of feed per day. However, in order to be able to absorb the nutrients from this quantity of feed, the animals need the help of millions of widely varying and highly specialised bacteria
that colonise the stomachs and digestive tract. A research cooperation arrangement of scientists from the fields of animal nutrition and microbiology at the University of Hohenheim in Stuttgart is examining how the bacteria succeed in detaching valuable nutrients from the resistant plant mass. The study is focusing on the bacterium Prevotella spp., which accounts for up to 40 per cent of the bacteria in the rumen. The German Research Foundation (Deutsche Forschungsgemeinschaft – DFG) is funding the overall project with altogether € 450000. This makes it one of the research heavyweights at the University of Hohenheim.
Ruminants such as cattle have to obtain starch, protein, vitamins and minerals from plant nutrition. In order for them to be able to do this, highly specialised bacteria work at full speed in the rumen, the largest of the cow stomachs. ”The special achievement of the cow here is to obtain protein from solely vegetable diets“, explains the microbiologist and animal nutrition expert Junior Professor Dr. Jana Seifert.
Junior Professor Dr. Seifert and her colleague Professor Dr. Julia Fritz-Steuber assume that the bacterium Prevotella plays an important part in this process. ”As Prevotella accounts for a large share of the bacteria in the rumen, we assume that it also plays an important role in feed conversion. However, we do not yet know exactly how Prevotella obtains its energy from the feed“, explains Professor Fritz-Steuber, summarising the goal of the project.
The two microbiologists in the cross-faculty project are together investigating what substances the bacterium breaks down and what protein substances it forms from this. ”To do this we offer the bacterium different substances and watch which ones it takes up“, explains Professor Fritz-Steuber.
Junior Professor Seifert develops the findings from Professor Fritz-Steuber’s experiments further. However, she leaves the Prevotella bacterium in the rumen fluid. ”After all, we want to take into account what influence the other rumen fluid components have on the Prevotella activity.“
In a further step, Junior Professor Seifert comes even closer to the reality in the cow stomach. She repeats the feeding test in a mechanical model of the rumen. The model simulates the rumen movements that ensure that the stomach contents are constantly mixed by regular contraction of various muscles.