Ethical Guidelines for Animal Experimentation

The University of Bremen and its researchers are committed to the so-called 3 Rs principle, which provides the ethical framework for planning and conducting research involving animal experiments and is also the basis of the German Animal Welfare Act. The 3 Rs stand for:

Avoidance of animal experiments by using alternative methods.

Wherever possible, research topics are investigated using methods that do not involve animal experiments. In order to avoid animal experiments, alternative methods are always used if they are available, and work is carried out on the development of alternative methods if they are not yet available but appear to be achievable in principle. The German Animal Welfare Act, which regulates the legal framework for the execution of animal experiments, only allows animal experiments to be carried out if the scientific issue raised cannot be investigated by non-animal methods.

It is important to note that alternative methods are also always the result of scientific research. Suitable alternative methods often allow research questions to be investigated more quickly and with less effort and, for a variety of reasons, are also preferred by the scientific community to methods based on animal experiments. However, they are only preferred if they are actually suitable for the investigation of a scientific question. This is the case in some areas of biomedical research: today, for example, vaccines can essentially be produced with the aid of suitable equipment and procedures, whereas in the past animals had to be used for this purpose. However, incomprehensible physiological processes, such as the effect of a new type of vaccine in the body and the investigation of possible side effects, cannot be simulated on a computer, but depend on suitable animal models. Research into organ systems and how they interact with each other is also not possible without suitable animal models.

Reduction of the number of animals used for animal experiments.

If the research of a scientific question absolutely requires the use of animal experimental methods, the number of animals used for this purpose must be limited to the indispensable minimum. For this purpose, biometric methods are used, for example, with which the number of animals to be used can be calculated or estimated in advance in order to be able to statistically safeguard the issue to be investigated. This avoids using more animals than necessary.

Improvement of husbandry and experimental methods in order to limit the stress on the animals to the indispensable minimum.

The animal experimental methods and procedures used for researching scientific questions are in constant development. This also includes the objective of counteracting the stress on animals associated with the application of a particular method. Such methodological improvements relate to all levels of handling of the experimental animals. They start with the housing conditions of the animals, include training programs that, for example, allow blood sampling with the cooperation of the animal and thus reduce the stress associated with this, and include the concrete experimental methods that are improved in such a way that they minimize the stress associated with them. Refinement approaches may also aim to extract more knowledge from the data obtained, for example, by using novel data analysis approaches or complex statistical methods. Thus, they can also directly serve to reduce animal testing.

The measures to be taken into account within the framework of the 3 Rs principle are the subject of applications for animal experiments and are examined in detail when animal experiment applications are approved.

General Facts and Figures on Animal Testing

Despite an increase in spending on scientific research, the number of animal experiments has steadily decreased in Germany over the last 10 years. In 2020, a total of 2.5 million animals were used for biomedical research. About 80 percent of these were mice and rats, and another 10 percent or so were fish. The remaining 10 percent was distributed among various other animal species. About 0.1 percent of all laboratory animals are monkeys and prosimians (though not great apes).

Converted, this means that for each person living in Germany, about 2 mice and rats, 0.2 fish, and 0.2 other animals are used for the entirety of biomedical and veterinary research, for the development and testing of new drugs, and for all other purposes during a lifetime of 80 years. Approximately 70 percent of experiments are considered to be mildly stressful at most and about 25 percent of experiments are considered to be moderately stressful. Only 4 percent of all animal experiments conducted in Germany are considered severely stressful. These are mostly experiments that serve the specific research of a severe clinical picture and therefore require the replication of this disease in an animal model. About 6 percent of all experiments are carried out under general anesthesia without the animal waking up from the anesthesia afterwards.

At the University of Bremen, a very small number of animal experiments are performed on mice, rats, rhesus monkeys (macaques), and frogs overall (detailed information on the experiments can be found on the respective subpages). None of the various research projects presents more than a moderate level of stress at most. A medium-grade burden results in the domestic animal sector, for example, in the course of a sterilization operation.

More detailed information on the number of animal experiments carried out in Germany, the purpose of the animal experiments, and the degree of exposure can be found on the pages of the Federal Ministry of Food and Agriculture (BMEL), to which all the facts in this regard are sent by the local licensing authorities. An evaluation of laboratory animal numbers according to federal states is available at

Housing Standards

An important factor for the welfare of animals is their appropriate housing in modern animal facilities. The requirements for animal husbandry are specified in the relevant European Directive (EU 2010/63) for each animal species and are binding for legislation in the member states of the European Union. Beyond these requirements, the animal facilities at the University of Bremen have extensive, so-called Environmental Enrichment (enrichment of the living environment by species-specific activity material) to support the well-being of the animals. In addition, all animals are examined daily by expert staff with regard to their behavior and health.

The husbandries and laboratories at the University of Bremen are regularly inspected by the responsible authority. All factors related to the legal requirements are subject to control, e.g. proof that the animals are obtained from approved sources, proof that cleaning and hygiene procedures are carried out, control of animal husbandry including all aspects of husbandry (air exchange, temperature, light, noise level, activity opportunities, etc.), official inspection of the animals, proof of animal health, specific experimental procedures, etc.

Animal Welfare Officer and Animal Welfare Committee

Every public and private institution in Germany where researchers are allowed to conduct animal experiments is legally obliged to appoint an Animal Welfare Officer and an Animal Welfare Committee.

The Animal Welfare Officer (TSchB) advises the researchers conducting animal experiments on all issues concerning animal welfare and animal health. The person is involved in the planning and execution of the animal experimental studies carried out and has a controlling function in the execution of the experiments and the keeping of the animals. They are also the contact person for official inquiries and communication.

The Animal Welfare Officer is supported by the Animal Welfare Committee. The Animal Welfare Committee consists of five scientific and technical staff members from the field of animal experimental research at the University of Bremen - one person is the Animal Welfare Officer.

The Animal Welfare Committee regularly organizes training events for staff members working in the field of animal experimentation - for example, on questions of new (veterinary) medical findings in the performance of anesthesia or further possibilities for the implementation of the 3 Rs principles (Replacement, Reduction, Refinement).