Comparison with human nutrition
There is no doubt that the basic principles are exactly the same between animals and humans. The focus is on finding information on the various nutrients and their role in the body. One major difference between nutrition research on farm animals and humans is in the determination of the food consumed and in the control of lifestyle.
The farm animals have to do whatever the investigator decides. The type and amount of food is pre-determined. If there are any leftovers, these can all be measured. By contrast, humans would rarely submit to the detailed control that is the norm in animal experimentation.
There may be rare occasions when volunteers agree to participate in a specified regime, but usually this is only for a limited period.
Another difference is that the results of animal nutrition are usually put into practice in the real world and are therefore subject to evaluation. This rarely happens in the field of human nutrition. This means that poor quality research results can be accepted as valid for many years and have a major impact on policy.