“A Systematic Review of the Literature 1975–452020 on Nutritional Research in Cats”, 2022-05-23 ():
The aim of this paper is to compile studies on cat nutrition until 2020 in an overview.
For this purpose, 1,164 literature sources were first systematically selected according to specific criteria, catalogued and assigned to corresponding previously defined topic areas. Then, 491 literature sources were actually considered for the evaluation of this work.
Cats, as an obligate carnivore species, exhibit digestive and nutritional peculiarities.
In nutritional research, the assessment of energy requirements has been of great importance since the mid-1990s. When conducting studies on energy requirements, it seems to be of great importance to have a standardized experimental set-up that uses a uniform methodology and takes into account influencing components such as body constitution, sex, neutering status and age of the cats.
Research on protein requirements is beginning to come into focus about 10 years earlier. The cat can use amino acids for gluconeogenesis immediately after food intake. On the other hand, it has a limited ability to adapt the catabolic metabolism of enzymes in protein metabolism to a low protein diet.
The third major area of interest in cat nutrition has involved research on carbohydrate metabolism since the 1980s. The increasing use of carbohydrates, especially in dry food production, made it necessary to look at digestion, acceptability, and possible side effects for carnivores. For example, the cat exhibits reduced activity of the enzymes responsible for the digestion of carbohydrates. Interestingly, several studies have demonstrated good digestibility, especially of thermally digested carbohydrates. However, the acceptance of a feed with more than 30% carbohydrate content decreases substantially.
Controversial discussions exist with regard to the influence of dry feed administration on nutrition-related diseases. The focus here is on research into the development of obesity and diabetes mellitus. The relationship between dietary phosphate levels and the development of CNE in previously healthy cats or the progression of the disease in affected cats is currently the focus of research.
Interest also increased in the 2000s in studies of other minerals in feeds, as a direct link to diet-related diseases such as FLUTD and CNE could be established. Quite clear are the studies in the fats and vitamins section, which were conducted mainly in the 1980s and 1990s. Here, the results seem to provide little reason for further study designs.
Taken as a whole, the study results compiled here represent the difficulty of authoritative, long-term statements and recommendations on optimal nutrition for the cat. Thus, the recommendations of international associations for individual nutrients are constantly being questioned. For future studies, the focus should be on research and, above all, prevention of nutrition-related diseases. For a better comparability of the study results, a standardization of the study design would be desirable. Despite all the care taken in the development of an ideal feeding regime for the domestic cat, the individual and difficult-to-calculate factor will always be the animal owner, who must be able to implement the corresponding recommendations in the best possible way.