This is the 4978th most frequent Polish word.
pokarmowego
"Pokarmowego" means "of the digestive" or "related to food/nutrition."
In this sentence, "pokarmowy" functions as an adjective describing the type of system ("układ") being referenced, which is related to digestion.
Układ pokarmowy składa się z wielu narządów.
The digestive system consists of many organs.
Here, "pokarmowego" is used in its genitive singular form to describe the diseases affecting the digestive system.
Choroby układu pokarmowego mogą być poważnym problemem.
Diseases of the digestive system can be a serious issue.
The word "pokarmowy" is part of a descriptive phrase indicating the specific type of system (digestive) that varies between the animal types.