Animal by-products that are processed into pet food belong to so-called category 3. The components have been inspected by a veterinarian and legally do not pose any risk to the health of four-legged friends. They are therefore basically harmless.
However, inferior animal by-products do not have much nutritional value and can also cause minor problems such as digestive irregularities. Apart from possible deficiency symptoms, there are no known diseases that are caused by these components – on the contrary, high-quality by-products such as offal can definitely help the animals' health.