Zinc transferrin stimulates red blood cell formation in the head kidney of common carp (Cyprinus carpio).

The common carp is one of the few fish able to tolerate extremely low oxygen levels. These fish store zinc in their digestive tract tissue and head kidney at concentrations of 300-500μg/g of fresh tissue, which is 5-10 times higher than in other fish. Previous studies have indicated a link between the high zinc levels in the common carp and stress erythropoiesis.