Zinc

Functions
The element zinc is essential for plants, animals, and humans. It activates several enzymes and is a component of many important metallo-enzymes. Zinc is the most abundant intracellular trace mineral in animals and total body zinc content approaches that of iron. The element is critically involved in cell replication and in the development of cartilage and bone. Signs of zinc deficiency in animals and humans include retarded growth, abnormal skeletal formation, delayed sexual development, alopecia, dermatitis, abnormal feathering, and impaired reproduction in both males and females. Fetal abnormalities occur and hatchability of eggs is reduced.
Many animal diets require supplementation with zinc because of either low dietary levels or the presence of dietary factors that decrease bioavailability of the mineral (e.g. phytic acid). Zinc is primarily absorbed from the small intestine.
Zinc is supplemented in diets for all species of livestock in the range of 30 to 250 ppm to cover their requirements. The supplementation rate of zinc for poultry is mostly lowest, while this is highest for pigs.

Main sources

Zink oxide

Zink sulphate monohydrate

Quality and selection  parameters
Both zinc oxide and zinc sulphate ensure an excellent bioavailability of the supplied zinc source.The high bioavailability of both zinc compounds is well documented in the literature and an overview is presented in the EMFEMA Bioavailability Guide. The zinc bioavailabilities for zinc oxide and zinc sulphate show no meaningful differences in pigs and ruminants, in poultry however, some studies showed an equal availability for zinc oxide, while other studies showed a reduced availability compared to zinc sulphate. The scientific committee concluded that the relative zinc bioavailability for zinc oxide compared to zinc sulphate in poultry depended heavily on the processing method, origin, texture and Zn content of the zinc oxide.

Analytical methods

Zinc content

- EDTA tritration