What are zinc oxide and zinc sulphate?
Zinc oxide is a white to yellowish-white, water-insoluble powder. Pure ZnO contains about 80% zinc; feed-grade products are typically sold at around 72–80% Zn depending on the production route and raw material.
Zinc sulphate is a water-soluble salt. In feed it is mostly used as the monohydrate (ZnSO₄·H₂O, about 35% Zn), a free-flowing white powder; the heptahydrate (about 22% Zn) is less common because its higher water content makes it prone to caking. Both forms are standard ingredients of trace mineral premixes worldwide.
What does zinc do in animal feed?
- Enzymes and metabolism: zinc is a component or activator of hundreds of enzymes involved in protein, carbohydrate and nucleic acid metabolism.
- Skin, hooves and feathers: zinc supports keratin formation; deficiency is associated with parakeratosis in pigs, poor feathering in poultry and weaker hoof horn in cattle.
- Immunity: adequate zinc supports normal immune function and epithelial barrier integrity.
- Growth and appetite: zinc deficiency quickly reduces feed intake and growth in young animals.
- Reproduction: zinc is involved in sperm production, foetal development and normal fertility.
Zinc oxide or zinc sulphate?
Zinc sulphate is water-soluble and is generally regarded as having higher relative bioavailability than zinc oxide. Zinc oxide offers a higher zinc concentration, takes up less space in the premix, is not hygroscopic and is less reactive with vitamins, which is why it is widely used in premixes. The bioavailability of zinc oxide can vary between products depending on how it is made.
Organic sources such as zinc chelates and zinc proteinates are a further option where higher availability per unit of zinc is sought. Many formulations combine sources to balance cost, stability and availability.
How is the zinc requirement assessed?
Zinc requirements depend on species, age, production level and diet composition. Phytate in plant-based diets binds zinc and reduces its absorption, and high dietary calcium can worsen this effect in pigs and poultry; phytase use improves zinc availability. Because raw-material zinc is variable and partly unavailable, nutritionists usually add a defined amount of supplemental zinc through the premix rather than relying on raw materials.
Maximum total zinc levels in complete feed are regulated in many countries. In the EU, the use of high, pharmacological doses of zinc oxide in piglet feed was phased out in 2022. Local regulations and the product label always prevail.
Quality criteria
- Guaranteed zinc content, verified by analysis.
- Undesirable substances: lead, cadmium and arsenic, and dioxins for zinc oxide, especially when the raw material comes from recycled sources.
- Particle size and flowability for even distribution in the premix; dustiness for safe handling.
- Moisture and caking tendency, particularly for zinc sulphate.
- Certificate of analysis (CoA) and lot traceability.
CTF Premix and zinc oxide / zinc sulphate
Zinc oxide and zinc sulphate can be included in CTF Premix's mineral and vitamin-mineral premixes according to the customer's formulation, with the zinc source and level chosen together with our technical team for the target species. Premixes are produced at our Ankara facility under ISO 9001:2015 and GMP, and every lot has a certificate of analysis and lot traceability.
This page is for general information. Inclusion rates and product choice should be decided with a nutritionist, taking into account the species, the feed formulation and the applicable regulations.