What is diatomaceous earth?
Diatoms are single-celled algae that build intricate shells (frustules) of hydrated silica. Over geological time, these shells accumulated on lake and sea floors and formed diatomite deposits. The resulting material is light, highly porous and has a large surface area, so it can absorb several times its own weight in liquid.
Its main component is amorphous (non-crystalline) silica, with variable amounts of clay, carbonates and other minerals depending on the deposit.
What does it do in animal feed?
In feed, diatomaceous earth is used for its physical properties. It is essentially inert and does not supply meaningful nutrients.
- Anti-caking and flow agent: keeps powdered feeds, salts, mineral mixes and premixes free-flowing.
- Absorbent carrier: its porosity allows liquid ingredients to be absorbed and handled as a dry powder.
- Stored-grain protection: in storage, finely ground diatomaceous earth can damage the waxy outer layer of insects, so it is used as a physical grain protectant where permitted.
- Other claims: it is sometimes promoted for internal parasite control in livestock, but scientific evidence for this is limited and inconsistent, so such claims should be treated with caution.
Natural, calcined and flux-calcined forms
Diatomite is processed in different ways for different markets. Natural (uncalcined) diatomite is dried and milled and keeps its silica mainly in amorphous form. Calcined and flux-calcined grades, made by heating at high temperature (with a flux in the latter case), are used largely in industrial filtration; heating can convert part of the amorphous silica into crystalline silica (cristobalite).
Respirable crystalline silica is a recognised occupational inhalation hazard. For feed use, natural grades with low crystalline silica content and appropriate dust control are generally preferred, and the grade should be specified as suitable for feed.
How is inclusion assessed?
There is no nutritional requirement for diatomaceous earth. Its level is chosen according to the technological purpose: enough to keep a product free-flowing or to carry a given amount of liquid. It adds ash to the diet without adding nutrients, so it is kept to what the function requires. Use must follow the conditions set by feed legislation for the authorised product; local regulations and the product label always prevail.
Quality criteria for feed-grade diatomite
- Grade and silica form: feed-suitable grade, with crystalline silica (quartz, cristobalite) content specified and kept low.
- Purity: content of accompanying minerals and insolubles.
- Heavy metals and dioxins: within the undesirable-substance limits of feed legislation.
- Absorption capacity, particle size and bulk density: determine performance as a carrier and flow agent.
- Moisture and dust: affect storage stability and safe handling.
- Traceability: a certificate of analysis (CoA) and lot number for every batch.
CTF Premix and diatomaceous earth
CTF Premix produces montmorillonite-based toxin binders and feed-grade bentonite at its 10,000 m² facility in Ankara under ISO 9001:2015 and GMP. Requests involving diatomaceous earth, for example as a flow agent or carrier in a mineral-based product, are evaluated by our technical team according to the intended use. Every lot is traceable, and its certificate of analysis can be viewed on the batch verification page.
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.