Where does the activity of garlic come from?
Intact garlic cloves contain alliin, an odourless sulfur amino acid, and the enzyme alliinase in separate compartments. When the clove is crushed or cut, the enzyme converts alliin into allicin, the compound responsible for the sharp smell of fresh garlic.
Allicin is highly unstable. Within hours to days, and faster with heat, it transforms into other sulfur compounds such as diallyl sulfide, diallyl disulfide and diallyl trisulfide (the main components of garlic oil), and ajoene and vinyldithiins. This chemistry is the key to understanding garlic products: what a product contains depends strongly on how it was processed and stored.
Forms of garlic used in feed
- Dried garlic powder: preserves alliin and alliinase, so it is often characterised by its "allicin potential", the allicin that can form when the powder is wetted.
- Garlic oil: obtained by steam distillation; contains mainly allyl sulfides rather than allicin.
- Extracts: standardised on a defined marker compound or total sulfur compounds.
- Encapsulated and blended products: protected forms that improve stability during storage and pelleting, often combined with other plant extracts in phytogenic blends.
What does it do in animal feed?
Garlic is first of all a strong flavouring. Beyond that, research has looked at garlic and its sulfur compounds for several effects. Results vary with the product, dose and conditions, so they should be described with care.
- Poultry and pigs: studied for supporting gut health, influencing gut microbiota and antioxidant status, and for effects on growth performance; responses are not consistent across studies.
- Ruminants: garlic oil and its compounds have been investigated, mostly in laboratory studies, for effects on rumen fermentation and methane production.
- Palatability: the strong odour can improve or reduce feed intake depending on species and dose.
- Product taint: at high levels, garlic flavour may carry over into milk or eggs.
Regulatory status and claims
In many markets garlic preparations are regulated mainly as flavourings. In Canada, for example, garlic is accepted in livestock feed as a flavouring ingredient, and claims such as insect repellence are not acceptable feed claims. Garlic should not be presented as a replacement for antibiotics or as a treatment for disease. The permitted category, label wording and inclusion depend on local regulations and the product label, which always prevail.
Quality criteria
- Standardisation: declared content of allicin potential, allyl sulfides or total sulfur compounds, with the analytical method stated.
- Stability: protection against heat, oxygen and moisture; data on stability in premixes and during pelleting.
- Identity and origin: botanical identity and processing method (powder, oil, extract).
- Contaminants: microbiology, mycotoxins, heavy metals and, for extracts, solvent residues within feed limits.
- Traceability: a certificate of analysis (CoA) and lot number for every batch.
CTF Premix and garlic
Garlic-based phytogenic ingredients can be evaluated for inclusion in CTF Premix's custom premixes on request, taking into account the target species, the regulations of the destination market and the stability of the chosen form. Premixes are produced at our 10,000 m² facility in Ankara under ISO 9001:2015 and GMP with lot traceability, and each lot's 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.