What is vitamin K3?
Vitamin K is a group of naphthoquinones. Phylloquinone (K1) occurs in green plants and menaquinones (K2) are made by bacteria, including those in the digestive tract. Menadione (K3) has the same ring structure but no side chain; animals convert it in their tissues into menaquinone-4, the active form.
Pure menadione is poorly stable and irritating, so the feed industry uses its bisulfite addition compounds. These are crystalline, water-soluble and easier to standardise, and the label states the menadione equivalent so that different products can be compared.
What does vitamin K do in animal feed?
- Blood clotting: vitamin K is required to activate prothrombin and several other clotting factors in the liver; deficiency leads to prolonged clotting time and haemorrhages.
- Bone: it activates bone proteins such as osteocalcin, which are involved in bone mineralisation.
- Poultry: birds are the most sensitive species because of a short digestive tract and limited use of microbially produced vitamin K; signs include bruising and bleeding in muscles.
- Pigs: supplementation is standard, particularly where mouldy feed or certain antimicrobials may reduce microbial vitamin K supply.
- Ruminants: rumen microbes normally produce enough vitamin K; problems are linked mainly to antagonists such as dicoumarol in mouldy sweet clover.
MSB and MNB: the two main grades
- Menadione sodium bisulfite (MSB): the most widely used and most economical form. Commercial MSB contains at least about 50% menadione. It is available as a plain crystalline powder and as coated or stabilised grades with better resistance in premixes.
- Menadione nicotinamide bisulfite (MNB): menadione bound with nicotinamide, containing at least about 43–44% menadione. It is generally regarded as more stable than plain MSB and also supplies some nicotinamide (niacin activity).
- Both are white to slightly yellow crystalline powders. A third form, menadione dimethylpyrimidinol bisulfite (MPB, roughly 45% menadione), is permitted in some markets but is much less common; the current EU authorisation covers MSB and MNB only, and local regulations prevail.
Converting doses between MSB and MNB
Vitamin K3 levels in formulations are set as menadione, not as product weight. To convert, divide the menadione target by the menadione content of the specific lot shown on its certificate of analysis.
Example: to supply 2 g of menadione, about 4.0 g of MSB at 50% menadione is needed, or about 4.5 g of MNB at 44%. Mixing up product weight and menadione basis is a common source of under- or over-supply, so specifications should always state the basis. Levels themselves are set by a nutritionist according to species, age and risk factors; local regulations and the product label prevail.
Stability and quality criteria
- Menadione assay on the stated basis, confirmed by a certificate of analysis (CoA) for each lot.
- Moisture and heat sensitivity: vitamin K3 is among the less stable vitamins in premixes and during pelleting; coated grades and MNB are chosen when stability is critical.
- Interaction with choline chloride, trace mineral salts and alkaline conditions, which accelerate losses in concentrated premixes.
- Particle size and flowability for even distribution at low inclusion.
- User safety: the dust can irritate the skin, eyes and airways, so dust control and personal protective equipment are used during handling.
CTF Premix and vitamin K3
Vitamin K3 as MSB or MNB can be included in CTF Premix's vitamin, vitamin-mineral and custom premixes according to the customer's formulation, with the level declared as menadione. Choice of grade, carrier and the separation of sensitive vitamins from choline and trace minerals are considered for stability. Production takes place at our Ankara facility under ISO 9001:2015 and GMP, with a certificate of analysis and lot traceability for every batch.
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.