Vitamins are one of the most important additives in modern feed industry. The usage of complete vitamin premix along with minerals and other feed additives has been long discussed due to the loss of potency of various vitamins added. Vitamin losses are mainly attributed to shelf life and mixture composition.
Generally these types of complete premixes added to feed at lower levels will show higher vitamin losses, since they have a higher concentration of trace elements (catalytic effect). The detail of vitamin stability in feed containing mineral is given in table1. This also applied to 0.5% to 1% premixes, if they do not contain any choline chloride.
Table1: Vitamin stability in feed containing minerals.
Vitamin retention after storage (%)

	2 Months	4 Months
Vitamin A (cross-linked)	95	90
Vitamin A (not cross-linked)	60	35
Vitamin D3	95	90
Vitamin E adsorbate	90	85
Vitamin K3 (MNB)	80	70
Vitamin B1 (mono)	80	70
Vitamin B2	85	80
Vitamin B6	80	75
Vitamin B12	85	80
Biotin	90	85
Folic Acid	80	75
Niacin	95	95
Vitamin C coated	60	30
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Most of the vitamins are also stable within a certain pH range since most of then are around neutral point (pH 6-8). Vitamins B1 and B6 differ slightly as they prefer acidic conditions (pH3-5). When the pH is highly alkaline then one finds major losses of Vitamin E (can be found with high levels of manganese oxide pH11). Hence a more stable or coated form of vitamin E source is to be sued while using manganese oxide more than 8-10%.
Choline chloride in addition to being highly hygroscopic also has a adverse effect on vitamins e.g., K3, B1, B6, C and folic acid when added at levels of more than 5%. In such cases shelf life of premixes to be not more than 4 weeks.
On two months storage of mixed feed, minor losses of below 5% of most vitamins are registered with the exception of Vitamin K3 (MSB) with 20% degradation and vitamin C with 40% degradation. In pelleted, expanded and extruded feeds, vitamin losses depend on temperature and duration of processing and may be much higher. Retention levels are demonstrated in Tables 2 to 4.
Table2: Vitamin retention if pelleted mixed feeds
Vitamin retention after 2 months storage (%)

	2 months
Vitamin A (cross-linked)	90
Vitamin A (not cross-linked)	65
Vitamin D3	90
Vitamin E adsorbate	95
Vitamin K3 (MNB)	75
Vitamin B1 (mono)	90
Vitamin B2	95
Vitamin B6	85
Vitamin B12	80
Biotin	95
Folic Acid	80
Niacin	95
Vitamin C coated	95
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Table3: Vitamin retention after expansion
Vitamin retention after 2 months storage (%)

Vitamin A (cross-linked)	85
Vitamin A (not cross-linked)	30
Vitamin D3	90
Vitamin E adsorbate	90
Vitamin K3 (MNB)	20
Vitamin B1 (mono)	90
Vitamin B2	95
Vitamin B6	95
Vitamin B12	90
Biotin	95
Folic Acid	80
Niacin	95
Vitamin C	15
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Vitamin Product forms and Stabilizing methods
Product forms for different vitamins vary considerably depending on the type of mixture and treatment processes meted our to them. Losses of vitamin C pure during extrusion can go as high as 90-100% whereas its phosphate form does not deteriorate at all. Stabilizing technology is another important factor to be considered. Vitamin A stability is highly dependant on whether it is cross-linked or not. The cross linking of Vitamin A is done to render them insoluble in water and these are highly stable (compared to non cross-linked) in premixes, mineral premixes and mixed feed as well.
Table4: Vitamin retention after extrusion
Vitamin retention (%)

	After extrusion	After 1 month	After 3 months
Vitamin A (cross-linked)	95	90	80
Vitamin A (not cross-linked)	85	50	25
Vitamin D3	95	90	85
Vitamin E adsorbate	95	90	80
Vitamin K3 (MNB)	25	20	20
Vitamin B1 (mono)	95	90	85
Vitamin B2	95	90	90
Vitamin B6	95	90	85
Vitamin B12	80	80	80
Biotin	100	95	95
Folic Acid	95	90	85
Niacin	100	95	95
Vitamin C	10	5	0
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