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Research r...FinishersTrial report 780

Trial report 780: Vitamin D3 sources

- 25-hydroxy vitamin D3 as an alternative to the traditional vitamin D3 source

Vitamin D3 is added to pig feed in the form of cholecalciferol. For the pig to be able to utilize this form of vitamin D3, it must be transformed into 25-hydroxy vitamin D3 (HYD) via the liver. The addition of HYD will save the pig one step in the transformation process from vitamin D3 to HYD in the liver. HYD is the form of vitamin D3 that has the greatest biological value to the pig. The standard for vitamin D3 to pigs is stated in international units (i.u.) per FUgp, but can also be converted into microgram: 40 i.u. vitamin D3 equals 1 µg vitamin D3. In Denmark, the allowed maximum addition per kg complete pig diet is 2000 i.u. (=50 µg) total vitamin D3. The sum of these two vitamin D3 sources is called total vitamin D3.

In this trial, the effect of using vitamin D3 in the form of HYD on the production results in the period from weaning until slaughter was investigated. The dosage of total vitamin D3 in the feed in this trial was above the Danish standard [1]. The feed was formulated to contain the same amount of total vitamin D3 in the three groups:

  • Group 1: Vitamin D3 source - 100% vitamin D3
  • Group 2: Vitamin D3 source -  50% vitamin D3 & 50% HYD
  • Group 3: Vitamin D3 source - 100% HYD

Overall, the trial revealed no differences in production value or health for neither weaners nor finishers regardless of the vitamin D3 source added.


The highest content of total vitamin D3 in the blood was found among the pigs given 50% vitamin D3 and 50% HYD and that were actually given the highest dosage of total vitamin D3. The pigs given 100% HYD were actually given the lowest dosage of vitamin D3 when the analysed content was converted into content of total vitamin D3.


The highest bone strength was found among the pigs given 100% vitamin D3. The differences in bone strength between the three groups were so small that they did not influence the well-being of the pigs.


Updated: 20.02.2007


Hanne Maribo

Chief scientist, PhD

Tel.: +45 3339 4390