Degradation kinetics of vitamins in premixes for pig: effects of choline, high concentrations of copper and zinc, and storage time

OBJECTIVE: The present work was undertaken to evaluate the effects of storage time, choline chloride, and high concentrations of Cu and Zn on the kinetic behavior of vitamin degradation during storage in two vitamin premixes and four vitamin-trace mineral (VTM) premixes. METHODS: Two vitamin premixes (with or without 160,000 mg/kg of choline) were stored at 25°C and 60% humidity. Besides, four VTM premixes were used to evaluate the effects of choline (0 vs 40,000 mg/kg) and trace minerals (low CuSO(4)+ZnO vs high CuSO(4)+ZnO) on vitamin stability in VTM premixes stored in room, and the VTM premixes were stored in room temperature at 22°C. Subsamples from each vitamin and VTM premix were collected at 0, 1, 2, 3, 6, and 12 months. The retention of vitamin A (VA), vitamin D(3) (VD(3)), vitamin E (VE), vitamin K(3) (VK(3)), vitamin B(1) (VB(1)), vitamin B(2) (VB(2)), vitamin B(3) (VB(3)), vitamin B(5) (VB(5)), and vitamin B(6) (VB(6)) in vitamin premixes and VTM premixes during storage was determined. The stability of vitamins in vitamin premixes and VTM premixes was determined and reported as the residual vitamin activity (% of initial) at each sampling point. RESULTS: The effect of choline on VK(3) retention was significant in vitamin premixes (p<0.05). The negative effect of storage time was significant for the retentions of VD(3), VK(3), VB(1), VB(2), VB(5), and VB(6) in vitamin premix (p<0.05). For VTM premixes, negative effect of storage time was significant (p<0.05) for the losses of vitamin in VTM premixes. Choline and high concentrations of Cu and Zn significantly increased VA, VK(3), VB(1), and VB(2) loss during storage (p<0.05). The supplementation of high concentrations of Cu and Zn significantly decreased the concentrations of VD(3) and VB(6) (p<0.05) in VTM premixes at extended storage time. CONCLUSION: The maximum vitamin stability was detected in vitamin and VTM premixes containing no choline or excess Cu and Zn. The results indicated that extended storage time increased degradation of vitamin in vitamin or VTM premixes. These results may provide useful information for vitamin and VTM premixes to improve the knowledge of vitamin in terms of its stability.