## 4 Discussion
### Plasma Kinetic Behavior of Different Forms of Vitamin E  
In the current study, two treatment groups also displayed typical pharmacokinetic profiles for vitamin E. Plasma vitamin E (\(\alpha\)-tocopherol) concentrations peaked at approximately 12 h after administration. After this peak, the plasma concentration of \(\alpha\)-tocopherol decreased gradually and was followed by a typical appearance-elimination profile. The slow appearance of the peak value was likely the result of the digestion process of the diet and absorption from the chrome through the lymph, which is consistent with published literature on vitamin E absorption [12; 24]. The half-lives of the elimination rates for the two forms of vitamin E were compared with those of humans. Half-lives of vitamin E around 13 to 48 h [25] or even longer [26] are common. Because synthetic vitamin E (D, L-\(\alpha\)-tocopherol) features a combination of stereoisomers, the stereoisomers of \(\alpha\)-tocopherol have various biological activities (from 21% to 100%) [27]. Further, vitamin E absorption is similar to fat metabolism, but its uptake in the small intestine can be enhanced by simultaneous fat consumption. In addition, [PERSON] et al. observed that human plasma \(\alpha\)-tocopherol reached its maximum concentrations at 12 h [28], which is similar to our results. This similarity in kinetics may indicate a parallel between pigs and humans related to the morphological functions of the gut.  
Both the AUC and C\({}_{\text{max}}\) values of the microencapsulated vitamin E were markedly higher than those of the non-microencapsulated vitamin E. This study demonstrates that microencapsulated vitamin E has a dramatic and rapid effect in increasing the \(\alpha\)-tocopherol mass in plasma. In an initial 3 h experiment, the plasma concentration-time profiles of vitamin E in both groups were similar. However, at approximately 12 h, both groups reached their respective maximum concentrations of \(\alpha\)-tocopherol. [PERSON] et al. revealed the relationship between vitamin E concentration in the pig diet and blood vitamin E concentrations [29]. This dose-response relationship shows that the vitamin E level in the diet is the main factor that modulates blood \(\alpha\)-tocopherol concentrations; over 95%of the maximal blood \(\alpha\)-tocopherol concentration is reached when the dietary dosage is 30 mg/kg. In the present study, oral administration of a dietary dose of 30 mg/kg microencapsulated vitamin E efficiently increased vitamin E bioavailability compared to the same dose of non-microencapsulated vitamin E. Cross-linked or matrix materials are essential factors in controlling the release of vitamins. Many candidates for microencapsulation, such as polysaccharides (alginate xanthan gum and chitosan), proteins (whey protein and gelatin), and lipids (milk fat and hydrogenated fat), have been used to encapsulate vitamins to protect those vitamins during storage and promote effective delivery to the gut. The microencapsulated vitamin used in this study was coated with hydrogenated fat via the spray-drying technique. A previous study reported the slow release of the vitamin in the digestion process when encapsulating the vitamin with hydrogenated fat [30], As well as high stability during storage and processing [4; 5]. According to these authors, solid lipid-based vitamin E is more susceptible to enzymatic digestion and breakdown.