## 2 Materials and Methods
### Animals, Housing, and Sample Collection
The dietary treatments included the basal diet with the NRC level of vitamins, a diet with 75% the commercial recommendation of vitamins (CRV) level of vitamins, one with a 100% CRV level of vitamins, one with a NRC level of microencapsulated vitamins, one with a 75% CRV level of microencapsulated vitamins, and one with a 100% CRV level of microencapsulated vitamins. The CRV level was chosen based on the vitamin recommendation for pigs provided by the DSM Nutritional Products and Trouw Nutrition company [13; 14]. The six vitamin premixes formulations are presented in Table 2 and were designed to comprise at 0.03% of the diets. All dietary treatments were formulated using similar concentrations of metabolized energy, standardized ileal digestible amino acids (lysine, methionine, threonine, tryptophan, and valine), calcium, standardized total tract digestible phosphorus, and trace minerals (Table 3). These nutrients met the NRC requirement estimates for weaned piglets [15]. The experiment lasted 28 d. The pigs were housed in a nursery pen equipped with a nipple waterer and a 3-hole plastic and metal feeder. Pigs were given ad libitum access to feed and water during the whole trial period. All pigs had their weights recorded at the beginning, middle, and end of the trial. We recorded the amount of feed offered to each pen and the amount of feed left in the feeder. The average daily gain (ADG), average daily feed intake (ADFI), and gain:feed (G:F) ratio were calculated. On day 29 after the pigs has fasted for 12 h, one pig/per pen close to the average group BW was selected to collect a blood sample. All blood samples (collected from Exp. 1 and 2) were allowed to clot at room temperature for 20 min and were centrifuged at 3000\(\times\) g at 4 \({}^{\circ}\)C for 10 min. Plasma subsamples were then removed to new a PE tube, and stored at \(-80\)\({}^{\circ}\)C until the pending vitamin analysis. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Item**} & \multicolumn{2}{c}{**Non-Microencapsulated Vitamins**} & \multicolumn{4}{c}{**Microencapsulated Vitamins**} \\ \cline{2-7}  & **NRC** & **75\% CRV** & **100\% CRV** & **NRC** & **75\% CRV** & **100\% CRV** \\ \hline Vitamin, unit/kg & & & & & & \\ Vitamin A, IU & 5.833,333.33 & 25,000,000.00 & 33,333,333.33 & 5,833,333.33 & 25,000,000.00 & 33,333,333.33 \\ Vitamin D\({}_{3}\), IU & 666,666.67 & 4,500,000.00 & 6,000,000.00 & 66,666.67 & 4,500,000.00 & 6,000,000.00 \\ Vitamin E, IU & 36.67 & 175.00 & 233.33 & 36.67 & 175.00 & 233.33 \\ Vitamin K\({}_{3}\), mg & 1.67 & 15.00 & 20.00 & 1.67 & 15.00 & 20.00 \\ Biotin, mg & 0.17 & 0.50 & 0.67 & 0.17 & 0.50 & 0.67 \\ Folic acid, mg & 1.00 & 3.75 & 5.00 & 1.00 & 3.75 & 5.00 \\ Niaicin, mg & 100.00 & 87.50 & 116.67 & 100.00 & 87.50 & 116.67 \\ Pantothenate, mg & 30.00 & 62.50 & 83.33 & 30.00 & 62.50 & 83.33 \\ Thiamine, mg & 3.33 & 7.50 & 10.00 & 3.33 & 7.50 & 10.00 \\ Riboflavin, mg & 10.00 & 25.00 & 33.33 & 10.00 & 25.00 & 33.33 \\ Vitamin B\({}_{6}\), mg & 10.00 & 15.00 & 20.00 & 10.00 & 15.00 & 20.00 \\ Vitamin B\({}_{12}\), \(\mu\)g & 50.00 & 97.50 & 130.00 & 50.00 & 97.50 & 130.00 \\ \hline \hline \end{tabular}  
* NRC = basal diet for National Research Council (NRC) recommendation level of vitamins, 75% CRV = basal diet for 75% commercial vitamin recommendation, 100% CRV = basal diet for 100% commercial vitamin recommendation.  
\end{table} 
Table 2: The composition of vitamin premixes used in each treatment for experimental 2 [1].