Abstract
This study was conducted to examine the effects of dietary xylooligosaccharide on UDP-glucuronyl transferase (UDP-GTase) activity and excretion of fecal sterols in rat fed high cholesterol diet. Sprague-Dawley male rats weighing 100$\pm$10 g were randomly divided into five groups, one with normal diet and four with high cholesterol diets containing 1% cholesterol (w/w). The high groups with cholesterol diet groups were classified into xylooligosaccharide free diet (C), 5% xylooligosaccharide diet (C5XO), 10% xylooligosaccharide diet (C10XO), and 15% xylooligosaccharide diet (C15XO) group according to the five groups of dietary xylooligosaccharide by weights. The experimental diets were fed ad libidum for 4 weeks. Fecal weights were increased 86% by xylooligosaccharide. Fecal total lipid contents including fecal neutral and acidic sterols in xylooligosaccharide groups were significantly higher than those of the normal and C groups, and especially that of C10XO group was the highest among all experimental groups. Activity of UDP-glucuronyl transferase (UDP-GTase) in liver in C group was 35% higher than that of normal group and the activities in C5XO, C10XO and C15XO groups were 15%, 41%, and 21% higher than in C group, respectively. Fecal bile acid excretions per day were increased 3.1, 3.6 and, 2.8 folds in C5XO, C10XO, and C15XO groups, respectively, compared with that of C group. Contents of neutral sterol, coprostanol, and coprostanone were higher in xylooligosaccharide groups than in C group. These results suggest that dietary xylooligosaccharide may act as potential substitute for a dietary fiber capable of improving a gastrointestinal function and lipid metabolism.
고콜레스테롤 식이 흰쥐에서 xylooligo당이 간조직중의 UDP-glucronyl transferase 활성과 분변을 통한 지질, 담즙산 및 중성 sterol류의 배설 및 장기능개선 효과를 관찰하였다. 실험동물은 100$\pm$10g의 Sprague-Dawley 횐쥐를 이용하여 정상 식이군과 1% 고콜레스테롤 실험군으로 나누고 다시 실험군은 1%의 고콜레스테롤 식이에 xylooligo당을 0%, 5%, 10% 및 15% 농도 첨가군(C, C5XO, C10XO 및 C15XO군)로 나누어 각군마다 10마리씩 4주간 자유섭식 시켰다. 분변중의 총지질 및 TG함량은 C군에 비해 xylooligo당 공급군에서 현저하게 증가되었다. 간 microsome의 UDP-glucuronyl transferase의 활성은 정상군에 비해 C군에서 35% 증가되었고 또 C5XO, C10XO 및 X15XO군은 C군에 비해 15%, 41% 및 21%씩 각각 증가되었다. 분변중의 bile acid 함량은 C군에 비해 C5XO, X10XO 및 C15XO군에서 3.1배, 3.6배, 2.8배씩 각각 증가되었다. 분변중 중성 스테롤류인 cholesterol, coprostanol, coprostanone 함량은 C군에 비해 xylooligo당 공급군에서 현저하게 증가되었다. 이상의 결과에서 xylooligo당은 고콜레스테롤 식이 횐쥐에서 간조직의 UDP-GTase활성을 증가시키고 분변으로 총지질 및 중성지방 그리고 스테롤류의 배설을 증가시키는 효과가 있었고 또 분변량도 증가시키는 장기능 개선 효과도 뚜렷하였다.