Effect of fructo-oligosaccharide on nitrogen utilization in guinea pigs

The present study was conducted to determine the effects of fructo-oligosaccharide (FOS) on the nitrogen (N) utilization and digestibilities of dietary nutrients through cecotrophy in guinea pigs. Adult male guinea pigs that were housed or not housed in wooden frames to prevent cecotrophy were fed a commercial pellet diet (50 g/day) with 3% and 5% glucose or FOS for 8 days in individual metabolism cages. In the guinea pigs allowed cecotrophy, addition of FOS to the diet had no significant effects on body weight gain or apparent digestibility of N, but showed significantly lower value for the urinary N excretion and acid-detergent fiber digestibility (P < 0.05 and P < 0.01, respectively) and significantly higher value for N retention and the N retention rate (P < 0.05). In the guinea pigs prevented from cecotrophy, FOS had no effect on N retention, but showed tendencies toward a higher value for fecal N excretion and a lower value for urinary N excretion. These results suggest that FOS stimulates cecal microbial proliferation, thereby improving N utilization in guinea pigs.