Dietary phosphatidylcholine improves maze-learning performance in adult mice

The effect of phosphatidylcholine (PC) on maze-learning performance was investigated in adult mice. Three-month-old mice were given a semipurified diet of 1%, 2.5%, or 5% PC over a period of 4 months, with their maze-learning ability assessed beginning at 3 months after the start of the experiment and again 4 and 8 days later. This entailed the measurement of the time required by the mice to reach the maze exit and counting the number of times that mice strayed into blind alleys in the maze. During trial 1, mice in the 5% PC diet group required significantly less time to reach the maze exit compared with the control group (P < .05), while mice in the 1% and 2.5% PC dietary groups tended to require a shorter time to find the exit, but the differences were not significant. The number of times that mice strayed into blind alleys in the maze was significantly fewer in the 2.5% and 5% PC diet groups than in the control group during trial 1 (P < .05). The PC diets increased the percentages of docosahexaenoic and arachidonic acids in serum but had a lesser effect on brain fatty acid composition. These results suggest that the intake of 5% PC diet improves learning ability in adult mice and that the improved brain function may be related to the provision of choline.