Abstract: Objective To study the effects of different dosages and different molecular weights chitosan on mice swimming time and changes of blood glucose, lactic acid and glycogen content in mice. Methods: The test groups were given chitosan by oral administration. 18 days later, the swimming time, blood glucose and lactic acid were determined. 24 days later, liver and muscle glycogen were assayed. Results: In contrast with the control group, chitosan could prolong the swimming time, speed up the recover of blood glucose, scavenge lactic acid, and increase the liver and muscle glycogen content. At the same time, low molecular weight chitosan displayed better effect than high molecular weight chitsoan of the same dosage. Conclusion: Chitosan had anti-fatigue effects on mice and low molecular weight chitosan exhibited better effect.

Key words: chitosan, glucose, lactic acid, glycogen, anti-fatigue