Effects of sweet cassava polysaccharide extracts on endurance exercise in rats

Background: Sweet cassava tubers have abundant carbohydrates consisting of monosaccharides and polysaccharides. In addition, polysaccharides extracted from plants improve sports performance, according to recent studies. We therefore examined whether the administration of sweet cassava polysaccharides (SCPs) benefited endurance performance in rats Methods: Male Sprague-Dawley rats (n = 30, 7 weeks old) were divided into three groups: control (C), exercise (Ex), and exercise plus SCPs administration (ExSCP) (at a dose of 500 mg/kg body weight by gastric intubation for six days in addition to standard rat food and water). An exercise program was implemented in the Ex and ExSCP groups for five days (with no exercise on the sixth day), and then all rats were sacrificed to determine the glycogen content of the gastrocnemius and soleus muscles, and the blood metabolites after the ExSCP and Ex groups had completed exhaustive running. Results: The running time to exhaustion of the ExSCP group was significantly longer than that of the Ex group by 49% (64 vs. 43 min). After running to exhaustion, it was seen that although the glycogen content in the soleus and gastrocnemius muscles of the Ex and ExSCP groups was lower compared to the C group, values in the ExSCP group were significantly higher than in the Ex group (p < 0.05). In addition, blood glucose and free fatty acid (FFA) levels were significantly higher in the ExSCP than in the Ex group (p < 0.05). However, no significant differences for blood glucose or FFA were found between the ExSCP and C groups. Conclusions: SCP supplementation can prolong exercise endurance in rats. Higher muscle glycogen levels and stable glucose and FFA concentrations in the circulation contributed to the prolonged time to exhaustion.