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Fermented soymilk increases voluntary wheel running activity and sexual behavior in male rats
Takuya Sato1, Yasutomo Shinohara, Daisuke Kaneko
1Kikkoman USA R&D Laboratory Inc., 505 South Rosa Road, Suite 107, Madison, WI 53719, USA. tsato@kikkoman.com
Abstract:
Wheel running by rodents is thought to reflect voluntary exercise in humans. The present study examined the effect of fermented soymilk (FSM) on voluntary wheel running in rats. FSM was prepared from soymilk (SM) using the bacteria Leuconostoc pseudomesenteroides. The rats were fed a normal diet for 3 weeks followed by a 3-week administration of diet containing FSM or SM (5% w/w), and then the diets were switched back to a normal diet for 3 weeks. The voluntary wheel running activity was increased by FSM administration, although no changes were observed by SM administration. This effect was observed 2 weeks after FSM administration and lasted 1 week after deprivation of FSM. Then we evaluated the effect of FSM on sexual behavior in male rats. FSM administration for 10 days significantly increased the number of mounts. The protein expression of tyrosine hydroxylase (TH) increased in the hippocampus by FSM administration and it is suggested that FSM may change norepinephrine or dopamine signaling in the brain. Our study provides the first evidence that FSM increases voluntary wheel running activity and sexual behavior and suggests that TH may be involved in these effects.
Insights
Fermented soymilk (FSM) significantly boosted voluntary wheel running in rats, mimicking human exercise. This dietary supplement also enhanced male rat sexual behavior, with potential brain signaling implications.
Area of Science:
- Nutrition Science
- Neuroscience
- Animal Behavior
Background:
- Voluntary wheel running in rodents is a model for human exercise.
- The impact of fermented soymilk (FSM) on animal behavior and physiology is not well-understood.
- Soymilk fermentation involves specific bacterial cultures, such as Leuconostoc pseudomesenteroides.
Purpose of the Study:
- To investigate the effects of fermented soymilk (FSM) on voluntary wheel running activity in rats.
- To evaluate the influence of FSM on sexual behavior in male rats.
- To explore potential neurobiological mechanisms, such as tyrosine hydroxylase (TH) expression, underlying FSM's effects.
Main Methods:
- Rats were fed a normal diet, followed by diets containing either FSM or soymilk (SM) (5% w/w) for 3 weeks, with a subsequent return to a normal diet.
- Voluntary wheel running activity was monitored throughout the study.
- Sexual behavior in male rats was assessed after 10 days of FSM administration.
- Protein expression of tyrosine hydroxylase (TH) in the hippocampus was analyzed.
Main Results:
- FSM administration significantly increased voluntary wheel running activity, an effect observed after 2 weeks and persisting for 1 week after FSM withdrawal.
- Soymilk (SM) administration alone did not alter wheel running activity.
- FSM significantly increased the mount frequency in male rats.
- FSM administration led to increased tyrosine hydroxylase (TH) protein expression in the hippocampus.
Conclusions:
- Fermented soymilk (FSM) enhances voluntary physical activity and sexual behavior in rats.
- The observed behavioral effects may be mediated by changes in brain neurotransmitter systems, potentially involving norepinephrine or dopamine signaling, as indicated by increased TH expression.
- This study provides novel evidence for the ergogenic and behavioral effects of FSM.
