Chronic Oral Intake of Soy Peptide Alleviates Anhedonia in Normally Housed Male C57BL/6J Mice.

The impact of long-term soy peptide consumption on mood-related behavior in adult male mice was studied under normal housing conditions. Male C57BL/6J mice were fed a modified AIN-93M diet containing 7% soy peptide for 70 d. Sucrose preference and tail suspension tests were conducted to evaluate anhedonia and despair, respectively. Mice fed soy peptide consumed more sucrose than those in the control group fed AIN-93M in the sucrose preference test. However, no significant difference was observed in the total immobility time between the two groups in the tail suspension test. These findings suggest that chronic soy peptide intake may attenuate anhedonia, a hallmark symptom of major depressive disorder characterized by decreased sensitivity to reward and pleasure.