Effects of a soybean milk product on feto-neonatal developmentin rats

Since estrogenic pollutants and phytoestrogens can cause the disorder of the reproductive system, the effects of asoybean milk product (Vegemil? containing 162 ppm isoflavones) on the feto-neonatal development, including malereproductive function, were investigated. Pregnant rats were fed the soybean milk (5% or 100% in drinking water)from gestational day (GD) 6 to parturition or to post-natal day (PND) 56. Specifically, the rats were divided into 4groups: the control group (drinking water), the GD5% group (5% soybean milk during only the GD period), the GDPND5% group (5% soybean milk during the GD and PND periods), and the GD-PND100% group (100% soybeanmilk instead of water during the GD and PND periods). During the gestational, lactational, and developmentalperiods, the reproductive and developmental parameters of dams and offspring were observed. Feeding soybean milkdid not affect the birth and physical development of both male and female offspring. At PND57, the weights of thetestes and epididymides of F1 males significantly increased by feeding a high concentration of the soybean milk (GDPND100%). In addition, feeding of the soybean milk during both the GD and PND periods (GD-PND5% and GDPND100%) enhanced the sperm counts and motility. The results indicate that soybean milk is safe for embryos,fetuses, and offspring, and improves the post-generational development of male reproductive function.