Morphology of Reproductive Organs, Semen Quality and Sexual Behaviour of the Male Rabbit Exposed to a Soy-containing Diet and Soy-derived Isoflavones during Gestation and Lactation

Abstract

Placental and breastfeeding transfer of soy isoflavones are potential routes for animal and human exposure to phytoestrogens, and reproductive dysfunctions have been linked to early exposure to these compounds. So, the aim of this study was to investigate the effects of perinatal (intrauterine and lactational) exposure to soy-containing diet and soy-derived isoflavones on the reproductive parameters of male rabbits. For this purpose, 12 female rabbits were randomly assigned to receive: (1) a soy- and alfalfa-free diet (control diet); (2) a soy- and alfalfa-free diet supplemented with 10 mg/kg body wt/day of soy isoflavones; (3) a soy- and alfalfa-free diet supplemented with 20 mg/kg body wt/day of soy isoflavones; and (4) a diet containing 18% of soy meal, throughout gestation and lactation. Weight and morphology of the reproductive organs of some of the male offspring were evaluated at weaning (between days 29 and 31). The remaining males were placed on the control diet from weaning to adulthood (gestational and lactational exposure only). Sexual behaviour, semen quality and reproductive organs' morphology were evaluated after puberty. There were no significant differences in litter size and gestation duration between control and treatment groups. Perinatal exposure to soy-containing diet and soy isoflavones did not alter testis, epididymides, proprostate and prostate weight and gross morphology. After puberty, sexual behaviour and semen parameters did not differ significantly from the control group. These results indicate that intrauterine and lactational exposure to soy-containing diet and soy-derived isoflavones may not adversely affect reproductive development and function of male rabbits.