[Effects of soybean isoflavone on reproductive development in SD rats]

To assess the effects of soybean isoflavone on reproductive development in SD rats.

Forty 4 week-old SD rats (20 males and 20 females) were randomly divided into a control group and a soy isoflavone (SI) group according to their body mass, and were fed with normal diet or normal diet added with soy isoflavone (100 mg/kg BW), respectively. The body weight, daily food intake, estrous cycle, fertility index, pregnant index, gestation length, number of pups, blood hormone level, the weight of reproduction organ and the quality of sperm of the parental generation and the sex ratio, anogenital distance, vagina opening time, prepuce separation time of F1 generation were recorded. The data were analyzed by two independent t test, and the data of pups in each litter were analyzed as a unit.

Compared with the control group, the body weight and food utilization of male and female rats in SI group were lower before copulation (P < 0.05). The total number of sperm of parental males was higher (P < 0.05). Serum luteinizing hormone (LH) level of parental male was lower (P < 0.05), serum luteinizing hormone (LH), prolactin (PRL) and progesterone (P) of parental female were lower in SI group (P < 0.05). There were no significant differences of other indices such as estrous cycle, mating index, fertility index between two groups.

SI has certain effect on the bodyweight of parental males, food utilization of females, and the total number of sperm and the level of some hormones.