Effect Of Cow's Milk On The Reproductive System Of The ICR Mice

Objective: In the present study, IRC mice were treated with different doses of milk in long term to make two-generation reproduction study.The aim of the study was to examine the effectiveness of milk on general growth and reproductive development in mice.Method: Three-week-old IRC mice, 48 males and 48 females, were randomly divided into 4 groups:â… . 5ml milk treatment group,â…¡. 10 ml milk treatment group,â…¢. 15 ml milk treatment group,â…£. control group.After 12 weeks of treatment, each female was placed with a single randomly selected male of the same group for mating on the day of proestrus. At the day 6 of mating, the parental males were killed. The parental females were killed after weaning of filial generation mice. Filial generation mice of the same group were selected to repeat the experiments of the parental mice.During feeding period, general condition, body weight, food consumption, mating rate, pregnancy rate of mice were ovserved. After feeding period and sacrificed the mice, some indexes were observed including histological observation on the reproduction organs of the ICR mice, sperm count, detection of serum hormone levels using radioimmunoassay. The data were analyzed by SPSS 13.0.Results:1 General conditionDuring the 2-generation reproduction test, a good growth condition, normal activities of mice were observed, and there was no death in the whole process.2 the changes of body weightThe growth of body weight in the parental males of the groupâ… andâ…¡was faster compared with the groupâ…£with statistical significance (P<0.05), but there was no significant difference between groupâ…¢andâ…£, as well as groupâ… ,â…¡andâ…¢(P>0.05). The weight of the other groups of parental mice have no significant differences(P>0.05). No significant difference was found among all the groups of the offspring mice(P>0.05).3 food consumptionIn comparison with the groupâ…£, the food consumption was lower in male parent of groupâ… ,â…¡andâ…¢with statistical significance (P<0.05), but no significance was found between groupâ… ,â…¡andâ…¢themselves(P>0.05). As well as the parental females, there was no significant difference between the offspring mice groups(P>0.05).4 genital wet weight and relative weight of the ICR mice It showed no difference in the genital wet weight between the parent mice and the offspring mice(P>0.05). Compared with the groupâ…£, testes wet weight in male offspring groupâ… ,â…¡andâ…¢was lower(P<0.05), while those of the other male mice groups had no statistical significance(P>0.05).Testes relative weight in male offspring groupâ…¡was significantly lower compared with the groupâ…£,(P<0.05), while those of the other male mice groups had no significant significance(P>0.05).In comparison with the groupâ…£, epididymal wet weight in male offspring groupâ…¡andâ…¢was lower with statistical significance (P<0.05). As well as the groupâ… ,â…¡andâ…¢, there was no difference between the male offspring mice groupsâ… andâ…£(P>0.05).5 histological observation on the reproduction organs of the ICR miceThere was no abnormal histological observation on the testes and epididymis of the parent and offspring male mice.The phenomenon of the proliferation of endometrial status had been seen in the parent and offspring female mice, but with none abnormal ovary histological observation .6 sperm countThe results of sperm count of male parent mice and male offspring mice showed that there was no difference between groupâ… ,â…¡,â…¢andâ…£(P>0.05)7 mating rate,pregnancy rateThere was no significant difference in the mating rate and the pregnancy rate of the male parent mice(P>0.05), and there was also no significant difference in the mating rate and the pregnancy rate of the offspring parent mice(P>0.05).8 Detection of serum hormone levelsIn parent , no significant difference of serum estradiol,estriol and testosterone was found in females and males(P>0.05).Compared with the groupâ…£, estriol level in male offspring groupâ… ,â…¡andâ…¢was lower with statistical significance (P<0.05),But there was no significant difference in groupâ… ,â…¡andâ…¢themselves(P>0.05), testosterone level in male offspring groupâ… ,â…¡andâ…¢was lower compared with the groupâ…£(P<0.05), but no significant difference was found in groupâ… ,â…¡andâ…¢themselves(P>0.05).Conclusion:1 dringking large quantities of milk for a long-term have less effect on the genital system of the parental ICR mice,but could decrease the serum testosterone level of the male offspring mice.2 The intake of cow's milk in this cross-mating study produced a few adverse effects in reproductive system in mice. Further studies should be conducted of milk on reproductive health.