Effects Of Compound Sterility Agent EP-1 On Fecundity Of Two Male

China is a country with sever rodent problems. In each year, the loss in agriculture, forestry and stockbreeding caused by rodent damages is great grievous, which with over 10 billion yuan. In addition, as rodent density increase due to global warming, drought exacerbating and other factors, the problem of mice infectious disease become increasingly serious. In short, Rodents cause great threat to our national economy and population health. For a long history, people use large quantity of chemical baits to kill rodents. Although the local rodent problems were solved in a short time, it causes more problems at the same time, including environmental pollution, rodent population rebound, ecological balance destroying and natural predators poisoning.To explore a method with lower toxicity, and can control rodent populations for a long time, is of great importance. The new method can also reduce agro-forestry losses and avoiding contagious diseases.Birth control technology has opened up new ideas and new ways.The main mechanism of infertility is interfering the female, male sex hormone levels, triggering endocrine disorders to achieve lower fertility purposes. In addition, the infertile original individuals are still alive and occupy their niches to maintain the original community pressure, which can inhibit the recovery and development of the population in the long term. Levonorgestrel-Quinestrol complexes (EP-1) is a kind of hormone infertility agents, its significant role in infertility has been verified in many anti-fertility experiments about reproductive, physiology and outside practice on many kinds of rodents. Based on above background, the research is aimed to detect the effects of complex infertility agent EP-1 on these two rodents (Apodemus agrarius from Chang’an County and Apodemus draco from Foping Nature Reserve) and test the population control effect in the fields.(1) As the first step, the study is undertaked in laboratory. The test mice were randomly divided into one-dose treated group (ODT,30mg/kg, once gavage), multi-dose treat group (MDT,30mg/kg, twice gavage) and control group (the same amount of edible oils),in order to find how EP-1 affected their reproductive organs and serum hormone levels. Experimental results were as follows:Apodemus draco:15th day after initial treatment, the esticles, epididymis weight in ODT group and MDT group were significantly decreased compared with the control group, Seminal vesicle weight was significantly lower in ODT group, while MDT group showed slight decrease. The average weights of the three glands were no significant differences between ODT and MDT group, showed that EP-1 effects on mice gonads unenhanced with increasing dose. Compared with the control group, serum testosterone levels in treatment group were significantly decreased, the decline in sperm density is also large, decreased by 86.31% (ODT group) and 89.83% (MDT group) respectively. Day 45 after drug treatment, indicators change slightly undulating than 15 days, but not significant, indicating that efficacy has not diminished in a month. Microscopic examination found that, at day 15, most seminiferous tubule was empty and ulcer-like, with epithelial thinning, spermatogenic cells in the inner tubes appeared loose and impaired in varying degrees. It is more serious in 45th days.Apodemus agrarius:at the 15th and 45th day after drug treatment, the average weights of testis, epididymis and seminal vesicle occurred significant reduced than the control groups. At the 15th days, the average weight of these glands much lighter in MDT group than ODT group; a month passed; the average weight of MDT group rebounded and slightly heavier than ODT group, we do not know whether this is a sign of recovery. Experimental serum testosterone levels and sperm density were also significantly lower than the control group, but this difference between the two indicators at two time points was not significant in day 15 and 45 after drug treatment. Microscopic examination found that test rat’s testis seminiferous tubules inside was ulcer-like appearance and more than 50% of them were cavity at the 15th day, which increased to nearly 80% a month later.These results suggest that EP-1 can cause a serious decline in reproductive organs of male Apodemus draco and Apodemus agrarius, and significantly inhibit the secretion of serum testosterone, thereby reducing its fertility.(2) To further proving the infertility effect of EP-1, the study fed male Apodemus agrarius with 0.005% EP-1 bait for 2 weeks, then paired them with female individuals(male:female=1:2).We recorded their breeding conditions for 60 days continuously. It was found that compared with the control group/the time of conception in bait group delayed 13 days or so, the pregnancy rate decreased by two-thirds, and female average litter size decreased 70.1%.(3) In the third part of the study we select five plots(100 m × 100 m) in Chang’an District, then numbered them (1-5),the No.l plot was used for comparison, does not put any baits (control plot); capture rodents in the No.2 plot for laboratory studies (capture plot); monitor rodent population density in the No.3-5 plots (monitor plot).From the beginning of April, put infertility bait in No.2-5 plots randomly, then monthly survey rodent density to studied the effect of EP-1 on rodents density controlling. Begin in April and end in September, monitoring results for six consecutive months showed that the average capture rate is 4.72% in control plot, the lowest rate in May (0.56%), while the highest in June and July (7.78%); the average capture rate in monitor plots is 1.45%, the lowest rate in June and September (0.37%), while the highest in May (3.33%). These results imply that EP-1 has greatly inhibited the increase of Apodemus agrarius population.