Study On The Antifertility Action Of Neem Oil On Plateau Pika And Its Toxicology

The Plateau Pika are the animals of Mammals, Lagomorpha Ochotonidae, spread over the alpine meadows of 3200-3700m altitude.Because the damage of traditional deratization drugon the environment is too large and it also has long-term toxicity of residual hazards, the existing deratization preparations has gradually became to be natural deratization agent. Among which controlling the harmful rat breed speed through antisterility mechanism is a kind of green scientific deratization harm method effective disaster with its effective disaster mitigated and no damage on the ecological environment and biologic chain. The Neem (Azadirachta indica A. Juss.) is Meliaceae Melia trees, native to the Indian subcontinent, The Neem oil is a vegetable oil obtained from the neem seed by cold pressing on the machines that have good acaricidal, antibacterial and antisterility pharmacological activities. This study intends to make neem oil into granules and to study its effect on ingestion coefficients, the best concentration, and antifertility actionof plateau pika; meanwhile,systematically study the acute toxicity, accumulative toxicity, subacute toxicity and chronic toxicity effects of neem oil, in order to provide toxicology safety scientific basis for using neem oil to control rodent in the actual production.The main study results are as follows:1. Research on the antifertility action of neem oil granules on plateau pika:The ingestion coefficients was studied with the concentration of 30% and 40% of neem oil granules for rodents'ambisexual sterility respectively, and the apoptotic cells of oviduct and uterine were measured with immunohistochemical approach.The results showed that: The ingestion coefficients of concentration of 30% and 40% neem oil granules were 0.97 and 1.87, the difference was significant(p<0.05); The antifertility rate was 70% on plateau pika with 40% neem oil granules,it caused serious damages on testicle, epididymal duct. hystera, oviduct and ovary and promote apoptosis in uterine cells. So the 40% neem oil granules had good palatability and significant antifertility effect, and it could be prospective in rodents' control on the grassland.2. Research on the acute toxicity of neem oil on mice:Activity condition and death condition of mice in the test group were observed within fourteen days with different concentration of solutions of neem oil,and the modified Karber method was used to determine LD50 of neem oil and confidence level in the acute toxicity test. The results showed that:The LD50 of neem oil in mice was 31.95 g/kg,so it belonged to the non-toxic substance.3. Research on the accumulative toxicity of neem oil on mice:After cotinuous oral neem oil at a fixed dose (1/5LD50) in mice of the test group for 28 days, the accumulative coefficient(k) were studied to apprase the accumulative toxicity of neem oil, feed consumption and organ coefficient of heart, liver, spleen, lung, kidney in both test group and control group were analysized in the accumulative toxicity test. The results showed that:there is no significant difference in feed consumption and organ coefficient of mice between the test group and the control group. Neem oil has no accumulative toxicity in mice.4. Research on the subacute toxicity of neem oi on mice:Eighty mice were divided into three experiment groups and one control group at random (10 per sex).The mice from experiment groups were orally administrated with neem oilfor 28 days, with the dose of 0 mg/kg,177 mg/kg,533 mg/kg/and 1600 mg/kg respectively.The general clinical manifestations, changes of body weight, food consumption, serum biochemistry, organ coefficient of heart, liver, spleen, lung, kidney and pathological examinations of heart, liver, spleen, lung, kidney, testicle were examed during the test period.The results showed that:The body weight, serum biochemistry, organ coefficient of heart, liver, spleen, lung, kidney in three experiment groups had no statistical difference compared with those of the control group. The food consumption of mice at the dose of 1600 mg/kg was decreased significantly in the last two weeks while those from the other experiment groups had no significant change compared with the control group. The pathological examinations showed that the 1600 mg/kg dose of neem oil had varying degrees of damage on each organ, mainly were granular and fatty degeneration on cell. Neem oil had slight subacute toxicity in mice at the dose of 1600 mg/kg.5. Research on the subchronic toxicity of neem oi on mice:Eighty mice were divided into three experiment groups and one control group at random (10 per sex).The mice from experiment groups were orally administrated with neem oil for 90 days, with the dose of 0 mg/kg,177 mg/kg,533 mg/kg,1600 mg/kg respectively,then continued to observe all change of each mice for 30 days after stopping giving neem oil. At the 90th day and the 120th day, the general clinical manifestations, serum biochemistry, organ coefficient of heart, liver, spleen, lung, kidneys and histopathology of heart, liver, spleen, lung, kidney, testicle and ovaries were examined. The results showed that:The serum biochemistry, organ coefficient of heart, liver, spleen, lung, kidney in three experiment groups had no statistical difference compared with those of the control group. At the 90th day, the pathological examinations showed that 177 mg/kg and 533 mg/kg dose of neem oil had low damage on each organ, such as slight vascular congestion, while 1600 mg/kg dose of neem oil had varying degrees of damage on each organ, the damage was more serious on liver and kidneys,mainly were degeneration on cell. After recovery for 30 days,the degree of injury to the tissues was lessened or even to be restored. The level at which no adverse effects was 177 mg/kg for mice and the target organs of neem oil were determined to be testicle, liver and kidneys.