| Some species of Oxytropis plants were the most serious poisonous weeds for livestock on China's grassland and all over the world. Oxytropis poisoning existed widely in nine provinces of the northwest, southwest and north of China. There were more than 20 species including Oxytropis kansuensis, O. ochrocephala et al, which have caused large poisoning disaster. Oxytropis plants induced huge economic losses as high as 10 billion Yuan every year, and became one of"three poisonous weeds disaster"in china. Oxytropis plants not only induced animal's death, but also seriously affect the animal's reproductive function, resulting in infertility, miscarriage, fetal malformation, male livestock loss of libido, decreased semen quality, etc. It hindered the work of improving livestock breeds, and has seriously hampered the development of grassland animal husbandry in China. Preliminary studies confirmed that the major toxicity of Gansu Oxytropis is swainsonine. It was firstly isolated and named by Colegate, et al from swainsine canecens. The main toxic component of swainsonine is firstly isolated from O.ochrocephala by Chinese scholar Cao Guangrong. There were many studies of the Gansu Oxytropis toxicity in animals, but few in rabbits. In order to provide basic information for toxicological studies of Gansu Oxytropis, the study of the toxic effects on experimental rabbits with different doses of the Gansu Oxytropis was carried out, and obtaining the following results.1. Changes in clinical symptoms In being fed Gansu Oxytropis pellets after 18 days, a pregnant doe of groupⅢaborted; rabbits of groupⅡandⅢappeared as the spirit of gloomy, a mild appetite diminished, slow response, hind limb weakness, decubitus and other clinical manifestations in 35th days; there was no abnormalities in rabbits of group. It showed that poisoning symptoms of the experimental rabbits aggravated as the Oxytropis intake increasing.2. Changes in body weight The body weight of rabbits of group significantly increased only in 42th to 70th days, with significantly increasing of rabbits of groupⅡandⅢthroughout the trial period. It showed that as the Gansu Oxytropis intake increasing, body weight increased, having a significant dose effect.3. Changes in blood parameters RBC, PVC, Hb, WBC and other blood indexes of rabbit blood in different doses were tested and compared. The results showed that RBC, PCV, Hb of rabbit blood in three groups by continuous feeding of Gansu Oxytropis presented rising trend, and consistent with increasing weight of the experimental rabbit. It indicated that the experimental rabbits had tolerance with Gansu Oxytropis and could utilized nutritional ingredient of it. Lymphocytes were significantly higher than baseline after 70 days, then decreased. As continuous feeding of Gansu Oxytropis, which has enhanced lymphocyte proliferation of rabbit spleen, when accumulation of swainsonine in the rabbits has reached a certain dosage, resulting in vacuolar degeneration of immune organ cell; it affected the mature of lymphocytes.4. Changes in blood biochemical indicator GOT, GPT, LDH, AKP activity and BUN, CRE content of rabbit blood in different doses were tested and compared. The results showed that blood biochemical indicator of AKP, GOT and BUN of there groups were significantly higher and increased by the dose of Oxytropis increasing. GPT in serum significantly decreased, which show it had a damaging effect on the heart, liver, kidney and other solid organ, and the greater dose was, the more severe damage was, when test rabbits fed with Gansu Oxytropis. CRE did not change during the test, whether it is concerned with that glomerular filtration rate has not completely lost after liver damaged, but should be researched further. The LDH activity increased in all experimental groups from 14th day, and reached the highest in 28th days, and then down. It was significantly different compared with baseline. Whether it is concerned with that as this tissue and organ damage to a certain extent, then the damage were no longer aggravated, which also need to be studied.5. Analyses of serum protein The number of total serum protein, globulin and albumin of difference dose treated rabbits was determined. The results show that no significant difference between total serum protein andα-globulin; the number of globulin of rabbit from each treated group had an increasing trend after 14th day, and the result ofⅡandⅢtreated group exist the significant difference from control at 84th day; the number ofβ-globulin of rabbit from each treated group increased after 14th day, and the result of each treated group exist the most significant difference from control during 70-98 day; the number ofγ-globulin of rabbit from each treated group increased largely after 14th day; The number of albumin decreased largely after the 56th day; the number of Albumin/Globulin(A/G) of three treated group all had the decreasing trend during treatment. The results show that rabbit organ parenchymatosum, such as liver, was damaged after eating difference dose Kansu crazyweed herb.6. Changes from gross anatomy The rabbits from each treated group was killed after 120 day eating Kansu crazyweed herb, and their organization (heart, liver, lungs and kidney et al.) was observed. In the first group, the pathological condition characterized by splenomegaly, and no significant change in heart, liver and kidney; in the second group, the pathological condition was splenomegaly, brittleness of liver increasing, epinephelos urine in bladder, no significant change in others; in the third group, the pathological conditions were splenomegaly and texture significantly soft, hepatomegaly, pneumonectasis characterized by pale asphyxia, tension envelope, unsharp border, petechial hemorrhage, enlargement of the right ventricle with stickiness, thin ventricular wall, loose cranium with increasing fragility, slightly swelling kidney, slightly valgus section, hard stripping envelope.7. Pathologic histology changes Pathological changes of the heart, liver, lung, kidney, brain, cerebellum, lymph nodes and other tissues and organs were observed. The results showed that it was characterized with extensive vacuolar degeneration in the liver, kidney, brain cells microscopically, especially in brain, and pathologic histology changes in experimental rabbits, which had a dose-response relationship, and it aggravated as the dose of Gansu Oxytropis increased.
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