| Deltamethrin which was a type II pyrethroid caused severe contamination to theenvironmen with its wide use in agriculture in recent years. This master paper used tilapiaas experiment animal, applied molecular biology, cell biology etc. technology, studied theinfluences produced by deltamethrin on tilapia from acute toxicity trials, accumulation andrelease rules, immune system, antioxidize system, and heredity effect, from the wholeliving, organ and cell level and molecule level evaluated the satey of deltamethrin.The results of acute toxicity revealed that 96hLC50 of deltamethrin was 23.7/μg/L fortilapia with mean body weight 70.0g±5.0g and mean body length 13.0±1.0cm. Accordingto the methods of biological detect, deltamethrin was a high toxic pesticide for tilapia.Based on the acute toxicity trial, the following concentration series below 1/2 96hLC50that were 1μg/L, 2μg/L, 3μg/L, 5μg/L and 10μg/L were established to infect tilapia.Analyzing continual exposure to low dosage deltamethrin for the impact of physiochemicaland hereditary oftilapia. We get a conclusion that:1) Results indicated that accumulation of deltamethrin in tilapia reached balance at thefifth to twentieth days and the maximal enrichment coefficients of muscle and organ were1.85 and 2.20. Accumulation capacity of muscle was less than that of liver whiledeltamethrin release of muscle was quicker than that of liver.2) There were obvious pathological changes in liver of tilapia after its continualexposure to deltamethrin for 25 days, but organ coefficients did not occur obvious changes.As for spleen, it did not take on any obvious changes compared with the contrast inanatomization shape and organ coefficients.The influences on lysozyme by deltamethrin intilapia were that low concentration lysozymes (2μg/L-5μg/L) had the tendency of arisingfirst and declining after, whereas the tendency was contrary for high concentrationlysozymes (10μg/L) . With the increasement of exposure time, all trial groups restored tonatural levels at the twentieth day. Lysozemes content in serum was steady until the end ofthe trial and was not obviously different from the contrast. The outcome revealed that theeffects on lysozemes in serum by deltamethrin was reversible for tilapia.3) The outcomes from AchE showed that water temperature changes from 23℃to 27℃had not any influences on AchE activity detection in serum for tilapia. Inhibitpercentage of AchE activity exceeded 30％and the highest was 62.3％except the group of1.0μg/L the inhibition percentagy of which was lower than 15％. So concentration above2.0ug/l had inhibition on AchE for tilapia.4) After exposure to 1.0ug/1 of deltamethrin for 25 days, GSH contents and activitiesof GST, CAT and MAO in muscle and liver had not any significantly difference(P＞0.05),but GSH contents and activities of GST,CAT and MAO all occurred dynamic varietiesafter exposure to deltamethrin above 2.0 ug/l: (a) Under the deltamethrin intimidation, thetendency of GSH contents and GST activities were arising first then declining after and thevariety degree in liver was bigger than that of muscle. At the end of trial, GSH content inother groups had some changes compared with the contrast except for the group of 1.0 ug/l,but GST activity was different significantly from the contrast(P＜0.01) , 7.6％- 53.9％beneath contrast group. (b) CAT activity tendency was decreasing first then arising after and variety degree in liver was bigger than that of muscle. At the end of trial, CAT activityin other groups had some changes compared with the contrast except for the group of 1.0ug/L. CAT activity in muscle is lower 17.4％than the contrast group, the most reduction ofCAT activity in organ between 59.9％-72.9％(P＜0.01); (c) MAO variety was arising first,then declining and restoring at last and variety degree in liver was lower than that in muscle.At the end of trial, MAO activity in other groups had some changes compared with thecontrast except for the group of 1.0 ug/L.5)The results from cell level trial indicated that genome DNA of tilapia was influencedby deltamethrin above 3.0 ug/1 after continual exposure for 3 days and primer S326 coulddetect the DNA variety induced by deltamethrin. Continual exposure to deltamethrin above3.0 ug/l coule induce peripheral red cell to produce micronuclei. Micronuclei frequency hadobvious concentration effect and time effect with deltamethrin concentration increased andexposure time prolonged.The results revealed that deltamethrin above 2.0 ug/l produced influences onphysiological mechanism of tilapia. For the security of aquaculture and food available,deltamethrin concentration shoule be below 1.0 ug/l in aquaculture for edible quality.
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