Effects Of Japanese Medaka After Long Term Exposed To Deca-BDE And Medicine Control Desease Of Channel Catfish

The experiment was conducted to evaluate the impact of environmental endocrinediscruptors, deca-BDE, with long term exposure to Japanese medaka, also drugs thattreated bacteroidal diseases in channel catfish had been selected and used them astreatment drugs in outdoors experiments. The results revealed that:1. deca-BDE did not affect the growth of F₀ medaka with long term exposure, butaffect the length and weight of F₁ medaka and there was no significant difference betweentreatment groups. Japanese medaka(F₀ generation) was exposed to deca-PBDE for 30 or60 days, and the effect of liver somatic index and gonad somatic index were recepted indifferent degree, that of male medaka was more severely than female. Japanesemedaka(F₁ generation) was exposed for 90 days, the liver somatic index and gonadsomatic index of male medaka in treatment groups was lower than control or solventgroup, has no significantly difference, but female medaka had negative results.2. Japanese medaka(F₀ generation) was exposed to deca-PBDE for 15, 30, 60 days,EROD activity decreased significantly in 1 ng/L,10 ng/L,10μg/L,100μg/Lconcentration after 15 days; in 100 ng/L concentration after 30days; in 100μg/Lconcentration after 60 days. During experiment there was no medaka died, theproductivity, fertilization ratio and hatching ratio did not vary significantly betweentreatment and control groups for two generation exposure. Sex ratio (female: male) ofmedaka(F₁ generation) did not vary significantly between treatment and control groups,but medaka(F₂ generation) decreased significantly that occurred in 10μg/L upwards.3. After being exposed for 60 days, deca-PBDE did not affect significantly plasmaVTG levels in rnedaka (F₀ generation), although it indicated weak estrogenicactivity. There was no obvious tissue lesion occurred in 1μg/L downwards, butaccumulated eosinophilic material, swelling of hepatocytes, dwindled cells nucleolus andglycogen and/or lipid deposits were observed in male medaka liver organ in 1μg/L,10μg/L concentration. In addition, Inhibitive testis of a male from 10μg/L was observed,Regressed ovary of a female exposed to 10μg/L, many previtellogenic occytes (Po) wereshown.4. Oxytetracycline and Norfloxacin with lower minimum inhibitory concentration(MIC) and minimum bactericidal concentration (MBC) were selected and used astreatment drugs in outdoors experiments. The diseased channel catfishs in 10 cages werefed with the feed added with Oxytetracycline and Norfloxacin at proporation of 15 mg/Kg (fish weight) and the mortality of channel catfishs descended significantly after 2 daysand did not die after 5 days. The results showed that Oxytetracycline and Norfloxacinhave satisfying efficiency in treating bacteroidal diseases in channel catfish.