The Response Characteristics Of Rana Spinosa

The acute ammonia stress experiment of the tolerance and response characteristics of Rana spinosa tadpoles[(1.932±0.204)cm total length and(1.386±0.055)g weight] was carried out at the temperature 24±0.2 °C and p H 7.5±0.06. Meanwhile, The 6d and 12 d of recovery toxicity tests of remaining Rana spinosa tadpoles after sampling in aerated tap-water were carried out.The result showed that :(1) The LC50 of Rana spinosa tadpole at 24、48、72 and 96 h were 17.75 mg/L、15.17 mg/L、14.86 mg/L、14.68 mg/L, respectively; the toxicity accumulation coefficient MAC after 48h、72h、96h were 84.04%、10.1%、5.86%, respectively.(2) The ammonia nitrogen have the excitatory effects of low-level to the oxygen consumption rate, suffocation point of Rana spinosa tadpoles. The oxygen consumption rate showed a significant difference with the normal control group(P < 0.05) when the concentration of ammonia nitrogen from 2.45mg/L to 12.25mg/L. And the suffocation point of Rana spinosa tadpoles would show the excitatory effects of low-level from 0mg/L to 9.80mg/L, the effect would reach peak when the concentration of ammonia nitrogen was 4.90mg/L, at this time, the content of dissolved oxygen was only 0.63mg/L, and showed a significant difference with the normal control group(P < 0.05).(3) As time went on, the activities of Rana spinosa tadpoles would show a trend of swimming slowly firstly during the low ammonia nitrogen concentration range and then swimming fastly, even moving up and down fastly; the body colour would change from black to pale, the changing of tail colour was obvious; after the Rana spinosa tadpoles dissected, we could see the colour of liver was changed from red to yellow. These characteristics had positive correlation with accumulation of toxins. So we could treat tail skin tissue and liver as an indication organ or tissue of ammonia poisoning.The enzyme activitives of SOD、GSH、CAT in liver and the enzyme activity of SOD、CAT in tail skin tissue of Rana spinosa tadpole all experienced a process of rising firstly and then declining under different ammonia concentrations for 24h、48h、72h、96h. The enzyme activitives of SOD in liver and tail skin tissue of Rana spinosa tadpole would reach the highest goal when the ammonia concentration was 2.45mg/L; the enzyme activitives of GSH and CAT in the liver with CAT in tail skin tissue of Rana spinosa tadpole all would reach the peak when the ammonia concentration was 14.70mg/L. But the activity of ATP in tail skin tissue of Rana spinosa tadpole experienced a process of declining with the rising of ammonia concentration, and have a big difference with control group(P<0.05).The enzyme activitives of antioxidases in the liver and tail skin tissue all showed a big difference with the control group(P < 0.05) after recoverying for 6d and 12d; Otherwise, exceptly, the activitives of ATP in tail skin tissue showed a process of declining, the activitives of the other antioxidases experienced a process of rising firstly and then declining with the rising of the concentration of ammonia nitrogen, and the activitives of ATP of high concentration of ammonia nitrogen group would tend to be stable.