RESUMEN
In this research, the continuous physiological changes of zebrafish (Danio rerio) in 0.1⯵g/L thallium (Tl) in 15 days were investigated. The results showed that Tl(I) stress had a significant positive linear correlation with zebrafish ammonia nitrogen excretion (ANE) (pâ¯<â¯0.001), and the mean value of ANE in Tl(I) treatment (435⯱â¯227â¯mg/kg/h) was approximately 2 times higher than in the control group (239⯱â¯168â¯mg/kg/h), which suggested that ANE was suitable for Tl(I) stress assessment. A substantial difference based on oxygen consumption rate (OCR) between the control group (587⯱â¯112â¯mg/kg/h) and Tl(I) treatment (260⯱â¯88â¯mg/kg/h) with a high significance pâ¯<â¯0.001 could be observed, and the results indicated that Tl(I) played a negative role in OCR of zebrafish. The characteristics of both ANE and OCR changes under slight Tl(I) stress could be reflected by the ammonia quotient (AQ). It was noteworthy that AQ increased rapidly in first 6â¯h from 0.66 to 4.50, which was 3 times higher than 1.2, indicating rapid increase in both anaerobic energy utilization and protein metabolism in 0.1⯵g/L Tl(I) exposure. It is concluded that the physiological changes of zebrafish based on metabolism can be regarded as a sensitive biological indicator of Tl(I) pollution, which could work as a substitute of potassium that disrupts the normal biological metabolism in the process of transport.