Effect of dissolved oxygen stress on respiration physiology and nitrogen metabolism in Rhodeus sinensis

Abstract:

The respiration physiology and nitrogen metabolism of Rhodeus sinensis were studied with closed respirometry at (23.2±0.2) ℃, and under such condition, the dissolved oxygen reduced gradually. The results showed that the oxygen consumption rate (OCR) and ammonia excretion rate (AER) of Rhodeus sinensis with satiety and hunger were 0.441 mg/(g·h), 0.297 mg/(g·h)and 1.6 μg/(g·h), 0.5 μg/(g·h) respectively. Rhodeus sinensis floated head and died when the dissolved oxygen was less than 1.5 mg/L and 0.31 mg/L,respectively. OCR and AER reduced significantly as the dissolved oxygen reduced,and then there were diurnal variations in both OCR and AER.Water quality was deteriorating as the dissolved oxygen was reducing,because the ammonia and nitrite increased obviously in aquarium. The present study preliminarily revealed that dissolved oxygen stress would have a significant influence on the respiratory metabolism and nitrogen metabolism of Rhodeus sinensis.So, it was necessary to keep dissolved oxygen above 1.5 mg/L for feeding and transporting of Rhodeus sinensis, and it was a good choice for transporting with hunger.