Use of oxytetracycline for the treatment of tremor disease in the Chinese mitten crab Eriocheir sinensis

摘要

ABSTRACT: The causative agent of tremor disease (TD) in the Chinese mitten crab Eriocheir sinensis has been shown to be a member of the genus Spiroplasma. In the present study, a susceptibility test indicated that oxytetracycline (OTC) has both a high degree of efficacy in the inhibition of Spiroplasma and a broad range of safe concentrations. Treatment experiments showed that the best concentration of OTC for use against TD was 40 mg OTC kg–1 crab weight. Acute toxicity experiments demonstrated that the 24 and 48 h median lethal dosages (LD₅₀) of OTC for this species of crab were 366 and 340 mg OTC kg–1 crab body weight, respectively, while the safe concentration was 82.5 mg OTC kg–1 crab weight. We suggest that OTC has potential as a highly effective inhibitor of Spiroplasma pathogens in aquatic animals and has been proven to be a potent, safe and low cost cure for TD. This represents a novel use of OTC in the therapeutic treatment of an aquacultural disease caused by a Spiroplasma pathogen.