Acute toxicity of light and several herbal medicines on ciliate Diophrys appendiculata
ZHENG Xiaonan1, WANG Hongyu1, LI Xuehan1, Lü Xianglin1, QI Hongli1,2*
1.Tianjin Key Laboratory of Aqua-Ecology and Aquaculture, College of Fisheries, Tianjin Agricultural University, Tianjin 300384, China; 2.Laboratory of Protozoology, Ocean University of China, Qingdao 266003, China
Abstract: Toxicity of 13 kinds of Chinese herbal medicines including Cortexdictamni, Sophoraeflavescentis, Herbaandrographis, Fructustoosendan, Fructusquisqualis, Pseudolarixamabilis, Agrimoniapilosa, Carpesiumabrotanoides, Arecacatechu, Gleditsiasinensis, Radixstemonae, Fructuscnidii and Rhizomaarisaematis at a dose of 900 mg/L to ciliate Diophrysappendiculata were screened by static bioassay test at normal light-dark (14L∶10D) and complete darkness. It was found that Arecacatechu， Agrimoniapilosa and Pseudolarixamabilis had better efficacy for killing the ciliate among the 13 kinds of Chinese herbal medicines at concentration of 900 mg/L. Then acute toxicity of Arecacatechu(at a dose of 0, 30, 40, 50, 60, 70, and 80 mg/L), Pseudolarixamabilis(at a dose of 0, 190, 210, 230, 250, 270, and 290 mg/L), and Agrimoniapilosa (at a dose of 0, 310, 340, 370, 400, 430, and 460 mg/L) to the ciliate was determined in order to prevent and control pathogenetic ciliate in aquaculture. The results showed that 100% of the ciliate was found to be dead at Arecacatechu concentration of 80 mg/L for 48 h at normal light-dark, and 97.8% of the ciliate dead for the 96 h at complete darkness. 100% mortality was observed in the ciliate exposed to Agrimoniapilosa concentration of 460 mg/L， for 72 h at normal light-dark, and 77.8% mortality was observed in the ciliate exposed to Agrimoniapilosa concentration of 460 mg/L for 96 h at complete darkness. The ciliate exposed to Pseudolarixamabilis concentration of 290 mg/L for 96 h had 90.0% of mortality at normal light-dark and 84.4% of mortality at complete darkness. The 24 h LC50 to the ciliate was shown to be 65.964 mg/L in Arecacatechu， 261.194 mg/L in Pseudolarixamabilis and 419.169 mg/L in Agrimoniapilosa at normal light-dark, showing the descending acute toxicity order of the Chinese herbal medicines as Arecacatechu > Pseudolarixamabilis >Agrimoniapilosa. The findings indicate that Arecacatechu, Agrimoniapilosa and Pseudolarixamabilis can treat the harmful ciliates in aquaculture， Arecacatechu being used as the first medicinal plant at the optimal concentration of the 80 mg/L to control ciliate D.appendiculata.
2020, Vol. 35 
