Effects of disinfectants on population growth of Fabrea salina

Fabrea salina can be used as a first feed for marine economic animals. In order to investigate the toxic effects and population dynamics of three disinfectants, potassium permanganate, povidone-iodine and dibromohydantoin, on F. salina, we conducted a static water test to study the growth rate (r) and generation time (G) changes of F. salina by different concentrations of these three disinfectants. The results show that the 24 h LC₅₀ values of potassium permanganate, dibromo hydantoin and povidone iodine were 1.182, 1.067 and 18.451 mg∙L⁻¹, respectively; the 48 h LC₅₀ values were 0.925, 0.748 and 19.620 mg∙L⁻¹, respectively; the safe concentrations (SC) were 0.170, 0.110 and 6.655 mg∙L⁻¹, respectively. The sensitivity of F. salina to these disinfectants followed a descending order of dibromohydantoin > potassium permanganate > povidone iodine. Besides, the most significant inhibition for F. salina growth was observed at 0.074 8 mg∙L⁻¹ of dibromo hydantoin, 1.962 mg∙L⁻¹ of povidone iodine and 0.092 5 mg∙L⁻¹ of potassium permanganate (p<0.01), with corresponding growth rates (r) of (0.57±0.009), (0.57±0.005) and (0.47±0.007) d⁻¹, and generation times (G) of (1.23±0.2), (1.22±0.011) and (1.30±0.078) d, respectively. The safe concentrations of potassium permanganate, povidone iodine and dibromo hydantoin obtained in this test were all lower than the dosages employed in aquaculture. Thus, attention should be paied to the dosage of these disinfectants when using F. salina as a first feed.