Use of common salt (NaCl) in the control Epistylis sp. in hybrid sorubim

Epistylis sp. is an emerging parasite in Brazil and is commonly found in surubim Pseudoplatystoma spp. during the initial stages of production and, therefore, requires the establishment of prophylactic and therapeutic measures, aiming at its control. Therefore, the present study aimed to evaluate the use of common salt to control Epistylis sp. in surubim juveniles. The fish (n = 48) were randomly divided into three treatments, and a control group, with three replicates each. The treatments consisted of three therapeutic baths performed every 48 hours for 20 minutes with different concentrations of common salt: 0.0%, 1.0%, 1.5% and 2.0%. The experiment lasted six days. Twentyfour hours after the last bath, the fish were sampled to check for the presence of the parasite and blood collection. Salt treatments of 1.5% and 2.0% were effective in eliminating parasites in 82% and 78% of treated fish, respectively. Fish subjected to the 2.0% salt bath showed higher hematocrit and hemoglobin values (P <0.05) compared to fish in the control group, in addition to changes in leukocyte values. Common salt can be used to control Epistylis sp. in naturally infected surubim juveniles.