Determination the lethal range and effects of tobacco extract on the rainbow trout (Oncorhynchus mykiss) fingerlings

The aim of this study is to evaluate the toxicity of tobacco extract on rainbow trout. According to studies, has been investigated more on harmful effects of tobacco and their compounds on human and less attention has been paid to beneficial use in industries. This study can be considered as a first step in the identification and development of tobacco beneficial use in other industries. Acute toxicity test was carried out in static condition according to the O.E.C.D standard method for 4 days and physicochemical parameters of water were controlled including pH, dissolved oxygen and temperature. Thirty trout with an average weight of 5 ± 0.02 g were stocked in each treatment. After obtaining a lethal concentration range, the final treatments was carried out with five treatments to determine the lethal concentration (LC50 96 h). Quantitative results were analyzed by SPSS software version 16 and Probit statistical method with a confidence level of 95%. The lethal concentration of (LC50 96 h) tobacco extract for rainbow trout was 3.55 mg per liter and the no observed effect concentration (NOEC) be the equivalent of 0.35 mg per liter. Concentration of 0.01 LC50 96h recommended as safe level for aquaculture. While in the current study, concentration of 0.03 mg per liter is recommended for the rearing of rainbow trout larvae. It is recommended to use an aqueous extract of tobacco in low concentrations in trout farms, and according to the findings, also suggest non-toxic, effective and maximum allowable concentration of 0.03 mg per liter for safe use on farms.