SUBLETHAL EFFECTS OF TETRACHLOROGUAIACOL ON JUVENILE RAINBOW-TROUT, ONCORHYNCHUS-MYKISS, FOLLOWING ACUTE AND CHRONIC EXPOSURE

Following either a 24-h (acute) or 25-d (chronic) exposure to tetrachl oroguaiacol (TeCG), a component of bleached krait mill effluent (BKME) , juvenile rainbow trout, Oncorhynchus mykiss, were examined for effec ts on several biochemical parameters, swimming performance, and diseas e resistance. Acute exposure resulted in increased levels of plasma co rtisol and lactate and reductions in liver glycogen and protein, splee n somatic index, leucocrit, hemoglobin, swimming performance, and dise ase resistance. Chronic exposure resulted in most parameters remaining at control levels with the exception of leucocrit which was elevated, plasma cortisol which decreased, and disease resistance which was imp aired. These findings correlate well with a previously proposed classi c stress response for mammals and are generally consistent with studie s in which fish were exposed to whole BKME. The 96-h LC(50) for juveni le rainbow trout exposed to TeCG was estimated at 0.37 mg.L(-1).