Optimization of recovery patterns in common carp exposed to roundup using response surface methodology: Evaluation of neurotoxicity and genotoxicity effects and biochemical parameters

• We optimized the recovery conditions for the common carp exposed to Roundup®.
• Optimization of recovery conditions led to reduce the damage and abnormal levels.
• The results showed that recovery time had the dominant effect on detoxification.
• The response surface methodology (RSM) has been applied for models development.
• The polynomial equations made by RSM were efficient to predict the responses.

The present study is the first report on optimization of recovery conditions of fishes exposed to pesticides using response surface methodology-central composite rotatable design (RSM-CCRD). The sub-lethal toxicity bioassay of Roundup® (2 ppm ~10 percent LC50, 96 h) in common carp (1, 4, 9, 16, 25, 35 and 40 day) was investigated. After exposure for 16 days to Roundup®, some the fishes were introduced to herbicide-free water. The effects of four recovery parameters including time (5–25 d), temperature (18–26 °C), water exchange rate (WER, 10–30), and salinity (0–8 ppt) on the levels of biomarkers of genotoxicity (DNA damage), neurotoxicity (acetylcholinesterase activity (AChE)), and the serum alanine (ALT) and aspartate (AST) aminotransferase in plasma were studied. The polynomial equations were significantly fitted for all response variables with high R2 values (>0.95), which revealed no indication of lack of fit. The optimum conditions for the maximum AChE activity (37.14 nmol/min/mg protein) and the minimum levels of DNA damage (8.00 percent tail DNA), ALT (27.0 IU/L) and AST (91.0 IU/L) were time of 20 d, temperature of 20 °C, WER of 25 and water salinity of 6 ppt. Thus, a promising improvement for the recovery trend of fishes exposed to Roundup® stress was obtained under the optimized conditions using RSM-CCRD.