Oxidative stress, haematology and histology biomarkers of African clariid catfish clarias gariepinus(Burchell 1822) to glyphosate-based herbicide GBHG, ‘Glycot’
Michael Anayo Israel, Joseph Ikechukwu Chidobem, Ezike Christopher Onyemaechi
Fish were exposed to acute doses: 31, 33, 35, 37, 39 and control (0.00) mg glycot L-1 of clean water and obtained 96h LC50 value of 33.9 mgL-1 and a logarithmic probit line y = 20.11x - 25.80, R² = 0.972. Sub -acute doses: 3.39, 6.78, and 16.95mgL-1 of the same, corresponding to 1/10 LC50=3.39 mgL-1, 1/5 LC50=6.78 mgL-1, ½ LC50=16.95 mgL-1’ were generated. The 96 h LC50 of the herbicide to the fish corresponds to 96h safety dose of 1/100 LC50 = 0.339 mgL-1. Catalase CAT was significantly (p<0.05) inhibited in treatments compared to control, and it ranged from the highest value of 0.74 umol mm-1 mg protein-1 in control to the lowest value of 0.21 umol mm-1 mg protein-1 in exposed group to 16.95 mg/L on day 4 but returned to control value on day 8 in all the treatments (figure 2). Superoxide disimutase SOD was significantly (p<0.05) inhibited among exposed fish compared to control on days 1-4. A range of 11.60 U mg protein -1 in control on day 1 to lowest value of 6.50 U mg protein -1 returned to control value on day 8. Similarly GPX was significantly inhibited to a lowest value of 4.25 in fish exposed to 3.5mg/L compared to the highest value of 9.36 in control fish on day 4 but returned to control value with a high value of 9.25 umol-1 min protein-1. Similarly, Lipid peroxidation LPO ranged from the highest value of 6.8 mMole/TBARS/ mg protein in 16.95mg/L to a lowest value of 6.41 mMole/TBARS/ mg protein in control on day 4, returned to the control value on day 8. The hematological parameters were significantly reduced in the treated values of PCV and ranged from 20.00±0.19 – 23.33±0.55 %) below the value of 28.33±0.61% recorded in the control. Similarly, the red blood cells RBC, and haemoglobin HB recorded inhibited ranges of 8.58±0.21 - 9.10±0.03 x 106 mm3 below their elevated respective controls of 10.06±0.03 x 106 mm3 and 8.73±0.05. However the white blood cells WBC and platelets PL recorded elevated ranges of 12934.00±544.68 - 13700.00±485.72 x 103 mm3 and 15933.33±322.79 above their respective control values of 9466.66 0.09±96.86 x 103 mm3 and 15633.33±181.89. Histology of gills exposed to glyphosate indicated lamellae degeneration, primaryand secondary lamellae degenerations/talengietasis/oedema, liver exposed to glyphosate showing intercellular dilatations, hyperplasia/cirrhosis and thickening of portal tract/fatty degeneration while muscles exposed to the sames showed evidence of splitting of fibre, atrophy and cell degeneration. The present finding indicated that glyphosate based herbicide glycot impaired haematology, antioxidative stress enzymes and vital histology of C. gariepinus and could serve as an early warning signs toward ecotoxicological hazards prevetion and remediation in aquatic ecosystems.