Abstract

Tank-raised Clarias gariepinus (mean weight, 250.04 ± 50.22 g, SD: mean total length 30.05 ± 4.05 cm, SD) were intramuscularly injected with aqueous extracts (2 ml/kg weight of fish) of various concentrations (2.00, 4.00, 6.00, 8.00 and 10.00 ppm) of leaves Lepidagathis alopecuroides. The extract was administered to five replicates/treatment level and a control injected with distilled water. On the fourteenth day, samples of organs (kidney, liver and gill) and muscle tissue were analysed for alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST) and lactate dehydrogenase (LDH). ALP activity in the treated group the was inhibited below the control, 376.65 ± 222.50 IU/L, but at 87.18% elevation at 10.00 ppm (705.00 ± 83.55 UI/L), AST activity was inhibited from 546.65 ± 190.70 IU/L in the control to 223.75 ± 69.80 IU/L at 8.00 ppm extract.  ALT activity was inhibited with the lowest value, 30.00 ± 18.25 IU/L at 6.00 ppm, compared with the control, 53.35 ± 22.55 IU/L. LDH activity was excited 5.09, 23.54 and 5.49% at 2.00, 8.00 and 10.00 ppm extract respectively, above the control, 311.65 ± 58.35 IU/L.  The activities of the respective enzyme in the muscle of treated fish had maximum inhibition below their respective control values as follows: ALP, 41.67% at 10.00 ppm; AST, 39.53% at 2.00 ppm; ALT, 83.01% at 6.00 ppm, and LDH, 45.55% at 4.00 ppm). Activities of ALP, AST and ALT in the kidney were inhibited below the control and varied very widely among the enzymes.  However, LDH activity was excited in exposed fish with a peak, 592.50 ± 301.90 IU/L, 125.77% above the control, 231.65 ± 168.25 IU/L at 8.00 ppm. ALP activity in the liver was elevated at 2.00, 4.00 and 10.00 ppm; 25.00, 43.75 and 18.75%, respectively, above the control, 100.00 ± 20.00 IU/L. AST and ALT activities were either inhibited or excited. LDH activity was excited in the treated group (maximum, 887.50 ± 438.95 IU/L, 29.87% above control value, 683.35 ± 104.10 IU/L at 2.00 ppm. The relative activity of the ALP in the tissues was kidney>gill>liver>muscle; ALT activity was most pronounced in the kidney, but the pattern of ALT in the other tissues and that of AST varied very widely within each of the organs and among the various concentrations of the extract.  LDH activity was higher in the muscle tissues and liver than the kidney and gills, however, with no defined pattern relative to the exposure concentrations. Results from this study strongly suggest that all the enzymes assayed could be good indicators of L. alopecuroides toxicosis in C. gariepinus.

Key word: Alkaline phosphatase, alanine transaminase, aspartate transaminase, lactate dehydrogenase, Clarias gariepinus, Lepidagathis alopecuroides.