Edwin Gómez Ramírez
Roundup® Activo (RA) is one of the most used herbicide in Colombia to weed control in traditional and transgenic crops, although also is used in the drying of grains, maturation of sugar cane, and control of illicit crop. The objective that research was determinate the lethal concentration (LC5096h) of herbicide RA on fry and fingerling on native fish Piaractus brachypomus. During 96h an acute static toxicity tests were performed to determine the median lethal concentration of glyphosate in the commercial product RA. Eighteen concentration was evaluated (1.0, 1.7, 2.3, 3.1, 4.2, 5.6, 7.4, 10.0, 13.3, 17.7, 23.7, 31.6, 35, 42.1, 56.2, 74.9, 100, 163.3 mg/L). Ten Fry and five fingerlings were randomly introduced in aquarium of 20L. There aquariumswere marked as control (not treated with RA).The dead fishes were noted and removed instantly by histopathological studies. Finally the LC5096h was determinate by the probit analysis method.Gill and kidney were dissected and fixed in formaldehyde, dehydrated in alcohol, processed in paraffin and stained in H&E. In fry and fingerlings of P. brachypomusthe LC5096h were determinate in 7.4 mg/L and 35 mg/L respectively. The histopathological alteration enhance when increasing the concentration of glyphosate in the RA.The gill showed edema, lamellar fusion, thalangetasia, and damage in pillar cells. The kidney exhibit picnoticcells, damage in the Bowman capsule and degeneration in the tubular epithelium. The LC5096hin Fry and Fingerlings were lower than previous reported to P. brachypomus for Roundup® SL,which suggests greater toxicity ofRA.INV-ING2980.