Effects of glyphosate and 2,4- dichlorophenoxyacetic acid on the hatchability and larval development of african catfish (Clarias gariepinus)
Date
2019-12
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Federal University of Technology, Owerri.
Abstract
The effects of the exposure of glyphosate and 2, 4-dichlorophenoxyacetic acid, on the egg hatchability and larvae development ofCatfish (Clarias gariepinus)were evaluated using standard methods. Acute toxicity,hatchability of eggs, survivability of larvae, biochemical and histological parameters of reproductive organs and skin were evaluated. The acute lethal study of glyphosate and 2, 4-D on catfish fingerlings showed that no fish died within 24 hrs.
However, for the mixture of glyphosate and 2, 4-D, at higher concentrations death occurred, and the LD50was less than 2500mg/kg (2154.07mg/kg). There was a change inwater quality resulting from application of the toxicants compared to the control. There wasalso decrease in the hatchability of the eggsand reproductive success for the mixture of glyphosate and 2, 4-D treatments. The highest percentage mortalityand least percentage survivability(after fourteen
days) were recorded in the mixture of glyphosate and 2, 4-D-treated eggs (72±60 and 20±16.67 respectively). The mean weight gain value and the instantaneous growth rate, expressed as Specific Growth Rate (SGR), werelow in the mixture of glyphosate and 2, 4-D (0.75 ± 0.08g and 0.71 respectively) compared with control (2.24±0.22). Physical examination showed the larvae of the mixture of glyphosate and 2, 4-D to be smaller and lighter (tail region appeared transparent) relative to those from other treatments and control. Biochemical parameterson the liver revealed elevation in the activities of stimulating liver enzymes (GSH and GST)in all experimental groups (1.06/6.88E-06, 1.67/5.72E-06, 1.73/5.88E-06) compared with control (1.53/4.28E-06). There werealso elevation in the activities of the antioxidant enzymes such as Catalase (CAT), Superoxide dismutase (SOD), Glutathione Peroxidase (GPx), and lipid peroxidation compared with control. There was reduction in the total protein level for the glyphosate treatment (15.46g/l) compared to control (25.60g/l). The histological changes observed in this experiment revealed that glyphosate, 2, 4-D and their mixtures caused negative effects on the skin, testes and ova of Clarias gariepinus brood stocks. The fish organs examined showed varying degrees of pathological alterations/degenerations to the skin, testes and ova in all the treatments compared to the control. These results show that the herbicides, glyphosate and 2, 4-D, have toxic effects on the hatchability and survivability of Clarias gariepinus. These toxic effects were more deleterious when the two herbicides were mixed, as the synergistic effects greatly impeded fish reproduction
Description
Master’s thesis on "hatchability and larval development of african catfish (Clarias gariepinus)"
Keywords
Toxicity, hatchability, herbicide, histology, Clarias gariepinus, department of biotechnology
Citation
Alozie, S. N. (2019). Effects of glyphosate and 2,4- dichlorophenoxyacetic acid on the hatchability and larval development of african catfish. {Unpublished Master's Thesis}, Federal University of Technology, Owerrri.