Gonad pathology and intersex severity in pelagic (Tilapia zilli) and benthic (Neochanna diversus and Clarias gariepinus) species from a pesticide-impacted agrarian catchment, south-south Nigeria (original) (raw)
Related papers
Environmental Biology of Fishes, 1993
Anabas testudineus were treated with non lethal levels of metacid-50 (0.106 ppb) and carbaryl(1.66 ppm) for 90 days covering the pre-spawning and spawning phases of the annual reproductive cycle. The main purpose of the present work was to identify the effects of metacid-50 and carbaryl on the gonado somatic index (GSI) and ovarian and plasma estrogen level. There was no alteration in GSI until 15 days, initiating the inhibition on day 20 which further intensified from 20 to 90 days of exposure. Plasma and ovarian estrogen level significantly increased up to 15 days of exposure followed by a decline till the end of the experiment. It is noteworthy that the effect of pesticides on GSI is reflected in the ovarian estrogen level. This highlights the fact that at short-term exposures the nonlethal levels of pesticides have no inhibitory effect while at long-term exposure, the pesticides have potent inhibitory effect on the reproduction of fish.
Risks Induced by Pesticides on Fish Reproduction
Pollution of water resources with agricultural water drainage has a great risk on fish reproduction. Organophosphrous pesticides such as Malathion and dimethaote are frequently used in Egypt due to their highly effectiveness for controlling agriculture pests. These pesticides were found that have endocrine disrupting effect on fish reproduction through lowering sex steroid hormones (estradiol and testosterone). Endocrine disrupting pesticides also have been implicated in the impairment of fish fecundity, semen quality, hatchability and survivability of fishes. Sex steroid hormones, vitellogenin, organosomatic indices and histopathology are considered as biomarker tools used for assessing disrupting effect of pesticides on fish.
Environmental Toxicology and Pharmacology, 2009
This study assesses the effects of 1,1-bis (4-chlorophenyl)-2,2,2-trichloroethane (DDT) on the reproduction and gonadal histology of adult Mozambique tipalia (Oreochromis mossambicus). The fish were allowed to breed, following exposure to 2 and 5 jig/l of waterborne technical-grade DDT for 40 days. Fertilized eggs were artificially incubated. In the 5 jig/l exposure, posthatch survival was significantly lower, and prevalence of larval skeletal deformities significantly higher, compared to the control (p<0.05). Incomplete axial development was the common gross deformity in posthatch larvae, caused by failure to develop chondroblasts posterior to the buccopharyngeal cavity. There were no significant differences in the gonadosomatic index of exposed and non-exposed male and female adults. The exposure caused increased oocyte atresia in the ovaries and disorganization of seminiferous lobules in the testes of adults. DDT exposure reduced survival and increased deformities in larvae, at levels that did not cause severe histopathological changes to parental gonads.
International Journal of Scientific Research
The effects of pesticide monocrotophos (organophosphate), on the ovaries of freshwater murrel, Channa punctatus were studied. Exposures for 15 and 45 days with histological preparations at 1 ml L-1, and 2 ml L -1 sublethal concentrations along with control were examined. Pre spawned 10 fish (47.85±0.75gm; 17.80 ± 0.50cm) were randomly stocked in 50 L aquarium in triplicate groups for each treatment levels. The effects of monocrotophs were analysed after 15 and 45 days of exposure, respectively. The control contained an abundance of the different stages of oocytes (Oocytes I, II, III, and IV) and had an intact ovigerous lamellae and follicular lining. The control also contained a thick and complete ovarian wall with evident previtelline and euvitelline nucleoli. After 15 days of exposure the gonado somatic index (GSI) significantly (P<0.05) decreased in the two exposure concentration, where the maximum decrease in both GSI and ovary was observed at higher concentration i.e. 2 ml L...
Aquatic Toxicology, 2009
In arid regions of the southwestern United States, municipal wastewater treatment plants commonly discharge treated effluent directly into streams that would otherwise be dry most of the year. A better understanding is needed of how effluent-dependent waters (EDWs) differ from more natural aquatic ecosystems and the ecological effect of low levels of environmentally persistent organic wastewater compounds (OWCs) with distance from the pollutant source. In a controlled experiment, we found 26 compounds common to municipal effluent in treatment raceways all at concentrations <1.0 g/L. Male bonytail chub (Gila elegans) in tanks containing municipal effluent had significantly lower levels of 11-ketotestosterone (p = 0.021) yet higher levels of 17-estradiol (p = 0.002) and vitellogenin (p = 0.036) compared to control male fish. Female bonytail chub in treatment tanks had significantly lower concentrations of 17-estradiol than control females (p = 0.001). The normally inverse relationship between primary male and female sex hormones, expected in un-impaired fish, was greatly decreased in treatment (r = 0.00) versus control (r = −0.66) female fish. We found a similar, but not as significant, trend between treatment (r = −0.45) and control (r = −0.82) male fish. Measures of fish condition showed no significant differences between male or female fish housed in effluent or clean water. Inter-sex condition did not occur and testicular and ovarian cells appeared normal for the respective developmental stage and we observed no morphological alteration in fish. The population-level impacts of these findings are uncertain. Studies examining the long-term, generational and behavioral effects to aquatic organisms chronically exposed to low levels of OWC mixtures are needed.
Journal of Applied Ichthyology, 2008
The effects of DDT and its metabolites on the reproductive health of two fish species (Clarias gariepinus and Oreochromis mossambicus) were studied using the gonadosomatic index (GSI), gonadal histology and computer assisted sperm analysis (CASA). DDT and its metabolites, DDE and DDD are endocrine disrupting chemicals posing estrogenic and antiandrogenic properties, which have detrimental effects on growth and reproduction. Although DDT was banned internationally, it is still used for Malaria vector control in areas of South Africa. Both species were sampled at a reference site, Albasini dam (AD), (outside the DDT-sprayed area, <0.01 lg L)1 of DDT) and at an exposed site, Xikundu weir (XW), in the same river ± 70 km within the DDT-sprayed area, <0.01 lg L)1 of DDT. Gill nets were used to acquire a sample size of 10 male fish per site for each species. Both testes were dissected out and the GSI calculated. Uncontaminated milt was collected and analyzed using a novel CASA system based on open source software for characterization of sperm motility parameters. Testis tissue sampled for histology was fixed in Bouins and processed according to standard methods. The sample size obtained at the reference site (AD) was O. mossambicus n = 6, C. gariepinus n = 9; and at the exposed site (XW) was O. mossambicus n = 10, C. gariepinus n = 3. The GSI results showed a lower value for O. mossambicus at XW (0.06) (n = 13) than AD (0.12) (n = 6); U = 16.0, P = 0.044. However the opposite was true for C. gariepinus. Exposure to various environmental toxicants can result in gonadal changes such as decreased GSI, morphological alterations or both. Histological assessment showed histopathological alterations to testes tissue including intersex (only in O. mossambicus) and detachment of basal membranes. The CASA results showed a decrease in parameters from the reference site (AD) to the exposed site (XW) for both species. The decrease in percent motility (% MOT) for O. mossambicus from the reference site (AD) (n = 6) to the exposed site (XW) (n = 13) was statistically significant; U = 13.0, P = 0.023. C. gariepinus from the exposed site (XW) was most affected in terms of percent motility (10.00%) and velocity (67.94 lm s)1). Detailed assessment of the environmental effects of DDT in this area seems crucial before population impacts become evident.
Food and Chemical Toxicology, 2008
Investigation of lethal dose of c-HCH (gamma isomer of hexachlorocyclohexane), DDT (dichlorodiphenyltrichloroethane) and chlorpyrifos on spermatozoa motility after 40 days exposure in catfish, Heteropneustes fossilis was done under laboratory conditions. The sperm motility was done in the fishes captured from unpolluted ponds of Gujartal considering as reference site and polluted rivers Gomti and Ganga of north India at pre-spermiating stage. Results indicate that 1 ppm of c-HCH, DDT and chlorpyrifos was lethal dose on sperm motility. The motility of spermatozoa decreased in insecticide exposed fish as well as in the fishes of polluted rivers when compared with their respective controls. The sperm motility was highest at 1:2000 (testicular milt: extender) dilution and duration of sperm motility was 90 s after postactivation. The duration of motility also declined in the fishes captured from polluted rivers when compared with the same species captured from the reference site. It is concluded that the insecticides decrease the sperm motility and its duration in exposed fish as well as in the captured fishes from polluted rivers causing the decline in fish population of riverine systems due to influence of xenobiotics on the endocrine system.
Ecotoxicology and Environmental Safety, 2003
The EU-funded project IDEA aimed to evaluate (a) what parameters and endpoints allow the detection of endocrine-mediated developmental and reproductive effects of (xeno)estrogens in life cycle-and life stage-specific toxicity tests with the zebrafish Danio rerio, a small laboratory fish used in many ecotoxicity test guidelines, and (b) whether substances that act as estrogens in vertebrates may also adversely affect the development, differentiation, and reproduction of aquatic invertebrates. The invertebrate species investigated included Hydra vulgaris, Gammarus pulex, Chironomus riparius, Hyalella azteca, and Lymnaea stagnalis. The animals were exposed to the model estrogenic chemicals ethynylestradiol (EE2), bisphenol A (BPA), and octylphenol (OP), which exert their endocrine activity in vertebrates through the estrogen receptor. As endpoints, developmental and reproductive parameters at the organism level as well as molecular and cellular parameters were measured. Life cycle exposure of zebrafish to (xeno)estrogens induced a specific, partly irreversible response pattern, consisting mainly of (a) induction of vitellogenin (VTG), (b) alterations of gonad differentiation, (c) delay of first spawning, and (d) reduced fertilization success. The effects of EE2 on zebrafish were expressed at environmentally realistic concentrations, while BPA and OP became effective at concentrations higher than those usually found in the environment. The vitellogenic response was equally sensitive as the reproductive parameters in the case of EE2, but VTG was more sensitive in the case of BPA. Partial life cycle exposure of zebrafish had lasting effects on fish development and reproduction only when the fish were exposed during the stage of juvenile bisexual gonad differentiation. In (partial) life cyle and multigeneration studies with invertebrates, (xeno)estrogenic impact was assessed by a range of developmental and reproductive parameters including hatching, growth, moulting, mating behavior, and egg number. Several parameters were found to be responsive to (xeno)estrogens; however, most effects were induced only at higher, probably nonphysiological concentrations. Lowdose effects were observed in full life cycle experiments, particularly in the second generation. It remains to be established whether the estrogen-induced alterations in the invertebrate species indeed do result from disturbances of the endocrine system. The findings of the present research project support the development of appropriate testing methodologies for substances with estrogenic activity. r 2002 Elsevier Science (USA). All rights reserved. 0147-6513/03/$ -see front matter r 2002 Elsevier Science (USA). All rights reserved. PII: S 0 1 4 7 -6 5 1 3 ( 0 2 ) 0 0 0 3 9 -8
Ecotoxicology and Environmental Safety, 2019
The widespread use of the synthetic estrogen 17 α-ethinylestradiol (EE 2) has resulted in elevated levels in aquatic environments, where it is known to act as an endocrine disrupting chemical affecting fish and other aquatic organisms. Examining changes in the structure of the fish' gonads and liver has proven to be an effective approach for assessing these impacts. While changes have been reported for various fish species, it is not clear whether impacts are equally severe in live-bearing fishes. The present study looked at gonadal and liver development in EE 2-exposed least killifish (Heterandria formosa), a live-bearing Poeciliid. Exposures to 0, 5, or 25 ng/L EE 2 began within six days of birth and continued until fish became sexually mature 12-23 weeks later. Exposure to 5 ng/L EE 2 resulted in severe intersex in fish with external male characteristics, a slowdown of spermatogenesis in these intersex fish and a slowdown of oogenesis in the female fish. Moreover, these fish had a variety of liver injuries. Fish exposed to 25 ng/L EE 2 exhibited intersex but at a lower frequency than occurred at 5 ng/L. In contrast, liver damage and slowdown of both oogenesis and spermatogenesis exhibited the typical dose-dependence. These findings illustrate the importance of including histological analyses when assessing endocrine disruption in fish, demonstrate that the live-bearing mode of reproduction appears to provide limited protection from the effects of waterborne EE 2 , and provide further evidence that EE 2 has multiple impacts on fish health and reproduction that are severe enough to potentially affect fish populations.