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Results for “Reproductive Toxicology”

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At least 37 records · Page 2Linked to original sources
USGS1997

Fertilization of eggs of Lake Michigan lake trout Salvelinus namaycush in lake water: Effect of PCBs (Aroclor 1254)

Various studies indicate that PCBs appear to have an adverse effect on the viability of fertilized eggs and subsequent early life stages of lake trout and related species. Our tests detected no impairment of fertilization of lake trout eggs in PCB-dosed lake water. The concentration of PCBs in the fertilization medium that we used was more than 20 times as high as estimated ambient levels in southeastern Lake Michigan and it appears unlikley that ambient levels of PCBs in the water at fertilization would contribute significantly to the apparent widespread reproductive failure of lake trout there.

Bulletin of Environmental Contamination and Toxico↗
USGS2012

Ecotoxicology of mercury in fish and wildlife: Recent advances

A number of recent studies have documented subtle, yet potentially important effects of mercury on behavior, neurochemistry, and endocrine function in fish and wildlife at currently realistic levels of environmental exposure. Current levels of environmental methylmercury exposure are sufficient to cause significant biological impairment, both in individuals and in whole populations, in some ecosystems. Future toxicological studies on fish and wildlife will focus on linking biomarkers of methylmercury exposure and associated oxidative stress to effects on reproduction and population change; determining the genetic basis for mercury-related neurotoxic and other biological changes; determining the genetic basis for species differences in sensitivity to methylmercury; and linking toxic effects of methylmercury in individual animals to population-level changes.

Book chapter↗
USGS2011

Toxic effects of dietary methylmercury on immune function and hematology in American kestrels (Falco sparverius)

Fifty-nine adult male American kestrels ( Falco sparverius ) were assigned to one of three diet formulations including 0 (control), 0.6, and 3.9 &mu;g/g (dry wt) methylmercury (MeHg). Kestrels received their diets daily for 13 weeks to assess the effects of dietary MeHg on immunocompetence. Immunotoxic endpoints included assessment of cell-mediated immunity (CMI) using the phytohemagglutinin (PHA) skin-swelling assay and primary and secondary antibody-mediated immune responses (IR) via the sheep red blood cell (SRBC) hemagglutination assay. Select hematology and histology parameters were evaluated to corroborate the results of functional assays and to assess immunosuppression of T and B cell-dependent components in spleen tissue. Kestrels in the 0.6 and 3.9 &mu;g/g MeHg groups exhibited suppression of CMI, including lower PHA stimulation indexes ( p = 0.019) and a 42 to 45% depletion of T cell-dependent splenic lymphoid tissue ( p = 0.006). Kestrels in the 0.6 &mu;g/g group exhibited suppression of the primary IR to SRBCs ( p = 0.014). MeHg did not have a noticeable effect on the secondary IR ( p = 0.166). Elevation of absolute heterophil counts ( p < 0.001), the heterophil to lymphocyte ratio ( p < 0.001), and total white blood cell counts ( p = 0.003) was apparent in the 3.9 &mu;g/g group at week 12. Heterophilia, or the excess of heterophils in peripheral blood above normal ranges, was apparent in seven of 17 (41%) kestrels in the 3.9 &mu;g/g group and was indicative of an acute inflammatory response or physiological stress. This study revealed that adult kestrels were more sensitive to immunotoxic effects of MeHg at environmentally relevant dietary concentrations than they were to reproductive effects as previously reported.

Environmental Toxicology and Chemistry↗
USGS1990

Fluoride accumulation and bone strength in wild black-crowned night-herons

Fluoride was measured in femurs of black-crowned night-herons ( Nycticorax nycticorax ) living adjacent to a phosphate processing complex near Pocatello, Idaho. Fluoride (ash wt.) in femurs ranged from 540 μg/g to 11,000 μg/g and increased (P=0.0001) with age, but with no difference (P=0.80) between sexes. Adult males (⩾4 years) contained 5,409 μg/g compared to 6,042 μg/g for adult females. The tibiotarsus (=tibiae in text) increased in diameter with age (P=0.015) in this study; fluoride was nearly related (P=0.065) to the increase. As the diameter increased with age, wall thickness decreased (P=0.011) suggesting excessive internal bone resorption, but fluoride concentrations were not implicated in the relationship (p= 0.64). The apparent increase in diameter and decrease in wall thickness may have partially neutralized each other's effects on strength. Although significantly higher concentrations of fluoride were present in adults than in Third Year herons, no significant change in bone strength (maximum load or modulus of rupture) was detected between the two age classes, but three of the four comparisons showed adults with less strength ( i.e. , a hint of diminished strength with age). The tibiae of Hatch Year birds were significantly weaker than documented in older age classes, but incomplete growth was thought responsible. The strong relationship between age and fluroide concentrations reduced our ability to separate a “fluoride effect” from an “age effect.” Other authors believed fluoride was responsible for an increase in bone diameter and the fluoride residues encountered in adults were within the range indicative of poisoning in cattle. In addition, the adult night-herons had about 1.6 times higher fluoride concentrations than owls which showed reduced reproductive success under laboratory conditions.

Archives of Environmental Contamination and Toxico↗
USGS1988

Organochlorine pesticides, polychlorinated biphenyls, and mercury in osprey eggs – 1970-79 – And their relationships to shell thinning and productivity

Osprey ( Pandion haliaetus ) eggs were collected in 14 states in 1970–79 and analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), and mercury. Moderate shell thinning occurred in eggs from several areas. DDE was detected in all eggs, PCBs in 99%, DDD in 96%, dieldrin in 52%, and other compounds less frequently. Concentrations of DDT and its metabolites declined in eggs from Cape May County, New Jersey between 1970–72 and 1978–79. Eggs from New Jersey in the early 1970s contained the highest concentrations of DDE. Dieldrin concentrations declined in eggs from the Potomac River, Maryland during 1971–77. Five different contaminants were significantly negatively correlated with shell thickness; DDE was most closely correlated. Ten percent shell thinning was associated with 2.0 ppm DDE, 15% with 4.2 ppm, and 20% with 8.7 ppm in eggs collected from randomly selected nests before egg loss. Shell thickness could not be accurately predicted from DDE concentrations in eggs collected after failure to hatch, presumably because the eggs with the thinnest shells had been broken and were unavailable for sampling. DDE was also significantly negatively correlated with brood size. Other contaminants did not appear to adversely affect shell thickness or reproductive success.

Archives of Environmental Contamination and Toxico↗
USGS2010

North American osprey populations and contaminants: Historic and contemporary perspectives

Osprey ( Pandion haliaetus ) populations were adversely affected by DDT and perhaps other contaminants in the United States and elsewhere. Reduced productivity, eggshell thinning, and high DDE concentrations in eggs were the signs associated with declining osprey populations in the 1950s, 1960s, and 1970s. The species was one of the first studied on a large scale to bring contaminant issues into focus. Although few quantitative population data were available prior to the 1960s, many osprey populations in North America were studied during the 1960s and 1970s with much learned about basic life history and biology. This article reviews the historical and current effects of contaminants on regional osprey populations. Breeding populations in many regions of North America showed post-DDT-era (1972) population increases of varying magnitudes, with many populations now appearing to stabilize at much higher numbers than initially reported in the 1970s and 1980s. However, the magnitude of regional population increases in the United States between 1981 (first Nationwide Survey, ∼8,000 pairs), when some recovery had already occurred, 1994 (second survey, ∼14,200), and 2001 (third survey, ∼16,000–19,000), or any other years, is likely not a simple response to the release from earlier contaminant effects, but a response to multi-factorial effects. This indirect “contaminant effects” measurement comparing changes (i.e., recovery) in post-DDT-era population numbers over time is probably confounded by changing human attitudes toward birds of prey (shooting, destroying nests, etc.), changing habitats, changing fish populations, and perhaps competition from other species. The species' adaptation to newly created reservoirs and its increasing use of artificial nesting structures (power poles, nesting platforms, cell towers, channel markers, offshore duck blinds, etc.) are two important factors. The timing of the initial use of artificial nesting structures, which replaced declining numbers of suitable trees at many locations, varied regionally (much later in the western United States and Mexico). Because of the increasing use of artificial nesting structures, there may be more ospreys nesting in North America now than ever before. Now, with the impact of most legacy organic contaminants (DDT, other organochlorine [OC] pesticides, polychlorinated biphenyls [PCB], polychlorinated dibenzo- p -dioxins [PCDD], polychlorinated dibenzofurans (PCDF]) greatly reduced or eliminated, and some osprey populations showing evidence of stabilizing, the species was proposed as a Worldwide Sentinel Species for evaluating emerging contaminants. Several emerging contaminants are already being studied, such as polybrominated diphenyl ethers (PBDE) and perfluorinated acids and sulfonate compounds (PFC). The many advantages for continued contaminant investigations using the osprey include a good understanding of its biology and ecology, its known distribution and abundance, and its ability to habituate to humans and their activities, which permits nesting in some of the potentially most contaminated environments. It is a top predator in most ecosystems, and its nests are relatively easy to locate and study with little researcher impact on reproductive success.

Journal of Toxicology and Environmental Health, Pa↗
USGS2001

Dicofol residues in eggs and carcasses of captive American kestrels

American kestrels ( Falco sparverius ) were fed diets containing 0 (control), 1, 3, 10, and 30 μg/g (wet wt) of Kelthane®. Residues of dicofol and its metabolites were then analyzed in the eggs and carcasses of females. Significant differences occurred among treatments for residues of both p,p ′‐dicofol and p,p ′‐dechlorodicofol (DCD) in both eggs and carcasses and for p,p ′‐dicholorbenzophenone (DCBP) in eggs. Residue concentrations increased with increasing treatment exposure. Residues of p,p ′‐dicofol, p,p ′‐DCD, and p,p ′‐DCBP in eggs were significantly correlated with eggshell quality parameters. Significant correlations also occurred among contaminants in eggs and for individual contaminants between eggs and carcasses. The lowest‐observed‐dietary‐effect concentration for eggshell thinning was 3 μg/g, whereas 1 μg/g may be considered to be near a no‐observable‐adverse‐effect concentration. Concentrations of dicofol in potential prey items and eggs of wild birds generally have been lower than dietary‐effect concentrations or concentrations in tissues or eggs associated with eggshell thinning and reduced reproductive success.

Environmental Toxicology and Chemistry↗
USGS2002

Blood selenium concentrations and enzyme activities related to glutathione metabolism in wild emperor geese

In 1998, we collected blood samples from 63 emperor geese ( Chen canagica ) on their breeding grounds on the Yukon-Kuskokwim Delta (YKD) in western Alaska, USA. We studied the relationship between selenium concentrations in whole blood and the activities of glutathione peroxidase and glutathione reductase in plasma. Experimental studies have shown that plasma activities of these enzymes are useful biomarkers of selenium-induced oxidative stress, but little information is available on their relationship to selenium in the blood of wild birds. Adult female emperor geese incubating their eggs in mid-June had a higher mean concentration of selenium in their blood and a greater activity of glutathione peroxidase in their plasma than adult geese or goslings that were sampled during the adult flight feathermolting period in late July and early August. Glutathione peroxidase activity was positively correlated with the concentration of selenium in the blood of emperor geese, and the rate of increase relative to selenium was greater in goslings than in adults. The activity of glutathione reductase was greatest in the plasma of goslings and was greater in molting adults than incubating females but was not significantly correlated with selenium in the blood of adults or goslings. Incubating female emperor geese had high selenium concentrations in their blood, accompanied by increased glutathione peroxidase activity consistent with early oxidative stress. These findings indicate that further study of the effects of selenium exposure, particularly on reproductive success, is warranted in this species.

Alaska↗
USGS2009

A nonlethal microsampling technique to monitor the effects of mercury on wild bird eggs

Methylmercury is the predominant chemical form of mercury reported in the eggs of wild birds, and the embryo is the most sensitive life stage to methylmercury toxicity. Protective guidelines have been based mainly on captive-breeding studies with chickens (Gallus gallus), mallards (Anas platyrhynchos), and ring-necked pheasants (Phasianus colchicus) or on field studies where whole eggs were collected and analyzed and the effects of the mercury were measured based on the reproductive success of the remaining eggs. However, both of these methods have limitations. As an alternative, we developed a technique that involves extracting a small sample of albumen from a live egg, sealing the egg, returning the egg to its nest to be naturally incubated by the parents, and then relating the hatching success of this microsampled egg to its mercury concentration. After first developing this technique in the laboratory using chicken and mallard eggs, we selected the laughing gull (Larus atricilla) and black-necked stilt (Himantopus mexicanus) as test subjects in the field. We found that 92% of the microsampled laughing gull eggs met our reproductive endpoint of survival to the beginning of hatching compared to 100% for the paired control eggs within the same nests. Microsampled black-necked stilt eggs exhibited 100% hatching success compared to 93% for the paired control eggs. Our results indicate that microsampling is an effective tool for nonlethally sampling mercury concentrations in eggs and, as such, can be used for monitoring sensitive species, as well as for improving studies that examine the effects of mercury on avian reproduction.

Environmental Toxicology and Chemistry↗
USGS1996

Effects of boron and selenium on mallard reproduction and duckling growth and survival

Boron (B) and selenium (Se) sometimes occur together in high concentrations in the environment and can accumulate in plants and invertebrates consumed by waterfowl. One hundred twenty-six pairs of breeding mallards (Anas platyrhynchos) were fed diets supplemented with B (as boric acid) at 0, 450, or 900 ppm, in combination with Se (as seleno-DL-methionine) at 0, 3.5, or 7 ppm, in a replicated factorial experiment. Ducklings produced received the same treatment combination as their parents. Boron and Se accumulated in adult liver, egg, and duckling liver. In adults, B and Se caused weight loss, and B decreased hemoglobin concentration, egg weight, and egg fertility. Both B and Se reduced hatching success and duckling weight, and B reduced duckling growth and duckling production, and caused several alterations in duckling liver biochemistry. Duckling survival was not reduced by B or Se, and neither B nor Se had histopathologic effects on adult or duckling liver, kidney, or spleen. There was little evidence of interaction between B and Se. This study demonstrated that B and Se, in the chemical forms and at the dietary levels administered in this study, can adversely affect mallard reproduction and duckling growth.

Environmental Toxicology and Chemistry↗
USGS1985

Effects of fluoride on screech owl reproduction: Teratological evaluation, growth, and blood chemistry in hatchlings

The effects on reproduction in screech owls ( Otus asio ) of chronic dietary sodium fluoride administration at 0, 40, and 200 ppm were examined. Fluoride at 40 ppm resulted in a significantly smaller egg volume, while 200 ppm also resulted in lower egg weights and lengths. Day-one hatchlings in the 200 ppm group weighed almost 10% less than controls and had shorter crown-rump lengths. No gross abnormalities were apparent. Skeletal clearing and staining revealed significantly shorter tibiotarsus lengths in the 40 ppm and 200 ppm groups and a shorter radius-ulna length in the 200 ppm group. By 7 days of age, body weights and lengths did not differ from controls, but the tibiotarsus in the 200 ppm group remained shorter. No significant differences were detected in hematocrit, hemoglobin, plasma calcium or alkaline phosphatase. Plasma phosphorus levels were higher in the 40 ppm group than in controls. These results, in combination with the findings of Pattee et al. [25], revealed significant impairment of overall reproduction, suggesting that sodium fluoride could cause slight to moderate reproduction disorders in owls in fluoride-polluted areas.

Toxicology Letters↗
USGS2001

Decreased glutathione S-transferase expression and activity and altered sex steroids in Lake Apopka brown bullheads (Ameriurus nebulosus)

A number of freshwater lakes and reclaimed agricultural sites in Central Florida have been the receiving waters for agrochemical and municipal runoff. One of these sites, Lake Apopka, is also a eutrophic system that has been the focus of several case studies reporting altered reproductive activity linked to bioaccumulation of persistent organochlorine chemicals in aquatic species. The present study was initiated to determine if brown bullheads (Ameriurus nebulosus) from the north marsh of Lake Apopka (Lake Apopka Marsh) exhibit an altered capacity to detoxify environmental chemicals through hepatic glutathione S-transferase (GST)-mediated conjugation as compared with bullheads from a nearby reference site (Lake Woodruff). We also compared plasma sex hormone concentrations (testosterone, 17-?? estradiol, and 11 keto-testosterone) in bullheads from the two sites. Female bullheads from Lake Apopka had 40% lower initial rate GST conjugative activity toward 1-chloro-2,4-dinitrobenzene (CDNB), 50% lower activity towards p-nitrobutyl chloride (NBC), 33% lower activity toward ethacrynic acid (ECA), and 43% lower activity toward ??5-androstene-3,17-dione (??5-ADI), as compared with female bullheads from Lake Woodruff. Enzyme kinetic analyses demonstrated that female bullheads from Lake Apopka had lower GST-catalyzed CDNB clearance than did female Lake Woodruff bullheads. Western blotting studies of bullhead liver cytosolic proteins demonstrated that the reduced GST catalytic activities in female Lake Apopka bullheads were accompanied by lower expression of hepatic GST protein. No site differences were observed with respect to GST activities or GST protein expression in male bullheads. Female Lake Apopka bullheads also had elevated concentrations of plasma androgens (testosterone and 11-ketotestosterone) as compared with females from Lake Woodruff. In contrast, male Lake Apopka bullheads had elevated levels of plasma estrogen but similar levels of androgens as compared with male bullheads from Lake Woodruff. Collectively, our studies indicate the presence of reduced GST protein expression, reduced GST conjugative capacity and altered sex steroid homeostasis in female bullheads from a contaminated field site in Central Florida. The implications of these physiological alterations in terms of pollutant biotransformation and reproduction are discussed. ?? 2001 Elsevier Science B.V. All rights reserved.

Aquatic Toxicology↗
USGS2016

Evaluation of potential mechanisms of atrazine-induced reproductive impairment in fathead minnow ( Pimephales promelas ) and Japanese medaka ( Oryzias latipes )

Atrazine has been implicated in reproductive dysfunction of exposed organisms, and previous studies documented decreased egg production in Japanese medaka ( Oryzias latipes ) and fathead minnows ( Pimephales promelas ) during 30-d to 38-d exposures to 0.5 µg/L, 5 µg/L, and 50 µg/L atrazine. The authors evaluated possible mechanisms underlying the reduction in egg production. Gene expression in steroidogenesis pathways and the hypothalamus–pituitary–gonad axis of male and female fish was measured. Atrazine did not significantly induce gonad aromatase ( cyp19a1a ) expression. An atrazine-induced shift in the number of females in an active reproductive state was observed. Expression of the egg maturation genes vitellogenin 1 ( vtg1 ) and zona pellucida glycoprotein 3.1 ( zp3.1 ) in medaka females was correlated and had a bimodal distribution. In both species, females with low vtg1 or zp3.1 expression also had low expression of steroidogenesis genes in the gonad, estrogen receptor in the liver, and gonadotropins in the brain. In the medaka, the number of females per tank that had high expression of zp3.1 was significantly correlated with egg production per tank. The number of medaka females with low expression of zp3.1 increased significantly with atrazine exposure. Thus, the decline in egg production observed in response to atrazine exposure may be the result of a coordinated downregulation of genes required for reproduction in a subset of females.

Environmental Toxicology and Chemistry↗
USGS1986

Reproduction of bobwhites fed different dietary concentrations of an organophosphate insecticide, methamidophos

Pairs of first-year breeding bobwhites were fed constant or variable concentrations of methamidophos for 15 days, or a control diet in a pair-fed design in which they were matched by body weights to pairs in the constant group. Treatments for the constant group were 5.0, 7.8, 12.3, 19.2, and 30.0 ppm for 5 pairs at each concentration. The number of pairs per concentration and peak concentrations for the variable pairs were identical to the constant dosages. Concentrations for the variable group were increased by a factor of four during two 3-day periods in order to reach the peak concentrations on days 7–9 after which they were decreased by 18% every 3 days to correspond to an environmental half-time of 10.5 days. Food consumption, egg production, hatchability of eggs under artificial incubation, and survival of hatched chicks for 2 weeks were recorded for each pair during 15-day treatment and 21-day posttreatment periods. Mortality was high in the highest constant dosage (2/10) and the associated pair-fed groups (3/10). Food consumption and egg production rates were negatively dose-related during the treatment period in the constant and variable groups. The laying rate of pair-fed hens was reduced to the same extent as in the constant group. Reproductive inhibition was not permanent and pairs resumed laying after a dose-related recovery interval. No dose-related effects on hatchability or chick survival were detected. Furthermore, there was no evidence of a pesticide effect on reproduction in addition to that exerted through pesticide-induced anorexia.

Archives of Environmental Contamination and Toxico↗
USGS2023

Toxicological effects assessment for wildlife in the 21st Century: Review of current methods and recommendations for a path forward

Model species (e.g., granivorous gamebirds, waterfowl, passerines, domesticated rodents) have been used for decades in guideline laboratory tests to generate survival, growth and reproductive data for prospective Ecological Risk Assessments (ERAs) for birds and mammals, while officially adopted risk assessment schemes for amphibians and reptiles do not exist. There are recognized shortcomings of current in vivo methods as well as uncertainty around the extent to which species with different life histories (e.g., terrestrial amphibians, reptiles, bats) than these commonly used models are protected by existing ERA frameworks. Approaches other than validating additional animal models for testing are being developed, but incorporation of such new approach methodologies (NAMs) into risk assessment frameworks will require robust validations against in vivo responses. This takes time, and the ability to extrapolate findings from non-animal studies to organism- and population-level effects in terrestrial wildlife remains weak. Failure to adequately anticipate and predict hazards could have economic and potentially even legal consequences for regulators and product registrants. In order to be able to use fewer animals or replace them altogether in the long-term, vertebrate use and whole organism data will be needed to provide data for NAMs validation in the short term. Therefore, it is worth investing resources for potential updates to existing standard test guidelines used in the laboratory as well as addressing the need for clear guidance on conduct of field studies. Herein we review the potential for improving standard in vivo test methods and for advancing the use of field studies in wildlife risk assessment, as these tools will be needed into the foreseeable future.

Integrated Environmental Assessment and Management↗
USGS2007

Bayesian multimodel inference for dose-response studies

Statistical inference in dose-response studies is model-based: The analyst posits a mathematical model of the relation between exposure and response, estimates parameters of the model, and reports conclusions conditional on the model. Such analyses rarely include any accounting for the uncertainties associated with model selection. The Bayesian inferential system provides a convenient framework for model selection and multimodel inference. In this paper we briefly describe the Bayesian paradigm and Bayesian multimodel inference. We then present a family of models for multinomial dose-response data and apply Bayesian multimodel inferential methods to the analysis of data on the reproductive success of American kestrels (Falco sparveriuss) exposed to various sublethal dietary concentrations of methylmercury.

Environmental Toxicology and Chemistry↗