Perfluorooctanoic acid exposure impact a trade-off between self-maintenance and reproduction in lizards (Eremias argus) in a gender-dependent manner

Effects of perfluorooctane sulfonate (PFOS) on a novel reptilian toxicity test species, the brown anole (Anolis sagrei)

Per- and polyfluoroalkyl substances (PFAS) are a broad class of chemicals with high environmental persistence and growing ecological and human health concern. Perfluorooctane sulfonate (PFOS) is among the most detected PFAS in environmental sampling and is often at high concentrations and has been measured in a variety of ecological receptors from around the globe. Despite the prevalence of PFOS, there are still important data gaps with regard to toxicity. For example, although studies have confirmed PFOS accumulation in tissues of wild reptiles, reptilian laboratory toxicity data are lacking. The purpose of this study was, first, to develop toxicity testing protocols using the brown anole, Anolis sagrei, and, second, to conduct PFOS dosing studies to generate toxicity data to support ecological risk assessment of reptiles. We conducted two studies in which subadult males and then mature males were dosed with PFOS via pseudo-gavage with maximum doses in the range of 2 mg/kg/day. Subadults were exposed for 35 days and adult males were exposed for 90 days. Although no significant mortality was observed, subadult male size and growth rate were significantly affected by PFOS at 2.98 mg/kg/day with a corresponding no effect level of 0.20 mg/kg/day and corresponding 10% and 20% effect levels for growth rate of 0.22 and 0.44 mg/kg/day, respectively. There were no significant effects on size metrics of mature male anoles from the 90-day study, although several metrics showed dose-dependent decreases. These data may serve as the basis for toxicity reference values for use in ecological risk assessments of PFAS-contaminated sites in which reptiles may be exposed.

Insights into toxicological mechanisms of per-/polyfluoroalkyl substances by using omics-centered approaches

The extensive presence of per-/polyfluoroalkyl substances (PFASs) in the environment and their adverse effects on organisms have garnered increasing concern. With the shift of industrial development from legacy to emerging PFASs, expanding the understanding of molecular responses to legacy and emerging PFASs is essential to accurately assess their risks to organisms. Compared with traditional toxicological approaches, omics technologies including transcriptomics, proteomics, metabolomics/lipidomics, and microbiomics allow comprehensive analysis of the molecular changes that occur in organisms after PFAS exposure. This paper comprehensively reviews the insights of omics approaches, especially the multi-omics approach, on the toxic mechanisms of both legacy and emerging PFASs in recent five years, focusing on hepatotoxicity, developmental toxicity, immunotoxicity, reproductive toxicity, neurotoxicity, and the endocrine-disrupting effect. PFASs exert various toxic effects via lipid and amino acid metabolism disruption, perturbations in several cell signal pathways, and binding to nuclear receptors. Notably, integrating multi-omics offers a thorough insight into the mechanisms of toxicity associated with PFASs. The gut microbiota plays an essential regulatory role in the toxic mechanisms of PFAS-induced hepatotoxicity. Finally, further research directions for PFAS toxicology based on omics technologies are prospected.

Life-history traits trade-off in gecko (Gekko japonicus) under the influence of climate warming and spirotetramat: Different adaptations to stressors in female and male

Global warming and rising surface temperatures are adversely affecting organisms. As the use of pesticides increases, concerns about their impacts on non-target organisms are growing. However, climate warming and pesticides may interact to produce combined effects on organisms. In this study, we exposed the geckos (Gekko japonicus) to different doses of spirotetramat (0, 15, and 30 mg/kg) and at different temperatures (25 °C and 30 °C) for 30 days. To investigate the effects of warming and spirotetramat on the trade-off in life-history traits of G. japonicus, we analyzed the energy allocation of the geckos under environmental stress. The results showed that females tended to allocate a significant amount of energy for self-maintenance and reduce investment in reproduction, which is a "conservative" life-history strategy. In contrast, males adopted a "risky" life-history strategy, tending to increase investment in reproduction while reducing immunity. However, in the long run, both reducing energy allocation towards reproduction and reducing investment in immunity can have adverse effects on the sustainable development of the population.

Forever chemicals don't make hero mutant ninja turtles: Elevated PFAS levels linked to unusual scute development in newly emerged freshwater turtle hatchlings (Emydura macquarii macquarii) and a reduction in turtle populations

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants known to pose significant risks to human and wildlife health. Freshwater turtles (Emydura macquarii macquarii), as long-lived species inhabiting aquatic ecosystems, are particularly vulnerable to PFAS bioaccumulation. This study investigated the multifaceted impact of PFAS contamination on these turtles, focusing on metabolic disruptions, reproductive success, hatchling health, and population impacts. Comprehensive analyses, including proteomics, lipidomics, metabolomics, and histopathology, were conducted on turtles from PFAS-impacted, control, and reference sites. The findings reveal significant metabolic disruptions in PFAS-exposed turtles, with alterations in amino acid and lipid metabolism, energy production, and oxidative stress responses. Proteomic analysis identified several health biomarkers indicative of early disease progression. Despite high levels of PFAS in tissues and organs, no gross or histopathological phenotypical abnormalities were directly linked to PFAS exposure. Gravid females from contaminated sites exhibited altered egg composition, particularly in magnesium to calcium ratios, potentially affecting eggshell strength. Biochemical profiles of egg albumin and yolk indicated significant differences in metabolites and lipids between contaminated and reference sites, suggesting potential impacts on embryo development. Hatchling deformities were notably higher and with increased frequency in terms of the types of deformities at the PFAS-impacted sites, with common defects including abnormal intergular scale shapes and marginal scale counts. Furthermore, the demographic profile of the turtle population showed a lack of juvenile turtles at contaminated sites, indicating reduced recruitment and potential long-term population declines. This indicates a field-based demonstration of an Adverse Outcome Pathway, from elevated levels of PFAS in the turtles, to biochemical perturbations within the animals, and finally population effects. These findings underscore the urgent need for regulatory measures to address PFAS contamination and its detrimental effects on wildlife.

Lipid metabolism in crocodilians: A field with promising applications in the field of ecotoxicology

In the last years, lipid physiology has become an important research target for systems biology applied to the field of ecotoxicology. Lipids are not only essential components of biological membranes, but also participate in extra and intracellular signaling processes and as signal transducers and amplifiers of regulatory cascades. Particularly in sauropsids, lipids are the main source of energy for reproduction, growth, and embryonic development. In nature, organisms are exposed to different stressors, such as parasites, diseases and environmental contaminants, which interact with lipid signaling and metabolic pathways, disrupting lipid homeostasis. The system biology approach applied to ecotoxicological studies is crucial to evaluate metabolic regulation under environmental stress produced by xenobiotics. In this review, we cover information of molecular mechanisms that contribute to lipid metabolism homeostasis in sauropsids, specifically in crocodilian species. We focus on the role of lipid metabolism as a powerful source of energy and its importance during oocyte maturation, which has been increasingly recognized in many species, but information is still scarce in crocodiles. Finally, we highlight priorities for future research on the influence of environmental stressors on lipid metabolism, their potential effect on the reproductive system and thus on the offspring, and their implications on crocodilians conservation.

Poly- and perfluoroalkyl substances (PFASs) in amphibians and reptiles - exposure and health effects

Poly- and perfluoroalkyl substances (PFASs) are commonly used in various industries and everyday products, including clothing, electronics, furniture, paints, and many others. PFASs are primarily found in aquatic environments, but also present in soil, air and plants, making them one of the most important and dangerous pollutants of the natural environment. PFASs bioaccumulate in living organisms and are especially dangerous to aquatic and semi-aquatic animals. As endocrine disruptors, PFASs affect many internal organs and systems, including reproductive, endocrine, nervous, cardiovascular, and immune systems. This manuscript represents the first comprehensive review exclusively focusing on PFASs in amphibians and reptiles. Both groups of animals are highly vulnerable to PFASs in the natural habitats. Amphibians and reptiles, renowned for their sensitivity to environmental changes, are often used as crucial bioindicators to monitor ecosystem health and environmental pollution levels. Furthermore, the decline in amphibian and reptile populations worldwide may be related to increasing environmental pollution. Therefore, studies investigating the exposure of amphibians and reptiles to PFASs, as well as their impacts on these organisms are essential in modern toxicology. Summarizing the current knowledge on PFASs in amphibians and reptiles in a single manuscript will facilitate the exploration of new research topics in this field. Such a comprehensive review will aid researchers in understanding the implications of PFASs exposure on amphibians and reptiles, guiding future investigations to mitigate their adverse effects of these vital components of ecosystems.

Inulin alleviates perfluorooctanoic acid-induced intestinal injury in mice by modulating the PI3K/AKT/mTOR signaling pathway

Perfluorooctanoic acid (PFOA) is a widely used industrial compound that has been found to induce intestinal toxicity. However, the underlying mechanisms have not been fully clarified and effective interventions are rarely developed. Inulin, a prebiotic, has been used as a supplement in human daily life as well as in gastrointestinal diseases and metabolic disorders. In this study, male mice were exposed to PFOA with or without inulin supplementation to investigate the enterotoxicity and potential intervention effects of inulin. Mice were administered PFOA at 1 mg/kg/day, PFOA with inulin at 5 g/kg/day, or Milli-Q water for 12 weeks. Histopathological analysis showed that PFOA caused colon shortening, goblet cell reduction, and inflammatory cell infiltration. The expression of the tight junction proteins ZO-1, occludin and claudin5 significantly decreased, indicating impaired barrier function. According to the RNA-sequencing analysis, PFOA exposure resulted in 917 differentially expressed genes, involving 39 significant pathways, such as TNF signaling and cell cycle pathways. In addition, the protein expression of TNF-α, IRG-47, cyclinB1, and cyclinB2 increased, while Gadd45γ, Lzip, and Jam2 decreased, suggesting the involvement of the TNF signaling pathway, cell cycle, and cell adhesion molecules in PFOA-associated intestinal injury. Inulin intervention alleviated PFOA-induced enterotoxicity by activating the PI3K/AKT/mTOR signaling pathway and increasing the protein expression of Wnt1, β-catenin, PI3K, Akt3, and p62, while suppressing MAP LC3β, TNF-α, and CyclinE expression. These findings suggested that PFOA-induced intestinal injury, including inflammation and tight junction disruption, was mitigated by inulin through modifying the PI3K/AKT/mTOR signaling pathways. Our study provides valuable insights into the enterotoxic effects of PFOA and highlights the potential therapeutic role of inulin.

Perfluorooctanoic acid exposure leads to defect in follicular development through disrupting the mitochondrial electron transport chain in granulosa cells

Perfluorooctanoic acid (PFOA) is a persistent environmental pollutant that can impair ovarian function, while the underlying mechanism is not fully understood, and effective treatments are lacking. In this study, we established a mouse model of PFOA exposure induced by drinking water and found that PFOA exposure impaired follicle development, increased apoptosis of granulosa cells (GCs), and hindered normal follicular development in a 3D culture system. RNA-seq analysis revealed that PFOA disrupted oxidative phosphorylation in ovaries by impairing the mitochondrial electron transport chain. This resulted in reduced mitochondrial membrane potential and increased mitochondrial reactive oxygen species (mtROS) in isolated GCs or KGN cells. Resveratrol, a mitochondrial nutrient supplement, could improve mitochondrial function and restore normal follicular development by activating FoxO1 through SIRT1/PI3K-AKT pathway. Our results indicate that PFOA exposure impairs mitochondrial function in GCs and affects follicle development. Resveratrol can be a potential therapeutic agent for PFOA-induced ovarian dysfunction.

Bioaccumulation and metabolic impact of environmental PFAS residue on wild-caught urban wetland tiger snakes (Notechis scutatus)

PFAS contamination of urban waters is widespread but understanding the biological impact of its accumulation is limited to humans and common ecotoxicological model organisms. Here, we combine PFAS exposure and bioaccumulation patterns with whole organism responses and omics-based ecosurveillance methods to investigate the potential impacts of PFAS on a top predator of wetlands, the tiger snake (Notechis scutatus). Tiger snakes (18 male and 17 female) were collected from four wetlands with varying PFAS chemical profiles and concentrations in Perth, Western Australia. Tiger snake livers were tested for 28 known PFAS compounds, and Σ28PFAS in liver tissues ranged between 322 ± 193 μg/kg at the most contaminated site to 1.31 ± 0.86 μg/kg at the least contaminated site. The dominant PFAS compound detected in liver tissues was PFOS. Lower body condition was associated with higher liver PFAS, and male snakes showed signs of high bioaccumulation whereas females showed signs of maternal offloading. Biochemical profiles of snake muscle, fat (adipose tissue), and gonads were analysed using a combination of liquid chromatography triple quadrupole (QqQ) and quadrupole time-of-flight (QToF) mass spectrometry methodologies. Elevated PFAS was associated with enriched energy production and maintenance pathways in the muscle, and had weak associations with energy-related lipids in the fat tissue, and lipids associated with cellular genesis and spermatogenesis in the gonads. These findings demonstrate the bioavailability of urban wetland PFAS in higher-order reptilian predators and suggest a negative impact on snake health and metabolic processes. This research expands on omics-based ecosurveillance tools for informing mechanistic toxicology and contributes to our understanding of the impact of PFAS residue on wildlife health to improve risk management and regulation.

Multigenerational effects of arsenate on development and reproduction in marine copepod Tigriopus japonicus

Arsenic (As) is a persistent toxic substance, however, its toxicity to marine zooplankton remains unclear. In this study, copepods were exposed to a series of dissolved arsenate (As(V)) for four generations (F0-F3) and subsequently depurated in clean seawater for two generations (F4-F5) to assess multigenerational toxicity of As(V). As(V) exposure prolonged copepod development. The development time were 1.9, 2.4, and 3.4 days longer than the control in F0 when exposed to 50, 100, and 500 μg/L As(V), respectively, and the toxicity increased with generations. Moreover, As(V) reduced the reproductive capacity of copepods, and this effect become more severe during generation succession. The 10-day fecundities were reduced from 80 to 85 eggs per female in the control to 42 eggs per female, the lowest level, in 500 μg/L As(V) exposure group in F3. Nevertheless, the fecundity was recovered to the control level in the offspring of the 50 and 100 μg/L As(V) exposed groups (F4), suggesting it was an acclimation effect of copepods during As(V) exposure. In addition, the survival rate, development time, and reproductive parameters were significantly correlated with the As accumulation in copepods. Overall, As(V) exposure caused As bioaccumulation which negatively affected copepods' survival, development, and reproductive traits, and this toxic effect was amplified with generations and concentrations. Therefore, the multigenerational toxicity of As should be considered in the environmental risk assessments.

The combined effects of atrazine and warming on environmental adaptability in lizards (Eremias argus) from the perspective of a life-history traits trade-off: Gender differences in trade-off strategies may reverse mortality risk

Life-history theory suggests that organisms must distribute a limited share of their energetic resources among competing life-history trait demands. Therefore, the trade-off strategies individuals develop for particular life-history traits in a given environment may profoundly impact their environmental adaptability. In this study, lizards (Eremias. argus) were exposed to single and combined atrazine (4.0 mg·kg^-1 and 20.0 mg·kg^-1) and different temperatures (25 °C and 30 °C) for 8 weeks during the breeding season. The effects of atrazine and warming on the adaptability of lizards were explored by examining changes in trade-offs via several key life history traits (i.e., reproduction, self-maintenance, energy reserves, and locomotion). The results show that after atrazine exposure at 25 °C, both female and male lizards tended to allocate energy to self-maintenance by reducing energy allocation to reproductive process. The lower energy reserves of males are considered a "risky" life-history strategy and the observed higher mortality may be related to atrazine-induced oxidative damage. The retention of energy reserves by females not only ensured their current survival but also facilitated survival and reproduction in subsequent stages, which can be regarded as a "conservative" strategy. However, under high temperature and/or combined atrazine exposure, the "risky" strategy of males caused them to consume more energy reserves to invest in self-maintenance, which ensured their immediate survival, and profited from more rapid degradation of atrazine. In contrast, the "conservative" strategy of females could not meet their higher reproductive and self-maintenance demands under high temperatures, and the elevated reproductive oxidative and metabolic costs led to individual mortality. Gender differences in life-history trade-off strategies can directly lead to "winners" and "losers" from environmental stress within a species.

Per- and polyfluoroalkyl substances exposure and bone mineral density in the U.S. population from NHANES 2005-2014

BACKGROUND

Environmental exposures such as perfluoroalkyl substances (PFASs) were considered potential risks for bone mineral density (BMD).

OBJECTIVE

To examine the associations between PFASs and BMD among the U.S. population.

METHODS

This study included a total of 6416 participants from the National Health and Nutrition Examination Survey (NHANES 2005-2014). Multiple linear regression models were used to analyze the associations between serum PFASs and BMD and the coefficient β with 95% confidence intervals (95% CI) was calculated as the effect estimate. Covariates such as age, race, BMI, smoking, alcohol intake, milk intake, and physical activity were adjusted in these models. Additionally, gender and menopausal period were considered in further subgroup analyses.

RESULTS

Based on the combined data of NHANES 2005-2014, the effects from exposure to PFASs on BMD were found with gender and menopausal status differences. Positive associations were found in PFOA (β = 0.010; 95% CI: 0.003, 0.016), PFHxS (β = 0.007; 95% CI: 0.003, 0.012), and PFNA (β = 0.001; 95% CI: 0.001, 0.017) in total population. Negative associations for PFOA (β = -0.020; 95% CI: -0.029, -0.012), PFOS (β = -0.011; 95% CI: -0.028, -0.011), PFHxS (β = -0.019; 95% CI: -0.025, -0.013), PFDE (β = -0.010; 95% CI: -0.016, -0.005), and PFNA (β = -0.011; 95% CI: -0.021, -0.002) were found in women, while no significant association was found in men. In further subgroup analyses, women in pre-menopause status showed consistent negative associations.

SIGNIFICANCE

PFASs exposure may be associated with BMD and gender and menopausal status confound the associations.

A review of omics-based PFAS exposure studies reveals common biochemical response pathways

Per and Polyfluoroalkyl Substances (PFAS) are a diverse group of man-made chemicals with a range of industrial applications and which are widespread in the environment. They are structurally diverse but comprise a common chemical feature of at least one (though usually more) perfluorocarbon moiety (-C_nF_2n-) attached to a functional group such as a carboxylic or sulphonic acid. The strength of the Carbon-Fluorine bond means the compounds do not break down easily and can thus bioaccumulate. PFAS are of high concern to regulators and the public due to their potential toxicity and high persistence. At high exposure levels, PFAS have been implicated in a range of harmful effects on human and environmental health, particularly problems in/with development, cholesterol and endocrine disruption, immune system function, and oncogenesis. However, most environmental toxicology studies use far higher levels of PFAS than are generally found in the environment. Additionally, since the type of exposure, the PFAS used, and the organisms tested all vary between studies, so do the results. Traditional ecotoxicology studies may thus not identify PFAS effects at environmentally relevant exposures. Here we conduct a review of omics-based PFAS exposure studies using laboratory ecotoxicological methodologies and environmentally relevant exposure levels and show that common biochemical response pathways are identified in multiple studies. A major pathway identified was the pentose phosphate shunt pathway. Such molecular markers of sublethal PFAS exposure will greatly benefit accurate and effective risk assessments to ensure that new PFAS regulations can consider the full effects of PFAS exposure on environmental and human health receptors.

Fat rather than health - Ecotoxic responses of Bufo raddei to environmental heavy metal stress during the non-breeding season

The non-breeding season is a critical period for iteroparous animals to repair damage and store energy, which is crucial for future survival and reproductive success. However, it is unknown how animals allocate energy efficiently among reproduction, self-maintenance, and repair of oxidative damage caused by breeding during the non-breeding period, particularly under pollution. In the present study, the self-maintenance response and reproductive strategy of Bufo raddei to long-term environmental heavy metal stress was explored during the non-breeding season. Heavy metal enrichment level, organ coefficients, nutritional status, gonadal developmental level, oxidation level, and the immune status of B. raddei during the non-breeding season were tested, energy allocation preferences and energy consumption costs were analyzed. The results revealed significant heavy metal accumulation through biomagnification in the organs of B. raddei from the polluted area. Under long-term environmental heavy metal pollution, the energy investment by B. raddei for growth and energy storage was higher than that for health-maintenance during the early life cycle stage. The energy inputted for immune and antioxidant functions was significantly lower, and the energy inputted for self-maintenance during the early life stage was significantly higher than that during the late stage. B. raddei from a heavy metal polluted area spent more energy consumption cost on immunity and oxidative stress, but suffered higher oxidative stress and lower immune status. Moreover, the reproductive input of individuals in a heavy metal polluted area was generally low during the non-breeding season, and the energy input for reproduction limited the energy input for self-maintenance in females.

Perturbation of the gut microbiome in wild-caught freshwater turtles (Emydura macquarii macquarii) exposed to elevated PFAS levels

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent and pervasive. Understanding the toxicity of PFAS to wildlife is difficult, both due to the complexity of biotic and abiotic perturbations in the taxa under study and the practical and ethical problems associated with studying the impacts of environmental pollutants on free living wildlife. One avenue of inquiry into the effects of environmental pollutants, such as PFAS, is assessing the impact on the host gut microbiome. Here we show the microbial composition and biochemical functional outputs from the gut microbiome of sampled faeces from euthanised and necropsied wild-caught freshwater turtles (Emydura macquarii macquarii) exposed to elevated PFAS levels. The microbial community composition was profiled by 16S rRNA gene sequencing using a Nanopore MinION and the biochemical functional outputs of the gut microbiome were profiled using a combination of targeted central carbon metabolism metabolomics using liquid chromatography coupled to a triple quadrupole mass spectrometer (LC-QqQ-MS) and untargeted metabolomics using liquid chromatography coupled to a quadrupole time of flight mass spectrometer (LC-QToF-MS). Total PFAS was measured in the turtle serum using standard methods. These preliminary data demonstrated a 60-fold PFAS increase in impacted turtles compared to the sampled aquatic environment. The microbiome community was also impacted in the PFAS exposed turtles, with the ratio of Firmicutes-to-Bacteroidetes rising from 1.4 at the reference site to 5.5 at the PFAS impacted site. This ratio increase is indicative of host stress and dysfunction of the gut microbiome that was correlated with the biochemical metabolic function data, metabolites observed that are indications of stress and inflammation in the gut microbiome. Utilising the gut microbiome of sampled faeces collected from freshwater turtles provides a non-destructive avenue for investigating the impacts of PFAS in native wildlife, and provides an avenue to explore other contaminants in higher-order taxa within the environment.

Possible changes in trade-off strategy in female lizards (Eremias argus) during hibernation following exposure to chlorantraniliprole: Impact on the HPG axis and the energy mobilization

Hibernation is a short-term survival strategy for ectotherms to cope with cold weather and food shortages. The energy sources stored before hibernation are used not only in the winter, but also in preparation for reproduction. Reproductive physiology and behavior are primarily regulated by the hypothalamus-pituitary-gonad (HPG) axis. In this study, we examined endocrine hormone changes in the HPG axis of female lizards (Eremias argus) after chlorantraniliprole insecticide (CAP) exposure during hibernation. The levels of gonadotropin-releasing hormone, luteinizing hormone, follicle-stimulating hormone and progesterone were significantly decreased and the level of testosterone (T) was significantly increased after 135d experiment. This study verified the possible endocrine disrupting effects of CAP. More energy material consumption was observed in CAP treated group. Female E. argus preferred to invest energy to present survival when exposed to CAP, rather than to reserve material for following reproductive activity.

Bioaccumulation and metabolic response of PFAS mixtures in wild-caught freshwater turtles (Emydura macquariimacquarii) using omics-based ecosurveillance techniques

PFAS mixtures in the environment are common and identifying PFAS constituents, bioaccumulation, and biological impacts of mixtures remains a challenge. Here, an omics-based ecosurveillance approach was taken to investigate the impacts of PFAS pollution in freshwater turtles (Emydura macquariimacquarii). Four turtles were collected from an impacted waterway downstream from an industrial source of PFAS contamination in Queensland, Australia and analysed for 49 different PFAS. One turtle was collected from a suitable control site. PFAS concentrations were quantified in turtle serum using an established targeted methodology. The serum PFAS concentration was ten-fold greater at the impacted site (Σ49 PFAS 1933 ± 481 ng/mL) relative to the control sample (Σ49 PFAS 140 ng/mL). Perfluorooctane sulfonate (PFOS; 889 ± 56 ng/mL) was 235 times higher in turtle serum than in the water that they were collected from (ΣPFAS 32.0 μg/L). Perfluorobutane sulfonamide (FBSA; 403 ± 83 ng/mL) and perfluorohexane sulfonamide (FHxSA; 550 ± 330 ng/mL) were also reported at substantial concentrations in the serum of impacted turtles. Biochemical profiles were analysed using a mixture of liquid chromatography triple quadrupole (QqQ) and quadrupole time-of-flight (QToF) mass spectrometry methodologies. These profiles demonstrated a positive correlation in the impacted turtles exposed to elevated PFAS with an enhanced purine metabolism, glycerophosphocholines and an innate immune response, which suggest an inflammation response, metabolic preservation and re-routing of central carbon metabolites. Conversely, lipid transport and binding activity were negatively correlated. Using these preliminary data, we were able to demonstrate the negative metabolic impact from PFAS mixtures on turtle metabolic health. With further research on a larger turtle cohort, omics-based data will contribute towards linking adverse outcome pathways for turtle populations exposed to PFAS mixtures. Moreover, expanding the use of ecosurveillance tools will inform mechanistic toxicological data for risk assessment and regulatory applications.

Impact of Oxidative Stress on Male Reproduction in Domestic and Wild Animals

Oxidative stress occurs when the levels of reactive oxygen species (ROS) overcome the antioxidant defenses of the organism, jeopardizing several biological functions, including reproduction. In the male reproductive system, oxidative stress not only impairs sperm fertility but also compromises offspring health and survival, inducing oxidative damage to lipids, proteins and nucleic acids. Although a clear link between oxidative stress and male fertility disorders has been demonstrated in humans and laboratory rodents, little information is available about the implications of impaired redox homeostasis in the male fertility of domestic and wild animals. Therefore, this review aims to provide an update regarding the intrinsic and extrinsic factors that are associated with oxidative stress in the male reproductive system and their impact on the reproductive performance of domestic and wild animals. The most recent strategies for palliating the detrimental effects of oxidative stress on male fertility are reviewed together with their potential economic and ecological implications in the livestock industry and biodiversity conservation.