Maternally Transferred Research Articles

Advancing Maternal Transfer of Organic Pollutants across Reptiles for Conservation and Risk Assessment Purposes.

Embryonic exposure through maternally transferred pollutants can affect embryo vitality, survival, and health. Reptiles face global declines and are sensitive to embryonic pollutant exposure. Yet, they are often neglected in pollution risk assessment and conservation. We analyzed maternal transfer of organic pollutants in reptiles through a systematic extraction, homogenization, and integration of published data on organic pollutants measured in mother-egg pairs into a comprehensive database (DOI:10.5281/zenodo.10900226), complemented with molecular physical-chemical properties of the pollutants. Over four decades, 17 publications provided 19,955 data points shifting from legacy to emerging contaminants although research on newer contaminants lags regulatory and societal demands. Challenges including taxonomic bias, heterogeneity in sampled tissues, and 73% of censored data complicate comparative analyses. However, significant opportunities were identified including the use of the turtle Malachlemys terrapin and snake Enhydris chinensis as flagship species where a large amount of data is available across tissues (allowing investigation into physiological relations) and compounds (allowing insights into maternal transfer across the chemical universe). Data on other freshwater and marine turtles provide the possibility of exploring taxonomic patterns in this subgroup. The analysis, integrated database, and discussion present opportunities for research in an era where science needs to achieve more with limited wildlife data.

Studying mixture effects on uptake and tissue distribution of PFAS in zebrafish (Danio rerio) using physiologically based kinetic (PBK) modelling

Per- and polyfluoroalkyl substances (PFAS) are ubiquitously distributed in the aquatic environment. They include persistent, mobile, bioaccumulative, and toxic chemicals and it is therefore critical to increase our understanding on their adsorption, distribution, metabolism, excretion (ADME). The current study focused on uptake of seven emerging PFAS in zebrafish (Danio rerio) and their potential maternal transfer. In addition, we aimed at increasing our understanding on mixture effects on ADME by developing a physiologically based kinetic (PBK) model capable of handling co-exposure scenarios of any number of chemicals. All studied chemicals were taken up in the fish to varying degrees, whereas only perfluorononanoate (PFNA) and perfluorooctanoate (PFOA) were quantified in all analysed tissues. Perfluorooctane sulfonamide (FOSA) was measured at concerningly high concentrations in the brain (Cmax over 15 μg/g) but also in the liver and ovaries. All studied PFAS were maternally transferred to the eggs, with FOSA and 6:2 perfluorooctane sulfonate (6,2 FTSA) showing significant (p < 0.02) signs of elimination from the embryos during the first 6 days of development, while perfluorobutane sulfonate (PFBS), PFNA, and perfluorohexane sulfonate (PFHxS) were not eliminated in embryos during this time-frame. The mixture PBK model resulted in >85 % of predictions within a 10-fold error and 60 % of predictions within a 3-fold error. At studied levels of PFAS exposure, competitive binding was not a critical factor for PFAS kinetics. Gill surface pH influenced uptake for some carboxylates but not the sulfonates. The developed PBK model provides an important tool in understanding kinetics under complex mixture scenarios and this use of New Approach Methodologies (NAMs) is critical in future risk assessment of chemicals and early warning systems.

Maternal Transfer and Effects of Selenium on Early Life Stage Development of Redside Shiner (Richardsonius balteatus).

Maternal transfer of selenium (Se) to developing fish eggs during vitellogenesis can cause larval deformity and mortality. Previous studies have shown wide variation among fish species in both the magnitude of maternal transfer (exposure) and the egg Se concentration causing effects (sensitivity). We studied maternal transfer and effects of Se on early life stage development, survival, and growth of redside shiner (Richardsonius balteatus), a small-bodied cyprinid that has been reported to have relatively high ovary:muscle Se concentration ratios. Gametes were collected from lentic areas in southeast British Columbia (Canada) with a range of dietary Se concentrations related to weathering of waste rock from coal mining. Eggs were fertilized and reared in the laboratory from hatch to the onset of exogenous feeding. Larvae were assessed for survival, length, weight, Se-characteristic deformities, and edema. Eggs from a total of 56 females were collected, with egg Se concentrations from 0.7 to 28 mg/kg dry weight. Maternal transfer varied among sites, with egg:muscle Se concentration ratios ranging from <1 to >4. We also found that sampling residual ovaries can overestimate Se concentrations in ripe eggs by up to a factor of 5.7. A correlation between larval weight and egg Se concentration was identified, although the relationship was weak (r2 < 0.1) and appeared to be a site effect. No other relationships were observed between larval endpoints and egg Se concentrations up to the highest concentration tested, indicating that the effects threshold for this species may be >28 mg/kg dry weight in eggs. These data indicate that redside shiner is less sensitive to maternally transferred Se than most other tested fish species. Environ Toxicol Chem 2023;42:2350-2357. © 2023 SETAC.

The mercury flow through a terrestrial songbird food chain in subtropical pine forest: Elucidated by Bayesian isotope mixing model and stable mercury isotopes

In order to comprehend the transfer of inorganic mercury (IHg) and methylmercury (MeHg) within food chains in terrestrial pine forests, we collected samples of Great Tit nestlings, common invertebrates, plants, and soil in a subtropical pine forest and used Bayesian isotope mixing model analysis, Hg daily intake, and stable Hg isotopes to elucidate the flow of MeHg and IHg in these food chains. Results indicate that caterpillars and cockroaches are the predominant prey items for nestlings, accounting for a combined contribution of 81.5%. Furthermore, caterpillars, cockroaches, and spiders were found to contribute the most (∼80%) of both IHg and MeHg that dietary accumulated in nestlings. The provisoned invertebrates tend to supply more IHg and diluting the proportion of MeHg as total Hg (MeHg%). Notably, nestling feathers displayed the highest Δ199Hg values but a relatively lower MeHg%, suggesting an imbalanced incorporation of Hg from maternal transfer and dietary accumulation during the nestling stage. This study highlights the efficacy of nestlings as indicators for identifying Hg sources and transfers in avian species and food chains. However, caution must be exercised when using Hg isotope compositions in growing feathers, and the contribution of maternally transferred Hg should not be ignored.

Development of a Kinetic ELISA and Reactive B Cell Frequency Assay to Detect Respiratory Syncytial Virus Pre-Fusion F Protein-Specific Immune Responses in Infants.

Respiratory syncytial virus (RSV) is a major cause of respiratory disease in infants, making vaccination an attractive preventive strategy. Due to earlier reports of vaccine-enhanced disease in RSV-naive children, assessing prior RSV infection is critical for determining eligibility for future infant vaccine trials. However, this is complicated by the presence of maternally transferred maternal antibodies. We sought to develop assays that measure immune responses to RSV pre-fusion (F) protein that discriminates between maternal and infant responses. We measured RSV-specific responses in two groups of children <3 years of age; those with laboratory-confirmed RSV (RSV-infected) and those enrolled prior to their first RSV season (RSV-uninfected). Serial blood samples were obtained and recent infections with RSV and other respiratory viruses were assessed during follow-up. An RSV pre-F-specific kinetic enzyme-linked immunosorbent assay (kELISA) and an F-specific reactive B cell frequency (RBF) assay were developed. One hundred two young children were enrolled between July 2015 and April 2017; 74 were in the RSV-uninfected group and 28 were in the RSV-infected group. Participants were asked to provide sequential blood samples over time, but only 53 participants in the RSV-uninfected group and 22 participants in the RSV-infected groups provided multiple samples. In the RSV-infected group, most had positive kELISA and RBF during the study. In the RSV-uninfected group, two patterns emerged: declining kELISA values without reactive B cells, due to maternal transplacental antibody transfer, and persistently positive kELISA with reactive B cells, due to asymptomatic undiagnosed RSV infection. A kELISA targeting RSV pre-F epitopes and an RBF assay targeting RSV F-specific B cells generally allow discrimination between maternally and infant-derived antibodies.

Maternal transfer of IgA and IgG SARS-CoV-2 specific antibodies transplacentally and via breast milk feeding.

Although there have been many studies on antibody responses to SARS-CoV-2 in breast milk, very few have looked at the fate of these in the infant, and whether they are delivered to immunologically relevant sites in infants. Mother/infant pairs (mothers who breast milk fed and who were SARS-CoV-2 vaccinated before or after delivery) were recruited for this cross-sectional study. Mother blood, mother breast milk, infant blood, infant nasal specimen, and infant stool was tested for IgA and IgG antibodies against SARS-CoV-2 spike trimer. Thirty-one mother/infant pairs were recruited. Breast milk fed infants acquired systemic anti-spike IgG antibodies only if their mothers were vaccinated antepartum (100% Antepartum; 0% Postpartum; P<0.0001). Breast milk fed infants acquired mucosal anti-spike IgG antibodies (in the nose) only if their mothers were vaccinated antepartum (89% Antepartum; 0% Postpartum; P<0.0001). None of the infants in either group had anti-spike IgA in the blood. Surprisingly, 33% of the infants whose mothers were vaccinated antepartum had high titer anti-spike IgA in the nose (33% Antepartum; 0% Postpartum; P = 0.03). Half-life of maternally transferred plasma IgG antibodies in the Antepartum infant cohort was ~70 days. Vaccination antepartum followed by breast milk feeding appears to be the best way to provide systemic and local anti-SARS-CoV-2 antibodies for infants. The presence of high titer SARS-CoV-2-specific IgA in the nose of infants points to the potential importance of breast milk feeding early in life for maternal transfer of mucosal IgA antibodies. Expectant mothers should consider becoming vaccinated antepartum and consider breast milk feeding for optimal transfer of systemic and mucosal antibodies to their infants.

Sex-Specific Bioaccumulation, Maternal Transfer, and Tissue Distribution of Legacy and Emerging Per- and Polyfluoroalkyl Substances in Snakes (Enhydris chinensis) and the Impact of Pregnancy.

The effects of sex and pregnancy on the bioaccumulation and tissue distribution of legacy and emerging per- and polyfluoroalkyl substances (PFASs) in Chinese water snakes were investigated. The bioaccumulation factor of PFASs showed a positive correlation with their protein-water partition coefficients (log KPW), and steric hindrance effects were observed when the molecular volume was > 357 Å3. PFAS levels in females were significantly lower than those in males. The chemical composition of pregnant females was significantly different from that of non-pregnant females and males. The maternal transfer efficiencies of perfluorooctane sulfonic acid were higher than those of other PFASs, and a positive correlation between the maternal transfer potential and log KPW was observed for other PFASs. Tissues with high phospholipid content exhibited higher concentrations of ∑PFASs. Numerous physiological changes occurred in maternal organ systems during pregnancy, leading to the re-distribution of chemicals among different tissues. The change in tissue distribution of PFASs that are easily and not-so-easily maternally transferred was in the opposite direction. The extent of compound transfer from the liver to the egg determined tissue re-distribution during pregnancy.

Maternally transferred thyroid hormones and life-history variation in birds.

In vertebrates, thyroid hormones (THs) play an important role in the regulation of growth, development, metabolism, photoperiodic responses and migration. Maternally transferred THs are important for normal early phase embryonic development when embryos are not able to produce endogenous THs. Previous studies have shown that variation in maternal THs within the physiological range can influence offspring phenotype.Given the essential functions of maternal THs in development and metabolism, THs may be a mediator of life‐history variation across species.We tested the hypothesis that differences in life histories are associated with differences in maternal TH transfer across species. Using birds as a model, we specifically tested whether maternally transferred yolk THs covary with migratory status, developmental mode and traits related to pace‐of‐life (e.g. basal metabolic rate, maximum life span).We collected un‐incubated eggs (n = 1–21 eggs per species, median = 7) from 34 wild and captive bird species across 17 families and six orders to measure yolk THs [both triiodothyronine (T3) and thyroxine (T4)], compiled life‐history trait data from the literature and used Bayesian phylogenetic mixed models to test our hypotheses.Our models indicated that both concentrations and total amounts of the two main forms of THs (T3 and T4) were higher in the eggs of migratory species compared to resident species, and total amounts were higher in the eggs of precocial species, which have longer prenatal developmental periods, than in those of altricial species. However, maternal yolk THs did not show clear associations with pace‐of‐life‐related traits, such as fecundity, basal metabolic rate or maximum life span.We quantified interspecific variation in maternal yolk THs in birds, and our findings suggest higher maternal TH transfer is associated with the precocial mode of development and migratory status. Whether maternal THs represent a part of the mechanism underlying the evolution of precocial development and migration or a consequence of such life histories is currently unclear. We therefore encourage further studies to explore the physiological mechanisms and evolutionary processes underlying these patterns.

Maternal transfer and biodistribution of citrate and luminogens coated silver nanoparticles in medaka fish

Given the wide applications of silver nanoparticles (AgNPs), it is necessary to evaluate their potentially adverse long-term effects. In this study, we performed a 100-day exposure of medaka fish to citrate and luminogens coated AgNPs and investigated the maternal transfer potentials and biodistribution of AgNPs. Following long-term AgNPs exposure, AgNPs were mainly distributed in the liver, followed by gills, intestine, and brain, but were also detected in the ovary and strongly colocalized with the dissolved Ag+. The quantified transfer efficiency of different Ag species was 1.56–5.07%. Long-term exposure of medaka to small size of AgNPs (20 nm) reduced the hatching rate attributable to the accumulation of AgNPs and their dissolved Ag+. The maternally transferred AgNPs were mainly concentrated in the Kupffer's vesicle of embryos, while their dissolved Ag+ was almost homogeneously distributed in the embryos. In contrast, the newly accumulated AgNPs were mainly absorbed at the chorion of embryos. During initial larval development, the maternally transferred AgNPs and their dissolved Ag+ were consistently concentrated in intestine. Significant dissolution of maternally transferred AgNPs occurred during larval development. Our results showed that long-term exposure to AgNPs caused distinct biodistribution in the next generation of medaka, and may have implications for assessing their potential adverse effects.

The role of maternally transferred antibodies in maternal performance in red deer

Maternal effects are ubiquitous. Yet, the pathways through which maternal effects occur in wild mammals remain largely unknown. We hypothesise that maternal immune transfer is a key mechanism by which mothers can affect their offspring fitness, and that individual variation in maternally derived antibodies mainly depends on a mother's characteristics and the environmental conditions she experiences. To test this, we assayed six colostrum-derived antibodies in the plasma of 1447 neonates in a wild red deer population. Neonatal antibody levels were mainly affected by maternal genes, environmental variation and costs of prior reproductive investment. We found consistent heterogeneity in maternal performance across traits, with mothers producing the heaviest calves also having calves with more antibodies. Unexpectedly, antibody levels were not associated with calf survival. We provide a unique example of how evolutionary theory on maternal effects can be used to gain insight into the causes of maternal effects in wild populations.

New Insights into IgZ as a Maternal Transfer Ig Contributing to the Early Defense of Fish against Pathogen Infection.

IgZ or its equivalent IgT is a newly discovered teleost specific Ig class that is highly specialized in mucosal immunity. However, whether this IgZ/IgT class participates in other biological processes remains unclear. In this study, we unexpectedly discovered that IgZ is highly expressed in zebrafish ovary, accumulates in unfertilized eggs, and is transmitted to offspring from eggs to zygotes. Maternally transferred IgZ in zygotes is found at the outer and inner layers of chorion, perivitelline space, periphery of embryo body, and yolk, providing different lines of defense against pathogen infection. A considerable number of IgZ+ B cells are found in ovarian connective tissues distributed between eggs. Moreover, pIgR, the transporter of IgZ, is also expressed in the ovary and colocalizes with IgZ in the zona radiata of eggs. Thus, IgZ is possibly secreted by ovarian IgZ+ B cells and transported to eggs through association with pIgR in a paracrine manner. Maternal IgZ in zygotes showed a broad bacteriostatic activity to different microbes examined, and this reactivity can be manipulated by orchestrating desired bacteria in water where parent fish live or immunizing the parent fish through vaccination. These observations suggest that maternal IgZ may represent a group of polyclonal Abs, providing protection against various environmental microbes encountered by a parent fish that were potentially high risk to offspring. To our knowledge, our findings provide novel insights into a previously unrecognized functional role of IgZ/IgT Ig in the maternal transfer of immunity in fish, greatly enriching current knowledge about this ancient Ig class.

Dynamics of maternally transferred antibodies against measles, mumps, and rubella in infants in Sri Lanka

BackgroundDetermining the dynamics of maternally transferred antibodies against measles, mumps, and rubella infections in infants is important for making evidence-based policy decisions regarding the timing of vaccination. MethodsThe levels of serum immunoglobulin G (IgG) developed against measles, mumps, and rubella infections were assessed using commercial ELISA kits in mother–newborn pairs (n = 294) and 6–12-month-old infants (n = 280) recruited from Colombo District, Sri Lanka. Antibody levels of mothers and their newborns were assessed with respect to sex and parity. Antibody levels and the protection conferred were assessed in a sample of infants who completed 6–12 months of age in relation to their age and sex. Antibody levels were compared between different age and sex groups using the Mann–Whitney U-test, and correlations of antibody titers were performed using the Spearman correlation test. ResultsThe prevalence rates of seropositivity for measles, mumps, and rubella were 91.5%, 89%, and 88%, respectively, in mothers, and 95%, 91.5%, and 93%, respectively, in their newborns. The newborns had mean IgG levels exceeding those of the mothers (P < 0.001). Mothers with natural infections had higher antibody levels compared to vaccinated mothers, which resulted in a higher level of maternal transfer. All of the infants who were 9–10 months of age or older were seronegative for measles, all of those who were 10–11 months of age or older were seronegative for rubella, and all of those who were 11–12 months old were seronegative for mumps. ConclusionsThe maternal transfer of antibodies to newborns is efficient and renders protection until the infants are 6–7 months old in the case of mumps and rubella and 7–8 months old in the case of measles. Hence infants remain vulnerable to infections before the first dose of the MMR vaccine.

Metal bioaccumulation and its genotoxic effects on eggs and hatchlings of giant Amazon river turtle (Podocnemis expansa).

The aim of this study was to assess whether possible metal contamination in the sediment of the nests of giant Amazon river turtle, Podocnemis expansa, could contaminate eggs and hatchlings, triggering genotoxic damage. Therefore, sediments of P. expansa nests from two sites in the Brazilian Amazon were evaluated, with the first being collected at Araguaia River and the second at Crixás-Açu River. Newly hatched offspring, eggs, and sediments were collected from the beaches of these two rivers and the quantification of metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn) was carried out by atomic absorption spectroscopy. All targeted metals were found in both sediment and P. expansa biological samples collected on the beaches presenting higher concentrations in the sediment of Crixás-Açu River. Metals found in the eggshells before nesting and in the egg contents were maternally transferred. Moreover, augmented concentration of metals led by metal transfer from the nests sediments were detected in the eggshells after nesting (ENH) and in the newly hatched offspring (H). Probably this metal relocation to the newly hatchlings augmented the frequency of micronuclei in their blood, presenting 15.25‰ in hatchling found in Crixás-Açu River beaches and 10‰ in newly hatched animals from Araguaia River beaches. These results indicate the occurrence of maternal transfer of metals (essential or not) to the eggs in testudines as well as a transference from the sediments to the nesting eggs, triggering genotoxic effects on the hatchlings.

HIV infection and placental malaria reduce maternal transfer of multiple antimalarial antibodies in Mozambican women

Maternal Plasmodium falciparum-specific antibodies may contribute to protect infants against severe malaria. Our main objective was to evaluate the impact of maternal HIV infection and placental malaria on the cord blood levels and efficiency of placental transfer of IgG and IgG subclasses. In a cohort of 341 delivering HIV-negative and HIV-positive mothers from southern Mozambique, we measured total IgG and IgG subclasses in maternal and cord blood pairs by quantitative suspension array technology against eight P. falciparum antigens: Duffy-binding like domains 3-4 of VAR2CSA from the erythrocyte membrane protein 1, erythrocyte-binding antigen 140, exported protein 1 (EXP1), merozoite surface proteins 1, 2 and 5, and reticulocyte-binding-homologue-4.2 (Rh4.2). We performed univariable and multivariable regression models to assess the association of maternal HIV infection, placental malaria, maternal variables and pregnancy outcomes on cord antibody levels and antibody transplacental transfer. Maternal antibody levels were the main determinants of cord antibody levels. HIV infection and placental malaria reduced the transfer and cord levels of IgG and IgG1, and this was antigen-dependent. Low birth weight was associated with an increase of IgG2 in cord against EXP1 and Rh4.2. We found lower maternally transferred antibodies in HIV-exposed infants and those born from mothers with placental malaria, which may underlie increased susceptibility to malaria in these children.

Effects of Maternally Transferred Egg Selenium on Embryo-Larval Survival, Growth, and Development in Arctic Grayling (Thymallus arcticus).

Selenium (Se) toxicity to fish is primarily manifested via maternal transfer to the eggs, which may result in adverse effects on larval survival and development. The present study assessed the effects of egg Se concentrations derived via maternal transfer on early life-stage development, survival, and growth of Arctic grayling (Thymallus arcticus), a salmonid species not previously assessed for Se sensitivity. Fish gametes were collected from 4 streams in Alaska known to exhibit a range of egg Se concentrations. Eggs were fertilized and reared in the laboratory from hatch through post-swim-up. Larvae were assessed for survival, length, and weight, as well as deformities (skeletal, craniofacial, fin-fold) and edema based on a graduated severity index. Eggs from a total of 47 females were collected, with egg Se concentrations ranging from 3.3 to 33.9 mg kg-1 dry weight. No relationships were observed between larval endpoints evaluated and parent females' egg, muscle, or whole-body Se concentrations. Therefore, Se 10% effective concentrations (EC10s) were defined as the maximum measured Se concentrations: >33.9, >17.6, and >19.7 mg kg-1 dry weight for eggs, muscle, and whole-body tissue, respectively. Collectively, these data indicate that Arctic grayling are relatively insensitive to maternally transferred Se compared to other fish species. Environ Toxicol Chem 2021;40:380-389. © 2020 SETAC.

Evidence and patterns of maternal transfer of metals and trace elements in Western tiger snakes (Notechis scutatus occidentalis) – a pilot study

AbstractUrban wildlife are regularly exposed to a variety of anthropogenic contaminants that have the potential to bioaccumulate in body tissues. As a consequence, developing embryos and offspring can be at risk from exposure to maternally accumulated contaminants, yet this has rarely been reported in reptiles. We opportunistically collected one pregnant Western tiger snake (Notechis scutatus occidentalis) from each of three wetlands with differing sediment metal contamination around Perth, and analysed maternal snake livers and three foetuses per litter for a suite of 17 elements representing either alkaline earth metals, transition metals or metalloids. We detected 14 elements, and compared their concentrations in maternal livers to foetus whole bodies to determine preliminary patterns of maternal transfer. Our results suggest antimony, arsenic, manganese, mercury, molybdenum and zinc are maternally transferred in Western tiger snakes. We urge further research to further quantify patterns of contaminant maternal transfer in viviparous snakes and determine their impacts on the development and health of contaminated offspring.

Direct Visualization and Quantification of Maternal Transfer of Silver Nanoparticles in Zooplankton.

The immense application of silver nanoparticles (AgNPs) in biomedical fields is likely to increase the exposure of humans. However, little is known about whether these nanoparticles can be maternally transferred, especially regarding their biodistribution in the younger generation, maternal transfer efficiency, and toxic effects. In the present study, maternal transfer of AgNPs in model zooplankton (Daphnia magna) was for the first time visualized and quantified. We found that AgNPs were transferred from mother to offspring and mainly accumulated in the lipids due to the strong colocalization with lipid droplets, which were the major energy sources of Daphnia embryos. In contrast, Ag+ was irregularly distributed in different sites, probably due to the mobility and reactivity of Ag+. The maternal transfer efficiency quantified by the radiolabeling methodology was 2.37 ± 0.25 and 6.05 ± 0.89% for 110mAgNPs and 110mAg, respectively. Furthermore, AgNPs and Ag+ significantly inhibited the reproduction capability of F0 and F1 generations, but such maternal toxic effect inhibition was only found within the first two broods of F0 and F1 generations. Our bioimaging findings demonstrated that AgNPs could be maternally transferred to the next generation; thus, it is critical to produce AgNPs with lower toxic effects, higher delivery efficacy, and more precise targeting.

Uptake, toxicity, and maternal transfer of cadmium in the oribatid soil mite, Oppia nitens: Implication in the risk assessment of cadmium to soil invertebrates

Cadmium (Cd) is a heavy metal of concern in contaminated sites because of its high toxicity to soil biota and humans. Typically, Cd exposure is thought to be dominated by dissolved Cd in soil pore water and, thus, dermal uptake. In this study, we investigated the uptake, toxicity, and maternal transfer of Cd in a standard soil invertebrate, the oribatid mite (Oppia nitens), which is common to boreal and temperate ecozones. We found total soil Cd predicted Cd uptake in adult and juvenile O. nitens with no significant uptake from pore water by juvenile mites. Cadmium significantly inhibited juvenile production and recruitment as well as reduced adult fecundity. Adult O. nitens maternally transferred 39–52% of their Cd body burden to juveniles (tritonymphs) while the maternally-acquired Cd accounted for 41% of the juvenile internal Cd load. Our results suggest that dermal adsorption of metal ions is not important for O. nitens and that maternal transfer of Cd in soil invertebrates has ecological and toxicological implications for populations of soil invertebrates. Maternal transfer should be incorporated as a criterion in setting environmental soil quality guidelines (SQGE) for cadmium and other non-essential heavy metals.

Phytogenic actives supplemented in hyperprolific sows: effects on maternal transfer of phytogenic compounds, colostrum and milk features, performance and antioxidant status of sows and their offspring, and piglet intestinal gene expression.

Phytogenic actives (PA) are plant-derived natural bioactive compounds that may promote livestock health and well-being, as well as improve growth performance and production efficiency. The current study aims to evaluate their effects on sows and their offspring. Eighty-one hyperprolific sows (up to parity 7) were assigned to 3 experimental treatments. Control sows were offered a nonsupplemented diet during gestation and lactation, and treated sows were fed the control diet supplemented with 1 g/kg of a blend of PA (BPA) in lactation (L) or during gestation and lactation (GL). An evaluation was made of placental and milk maternal transfer of these BPA and colostrum-milk features, sows and piglets antioxidant status, reproductive performance (litter size), body weight (BW) changes, weaning-estrus interval, and litter performance. Finally, piglet´s jejunum gene expression was measured. The BPA supplementation during gestation (GL) increased the number of piglets born alive (P = 0.020) and reduced (P < 0.05) the newborn piglets BW, while there were no differences among treatments on the suckling (day 20) and weaned (day 7) piglets BW (P > 0.05). Dietary phytogenic volatile compounds reached GL placental fluid, and milk of L and GL sows (P < 0.05). Moreover, colostrum protein in GL and milk fat content in L and GL were increased (P < 0.05). Milk of GL showed inhibitory activity against Bacillus subtilis and Staphylococcus aureus (P < 0.05). Antioxidant status of GL sows showed an enhanced (P < 0.05) of catalase (CAT) and total antioxidant capacity levels at early gestation (day 35), whereas higher levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) enzymes at late gestation (day 110). Likewise, GL newborn piglets showed higher CAT levels, whereas both CAT and SOD levels in suckling piglets, as well as CAT, SOD, and GSH-Px in weaned piglets, were increased in L and GL (P < 0.05). Jejunum messenger ribonucleic acid abundance of suckling piglets in L and GL groups showed overexpression of barrier function MUC2, digestive enzyme IDO, and immune response PPARGC-α, TNF-α, TGF-β1, and IL-10 genes (P < 0.05). In conclusion, dietary BPA supplementation in hyperprolific sows increased the litter size (born alive) and improved the composition and bioactivity of colostrum and milk, besides, modified the antioxidant status of sows and their offspring, as well as the suckling piglets gut health gene expression. Several BPA volatile compounds were prenatal and postnatal maternally transferred (placental fluid and milk).

In ovo exposure of fathead minnow (Pimephales promelas) to selenomethionine via maternal transfer and embryo microinjection: A comparative study

Selenium (Se) is an essential trace element of concern that is known to contaminate aquatic ecosystems as a consequence of releases from anthropogenic activities. Selenium is of particular toxicological concern for egg-laying vertebrates as they bioaccumulate Se through the diet and deposit excess Se to embryo-offspring via maternal transfer, a process which has been shown to result in significant teratogenic effects. The purpose of the present study was to determine and compare the in ovo effects of Se exposure on early development of a laboratory model fish species native to North American freshwater systems, the fathead minnow (Pimephales promelas), through two different exposure routes, maternal transfer and microinjection. For maternal transfer studies, fathead minnow breeding groups (3 females: 2 males) were exposed to diets containing Se-background levels (1.21 μg Se/g food, dry mass [dm]) or environmentally relevant concentrations of selenomethionine (SeMet; 3.88, 8.75 and 26.5 μg Se/g food dm) and bred for 28 days. Embryos were collected at different time points throughout the study to measure Se concentrations and to assess teratogenicity in embryos. While exposure to dietary Se did not negatively affect fecundity among treatment groups, the lowest treatment group (3.88 μg Se/g food dm) produced on average the most embryos per day, per female. The maternal transfer of excess Se occurred rapidly upon onset of exposure, reaching steady-state after approximately 14 days, and embryo Se concentrations increased in a dose-dependent manner. The greatest concentrations of maternally transferred Se significantly increased the total proportion of deformed embryo-larval fathead minnows but did not impact hatchability or survival. In a second study, fathead minnow embryos were injected with SeMet at concentrations of 0.00 (vehicle control), 9.73, 13.5 and 18.9 μg Se/g embryo dm. Microinjection of SeMet did not affect hatchability but significantly increased the proportion of deformed embryo-larval fish in a dose-dependent manner. There was a greater proportion of deformed fathead minnows at embryo Se concentrations of 18.9 μg Se/g embryo dm when exposed via microinjection versus maternal transfer at concentrations of 28.4 μg Se/g embryo dm. However, the findings suggest that both exposure routes induced analogous developmental toxicities in early life stage fish at Se concentrations between 9.73 and 13.5 μg Se/g embryo dm. Overall, this study demonstrated that microinjection has utility for studying the effects of Se in embryo-larval fish and is a promising method for the study of early life stage Se exposure in egg-laying vertebrates.