Because of its analgesic properties, acetaminophen (AAP) is widely used to relieve headache. AAP is generally considered safe for humans, but its effects on aquatic organisms are not well known. Here, we have hypothesis that effects of AAP on aquatic organisms would be environmental temperature dependent, because their physiological function depend on the temperature. To test this hypothesis, we used medaka (Oryzias latipes) as a model, because they can live at a wide range of temperatures (0–40 °C). We exposed medaka larvae to 0 (control), 50, or 150 mg/L of AAP at 15, 25 (optimal temperature), or 30 °C for 4 days. Egg yolk absorption was accelerated with raising temperature at any AAP dose. AAP exposure did not have biologically significant effects on survival ratio and body length of larvae at any tested temperature or dose, but heart rate decreased as the dose of AAP and environmental temperature increased. In addition, as the temperature increased, amount of ATP in individual larvae increased in control group, but decreased in AAP exposed group. Subsequently, exposure to 150 mg/L of AAP at 30 °C decreased the number of red blood cells in the gills; we used 150 mg/L of AAP in subsequent hematological and histological analyses. Hematological analysis showed that rising temperature increased the proportion of morphologically abnormal red blood cells in AAP-exposed larvae, suggesting that AAP induced anemia-like signs in larvae. Histological observation of the kidney, which is a hematopoietic organ in fish, revealed no abnormalities. However, in the liver, which is responsible for drug metabolism, the proportion of vacuoles increased with increasing temperature. Although the exposure concentration we tested was higher than environmentally relevant concentrations, our data indicated that rising temperature enhances the toxicity of AAP to medaka larvae, suggesting an ecological risk of AAP due to global warming.

Increasing concerns over bisphenol A (BPA) as an endocrine disrupting chemical (EDC) and its adverse effects on both humans and animals have led to the substitution by structural analogs, such as bisphenol F (BPF), in many application areas. Information regarding to the carry-over of this emerging chemical in farm animals is essential for legislation and risk assessment purposes. In this study, a large-scale number of animal experiments were designed to investigate the transfer of BPF from feed to eggs. One control and three experimental groups of laying hens (72 hens per group) were fed with basal diets and BPF-contaminated feed at concentration levels of 0.1, 0.5 and 2.5 mg kg⁻¹, respectively, for two weeks. The hens were then fed with BPF-free diets for a further four weeks. Eggs were collected daily, and separated into egg yolk and white for BPF analysis. The effects of different levels of BPF exposure on laying performance followed a non-monotonic dose-response curve, since low level BPF (0.1 mg kg⁻¹) exposure did increase the laying rate, mean egg weight and daily feed intake, while high level BPF (2.5 mg kg⁻¹) exposure showed a decreasing trend. BPF residues were detected in both egg yolks and whole eggs after two days of administration, and plateau phase was achieved within 9–18 days. There are clear linear dose-response relationships between the plateau BPF concentrations in feed and eggs. The residue of BPF was found mainly in egg yolks with conjugated form and depleted slowly (still detected 21 days after feeding the BPF-free diet of the high level group). Mean carry-over rate of 0.59% BPF from feed to eggs was obtained. Compared with the carry-over rates of PCBs and dioxins, BPF showed a relatively minor trend of bioaccumulation in eggs. To the best of our knowledge, this is the first report on the deposition, depletion, and bioaccumulation study of bisphenols in farm animals. The quantity of data can therefore be helpful in the frame of risk assessment, especially for a comprehensive estimation of consumer exposure to the residues of bisphenols.

A substantial increase in the usage of organophosphate esters (OPEs) as flame retardants and plasticizers in rubbers, textiles, upholstered furniture, lacquers, plastics, building materials and electronic equipment has resulted in their increasing concentrations in the environment over time. However, little is known about the concentrations and fate of OPEs and their metabolites (mOPEs) in biota, including chicken eggs. The aim of this study was to understand the spatial variation in the concentrations in chicken eggs and the partitioning between yolk and albumin. In total, 153 chicken eggs were purchased across Australia and analysed for 9 OPEs and 11 mOPE. Most of the compounds were found to be deposited in egg yolk, where diphenyl phosphate (DPHP, 3.8 ng/g wet weight, median) and tris(2-chloroisopropyl) phosphate (TCIPP, 1.8 ng/g wet weight, median) were predominant mOPE and OPE, respectively. Moreover, no spatial differences in concentrations of OPEs and mOPEs in eggs purchased from different locations were found in this study. Although comparable levels of ∑OPEs were detected in egg yolk and albumin, much higher concentrations of ∑mOPEs were found in yolk than albumin. Meanwhile, a negative correlation (R² = 0.964, p = 0.018) was found between the molecular mass of analytes and partitioning coefficient of Cyₒₗₖ/Cyₒₗₖ₊ₐₗbᵤₘᵢₙ (defined as chemical concentration in egg yolk divided by the sum of chemical concentrations in both yolk and albumin). These results indicate that n-octanol/water partition coefficients (log KOW) may not be a crucial factor in the distribution of OPEs and mOPEs between egg yolk and albumin, which is important in understanding distribution of emerging organic contaminants in biota.

This study analyzed trace elements (As, Ba, Cd, Cu, Fe, Mn, Pb, Zn) and stable isotopes of carbon and nitrogen in egg yolk samples of female green turtles that nested in Rocas Atoll, Brazil, in 2017 and 2018. The trace elements concentration varied between years, with higher concentrations in 2017, suggesting that the nesting groups come from different foraging sites. The isotopic data indicated high overlap between years (73%), leading to an ambiguous interpretation on the turtles' foraging site. The Normalized Total Load presented a low association (0.01 < R² < 0.41) with the stable isotopes. The Normalized Total Load that represents the trace element load in egg yolk is a holistic approach that can be applied elsewhere to predict ecotoxicology pathways in any animal species. We recommend a continuous monitoring to verify how the trace elements load behave in the nesting green turtles on Rocas Atoll.

During reproduction vitellogenin (VTG) is transported to vitellogenic oocytes as a precursor of egg yolk lipovitellin (LV). As VTG synthesis is affected by environmental stressors, it is widely used as biomarker in endocrine disruption studies. However, it has seldom been employed to evaluate invertebrate hydrocarbon pollution. An ELISA with anti-LV antibody was developed to evaluate the impact of water-soluble fraction of crude oil (WSF) on Macrobrachium borellii vitellogenesis. Prawn VTG concentration was within the range reported for other crustaceans; LV values were positively correlated with gonadosomatic index (GSI). Females at different vitellogenic stages were exposed to a sub-lethal concentration of WSF for 7days. Exposed animals with GSI>7 increased their VTG and LV titer as compared to control organisms (190% and 140%, respectively). VTG levels in M. borellii were upregulated and highly sensitive to WSF exposure. This assay could be employed as a biomarker for freshwater hydrocarbon pollution.

Monosodium glutamate (MSG) is a flavor enhancer commonly used in modern nutrition. In this study, it was aimed to determine the effect of in ovo administered MSG on the embryonic development of thymus, bursa of Fabricius, and percentages of alpha-naphthyl acetate esterase (ANAE) positive lymphocyte by using histological, histometrical, and enzyme histochemical methods in chickens. For this purpose, 410 fertile eggs were used. The eggs were then divided into five groups: group 1 (control group, n = 40 eggs), group 2 (distilled water-injected group, n = 62 eggs), group 3 (0.12 mg/g egg MSG-injected group, n = 80 eggs), group 4 (0.6 mg/g egg MSG-injected group, n = 90 eggs), and group 5 (1.2 mg/g egg MSG-injected group, n = 138 eggs), and injections were performed via the egg yolk. On the 18th and 21st days of the incubation, the eggs were randomly opened from each group until six live embryos were obtained. The embryos of each group were sacrificed by decapitation, and blood, thymus, and bursa of Fabricius tissue samples were taken from the obtained embryos. The MSG-treated groups were found to be retarded embryonic development of thymus and bursa of Fabricius tissue compared to the control and distilled water groups. MSG treatment also resulted in reduced lymphoid follicles count and follicle diameters in bursa of Fabricius (P < 0.05). The percentage of peripheral blood ANAE positive lymphocytes was significantly lower in the MSG-treated groups than in the control and distilled water groups (P < 0.05). In conclusion, it has been found that in ovo administered MSG can adversely affect the embryonic development of thymus and bursa of Fabricius and decrease percentage of ANAE positive lymphocyte.

In the eggs and developing chick livers in the two wild bird species, great cormorant and herring gull, the concentrations of a range of 15 perfluoroalkyl acids (PFAAs) were determined. Eggs of the two species were collected from Lake Vanern, Sweden, and analysed either as undeveloped egg (whole egg or separated into yolk and albumen) or incubated until start of the hatching process when the chick liver was removed and analysed. High levels of PFAAs were found in all matrixes except albumen. The predominant PFAA was perfluorooctane sulfonate (PFOS), which was found in the mu g/g wet weight (ww) range in some samples of cormorant whole egg, yolk and liver and herring gull egg yolk and liver. The average concentration in yolk was 1,506 ng/g ww in cormorant and 589 ng/g ww in herring gull. The average liver concentrations of PFOS were 583 ng/g ww in cormorant and 508 ng/g ww in herring gull. At these concentrations, biochemical effects in the developing embryo or effects on embryo survival cannot be ruled out. For perfluoroalkyl carboxylates (PFCAs), the liver/egg and liver/yolk concentration ratios increased with PFCA chain length in cormorant but not in herring gull, indicating that chain length could possibly affect egg-to-liver transfer of PFCAs and that species differences may exist.

INTRODUCTION: High concentrations of hexabromocyclododecane (HBCD) sometimes recorded in free-range hens' eggs are thought to be due to soil ingestion. Of the three stereoisomers of HBCD (α-, β-, and γ-HBCD), γ-HBCD is the main component in the commercial mixture, as well as in environmental matrices, whereas the isomer profile is α-dominated in biota. In fish and in mammals, this shift is thought to be due to a rapid elimination of γ-HBCD and to its bioisomerization to the more persistent α-HBCD. The aim of the current controlled study was to better understand the fate of ingested HBCD in laying hens. The isomer profile in soil being γ-dominated, excretion kinetics of γ-HBCD into egg yolk, and accumulation in liver and in abdominal fat were investigated. MATERIALS AND METHODS: Forty-eight laying hens were individually housed and fed with a spiked diet containing 1.1-ng γ-HBCD per gram for 21 days and with a clean diet for the following 18 days. Hens were sequentially slaughtered throughout the 39-day experiment. α-, β-, and γ-HBCD were analyzed in egg yolk, in abdominal fat, and in liver by LC-MS/MS. α- and γ-HBCD were quantified in the three tissues, while β-HBCD was never quantified. RESULTS AND CONCLUSION: Kinetics of the two isomers suggests that γ-HBCD is rapidly biotransformed and eliminated, and partly isomerized into the more persistent α-HBCD. Carry-over rate of ingested γ-HBCD to egg yolk was estimated at 1.2%. Estimated half-lives of γ-HBCD in egg yolk, in abdominal fat, and in liver were 2.9, 13, and 0.41 days, respectively.