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.

We exposed female European starlings to a pentabromodiphenyl ether (Penta-BDE) mixture through subcutaneous implants, and examined levels and profiles of polybrominated diphenyl ethers (PBDEs) together with reproductive effects. Sum PBDE levels increased significantly in the serum of the exposed females from 218 ± 43 to 23,400 ± 2035 pg/ml. Sum PBDE concentrations in the eggs of the exposed group ranged from 130 ± 12 to 220 ± 37 ng/g wet weight (ww). The profile in serum after egg laying was very similar to that in eggs. There were no detectable levels of HO-PBDEs in both serum and eggs. Fewer females of the exposed group initiated egg laying compared to the control group, although the difference was not significant. In addition, egg weight and volume were significantly higher in the exposed group. These results suggest that, at the investigated exposure levels (150 μg sum PBDEs/bird), PBDEs may have a negative effect on reproductive performance.

Resource acquisition and allocation impacts individual fitness. Using pellet analysis of breeding adults and stable isotopes of carbon and nitrogen of down feathers of Kelp Gull (Larus dominicanus) nestlings, we evaluated the relationship between urban refuse (beef and chicken) and natural food (fish) consumption of individual females during the pre-incubation period, with fecundity and young nesting's success in the Río de la Plata Estuary in Uruguay. Assimilated urban refuse positively correlated with egg weight and negatively with young nestling's success. This suggests a possible impact of urban refuse foraged by females during the pre-incubation period on their immediate fecundity (positively) and young nestling's survival (negatively). Differences between studies at the individual and colony levels are also discussed in light of an “ecological fallacy” of interpretation and we thus argue for the need of additional research to evaluate this relationship further, considering potential confounding factors.

Eggs from egrets (Egretta thula) were collected from Cartagena Bay and Totumo Marsh, two sites at the north of Colombia with different pollution background, and measured their morphometric parameters as well as total mercury (T-Hg) and calcium levels in eggshell. Statistically significant differences were observed for egg weight and size between the two sampling locations. T-Hg and calcium concentrations in eggshell were greater in eggs from Cartagena Bay, the industrial site, compared to Totumo Marsh, a non-industrial location. The opposite was observed for eggshell thickness (3.6% less in the bay). Pearson correlation analysis showed eggshell T-Hg negatively correlated with eggshell weight in eggs from the marsh (R=−0.795, P<0.006), but not from the bay (R=0.387, P=0.269), probably suggesting greater susceptibility to Hg in birds from the non-polluted site. In short, results suggest eggs from E. thula at Cartagena Bay have greater T-Hg concentrations and less eggshell thickness than those from Totumo Marsh.

This study evaluated the effect of Yucca schidigera extract on productive performance, egg quality, blood metabolites, immune function, and antioxidant parameters in laying hens. A total of 96 36-week-old hens were allocated into four groups, the control diet or the diet supplemented with 50, 100, or 150 mg/kg of yucca extract, from 36 to 52 weeks of age. Hens were divided into four equal groups replicated six times with four hens per replicate. As a result of this study, there were no linearly or quadratically differences in body weight change (BWC), feed consumption (FC), feed conversion ratio (FCR), and egg weight (EW) due to yucca treatments at different ages, except FCR and EW that were improved with yucca supplementation during 36–40 weeks of age. Supplemental dietary yucca up to 100 mg/kg diet led to significant improvement in egg number (EN) and egg mass (EM). Egg qualities were not linearly or quadratically affected by yucca treatments except shell thickness was quadratically (P < 0.001) increased with increasing yucca level up to 100 mg/kg diet. Dietary supplementation of yucca exhibited a positive impact on albumin and immunoglobulin G (IgG). Comparing to the control group, yucca addition to laying hen diets resulted in a significant linear (P < 0.001) and quadratic (P = 0. 010) decrease in blood ammonia-N and urea-N, respectively. The activity of superoxide dismutase (SOD) and reduced glutathione (GSH) level in serum were quadratically improved in yucca groups. The malondialdehyde (MDA) concentration was decreased with yucca addition in comparison with the control group. In conclusion, yucca supplemented up to 100 mg/kg diet can be used as effective feed additive to improve productive performance, blood profile, and antioxidant enzyme activities in laying hens.

Polycyclic aromatic hydrocarbons (PAHs) are widespread fused-ring contaminants formed during incomplete combustion of almost all kind of organic materials from both natural and anthropogenic sources. Some PAHs have been shown to be carcinogenic to humans, and a wide range of PAHs are found in wildlife all around the globe including avian species. The purpose of this project was to assess the effects of a standard mixture of 16 PAHs (United States Environmental Protection Agency) on the hepatic fatty acid β-oxidation in chicken embryos (Gallus gallus domesticus) exposed in ovo. The hepatic β-oxidation was measured using a tritium release assay with [9,10-³H]-palmitic acid (16:0) as substrate. Treated groups were divided into groups of 0.05, 0.1, 0.3, 0.5, and 0.8 mg PAHs/kg egg weight. The hepatic β-oxidation was reduced after exposure in ovo to the 16 PAHs mixture compared to control. The mechanisms causing reduced fatty acid oxidation in the present study are unclear, however may be due to deficient membrane structure, the functionality of enzymes controlling the rate of fatty acid entering into the mitochondria, or complex pathways connected to endocrine disruption. To the best of our knowledge, this is the first time a PAH-caused reduction of hepatic β-oxidation of fatty acids in avian embryos has been observed. The implication of this finding on risk assessment of PAH exposure in avian wildlife remains to be determined.

Perfluooctane sulfonate (PFOS) is considered an emerging pollutant because of its wide distribution in both aquatic and terrestrial ecosystems, as well as its potential toxicity to living organisms. Although PFOS environmental levels and the adverse effects on classical model organisms in toxicological studies are well known, including developmental alterations and alteration of oxidative status, its toxicity to free-living species has been seldom investigated. The aim of this study was to assess the potential toxicity of environmental levels of PFOS to yellow-legged gull (Larus michahellis) embryos under field experimental conditions. In a within-clutch experimental design, we injected two PFOS concentrations (100 ng PFOS/g egg weight and 200 ng PFOS/g egg weight) in ovo soon after laying. Eggs were collected when they reached the cracking stage. We investigated the effects of PFOS treatment, laying order and sex on both morphological and biochemical endpoints of embryos. Specifically, we assessed changes in embryo body mass and tarsus length, as well as in liver and brain mass. Moreover, the imbalance of oxidative status was evaluated in both liver and brain from embryos by measuring total antioxidant capacity (TAC) and total oxidant status (TOS), while the levels of protein carbonyl content (PCO) and DNA fragmentation were measured as oxidative and genetic damage endpoints, respectively. The concentrations of PFOS we tested did not significantly alter the morphological endpoints, independently of laying order and sex. Similarly, embryo oxidative status and oxidative and genetic damage were not significantly affected by PFOS in ovo exposure. These findings suggest that current environmental PFOS levels do not affect early development of yellow-legged gull embryos.

PURPOSE: Perfluorooctane sulfonate (PFOS) belongs to a group of chemicals called perfluoroalkyl acids that have been extensively used in various applications such as stain and oil resistant treatments for fabrics, fire-fighting foams, and insecticides. These chemicals present an environmental and health risk being present in many samples both in wildlife and humans. In this study, we investigate the effect of PFOS on fatty acid β-oxidation in developing chicken embryos. METHODS: Fertilized chicken eggs were exposed in ovo to PFOS at day 4 of incubation. On day 10, the eggs were dissected and livers were incubated in vitro with 3H-palmitic acid for 2 h. The media were collected, and after clean up, the amount of tritiated water was measured with liquid scintillation counting to determine the rate of palmitic acid β-oxidation. RESULTS: PFOS was found to induce fatty acid β-oxidation at doses starting from a lowest observed effect level (LOEL) of 0.1 μg/g egg weight. Maximum induction of 77 % compared to control was seen at 0.3 μg/g. CONCLUSIONS: The administered doses in which effects are seen are around and even lower than the levels that can be found in wild populations of birds. General population human levels are a factor of two to three times lower than the LOEL value of this study. The environmental contamination of PFOS therefore presents a possibility of effects in wild populations of birds.