Risk assessment of endocrine-active compounds in feeds

Toxicological Risk Analysis in Data-Poor Countries: A Narrative Approach to Feed an "Awareness Raising-Community Empowerment" Vortex

Background and objectives: With globalization of culture and products, choices and behaviors associated with the unawareness of toxicological risk factors result in human and environmental toxic exposures along with health disparities. Toxic exposures are risk factors for malnutrition and diseases, impairing the chances of being healthy and having a healthy adulthood for current and next generation(s). Increasing research funds, infrastructures, analytical data and risk assessment is a reality well worth attention in sub-Saharan Africa. These countries are still unprotected nowadays and are particularly exposed and data-poor in respect to risk factors (e.g., neurotoxicants, immunotoxicants and endocrine disruptors). This paper presents how-based on scientific literature-low-resource countries may achieve more with less. As one of the world's most important emerging markets, Africa can, and should, assess the benefits and risks of modernity versus tradition and ask for safe and quality products at affordable prices while producing safe and nutritious foods. Materials and Methods: Exempla and experiences of risk analysis based on participant observation in field anthropological research, consumer safaris and reportages in the field of food safety, environmental health and consumer products are discussed in terms of "narrative prevention" and its power to highlight previously unrecognized/overlooked real-life risk scenarios. Knowledge return initiatives are discussed in light of their power to feed awareness raising, informed choice and empowerment of communities. Results: In some cases, data exist but remain too sparse, unknown or underused; in other cases, the information is totally neglected. When there is international scientific evidence, a diagnostic risk assessment is feasible. Despite significant resource constraints, properly science-driven targeted reportages in data-poor countries can bridge the gaps between international scientific knowledge and the implementation of relevant findings in an "awareness-empowerment vortex". When a clear message promoting healthy choices and behaviors is given, African communities are ready to respond. Conclusions: Poor skills are an avoidable consequence of low national income. Narrative prevention does not replace scientific research but stimulates scientific research and toxicological risk analysis during the ongoing risk transition in Africa. While African populations increasingly aspire to improve life expectancy in health, increasing exposure to such new health risk factors in sub-Saharan Africa needs top-down choices for diseases prevention, One Health, as well as public awareness and empowerment towards everyday habits and health protective choices.

Endocrine Disrupters and the Safety of Food Chains

Endocrine disrupters (ED) are a heterogeneous group of chemicals including persistent contaminants, pesticides, as well as compounds present in consumer products and natural substances. For most ED, the food chain is a current major exposure route for the general population. ED can enter the food chain through the living environment (e.g., feeds, fertilizers) of food-producing organisms, be directly employed in food production (e.g., pesticides) or be released from food contact materials (such as bisphenol A or phthalates); in addition, the endocrine disruption potential of some natural compounds in edible plants, including the so-called phytoestrogens, should not be overlooked. An exposure assessment has to consider the specific liability of food commodities to contamination with specific ED (e.g., polychlorinated and polybrominated chemicals in lipid-rich foods). The paper discusses the main toxicological research issues in order to support the risk assessment of ED in food chains, including: the potential for additive, 'cocktail' effects (as from multiple pesticide residues); the long-term effects on target body systems (e.g., reproductive, nervous) elicited by exposure during prenatal as well as postnatal life stage windows, and toxicant/nutrient interactions (e.g., thyroid-targeting ED and iodine status). Food safety systems should exploit the available knowledge to improve prevention of long-term risks along the whole food chain.

Effect of 11β-hydroxyandrostenedione on European whitefish Coregonus lavaretus (Linnaeus, 1758)

The goal of the present research was to evaluate the efficiency of 11β-hydroxyandrostenedione (OHA) applied in the diet to achieve sex reversal in the European whitefish (Coregonus lavaretus). At 32day post-hatching, fish were reared in four groups: fish fed with 10ppm of OHA (10 OHA), fish fed with 20ppm of OHA (20 OHA), fish fed without OHA (C) and fish fed without OHA and reared in the water from 20 OHA group (R). The experimental groups were conducted in separate recirculation systems and the first phase of the experiment lasted 63days. For the histological analysis of the gonads, fish from all groups were reared without OHA treatment for an additional 91days (second phase). At the end of the first phase of the experiment, survival of the whitefish ranged from 34.5±11.1% to 51.5±7.3%. The final body weight and coefficient of variation in the weight ranged from 5.6±1.2g to 6.9±1.5g and from 21.5 to 22.7%, respectively. No negative effects of OHA treatment on the growth and the survival of the whitefish were found. Six histological categories of the whitefish gonads were observed. Apart from the typical ovaries and testes, two types of the intersexual gonads (ovotestis and testis-ova) and two types of the sterile-altered gonads were distinguished. No gonadal females were found among fish from any of OHA groups. Gonadal males constituted of 60% and 50% of the fish from 10 OHA and 20 OHA groups, respectively. Intersexes were observed in all groups with the highest proportion found among fish from R variant. Rate of sterile individuals in 10 OHA and 20 OHA groups was 17% and 30%, respectively. The proportion of fish with normal testes to fish with other types of gonad varied from 0.43:1 to 1.5:1 with the higher ratio observed in both OHA groups. Lack of the females among fish from OHA groups suggested OHA affected growth and development of ovaries in the whitefish. However, a high percentage of the sterile fish in both OHA treated groups indicated application of lower doses of OHA for masculinization of the whitefish in the further research.

Effect of various selenium doses on chromium(IV)-induced nephrotoxicity in a male chicken model

Our study aimed to explore whether Na₂SeO₃ (Se) can alleviate the nephrotoxicity induced by K₂Cr₂O₇ [Cr(VI)]. One hundred and five male chickens were randomly divided into seven groups with 15 chickens each group: The 6 experimental groups received K₂Cr₂O₇ alone or in combination with 0.31, 0.63, 1.25, 2.50, and 5.00 mg/kg for 42 days, respectively, while control group was treated with equivalent water. Exposure to Cr(VI) significantly increased MDA contents and organ coefficient, whereas decreased T-SOD activities, Ca²⁺-ATPase activities, mitochondrial membrane potential and GSH contents, and histological studies demonstrated renal damage. Above indicators were restored by Se supplement (0.31, 0.63, and 1.25 mg/kg), in which supplement with 0.63 mg/kg Se developed more effectively than the other two groups; on the contrary, in the groups of Se supplement with 2.50 and 5.00 mg/kg, the above indicators were not ameliorated and even exacerbated. This study demonstrated that Cr(VI) can result in kidney oxidative damage in male chickens, and Se of certain dose has the protective effects against Cr(VI)-induced nephrptoxicity.

The One Health Perspective in Trace Elements Biomonitoring

Health risks in both animals and humans are associated with chronic exposures to levels of trace elements (TE) eliciting toxic and/or antinutritional effects, including excess exposures to some essential elements. Interferences with essential TE may also lead to secondary nutritional deficiencies and/or imbalances. Although research is still required, biomarkers of exposure, including bioavailability, for TE are established tools for human biomonitoring that can also be applied to animal surveillance. Biomarkers of effect as well as, where available, of susceptibility and bioavailability are necessary to understand whether an ongoing exposure may pose a current or future health concern. In the field of animal health the use of biomarkers is less developed and less widespread than in human health; however, under a One Health perspective, animal biomonitoring can provide important information on the interfaces among humans, animals, and the environment, supporting the prevention and management of health risks. Therefore, a transfer of knowledge from human biomonitoring to farm or free-ranging animals is critical in a risk assessment framework from farm to humans. Advantages and critical aspects in designing and conducting integrative biomonitoring activities in humans and animals were critically reviewed focusing on biomarkers of exposure, effect, susceptibility, and bioavailability for toxic and essential TE. Highlighted aspects include TE metabolism, bioaccessibility, and interactions. Farm or free-ranging animals may provide noninvasive matrices suitable for evaluating animal welfare, environmental stressors, food safety, and potential risks for human health, as proposed by the interdisciplinary concept of One Health.

Evaluation of estrogenic activity in animal diets using in vitro assay

A yeast estrogen bioassay (RIKILT REA) was in-house validated for feed on the 5μg 17β-estradiol-equivalents per kg level according to EC Decision 2002/657/EC. All the performance characteristics met the criteria as defined in the Decision and the REA is able to detect 17β-estradiol in animal feed at a low level of 1.15-2μgkg(-1). Subsequently, the developed and validated procedure was applied to determine the estrogenic activity in 24 feed samples intended for food producing animals, pets and laboratory animals. Two batches of rodent diet Murigran and one dog feed have been presented as a suspect, i.e. gave responses above the determined decision limit (CCα) and detection capability (CCβ). In assessing the performance of the estrogenic activity in these diets evaluated by comparison with the 17β-estradiol calibration curve, 17β-estradiol-equivalence levels of 7.07μg EEQkg(-1) and 9.54μg EEQkg(-1) in two batches of rodent diet and 5.3μg EEQkg(-1) in dog feed have been established. The activities observed in the rodent feed could be explained by chemical analysis, revealing high amounts of genistein, daidzein and trace amounts of zearalenone. In addition, the estrogenic activity in one of rodent feed was above the established CCα, but below the CCβ values established and all other samples showed no estrogenic activity with responses below the CCα value, which corresponds to levels below 2μg EEQkg(-1).

Occurrence of deoxynivalenol and zearalenone in commercial fish feed: an initial study

The control of mycotoxins is a global challenge not only in human consumption but also in nutrition of farm animals including aquatic species. Fusarium toxins, such as deoxynivalenol (DON) and zearalenone (ZEN), are common contaminants of animal feed but no study reported the occurrence of both mycotoxins in fish feed so far. Here, we report for the first time the occurrence of DON and ZEN in samples of commercial fish feed designed for nutrition of cyprinids collected from central Europe. A maximal DON concentration of 825 μg kg(-1) feed was found in one feed whereas average values of 289 μg kg(-1) feed were noted. ZEN was the more prevalent mycotoxin but the concentrations were lower showing an average level of 67.9 μg kg(-1) feed.

Cadmium, lead, and chromium in large game: a local-scale exposure assessment for hunters consuming meat and liver of wild boar

Heavy metals are ubiquitous in soil, water, and air. Their entrance into the food chain is an important environmental issue that entails risks to humans. Several reports indicate that game meat can be an important source of heavy metals, particularly because of the increasing consumption of game meat, mainly by hunters. We performed an exposure assessment of hunters and members of their households, both adults and children, who consumed wild boar (WB) meat and offal. We estimated the amount of cadmium, lead, and chromium in the tissues of WB hunted in six areas within Viterbo Province (Italy) and gathered data on WB meat and offal consumption by conducting specific diet surveys in the same areas. The exposure to cadmium, lead, and chromium was simulated with specifically developed Monte Carlo simulation models. Cadmium and lead levels in WB liver and meat harvested in Viterbo Province (Italy) were similar to or lower than the values reported in other studies. However, some samples contained these metals at levels greater then the EU limits set for domestic animals. The chromium content of meat or liver cannot be evaluated against any regulatory limit, but our results suggest that the amounts of this metal found in WB products may reflect a moderate environmental load. Our survey of the hunter population confirmed that their consumption of WB meat and liver was greater than that of the general Italian population. This level of consumption was comparable with other European studies. Consumption of WB products contributes significantly to cadmium and lead exposure of both adults and children. More specifically, consumption of the WB liver contributed significantly to total cadmium and lead exposure of members of the households of WB hunters. As a general rule, liver consumption should be kept to a minimum, especially for children living in these hunter households. The exposure to chromium estimated for this population of hunters may be considered to be safe. However, a specific and complete assessment of chromium speciation in relevant dietary and environmental situations should be conducted.

Toxicants exposures as novel zoonoses: reflections on sustainable development, food safety and veterinary public health

The modern concept of zoonosis considers any detriment to the health and/or quality of human life resulting from relationships with (other) vertebrate or edible or toxic invertebrate animals. Whereas exposure to toxicants through foods of animal origin (a.o.) is a well-established issue, hereby we discuss it as novel zoonoses, from the standpoints of health implications as well as similarities and differences with classical zoonoses caused by biological agents. Novel toxicant-related zoonoses are linked with new issues in food safety, such as the environment-feed-food chain. In fact, the potential effect of the combined and repeated exposure to dietary toxicants is generally long-term and not readily discernible. Endocrine disrupting chemicals in staple foods of a.o. are discussed as a telling example of a food safety issue summing up critical points covered by the definition of sustainable development, also implicating health risks for generations to come. We suggest some critical points to implement the veterinary public health action in sustainable food safety, such as enhancement of Hazard Analysis and Critical Control Points systems for toxicological risk management.

Evaluation and validation of a novel Arxula adeninivorans estrogen screen (nAES) assay and its application in analysis of wastewater, seawater, brackish water and urine

A novel Arxula adeninivorans yeast estrogen screen (nAES) assay has been developed for detection of estrogenic activity in various liquid samples such as wastewater, seawater, brackish water and swine urine. Two bio-components were engineered to co-express the human estrogen receptor α (hERα) and an inducible reporter gene; either the non-conventional phytase gene (phyK, derived from Klebsiella sp. ASR1) or the non-conventional tannase gene (ATAN1, derived from Arxula). Both reporters were put under the control of an Arxula derived glucoamylase (GAA) promoter, which was modified by the insertion of two estrogen-responsive elements (EREs). The Arxula transformation/expression platform Xplor® 2, which lacks resistance markers and E. coli elements, was used to select stable mitotic transformants. They were then analyzed for robustness and suitability as the bio-component for the nAES assay. Two types of the nAES assay based on the reporter proteins phytase and tannase (nAES-P, nAES-T) were used in this work. The nAES-P type is more suitable for the analysis of seawater, brackish water and urine whereas the nAES-T type exhibited higher robustness to NaCl. Both assay types have similar characteristics for the determination of estrogen in sewage and urine samples e.g. 6-25 h assay period with detection and determination limits and EC(50) values for 17β-estradiol of 2.8 ng L(-1), 5.9 ng L(-1), 33.2 ng L(-1) (nAES-P) and 3.1 ng L(-1), 6.7 ng L(-1) and 39.4 ng L(-1) (nAES-T). Substrate specificity and analytical measurement range (AMR) for both assay types are also similar. These characteristics show that the nAES assay based on non-conventional salt tolerant yeast is applicable for a high throughput estrogen analysis in the environmental and regulatory control sectors.

Zearalenone occurrence and human exposure

Among the mycotoxins zearalenone (ZEA) is of interest because of the oestrogenic effects that it, and certain of its metabolites possess. The fungi that produce ZEA are found worldwide, particularly in cereal grains and derived products. This has prompted many surveys to detect these compounds in commodities and foods. As a result, the widespread occurrence of ZEA in foods is well documented. Previous summaries including extensive reports by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the European Commission's Scientific Cooperation on Questions Relating to Food (SCOOP), and others, have provided significant information on the occurrence of ZEA in commodities and foods. Publication of occurrence data has continued at a rapid pace, and certain of that data, as well as highlights from previous intake and exposure assessments, are summarised herein. Comparing estimates of intake (exposure) with previous estimates of tolerable daily intakes, suggests that, for many of the countries where exposure assessments have been done, the populations are exposed to levels that would be considered safe. The situation may be different in populations that consume large quantities of foods that are susceptible to contamination, or in instances where contamination is atypically high. For much of the world estimates of exposure have not been reported, meaning that for much of the world, the true extent of the relevance of ZEA to human health remains uncharacterised.