Acrylamide–occurrence in mixed concentrate feed for dairy cows and carry-over into milk

Maternal acrylamide exposure changes intestinal epithelium, immunolocalization of leptin and ghrelin and their receptors, and gut barrier in weaned offspring

Acrylamide (ACR) is an amide formed as a byproduct in many heat-processed starchy-rich foods. In utero ACR exposure has been associated with restricted fetal growth, but its effects of postnatal functional development of small intestine is completely unknown. The current study investigated the time- and segment-dependent effects of prenatal ACR exposure on morphological and functional development of small intestine in weaned rat offspring. Four groups of pregnant female Wistar rats were exposed to ACR (3 mg/kg b.w./day) for 0, 5, 10 and 15 days during pregnancy. Basal intestinal morphology, immunolocalization of gut hormones responsible for food intake and proteins of intestinal barrier, activity of the intestinal brush border disaccharidases, apoptosis and proliferation in intestinal mucosa were analyzed in offspring at weaning (postnatal day 21). The results showed that in utero ACR exposure disturbs offspring gut structural and functional postnatal development in a time- and segment-depended manner and even a short prenatal exposure to ACR resulted in changes in intestinal morphology, immunolocalization of leptin and ghrelin and their receptors, barrier function, activity of gut enzymes and upregulation of apoptosis and proliferation. In conclusion, prenatal ACR exposure disturbed the proper postnatal development of small intestine.

Prenatal acrylamide exposure results in time-dependent changes in liver function and basal hematological, and oxidative parameters in weaned Wistar rats

Acrylamide (ACR) is a toxic compound commonly found in fried, baked and heat-processed starchy foods. The current study investigated the time-dependent effects of maternal exposure to non-toxic ACR doses on the oxidative stress, liver function, and basal blood morphology of the rat offspring. Pregnant, Wistar rats were randomly divided into the control group or the groups administrated with ACR (3 mg/kg b.w./day): long exposure for 15 days, medium exposure for 10 days and short exposure for 5 days during pregnancy. Body mass, blood morphology and hematology, serum concentrations of growth hormone, IGF-1, TNF-α, IL-1β, IL-6 and insulin, liver histomorphometry, liver activity of beclin1, LC2B and caspase3, markers of oxidative stress and the activity of antioxidative enzymes in blood serum and the liver were measured in offspring at weaning (postnatal day 21). Even short prenatal exposure to ACR led to oxidative stress and resulted in changes in liver histomorphometry and upregulation of autophagy/apoptosis. However, the most significant changes were observed following the long period of ACR exposure. This study has shown for the first time that ACR is responsible for changes in body mass in a time-dependent manner, which could lead to more serious illnesses like overweight and diabetes later in life.

Developmental neurotoxicity of acrylamide and its metabolite glycidamide in a human mixed culture of neurons and astrocytes undergoing differentiation in concentrations relevant for human exposure

Neural stem cells (NSCs) derived from human induced pluripotent stem cells were used to investigate effects of exposure to the food contaminant acrylamide (AA) and its main metabolite glycidamide (GA) on key neurodevelopmental processes. Diet is an important source of human AA exposure for pregnant women, and AA is known to pass the placenta and the newborn may also be exposed through breast feeding after birth. The NSCs were exposed to AA and GA (1 ×10^-8 - 3 ×10^-3 M) under 7 days of proliferation and up to 28 days of differentiation towards a mixed culture of neurons and astrocytes. Effects on cell viability was measured using Alamar Blue™ cell viability assay, alterations in gene expression were assessed using real time PCR and RNA sequencing, and protein levels were quantified using immunocytochemistry and high content imaging. Effects of AA and GA on neurodevelopmental processes were evaluated using endpoints linked to common key events identified in the existing developmental neurotoxicity adverse outcome pathways (AOPs). Our results suggest that AA and GA at low concentrations (1 ×10^-7 - 1 ×10^-8 M) increased cell viability and markers of proliferation both in proliferating NSCs (7 days) and in maturing neurons after 14-28 days of differentiation. IC₅₀ for cell death of AA and GA was 5.2 × 10^-3 M and 5.8 × 10^-4 M, respectively, showing about ten times higher potency for GA. Increased expression of brain derived neurotrophic factor (BDNF) concomitant with decreased synaptogenesis were observed for GA exposure (10^-7 M) only at later differentiation stages, and an increased number of astrocytes (up to 3-fold) at 14 and 21 days of differentiation. Also, AA exposure gave tendency towards decreased differentiation (increased percent Nestin positive cells). After 28 days, neurite branch points and number of neurites per neuron measured by microtubule-associated protein 2 (Map2) staining decreased, while the same neurite features measured by βIII-Tubulin increased, indicating perturbation of neuronal differentiation and maturation.

Acrylamide Content in Breast Milk: The Evaluation of the Impact of Breastfeeding Women's Diet and the Estimation of the Exposure of Breastfed Infants to Acrylamide in Breast Milk

Acrylamide in food is formed by the Maillard reaction. Numerous studies have shown that acrylamide is a neurotoxic and carcinogenic compound. The aim of this study was to determine the level of acrylamide in breast milk at different lactation stages and to evaluate the impact of breastfeeding women's diet on the content of this compound in breast milk. The acrylamide level in breast milk samples was determined by LC-MS/MS. Breastfeeding women's diet was evaluated based on the 24 h dietary recall. The median acrylamide level in colostrum (n = 47) was significantly (p < 0.0005) lower than in the mature milk (n = 26)-0.05 µg/L and 0.14 µg/L, respectively. The estimated breastfeeding women's acrylamide intake from the hospital diet was significantly (p < 0.0001) lower than that from the home diet. We found positive-although modest and borderline significant-correlation between acrylamide intake by breastfeeding women from the hospital diet µg/day) and acrylamide level in the colostrum (µg/L). Acrylamide has been detected in human milk samples, and a positive correlation between dietary acrylamide intake by breastfeeding women and its content in breast milk was observed, which suggests that the concentration can be reduced. Breastfeeding women should avoid foods that may be a source of acrylamide in their diet.

A Review of Dietary Intake of Acrylamide in Humans

The dietary intake of acrylamide (AA) is a health concern, and food is being monitored worldwide, but the extent of AA exposure from the diet is uncertain. The aim of this review was to provide an overview of estimated dietary intake. We performed a PubMed search identifying studies that used dietary questionnaires and recalls to estimate total dietary AA intake. A total of 101 studies were included, corresponding to 68 original study populations from 26 countries. Questionnaires were used in 57 studies, dietary recalls were used in 33 studies, and 11 studies used both methods. The estimated median AA intake ranged from 0.02 to 1.53 μg/kg body weight/day between studies. Children were represented in 25 studies, and the body-weight-adjusted estimated AA intake was up to three times higher for children than adults. The majority of studies were from Europe (n = 65), Asia (n = 17), and the USA (n = 12). Studies from Asia generally estimated lower intakes than studies from Europe and the USA. Differences in methods undermine direct comparison across studies. The assessment of AA intake through dietary questionnaires and recalls has limitations. The integration of these methods with the analysis of validated biomarkers of exposure/internal dose would improve the accuracy of dietary AA intake exposure estimation. This overview shows that AA exposure is widespread and the large variation across and within populations shows a potential for reduced intake among those with the highest exposure.

Does the food processing contaminant acrylamide cause developmental neurotoxicity? A review and identification of knowledge gaps

There is a worldwide concern on adverse health effects of dietary exposure to acrylamide (AA) due to its presence in commonly consumed foods. AA is formed when carbohydrate rich foods containing asparagine and reducing sugars are prepared at high temperatures and low moisture conditions. Upon oral intake, AA is rapidly absorbed and distributed to all organs. AA is a known human neurotoxicant that can reach the developing foetus via placental transfer and breast milk. Although adverse neurodevelopmental effects have been observed after prenatal AA exposure in rodents, adverse effects of AA on the developing brain has so far not been studied in humans. However, epidemiological studies indicate that gestational exposure to AA impair foetal growth and AA exposure has been associated with reduced head circumference of the neonate. Thus, there is an urgent need for further research to elucidate whether pre- and perinatal AA exposure in humans might impair neurodevelopment and adversely affect neuronal function postnatally. Here, we review the literature with emphasis on the identification of critical knowledge gaps in relation to neurodevelopmental toxicity of AA and its mode of action and we suggest research strategies to close these gaps to better protect the unborn child.

Acrylamide-Induced Prenatal Programming of Bone Structure in Mammal Model

Acrylamide (AA) is a chemical substance with a potentially carcinogenic effect. Its presence in food or animal food arises from its thermal processing. The experiment was conducted to evaluate the effect of AA exposure (3.0 mg/kg. b.w./day) of pregnant dams during the second half of the pregnancy on bone development in offspring. As an model animal, guinea pig was used. While term body weight of newborns was not influenced by maternal AA treatment, shorter bones with reduced bone diaphysis cross-sectional area were observed in experimental group. Numerous negative, offspring sex-dependent effects of maternal AA exposure were observed in femoral epiphysis and metaphysis as well as the articular and growth plate cartilages. These effects resulted from the AA-induced alterations in bone metabolism, as indicated by the changes in the expression of numerous proteins involved in bone development: receptor activator of nuclear factor kappa-Β ligand (RANKL), tissue inhibitor of metalloproteinases 2 (TIMP-2), bone morphogenetic protein 2 (BMP-2), vascular endothelial growth factor (VEGF), and cartilage oligomeric matrix protein (COMP), all of whose expression was measured as well as distribution of immature collagen fibres was determined. Based on the results, it can be concluded that the exposure of pregnant dams to AA negatively affected the structure of compact bone in bone diaphysis, microarchitecture of trabecular bone in metaphysis and epiphysis as well as the structure of the articular and growth plate cartilages in their offspring. The AA-induced bone impairment increased osteoclast differentiation, as observed through the change in the RANKL/OPG ratio, which in turn inhibited osteoblast function by decreasing the expression of other proteins. The data of the present study suggests that maternal AA exposure can result in insufficient bone gain and even bone loss after the birth.

Antioxidant defence in the brain of 1-d-old chickens exposed in ovo to acrylamide

1. Acrylamide (ACR) is a potent neurotoxicant, although information on its toxic influence on the developing neural system is still limited. The effects of in-ovo-injected ACR on the antioxidant system activity in the brain of newly hatched chickens was examined. This model eliminated the mother's contribution to embryonic development. It was also recognised as an adequate model for animal embryonic development. 2. ACR was injected on d 4 of embryogenesis - in doses of 1.25 and 2.50 mg/egg (n = 40 eggs/group/120 eggs). The doses corresponded well with ACR doses used in other animal studies and their concentrations in certain animal feeds. 3. Mortality and incidences of malformations were not found to increase significantly. Significant depletion of glutathione was detected in the cerebellum, cerebrum and medulla oblongata of specimens exposed to the highest doses of ACR. Enzymatic activity was affected by the highest ACR doses. Glutathione peroxidase (GPx) activity increased significantly in the cerebrum, medulla oblongata and the hypothalamus. Superoxide dismutase (SOD) activity increased significantly in hypothalamus and decreased in cerebellum and cerebrum. A significant depletion of catalase (CAT) activity was detected in cerebellum. In the hypothalamus, the increased SOD/GPx and SOD/CAT ratios suggest the risk of H₂O₂. 4. It was concluded that ACR significantly influences the antioxidative defence in the chicken brain at doses of 1.25 and 2.50 mg/egg.

Estimating the transfer of contaminants in animal feedstuffs to livestock tissues, milk and eggs: a review

Literature studies on the transfer from livestock feed of residues of organic contaminants, metals and mycotoxins to edible livestock commodities have been reviewed. This review focuses on contaminants relevant to risks assessment of livestock feeds, especially those contaminants for which regulatory standards have been established. Those involved in the supply of livestock feed need to be aware of maximum levels for various contaminants in food and develop strategies to ensure food derived from livestock complies. An impediment to profiling feed ingredients has been the lack of accessible information on the transfer of residues from feed to tissues, milk and eggs derived from exposed livestock. Transfer factors are summarised for 72 contaminants for cattle, sheep, goats, pigs and poultry and can be used in the first tiers of risk assessment to identify contaminant and feed ingredient combinations that require management.

Machine vision detection of bonemeal in animal feed samples

There is growing public concern about contaminants in food and feed products, and reflection-based machine vision systems can be used to develop automated quality control systems. An important risk factor in animal feed products is the presence of prohibited ruminant-derived bonemeal that may contain the BSE (Bovine Spongiform Encephalopathy) prion. Animal feed products are highly complex in composition and texture (i.e., vegetable products, mineral supplements, fish and chicken meal), and current contaminant detection systems rely heavily on labor-intensive microscopy. In this study, we developed a training data set comprising 3.65 million hyperspectral profiles of which 1.15 million were from bonemeal samples, 2.31 million from twelve other feed materials, and 0.19 million denoting light green background (bottom of Petri dishes holding feed materials). Hyperspectral profiles in 150 spectral bands between 419 and 892 nm were analyzed. The classification approach was based on a sequence of linear discriminant analyses (LDA) to gradually improve the classification accuracy of hyperspectral profiles (reduce level of false positives), which had been classified as bonemeal in previous LDAs. That is, all hyperspectral profiles classified as bonemeal in an initial LDA (31% of these were false positives) were used as input data in a second LDA with new discriminant functions. Hyperspectral profiles classified as bonemeal in LDA2 (false positives were equivalent to 16%) were used as input data in a third LDA. This approach was repeated twelve times, in which at each step hyperspectral profiles were eliminated if they were classified as feed material (not bonemeal). Four independent feed materials were experimentally contaminated with 0-25% (by weight) bonemeal and used for validation. The analysis presented here provides support for development of an automated machine vision to detect bonemeal contamination around the 1% (by weight) level and therefore constitutes an important initial screening tool in comprehensive, rapid, and practically feasible quality control of feed materials.

Formation and Reduction of Acrylamide in Maillard Reaction: A Review Based on the Current State of Knowledge

The recent report of elevated acrylamide levels in heat processing foods evoked an international health alarm. Acrylamide, an acknowledged potential genetic and reproductive toxin with mutagenic and carcinogenic properties in experimental mammalians, has been found in various heat processing foods. Many original contributions reported their findings on the formation mechanism and possible reduction methods of acrylamide. The aim of this review article is to summarize the state-of-the-art about the formation and reduction of acrylamide in the Maillard reaction. This research progress includes mechanistic studies on the correlation between the Maillard reaction and acrylamide, the formation mechanism of acrylamide, the main pathways of formation and impact factors on formation including cultivars, storage temperature, storage time, heat temperature, heat time, environmental pH, concentration of precursors, effects of food matrixes, type of oil, etc. Meanwhile, primary mechanisms on the reduction of acrylamide as well as reduction pathways including material and processing related ways and use of exogenous chemical additives are systematically reviewed. The mitigation studies on acrylamide are also summarized by the Confederation of the Food and Drink Industries of the EU (CIAA) "Toolbox" approach.