Transfer of Aflatoxin B1 from Feed to Milk and from Milk to Curd and Whey in Dairy Sheep Fed Artificially Contaminated Concentrates

Mycotoxin sequestering agent: Impact on health and performance of dairy cows and efficacy in reducing AFM1 residues in milk

The objectives of this study were to evaluate the exposure to a diet naturally contaminated with mycotoxins on lactation performance, animal health, and the ability to sequester agents (SA) to reduce the human exposure to AFM1. Sixty healthy lactating Holstein cows were randomly assigned to two groups: naturally contaminated diet without and with the addition of a SA (20 g/cow/d AntitoxCooPil® -60% zeolite-40% cell wall-). Each cow was monitored throughout lactation. The concentration of aflatoxin B1 (AFB1) in feed and M1 (AFM1) in milk, health status, and productive and reproductive parameters were measured. AFB1 concentration in feed was very low (2.31 μg/kgDM). The addition of SA reduced the milk AFM1 concentrations (0.016 vs. 0.008 μg/kg) and transfer rates (2.19 vs. 0.77%). No differences were observed in health status, production and reproduction performance. The inclusion of SA in the diet of dairy cows reduce the risk in the most susceptible population.

Second order probabilistic assessment of chronic dietary exposure to aflatoxin M1 in Serbia

Considering the genotoxic and cancerogenic nature of aflatoxin M1 (AFM1), its presence in milk and dairy products may pose health risks for consumers. The chronic exposure was calculated using a two-dimensional (second order) Monte Carlo model. Results of 13 722 milk and dairy product samples analysed in the 2015-2022 period were used. Milk and dairy products intake information was collected with a Food Frequency Questionnaire (FFQ) validated by a 24-h recall-based method. Risk characterization was done by calculation of the Margin of Exposure (MOE) and by calculation of AFM1 induced number of hepatocellular carcinoma (HCC) cases. Mean AFM1 Estimated Daily Intake (EDI) was highest in children at 0.336 (CI: 0.294-0.385) ng kg^-1 bw day^-1, followed by adolescents with 0.183 (CI: 0.164-0.204), then adult females with 0.161 (CI: 0.146-0.179) and finally adult males with lowest EDI of 0.126 (CI: 0.115-0.139) ng kg^-1 bw day^-1. MOE values based on mean EDI for all population groups were above risk associated threshold and the number of possible HCC cases was in the range of 0.0002-0.0021 cases per year for 10⁵ individuals. The results suggest low health risks due to AFM1 exposure for the whole population. Still, this risk is not non-existent, especially for children as they have a higher ratio of the population exposed to risk associated AFM1 levels, with MOE values below risk indicating threshold starting at 77.5th percentile.

Incidence of aflatoxin M1 in cows' milk in Pakistan, effects on milk quality and evaluation of therapeutic management in dairy animals

The present study was aimed at measuring the concentration of aflatoxin M1 (AFM1) in the milk of Holstein Friesian cows, its effect on the milk quality and seasonal trends, as well as to investigate the efficacy of a commercial clay-based toxin binder. For this purpose, milk samples from dairy cows (n = 72) were collected and assayed for AFM1 before employing a clay-based toxin binder. The milk samples (n = 72) were collected from selected animals, revealing that 69.4% of the milk samples had AFM1 levels above the United States permissible limit (0.5 μg/kg). The incidence of AFM1 in milk during the winter and summer was 82.5% and 53.1%, respectively. Owing to the presence of AFM1, the level of milk fat, solids-not-fat, and protein were found to be low. Subsequently, the affected animals were divided into two groups, i.e., AFM1 positive control (n = 10) and the experimental group (n = 40). The experimental group of animals were fed the clay-based toxin binder at 25 g/animal/day. A progressive decrease of 19.8% in the AFM1 levels was observed on day 4 and on day 7 (53.6%) in the treatment group. Furthermore, the fat, solids-non-fat and protein increased significantly in the milk. In conclusion, a high level of AFM1 contamination occurs in the milk in Pakistan, affecting the quality of the milk production. Clay-based toxin binders may be used to ensure the milk quality and to protect the animal and consumer health.

Effects of chronic low-dose aflatoxin B1 exposure in lactating Florida dairy goats

In the past few years there has been a growing trend in the prevalence of aflatoxins, attributable to climate change, in substances destined for animal feeding, together with an increase in dairy product consumption. These facts have triggered great concern in the scientific community over milk pollution by aflatoxin M₁. Therefore, our study aimed to determine the transfer of aflatoxin B₁ from the diet into milk as AFM₁ in goats exposed to different concentrations of AFB₁, and its possible effect on the production and serological parameters of this species. For this purpose, 18 goats in late lactation were divided into 3 groups (n = 6) and exposed to different daily doses of aflatoxin B₁ (T1 = 120 µg; T2 = 60 µg, and control = 0 µg), during 31 d. Pure aflatoxin B₁ was administered 6 h before each milking in an artificially contaminated pellet. The milk samples were taken individually in sequential samples. Milk yield and feed intake were recorded daily, and a blood sample was extracted on the last day of exposure. No aflatoxin M₁ was detected, either in the samples taken before the first administration, or in the control group ones. The aflatoxin M₁ concentration detected in the milk (T1 = 0.075 µg/kg; T2 = 0.035 µg/kg) increased significantly on a par with the amount of aflatoxin B₁ ingested. The amount of aflatoxin B₁ ingested did not have any influence on aflatoxin M₁ carryover (T1 = 0.066% and T2 = 0.060%), these being considerably lower than those described in dairy goats. Thus, we concluded that the concentration of aflatoxin M₁ in milk follows a linear relationship with respect to the aflatoxin B₁ ingested, and that the aflatoxin M₁ carryover was not affected by the administration of different aflatoxin B₁ doses. Similarly, no significant changes in the production parameters after chronic exposure to aflatoxin B₁ were observed, revealing a certain resistance of the goat to the possible effects of that aflatoxin.

The Effects of Aflatoxin B1 Intake in Assaf Dairy Ewes on Aflatoxin M1 Excretion, Milk Yield, Haematology and Biochemical Profile

The aim of this study was to investigate the in vivo transfer of aflatoxin B1 (AFB1) to Assaf ewes' milk (aflatoxin M1, AFM1) and its effect on animal performance and health. Thirty Assaf ewes were allocated to three groups (C, L, H), and received a different individual daily dose of AFB1 (0, 40 and 80 μg) for 13 days. Milk (days 1, 2, 3, 4, 7, 14, 16 and 18) and blood (days 1, 7, 14 and 18) samples were collected. Milk yield, composition (except protein) and somatic cell counts (SCC) were not affected by AFB1 intake (p > 0.05). Haemoglobin concentration increased (p < 0.05) and haematocrit and alanine aminotransferase levels tended to increase (p < 0.10) in group H on day 14. AFM1 excretion was highly variable and detected in L and H animals from days 1 to 16 (3 days increase, 10 days steady-state, 3 days clearance). Carry-over rate (0.23%) was significantly higher in L (0.22-0.34%) than in H (0.16-0.19%) animals (p < 0.05). AFB1 daily doses of 40 to 80 µg do not impair milk yield; however, it may start affecting animals' health. Milk AFM1 depends mainly on the AFB1 intake whereas carryover rate is positively influenced by the level of milk production.

Determination of Aflatoxin M1 Levels in Some Honamli Goat Herds in Burdur Province

In this study, aflatoxin M1 (AFM1) levels were determined from the milk serum of 90 lactating Honamlı goats aged 2-6 years in 12 herds breeding Honamlı goats in Burdur Province in spring and April in 2021. A statistically significant difference was found between flock 1 and flock 4,5,6,7,8,9,10,11,12 and between flock 3 and flock 9 and 11 (p

Human Breast Milk Contamination with Aflatoxins, Impact on Children's Health, and Possible Control Means: A Review

Aflatoxins are natural toxicants produced mainly by species of the Aspergillus genus, which contaminate virtually all feeds and foods. Apart from their deleterious health effects on humans and animals, they can be secreted unmodified or carried over into the milk of lactating females, thereby posing health risks to suckling babies. Aflatoxin M1 (AFM1) is the major and most toxic aflatoxin type after aflatoxin B1 (AFB1). It contaminates human breast milk upon direct ingestion from dairy products or by carry-over from the parent molecule (AFB1), which is hydroxylated in the liver and possibly in the mammary glands by cytochrome oxidase enzymes and then excreted into breast milk as AFM1 during lactation via the mammary alveolar epithelial cells. This puts suckling infants and children fed on this milk at a high risk, especially that their detoxifying activities are still weak at this age essentially due to immature liver as the main organ responsible for the detoxification of xenobiotics. The occurrence of AFM1 at toxic levels in human breast milk and associated health conditions in nursing children is well documented, with developing countries being the most affected. Different studies have demonstrated that contamination of human breast milk with AFM1 represents a real public health issue, which should be promptly and properly addressed to reduce its incidence. To this end, different actions have been suggested, including a wider and proper implementation of regulatory measures, not only for breast milk but also for foods and feeds as the upstream sources for breast milk contamination with AFM1. The promotion of awareness of lactating mothers through the organization of training sessions and mass media disclosures before and after parturition is of a paramount importance for the success of any action. This is especially relevant that there are no possible control measures to ensure compliance of lactating mothers to specific regulatory measures, which can yet be appropriate for the expansion of breast milk banks in industrialized countries and emergence of breast milk sellers. This review attempted to revisit the public health issues raised by mother milk contamination with AFM1, which remains undermined despite the numerous relevant publications highlighting the needs to tackle its incidence as a protective measure for the children physical and mental health.

Characterization and mechanism of aflatoxin degradation by a novel strain of Trichoderma reesei CGMCC3.5218

Aflatoxins, which are produced mainly by Aspergillus flavus and A. parasiticus, are recognized as the most toxic mycotoxins, which are strongly carcinogenic and pose a serious threat to human and animal health. Therefore, strategies to degrade or eliminate aflatoxins in agro-products are urgently needed. We investigated 65 Trichoderma isolates belonging to 23 species for their aflatoxin B₁ (AFB₁)-degrading capabilities. Trichoderma reesei CGMCC3.5218 had the best performance, and degraded 100% of 50 ng/kg AFB₁ within 3 days and 87.6% of 10 μg/kg AFB₁ within 5 days in a liquid-medium system. CGMCC3.5218 degraded more than 85.0% of total aflatoxins (aflatoxin B₁, B₂, G₁, and G₂) at 108.2–2323.5 ng/kg in artificially and naturally contaminated peanut, maize, and feed within 7 days. Box–Behnken design and response surface methodology showed that the optimal degradation conditions for CGMCC3.5218 were pH 6.7 and 31.3°C for 5.1 days in liquid medium. Possible functional detoxification components were analyzed, indicating that the culture supernatant of CGMCC3.5218 could efficiently degrade AFB₁ (500 ng/kg) with a ratio of 91.8%, compared with 19.5 and 8.9% by intracellular components and mycelial adsorption, respectively. The aflatoxin-degrading activity of the fermentation supernatant was sensitive to proteinase K and proteinase K plus sodium dodecyl sulfonate, but was stable at high temperatures, suggesting that thermostable enzymes or proteins in the fermentation supernatant played a major role in AFB₁ degradation. Furthermore, toxicological experiments by a micronucleus assay in mouse bone marrow erythrocytes and by intraperitoneal injection and skin irritation tests in mice proved that the degradation products by CGMCC3.5218 were nontoxic. To the best of our knowledge, this is the first comprehensive study on Trichoderma aflatoxin detoxification, and the candidate strain T. reesei CGMCC3.5218 has high efficient and environment-friendly characteristics, and qualifies as a potential biological detoxifier for application in aflatoxin removal from contaminated feeds.

Preliminary sampling of aflatoxin M1 contamination in raw milk from dairy farms using feed ingredients from Rwanda

Milk is susceptible to aflatoxin M1 (AFM₁) contamination when dairy cattle consume feed contaminated with aflatoxins and is considered as a public health concern. This pilot study assessed the prevalence and amount of total aflatoxin contamination in commercially available dairy feed and the corresponding AFM₁ contamination in raw milk from samples collected at farms using local, commercially available dairy feed across Rwanda's five provinces. The inclusion criteria to select dairy farm participants were (1) to have at least two cows and (2) use of commercially prepared dairy feeds. Importantly, the majority of cattle rearing households in Rwanda rely principally on grazing or other freely available feedstock, rather than on commercially prepared feeds. In total, 170 raw milk samples were collected during one sampling period from dairy farms using commercially prepared dairy feeds. In addition, 154 dairy feed samples were collected simultaneously with the milk samples. These farms were previously targeted in a larger study measuring aflatoxin contamination of Rwandan feeds and feed ingredients. The mean AFM₁ concentration in these samples was 0.89 ± 1.64 µg/l (median: 0.33 µg/l) with a maximum of 14.5 µg/l. Maize bran was the principal dairy feed ingredient used by farmers in the sampling, representing more than 65% of the total feed samples collected, with mean aflatoxin concentration of 90.5 µg/kg (median 32.3 µg/kg). The authors note that this preliminary sampling is not generalizable across Rwandan milk production and consumption; the limited pilot study presented here was not designed with the robustness necessary for broad-scale generalization. Thus, the data presented should not be broadly applied outside of the context of the study.

In Vivo Kinetics and Biotransformation of Aflatoxin B1 in Dairy Cows Based on the Establishment of a Reliable UHPLC-MS/MS Method

The in vivo kinetics of aflatoxin B1 (AFB1) and its carry-over as aflatoxin M1 (AFM1) in milk as well as the toxin loads in the tissue of dairy cows were assessed through a repetitive feeding trial of an AFB1-contaminated diet of 4 μg kg-1 body weight (b.w.) for 13 days. This was followed by a clearance period that ended with a single dose trial of an AFB1-contaminated diet of 40 μg kg-1 b.w. An ultra-high performance liquid chromatography tandem mass spectrometry method was developed and successfully validated by the determination of linearity (R 2 ≥ 0.990), sensitivity (lower limit of quantification, 0.1-0.2 ng ml-1), recovery (79.5-111.2%), and precision relative standard deviation (RSD) ≤14.7%) in plasma, milk, and various tissues. The repetitive ingestion of AFB1 indicated that the biotransformation of AFB1 to AFM1 occurred within 48 h, and the clearance period of AFM1 in milk was not more than 2 days. The carry-over rate of AFM1 in milk during the continuous ingestion experiment was in the range of 1.15-2.30% at a steady state. The in vivo kinetic results indicated that AFB1 reached a maximum concentration of 3.8 ± 0.9 ng ml-1 within 35.0 ± 10.2 min and was slowly eliminated from the plasma, with a half-life time (T1/2) of 931.1 ± 30.8 min. Meanwhile, AFM1 reached a plateau in plasma (0.5 ± 0.1 ng ml-1) at 4 h after the ingestion. AFB1 was found in the heart, spleen, lungs, and kidneys at concentrations of 1.6 ± 0.3, 4.1 ± 1.2, 3.3 ± 0.9 and 5.6 ± 1.4 μg kg-1, respectively. AFM1 was observed in the spleen and kidneys at concentrations of only 0.7 ± 0.2 and 0.8 ± 0.1 μg kg-1, respectively. In conclusion, the in vivo kinetics and biotransformation of AFB1 in dairy cows were determined using the developed UHPLC-MS/MS method, and the present findings could be helpful in assessing the health risks to consumers.

Effects of Prenatal Exposure to Aflatoxin B1: A Review

Aflatoxins are mycotoxins produced as secondary fungal metabolites. Among them, aflatoxin B1 (AFB1) stands out due to its genotoxic and mutagenic potential, being a potent initiator of carcinogenesis. In this review, the outcomes from the published literature in the past 10 years on the effects of AFB1 pathophysiological mechanisms on embryological and fetal development are discussed. In several animal species, including humans, AFB1 has a teratogenic effect_, resulting in bone malformations, visceral anomalies, lesions in several organs, and behavioral and reproductive changes, in addition to low birth weight. The mutagenic capacity of AFB1 in prenatal life is greater than in adults, indicating that when exposure occurs in the womb, the risk of the development of neoplasms is higher. Studies conducted in humans indicate that the exposure to this mycotoxin during pregnancy is associated with low birth weight, decreased head circumference, and DNA hypermethylation. However, as the actual impacts on humans are still unclear, the importance of this issue cannot be overemphasized and studies on the matter are essential.

Adsorbents Reduce Aflatoxin M1 Residue in Milk of Healthy Dairy Cow Exposed to Moderate Level Aflatoxin B1 in Diet and Its Exposure Risk for Humans

This study investigated the effect of moderate risk level (8 µg/kg) AFB₁ in diet supplemented with or without adsorbents on lactation performance, serum parameters, milk AFM₁ content of healthy lactating cows and the AFM₁ residue exposure risk in different human age groups. Forty late healthy lactating Holstein cows (270 ± 22 d in milk; daily milk yield 21 ± 3.1 kg/d) were randomly assigned to four treatments: control diet without AFB₁ and adsorbents (CON), CON with 8 μg/kg AFB₁ (dry matter basis, AF), AF + 15 g/d adsorbent 1 (AD1), AF + 15 g/d adsorbent 2 (AD2). The experiment lasted for 19 days, including an AFB₁-challenge phase (day 1 to 14) and an AFB₁-withdraw phase (day 15 to 19). Results showed that both AFB₁ and adsorbents treatments had no significant effects on the DMI, milk yield, 3.5% FCM yield, milk components and serum parameters. Compared with the AF, AD1 and AD2 had significantly lower milk AFM₁ concentrations (93 ng/L vs. 46 ng/L vs. 51 ng/L) and transfer rates of dietary AFB₁ into milk AFM₁ (1.16% vs. 0.57% vs. 0.63%) (p < 0.05). Children aged 2–4 years old had the highest exposure risk to AFM₁ in milk in AF, with an EDI of 1.02 ng/kg bw/day and a HI of 5.11 (HI > 1 indicates a potential risk for liver cancer). Both AD1 and AD2 had obviously reductions in EDI and HI for all population groups, whereas, the EDI (≥0.25 ng/kg bw/day) and HI (≥1.23) of children aged 2–11 years old were still higher than the suggested tolerable daily intake (TDI) of 0.20 ng/kg bw/day and 1.00 (HI). In conclusion, moderate risk level AFB₁ in the diet of healthy lactating cows could cause a public health hazard and adding adsorbents in the dairy diet is an effective measure to remit AFM₁ residue in milk and its exposure risk for humans.

Aflatoxin B1 contamination of feedstuff on a dairy farm in Northern Peru and aflatoxin M1 concentrations in raw milk

Research regarding aflatoxin contamination levels in Peru is limited, although aflatoxin M1 (AFM1) and aflatoxin B1 (AFB1) require surveillance because of their toxicity. European regulations state that the harmonised maximum level (ML) is 5 μg/kg for AFB1 in feedstuffs and 0.05 μg/kg for AFM1 in milk. Our study aimed to determine the annual variation levels of AFB1 in ingredients used in feedstuffs for dairy cows and those of AFM1 in milk at a typical intensive dairy farm in Northern Peru. For 1 year, milk (n=529) and feedstuff samples (n=235) were collected and aflatoxin levels were determined using a lateral flow immunoassay. We found that 16% of milk samples had AFM1 contamination above the ML. AFM1 level was significantly higher (P<0.05) in December (end of spring) than that in all other months. Throughout the year, the most used feedstuffs were maize, soybean meal and whole soybean. Among the maize samples (n=77), 2.59% had an AFB1 level above the ML, whereas 45% had an AFB1 level below the ML. On the other hand, neither the soybean meal (n=69) nor whole soybean samples (n=64) had an AFB1 level above the ML, 46.4 and 20%, respectively. In 50% (n=10) of cottonseed meal samples, AFB1 level was above the ML; in 20% of wheat middling samples, it was above the ML. Cottonseed and wheat middling samples were used for 2 and 5 months, respectively. AFB1 level in feedstuff showed a significant difference in December (P<0.05) compared with other months, specifically for maize and soybean meal. As the AFM1 level in milk results from AFB1 contaminated feedstuff, our results emphasise the need to implement specific quality measures to reduce contamination.

Bio-Active Free Direct Optical Sensing of Aflatoxin B1 and Ochratoxin A Using a Manganese Oxide Nano-System

Aflatoxins-B1 (AFB1) and Ochratoxin-A (OchA) are the two types of major mycotoxin produced by Aspergillus flavus, Aspergillus parasiticus fungi, Aspergillus carbonarius, Aspergillus niger, and Penicillium verrocusumv. These toxins are mainly found in metabolite cereals, corn, coffee beans, and other oil-containing food items. Excessive consumption of these toxins can be carcinogenic and lead to cancer. Thus, their rapid testing became essential for food quality control. Herein, manganese oxide nanoparticles (MnO2 nps) have been proposed to explore the interaction with AFB1 and OchA using UV-visible spectroscopy. MnO2 nps were synthesized using the co-precipitation method. They were pure and crystalline with an average crystallite size of 5–6 nm. In the UV-vis study, the maximum absorbance for MnO2 nps was observed around 260 nm. The maximum absorbance for AFB1 and OchA was observed at 365 and 380 nm, respectively, and its intensity enhanced with the addition of MnO2 nps. Sequential changes were observed with varying the concentration of AFB1 and OchA with a fixed concentration of MnO2 nps, resulting in proper interaction. The binding constant (kb) and Gibbs free energy for MnO2 nps-AFB1 and OchA were observed as 1.62 × 104 L g−1 and 2.67 × 104 L g−1, and −24.002 and −25.256 kJ/mol, respectively. The limit of detection for AFB1 and OchA was measured as 4.08 and 10.84 ng/ml, respectively. This bio‐active free direct sensing approach of AFB1 and OchA sensing can be promoted as a potential analytical tool to estimate food quality rapidly and affordable manner at the point of use.

Occurrence of Aflatoxin M1 (AFM1) in Donkey Milk Collected in Northern Italy

Aflatoxin M1 (AFM1) is a well-known mycotoxin that can be found in the milk of animals that have ingested feed contaminated with aflatoxin B1 (AFB1). In Italy, the development of donkey farms is mainly due to growing request of donkey milk, which is considered an incomparable substitute for human mother's milk for its chemical composition and organoleptic characteristics. The aim of this study was to assess the occurrence of AFM1 in donkey milk produced in a farm in Northern Italy, also in view of the few data available about the presence of this mycotoxin in this type of milk. Therefore, 63 milk samples were collected and analyzed using a fast and sensitive HPLC and fluorescence detection (FLD) method previously optimized and validated. None of the milk samples collected were found to be contaminated at a level above the limit of quantification (LOQ) (0.0125 ng/mL), while only one sample showed traces of the mycotoxin at a concentration between the limit of detection (LOD) and LOQ (0.0044 ng/mL), well below the legal limit established for infant milk and follow-on milk (0.025 ng/mL). These results are in line with those of the few similar surveys carried out on donkey milk and seem to indicate a low risk of AFM1 contamination for this food.

The biochemical and metabolic profiles of dairy cows with mycotoxins-contaminated diets

BACKGROUND

Previous studies on the effects of mycotoxins have solely focused on their biochemical profiles or products in dairy ruminants. Changes in metabolism that occur after exposure to mycotoxins, as well as biochemical changes, have not been explored.

METHODS

We measured the biochemical and metabolic changes in dairy cows after exposure to mycotoxins using biochemical analyses and nuclear magnetic resonance. Twenty-four dairy cows were randomly assigned to three different treatment groups. Control cows received diets with 2 kg uncontaminated cottonseed. Cows in the 50% replacement group received the same diet as the control group, but with 1 kg of uncontaminated cottonseed and 1 kg of cottonseed contaminated with mycotoxins. Cows in the 100% replacement group received the same diet as the control, but with 2 kg contaminated cottonseed.

RESULTS

The results showed that serum γ-glutamyl transpeptidase and total antioxidant capacities were significantly affected by cottonseed contaminated with mycotoxins. There were also significant differences in isovalerate and NH3-N levels, and significant differences in the eight plasma metabolites among the three groups. These metabolites are mainly involved in amino acid metabolism pathways. Therefore, the results suggest that amino acid metabolism pathways may be affected by mycotoxins exposure.

Quantification of aflatoxin M1 carry-over rate from feed to soft cheese

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The levels of AFM₁ in milk produced in Argentina are relatively low.

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Milk production, fiber particle size and AFB₁ level affected the carry-over rate.

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The greatest proportion of AFM₁ in milk is detected in whey during cheese. production.

From January to December 2016, samples of milk and feeds of dairy cattle were monthly collected. The concentration of mycotoxins in all matrices was determined using the enzymatic immunoassay technique. The average concentration of aflatoxin B₁ (AFB₁), deoxynivalenol (DON) and zearalenone (ZEA) in feed was 3.01, 218.5 and 467 ug/kg, respectively. The average AFB₁ carry-over rate was 0.84% with a variation between 0.05 to 5.93%. Particle size of the feed (P = 0.030) and individual milk production (P = 0.001) affected this rate. Mini-soft cheeses were produced using milk naturally contaminated with aflatoxin M₁ (AFM₁) as raw material to study its distribution both in whey and in cheese. The average level of AFM₁ in milk was 0.014 μg/l. None of milk samples exceeded the maximum level accepted for AFB₁ by the Southern Common Market (MERCOSUR) legislation (0.5 μg/l) and only 5.5% of samples exceeded the European Union (UE) regulations (0.05 μg/l). After the cheese elaboration, the concentration of AFM₁ was determined in whey and in cheese. The greatest proportion (60%) was detected in whey while 40% AFM₁ remained in the cheese. However, the concentration of AFM₁ was higher in the cheese compared to the original milk.

l-Proline Alleviates Kidney Injury Caused by AFB1 and AFM1 through Regulating Excessive Apoptosis of Kidney Cells

The toxicity and related mechanisms of aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) in the mouse kidney were studied, and the role of l-proline in alleviating kidney damage was investigated. In a 28-day toxicity mouse model, thirty mice were divided into six groups: control (without treatment), l-proline group (10 g/kg body weight (b.w.)), AFB1 group (0.5 mg/kg b.w.), AFM1 (3.5 mg/kg b.w.), AFB1 + l-proline group and AFM1 + l-proline group. Kidney index and biochemical indicators were detected, and pathological staining was observed. Using a human embryonic kidney 293 (HEK 293) cell model, cell apoptosis rate and apoptotic proteins expressions were detected. The results showed that AFB1 and AFM1 activated pathways related with oxidative stress and caused kidney injury; l-proline significantly alleviated abnormal expressions of biochemical parameters and pathological kidney damage, as well as excessive cell apoptosis in the AF-treated models. Moreover, proline dehydrogenase (PRODH) was verified to regulate the levels of l-proline and downstream apoptotic factors (Bax, Bcl-2, and cleaved Caspase-3) compared with the control (p < 0.05). In conclusion, l-proline could protect mouse kidneys from AFB1 and AFM1 through alleviating oxidative damage and decreasing downstream apoptosis, which deserves further research and development.

Exposure Assessment and Risk Characterization of Aflatoxin M1 Intake through Consumption of Milk and Yoghurt by Student Population in Serbia and Greece

The objective of this research was to perform an exposure assessment of aflatoxin M1 (AFM1) intake through the consumption of milk and yoghurt by the student population in Serbia and Greece. A food consumption survey of milk and yoghurt was performed during the first half of 2018 in the two countries with at least 500 interviewees (aged between 18 and 27 years) per country, covering their dietary habits and body weight based on one-day and seven-day recall methods. Values for the concentration of AFM1 were extracted from published research. Finally, a Monte Carlo analysis of 100,000 iterations was performed to estimate the intake of AFM1 from the consumption of the two dairy products. Results revealed that the estimated average exposure of students to AFM1 was in the range of 1.238⁻2.674 ng kg^-1 bw day^-1 for Serbia, and 0.350⁻0.499 ng kg^-1 bw day^-1 for Greece, depending on the dietary recall method employed. High estimations for hepatocellular carcinoma (HCC) cases/year/10⁵ individuals, depending on the prevalence of Hepatitis B virus surface antigen positive individuals (HBsAg+), were 0.0036⁻0.0047 and 0.0007⁻0.0009 for Serbia and Greece, respectively. Presented Margin of Exposure (MOE) and Hazard Index (HI) values indicate increased risk from exposure to AFM1, particularly in Serbia.

Efficacy of Bacillus subtilis ANSB060 Biodegradation Product for the Reduction of the Milk Aflatoxin M₁ Content of Dairy Cows Exposed to Aflatoxin B₁

This study was conducted to determine the effect of Bacillus subtilis ANSB060 biodegradation product (BDP) in reducing the milk aflatoxin M₁ (AFM₁) content of dairy cows fed a diet contaminated with aflatoxin B₁ (AFB₁). Twenty-four Chinese Holstein cows (254 ± 19 d in milk; milk production 19.0 ± 1.2 kg d⁻¹) were assigned to three dietary treatments, as follows: (1) control diet (CON), consisting of a basal total mixed ration (TMR); (2) aflatoxin diet (AF), containing CON plus 63 μg of AFB₁ kg⁻¹ of diet dry matter; and (3) aflatoxin diet plus BDP (AF + BDP), containing AF plus BDP at 0.2% of diet dry matter. The experiment lasted 12 days, including an AFB₁-dosing period from days one to eight, followed by a clearance period from days nine to twelve. Milk samples were collected on days 2, 4, 6, and 8–12, and the plasma was sampled on day 9, before morning feeding. Short-term AFB₁ exposure did not affect the milk production and composition. The plasma biochemical indices, except for lactic dehydrogenase (LDH), were also not changed by the AFB₁ intake. The plasma LDH level was significantly elevated (p < 0.05) following dietary treatment with AFB₁, while no significant difference was observed between the AF + BDP and CON treatments. Adding BDP to the AFB₁-contaminaed diet resulted in a significant reduction in AFM₁ concentration (483 vs. 665 ng L⁻¹) in the milk, AFM₁ excretion (9.14 vs. 12.71 μg d⁻¹), and transfer rate of dietary AFB₁ to milk AFM₁ (0.76 vs. 1.06%). In conclusion, the addition of BDP could be an alternative method for reducing the dietary AFB₁ bioavailability in dairy cows.

Biological System Responses of Dairy Cows to Aflatoxin B1 Exposure Revealed with Metabolomic Changes in Multiple Biofluids

Research on mycotoxins now requires a systematic study of post-exposure organisms. In this study, the effects of aflatoxin B1 (AFB1) on biofluids biomarkers were examined with metabolomics and biochemical tests. The results showed that milk concentration of aflatoxin M1 changed with the addition or removal of AFB1. AFB1 significantly affected serum concentrations of superoxide dismutase (SOD) and malon dialdehyde (MDA), SOD/MDA, and the total antioxidant capacity. Significant differences of volatile fatty acids and NH₃-N were detected in the rumen fluid. Eighteen rumen fluid metabolites, 11 plasma metabolites, and 9 milk metabolites were significantly affected by the AFB1. These metabolites are mainly involved in the pathway of amino acids metabolism. Our results suggest that not only is the study of macro-indicators (milk composition and production) important, but that more attention should be paid to micro-indicators (biomarkers) when assessing the risks posed by mycotoxins to dairy cows.

Presence of unreported carcinogens, Aflatoxins and their hydroxylated metabolites, in industrialized Oaxaca cheese from Mexico City

Aflatoxins (AFs) are toxic secondary metabolites of the fungi Aspergillus flavus, A. parasiticus and A. nomius. The fungi produce these AFs in cereals, oilseeds and spices. AFs have damaging effects on all organisms, including humans, and their symptoms can be classified as acute (vomiting, hemorrhage and death) or chronic (immunodepression, Reye syndrome, Kwashiorkor, teratogenesis, hepatitis, cirrhosis, and various cancers). Basic AFs (AFB₁, AFB₂, AFG₁, and AFG₂) are metabolized in the liver or by microbes that produce hydroxylated metabolites (AFM₁, AFM₂, and AFP₁) and aflatoxicol (AFL), soluble in water and easy to dispose. Thus, AFs can be excreted in fluids, such as milk. AFs are not destroyed in the process of making cheese. The purpose of this study was to identify and quantify the AFs present in 30 samples of industrialized Oaxaca-type cheese sold in Mexico City. The average concentrations of AFs detected in the 30 samples of industrialized cheese were as follows: AFB₁ (0.1 μg kg^-1) in 20% (6/30); a trace amount of AFB₂ (0.01 < LOD) in only 3% (1/30); AFG₁ (0.14 μg kg^-1) in 10% (3/30); AFG₂ (0.6 μg kg^-1) in 30% (9/30); AFM₁ (1.7 μg kg^-1) in 57% (17/30); AFP₁ (0.03% μg kg^-1) in 3% (1/30); and AFL (13.1 μg kg^-1) in 97% (29/30). AFB₁ and AFL were the most abundant aflatoxins in Oaxaca-type cheese. However, eight aflatoxins were present, contributing an average of 15.7 μg kg^-1 AFs distributed among the 30 samples. The risk assessment analysis showed that there was no substantial risk for cancer due to AFs in industrialized Oaxaca cheese from Mexico City.

Silage review: Mycotoxins in silage: Occurrence, effects, prevention, and mitigation

Ensiled forage, particularly corn silage, is an important component of dairy cow diets worldwide. Forages can be contaminated with several mycotoxins in the field pre-harvest, during storage, or after ensiling during feed-out. Exposure to dietary mycotoxins adversely affects the performance and health of livestock and can compromise human health. Several studies and surveys indicate that ruminants are often exposed to mycotoxins such as aflatoxins, trichothecenes, ochratoxin A, fumonisins, zearalenone, and many other fungal secondary metabolites, via the silage they ingest. Problems associated with mycotoxins in silage can be minimized by preventing fungal growth before and after ensiling. Proper silage management is essential to reduce mycotoxin contamination of dairy cow feeds, and certain mold-inhibiting chemical additives or microbial inoculants can also reduce the contamination levels. Several sequestering agents also can be added to diets to reduce mycotoxin levels, but their efficacy varies with the type and level of mycotoxin contamination. This article gives an overview of the types, prevalence, and levels of mycotoxin contamination in ensiled forages in different countries, and describes their adverse effects on health of ruminants, and effective prevention and mitigation strategies for dairy cow diets. Future research priorities discussed include research efforts to develop silage additives or rumen microbial innocula that degrade mycotoxins.

The Toxic Effects of Aflatoxin B1 and Aflatoxin M1 on Kidney through Regulating L-Proline and Downstream Apoptosis

The toxic effects and potential mechanisms of aflatoxin B1 (AFB1), aflatoxin M1 (AFM1), and AFB1+AFM1 in the kidney were studied and compared in HEK 293 cells model and CD-1 mice model. The 35-day subacute toxicity mice model was constructed, biochemical indicators and kidney pathological staining were detected, kidney metabonomics detection was performed, and the metabolites were analyzed, and then the related toxicity mechanism was validated. Results showed that AFB1 (0.5 mg/kg), AFM1 (3.5 mg/kg), and AFB1 (0.5 mg/kg)+AFM1 (3.5 mg/kg) activated oxidative stress and caused renal damage. The relative concentration of the metabolite L-proline was found to be lower in aflatoxins treatment groups when compared with the control (P < 0.05). Moreover, with the treatment of aflatoxins, proline dehydrogenase (PRODH) and proapoptotic factors (Bax, Caspase-3) were upregulated, while the inhibitor of apoptosis Bcl-2 was downregulated, at both the mRNA and the protein levels, comparing with the control (P < 0.05). In addition, the combined effect of AFB1 and AFM1 was validated, for the toxicity of the combination was stronger than the other two groups. In conclusion, AFB1 and AFM1 caused kidney toxicity by activating oxidative stress through altering expression of PRODH and L-proline levels, which then induced downstream apoptosis.

The Toxic Effects of Aflatoxin B1 and Aflatoxin M1 on Kidney through Regulating L-Proline and Downstream Apoptosis

The toxic effects and potential mechanisms of aflatoxin B1 (AFB1), aflatoxin M1 (AFM1), and AFB1+AFM1 in the kidney were studied and compared in HEK 293 cells model and CD-1 mice model. The 35-day subacute toxicity mice model was constructed, biochemical indicators and kidney pathological staining were detected, kidney metabonomics detection was performed, and the metabolites were analyzed, and then the related toxicity mechanism was validated. Results showed that AFB1 (0.5 mg/kg), AFM1 (3.5 mg/kg), and AFB1 (0.5 mg/kg)+AFM1 (3.5 mg/kg) activated oxidative stress and caused renal damage. The relative concentration of the metabolite L-proline was found to be lower in aflatoxins treatment groups when compared with the control (P < 0.05). Moreover, with the treatment of aflatoxins, proline dehydrogenase (PRODH) and proapoptotic factors (Bax, Caspase-3) were upregulated, while the inhibitor of apoptosis Bcl-2 was downregulated, at both the mRNA and the protein levels, comparing with the control (P < 0.05). In addition, the combined effect of AFB1 and AFM1 was validated, for the toxicity of the combination was stronger than the other two groups. In conclusion, AFB1 and AFM1 caused kidney toxicity by activating oxidative stress through altering expression of PRODH and L-proline levels, which then induced downstream apoptosis.

Effect of adding clay with or without a Saccharomyces cerevisiae fermentation product on the health and performance of lactating dairy cows challenged with dietary aflatoxin B1

The study was conducted to examine the effect of supplementing bentonite clay with or without a Saccharomyces cerevisiae fermentation product (SCFP; 19 g of NutriTek + 16 g of MetaShield, both from Diamond V, Cedar Rapids, IA) on the performance and health of dairy cows challenged with aflatoxin B₁ (AFB₁). Twenty-four lactating Holstein cows (64 ± 11 d in milk) were stratified by parity and milk production and randomly assigned to 1 of 4 treatment sequences. The experiment had a balanced 4 × 4 Latin square design with 6 replicate squares, four 33-d periods, and a 5-d washout interval between periods. Cows were fed a total mixed ration containing 36.1% corn silage, 8.3% alfalfa hay, and 55.6% concentrate (dry matter basis). Treatments were (1) control (no additives), (2) toxin (T; 1,725 µg of AFB₁/head per day), (3) T + clay (CL; 200 g/head per day; top-dressed), and (4) CL+SCFP (CL+SCFP; 35 g/head per day; top-dressed). Cows were adapted to diets from d 1 to 25 (predosing period) and then orally dosed with AFB₁ from d 26 to 30 (dosing period), and AFB₁ was withdrawn from d 31 to 33 (withdrawal period). Milk samples were collected twice daily from d 21 to 33, and plasma was sampled on d 25 and 30 before the morning feeding. Transfer of ingested AFB₁ into milk aflatoxin M₁ (AFM₁) was greater in T than in CL or CL+SCFP (1.65 vs. 1.01 and 0.94%, respectively) from d 26 to 30. The CL and CL+SCFP treatments reduced milk AFM₁ concentration compared with T (0.45 and 0.40 vs. 0.75 µg/kg, respectively), and, unlike T, both CL and CL+SCFP lowered AFM₁ concentrations below the US Food and Drug Administration action level (0.5 µg/kg). Milk yield tended to be greater during the dosing period in cows fed CL+SCFP compared with T (39.7 vs. 37.7 kg/d). Compared with that for T, plasma glutamic oxaloacetic transaminase concentration, indicative of aflatoxicosis and liver damage, was reduced by CL (85.9 vs. 95.2 U/L) and numerically reduced by CL+SCFP (87.9 vs. 95.2 U/L). Dietary CL and CL+SCFP reduced transfer of dietary AFB₁ to milk and milk AFM₁ concentration. Only CL prevented the increase in glutamic oxaloacetic transaminase concentration, and only CL+SCFP prevented the decrease in milk yield caused by AFB₁ ingestion.

Effects of different sources of Saccharomyces cerevisiae biomass on milk production, composition, and aflatoxin M1 excretion in milk from dairy cows fed aflatoxin B1

The aim of the present study was to evaluate the effect of different sources of Saccharomyces cerevisiae (SC) biomass (20.0 g/d) obtained from sugarcane (cell wall, CW; dried yeast, DY; autolyzed yeast, AY) and the beer industry (partially dehydrated brewery yeast, BY) on milk production, fat and protein percentages, and aflatoxin M₁ (AFM₁) excretion in milk from dairy cows receiving 480 µg aflatoxin B₁ (AFB₁) per day. A completely randomized design was used with 2 lactating cows assigned to each of 10 dietary treatments, as follows: negative controls (no AFB₁ or SC-based biomass), positive controls (AFB₁ alone), DY alone, DY + AFB₁, BY alone, BY + AFB₁, CW alone, CW + AFB₁, AY alone, and AY + AFB₁. The cows in the aflatoxin treatment group received AFB₁ from d 1 to 6, while the SC biomass was administered with the AFB₁ bolus from d 4 to 6. Aflatoxin B₁ or SC-based products did not affect milk production or milk composition during the experimental period. Aflatoxin M₁ was detected in the milk from all aflatoxin treatment group cows, reaching maximum levels at d 3 and varying from 0.52 ± 0.03 to 1.00 ± 0.04 µg/L. At end of the treatment period, CW, AY, DY, and BY removed 78%, 89%, 45%, and 50% of AFM₁ from the milk, respectively, based on the highest level found on d 3. Results indicate a potential application of industrial fermentation by-products, especially CW and AY, as a feed additive in the diets of dairy cows to reduce the excretion of AFM₁ in milk.

Transfer of dietary aflatoxin B1 to milk aflatoxin M1 and effect of inclusion of adsorbent in the diet of dairy cows

The objectives of this study were to investigate the transfer of aflatoxin from feed to milk and to evaluate the effects of Solis Mos (SM; Novus International Inc., St. Charles, MO) on milk aflatoxin M1, plasma biochemical parameters, and ruminal fermentation of dairy cows fed varying doses of aflatoxin B1 (AFB1). Three groups of 8 multiparous Holstein cows in late lactation (days in milk = 271 ± 29; milk yield = 21.6 ± 3.1 kg/d) were assigned to 1 of 3 experiments in a crossover design. Cows in experiment 1 received no aflatoxin, cows in experiment 2 received 20 µg of AFB1/kg of dry matter, and cows in experiment 3 received 40 µg of AFB1/kg of dry matter. Cows in each experiment were assigned to 1 of 2 treatments: control or 0.25% SM. Each experiment consisted of 2 consecutive periods with the first 4 d (d 1 to 4) as adaptation, followed by AFB1 challenge for 7 d (d 5 to 11), and finally clearance for 5 d (d 12 to 16) in each period. Samples of total mixed ration and milk were collected on d 1, 2, and 10 to 14 of each period. Blood samples were collected from the coccygeal vein on d 1, 11, and 14 of each period. Rumen fluid was collected by oral stomach tube 2 h after the morning feeding on d 1 and 11 of each period. Adding SM to basal or AFB1-contaminated diets at 0.25% had no effect on lactation performance, liver function, or immune response. However, addition of SM improved antioxidative status, as indicated by increased plasma concentrations of superoxide dismutase and reduced malondialdehyde regardless of dietary AFB1 level. Addition of SM to the AFB1-free diet eliminated the background AFM1 in milk and increased total ruminal volatile fatty acid (99.6 vs. 94.2 mM) concentrations. Adding SM to the AFB1-contaminated diet in experiment 2 decreased the AFM1 concentration (88.4 vs. 105.3 ng/L) and the transfer of aflatoxin to milk (0.46 vs. 0.56%), and increased total volatile fatty acid concentration (99.8 vs. 93.4 mM). Adding SM to diets with 40 µg/kg of AFB1 did not elicit changes in rumen parameters or AFM1 output. These results indicated that adding SM to diets containing 0 or 20 µg of AFB1/kg decreased milk AFM1 concentration, improved antioxidative status, and altered rumen fermentation, whereas adding SM to a diet containing 40 µg of AFB1/kg did not reduce AFB1 transfer but did increase the antioxidant status of the liver.

A Survey on Aflatoxin M1 Content in Sheep and Goat Milk Produced in Sardinia Region, Italy (2005-2013)

In the present work the results of a survey conducted in Sardinia Region on Aflatoxin M1 (AFM1) contamination in milk of small ruminants from 2005 to 2013 are reported. A total of 517 sheep and 88 goat milk samples from bulk tank, tank trucks and silo tank milk were collected. Analyses were performed by the Regional Farmers Association laboratory using high-performance liquid chromatography following the ISO 14501:1998 standard. None of the sheep milk samples analysed during 2005-2012 showed AFM1 contamination. In sheep milk samples collected in 2013, 8 out of 172 (4.6%) were contaminated by AFM1 with a concentration (mean±SD) of 12.59±14.05 ng/L. In one bulk tank milk sample 58.82 ng/L AFM1 was detected, exceeding the EU limit. In none of goat milk samples analysed from 2010 to 2012 AFM1 was detected. In 2013, 9 out of 66 goat milk samples (13.6%) showed an AFM1 concentration of 47.21±19.58 ng/L. Two of these samples exceeded the EU limit, with concentrations of 62.09 and 138.6 ng/L. Higher contamination frequency and concentration rates were detected in bulk tank milk samples collected at farm than in bulk milk truck or silo samples, showing a dilution effect on AFM1 milk content along small ruminants supply chain. The rate and levels of AFM1 contamination in sheep and goat milk samples were lower than other countries. However, the small number of milk samples analysed for AFM1 in Sardinia Region in 2005-2013 give evidence that food business operators check programmes should be improved to ensure an adequate monitoring of AFM1 contamination in small ruminant dairy chain.

Anti-idiotypic nanobody-phage based real-time immuno-PCR for detection of hepatocarcinogen aflatoxin in grains and feedstuffs

Aflatoxins are a group of extremely toxic small molecules that have been involved in human hepatic and extrahepatic carcinogenesis as causative agents. Herein, we developed a real-time immuno polymerase chain reaction (IPCR) assay for the accurately quantitative detection of aflatoxins in agri-products base on a M13 phage containing aflatoxin anti-idiotypic nanobody and its encoding DNA which was used to design the specific primers. The limit of detection (LOD) of the assay is 0.02 ng/mL, which exhibits a 4-fold improvement over traditional phage ELISA. The developed method was successfully validated with the samples of corn, rice, peanut, and feedstuff, which are major aflatoxin-contaminated agri-products. And the recoveries were from 77.05 to 122.16%. For further validation, the developed assay was also compared with a reference HPLC method for the analysis of aflatoxins in corn and peanuts, and concordant results (R(2) = 0.991) were obtained. In this context, this study provides a novel opportunity to analyze aflatoxins in agri-products.