Aflatoxins absorption in the gastro-intestinal tract and in the vaginal mucosa in lactating dairy cows

Effect of the aflatoxins B1 and M1 on bovine oocyte developmental competence and embryo morphokinetics

Aflatoxins are considered as reproductive toxins for mammalian species. Here, we studied the effect of aflatoxin B1 (AFB1) and its metabolite aflatoxin M1 (AFM1) on the development and morphokinetics of bovine embryos. Cumulus oocyte complexes (COCs) were matured with AFB1 (0.032, 0.32, 3.2, 32 µM) or AFM1 (0.015, 0.15, 1.5, 15, 60 nM), then fertilized and the putative zygotes were cultured in an incubator equipped with a time-lapse system. Exposing COCs to 32 µM AFB1 or 60 nM AFM1 reduced the cleavage rate, whereas exposing them to 3.2 or 32 µM AFB1 further reduced the blastocyst formation. A delay was recorded for the first and second cleavages in a dose-dependent manner for both AFB1- and AFM1-treated oocytes. A delay was recorded in the third cleavage in the AFM1-treated group. To explore potential mechanisms, subgroups of COCs were examined for nuclear and cytoplasmic maturation (n = 225; DAPI and FITC-PNA, respectively), and mitochondrial function was examined in a stage-dependent manner. COCs were examined for their oxygen consumption rates (n = 875; Seahorse XFp analyzer) at the end of maturation, MII-stage oocytes were examined for their mitochondrial membrane potential (n = 407; JC1), and putative zygotes were examined using a fluorescent time-lapse system (n = 279; IncuCyte). Exposing COCs to AFB1 (3.2 or 32 µM) impaired oocyte nuclear and cytoplasmic maturation and increased mitochondrial membrane potential in the putative zygotes. These alterations were associated with changes in the expression of mt-ND2 (32 µM AFB1) and STAT3 (all AFM1 concentrations) genes in the blastocyst stage, suggesting a carryover effect from the oocyte to the developing embryos.

A network meta-analysis on the efficacy of different mycotoxin binders to reduce aflatoxin M1 in milk after aflatoxin B1 challenge in dairy cows

The objective of this network meta-analysis was to determine the efficacy of different mycotoxin binders (MTB) to reduce aflatoxin M1 (AFM1) in milk. A literature search was conducted to identify in vivo research papers from different databases. Inclusion criteria were in vivo, dairy cows, description of the MTB used, doses of MTB, aflatoxin inclusion in the diet, and concentration of AFM1 in milk. Twenty-eight papers with 131 data points were selected. Binders used in the studies were hydrated sodium calcium aluminosilicate (HSCAS), yeast cell wall (YCW), bentonite, and mixes of several MTB (MX). The response variables were AFM1 concentration, AFM1 reduction in milk, total AFM1 excreted in milk, and transfer of aflatoxin from feed to AFM1 in milk. Data were analyzed with CINeMA and GLIMMIX procedures with the WEIGHT statement of SAS (SAS Inst. Inc.). The AFM1 concentration in milk decreased for bentonite (0.3 µg/L ± 0.05; mean ± SE) and HSCAS (0.4 µg/L ± 0.12), and tended to decrease for MX (0.6 µg/L ± 0.13) but was similar for YCW (0.6 µg/L ± 0.12), compared with control (0.7 µg/L ± 0.12). The percentage reduction of AFM1 in milk was similar for all MTB and different from control with a range of reduction from 25% for YCW to 40% for bentonite. The excretion of AFM1 in milk was lower in YCW (5.3 µg/L ± 2.37), HSCAS (13.8 µg/L ± 3.31), and MX (17.1 µg/L ± 5.64), and not affected by bentonite (16.8 µg/L ± 3.33) compared with control (22.1 µg/L ± 5.33). The transfer of aflatoxin B1 from feed into AFM1 in milk was lowest in bentonite (0.6% ± 0.12), MX (1.04% ± 0.27), and HSCAS (1.04% ± 0.21), and not affected in YCW (1.4% ± 0.10), compared with control (1.7% ± 0.35). The meta-analysis results indicate that all MTB reduced the AFM1 transfer into milk, where bentonite had the highest capacity and YCW the lowest.

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.

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.

HPLC–MS/MS method for the simultaneous determination of aflatoxins in blood: toxicokinetics of aflatoxin B1 and aflatoxin M1 in rats

Mycotoxins are highly toxic fungal metabolites that can pose health threats to humans and animals. Aflatoxins are a type of mycotoxin produced mainly by Aspergillus flavus and A. parasiticus. A sensitive high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method with multiple reaction monitoring (MRM) modes was developed for the determination of aflatoxins in blood after acetonitrile precipitation extraction. The limits of quantification of aflatoxins ranged from 0.05 to 0.2 ng/mL. Intra-day accuracy ranged from 92 to 111.0%, and intra-day precision (n = 6) ranged from 1 to 8%. Inter-day accuracy and precision were 94.0–102.0% and 2.0–8.0%, respectively. The toxicokinetics of AFB1 and its metabolite AFM1 after a single oral administration (AFB1 1 mg/kg body weight) were studied in male Sprague–Dawley rats. The blood AFB1 and AFM1 profiles could be adequately described by a noncompartmental model. The highest concentration of AFB1 (Cmax 93.42 ± 23.01 ng/mL) was observed with Tmax at 0.15 ± 0.034 h. AFB1 was rapidly metabolized to AFM1 which reached its peak blood concentration (Cmax 53.86 ± 12.12 ng/mL) at 0.33 ± 0.11 h. The HPLC–MS/MS method was simple and sensitive, appropriate for studying the in vivo toxicokinetics of aflatoxins.

Environmental Pollutants, Mucosal Barriers, and Pathogen Susceptibility; The Case for Aflatoxin B1 as a Risk Factor for HIV Transmission and Pathogenesis

HIV transmission risk is dependent on the infectivity of the HIV+ partner and personal susceptibility risk factors of the HIV- partner. The mucosal barrier, as the internal gatekeeper between environment and self, concentrates and modulates the internalization of ingested pathogens and pollutants. In this review, we summarize the localized effects of HIV and dietary toxin aflatoxin B1 (AFB1), a common pollutant in high HIV burden regions, e.g., at the mucosal barrier, and evidence for pollutant-viral interactions. We compiled literature on HIV and AFB1 geographic occurrences, mechanisms of action, related co-exposures, personal risk factors, and HIV key determinants of health. AFB1 exposure and HIV sexual transmission hotspots geographically co-localize in many low-income countries. AFB1 distributes to sexual mucosal tissues generating inflammation, microbiome changes and a reduction of mucosal barrier integrity, effects that are risk factors for increasing HIV susceptibility. AFB1 exposure has a positive correlation to HIV viral load, a risk factor for increasing the infectivity of the HIV+ partner. The AFB1 exposure and metabolism generates inflammation that recruits HIV susceptible cells and generates chemokine/cytokine activation in tissues exposed to HIV. Although circumstantial, the available evidence makes a compelling case for studies of AFB1 exposure as a risk factor for HIV transmission, and a modifiable new component for combination HIV prevention efforts.

Colostrum fails to prevent bovine/camelid neonatal neutrophil damage from AFB1

Exposure to environmental toxicants that affect the immune system and overall health of many mammals is mostly unavoidable. One of the more common substances is the mycotoxins, especially carcinogenic aflatoxin (AF)B₁ which also causes immune suppression/dysregulation in exposed hosts. The present study analyzed the effects of naturally occurring levels of AFB₁ on apoptosis of healthy bovine and camelid neonatal neutrophils (PMN) that were isolated both before and after host consumption of colostrum. Cells from bovine and camel neonates (n = 12 sets of PMN/mammal/timepoint) were exposed for 24 h to a low level of AFB₁ (i.e. 10 ng AFB₁/ml) and then intracellular ATP content and caspase-3, -7, and -9 activities (determined by bioluminescence) were assessed. The results indicated a significant lessening of intracellular ATP content and equivalents of luminescence intensity in AFB₁-treated PMN in all studied samples, i.e. isolated pre-and post-colostrum consumption. In contrast, caspase-3, -7, and -9 activities in both pre- and post-colostrum consumption bovine and camelid PMN were noticeably increased (∼>2-fold). The damaging effects of AFB₁ were more pronounced in bovine neonate PMN than in camelid ones. These results showed that camelid or bovine neonatal PMN collected pre- and post-colostrum are sensitive (moreso after consumption) to naturally occurring levels of AFB₁. While merits of colostrum are well known, its failure to mitigate toxic effects of AFB₁ in what would translate into a critical period in the development of immune competence (i.e. during the first few days of life in bovine and camelid calves) is surprising. The observed in vitro toxicities can help clarify underlying mechanisms of immune disorders caused by AFs in animals/humans.

Aflatoxin in Dairy Cows: Toxicity, Occurrence in Feedstuffs and Milk and Dietary Mitigation Strategies

Aflatoxins are poisonous carcinogens produced by fungi, mainly Aspergillus flavus and Aspergillus parasiticus. Aflatoxins can contaminate a variety of livestock feeds and cause enormous economic losses, estimated at between US$52.1 and US$1.68 billion annually for the U.S. corn industry alone. In addition, aflatoxin can be transferred from the diet to the milk of cows as aflatoxin M1 (AFM1), posing a significant human health hazard. In dairy cows, sheep and goats, chronic exposure to dietary aflatoxin can reduce milk production, impair reproduction and liver function, compromise immune function, and increase susceptibility to diseases; hence, strategies to lower aflatoxin contamination of feeds and to prevent or reduce the transfer of the toxin to milk are required for safeguarding animal and human health and improving the safety of dairy products and profitability of the dairy industry. This article provides an overview of the toxicity of aflatoxin to ruminant livestock, its occurrence in livestock feeds, and the effectiveness of different strategies for preventing and mitigating aflatoxin contamination of feeds.

An overview of aflatoxin B1 biotransformation and aflatoxin M1 secretion in lactating dairy cows

Milk is considered a perfect natural food for humans and animals. However, aflatoxin B1 (AFB1) contaminating the feeds fed to lactating dairy cows can introduce aflatoxin M1 (AFM1), the main toxic metabolite of aflatoxins into the milk, consequently posing a risk to human health. As a result of AFM1 monitoring in raw milk worldwide, it is evident that high AFM1 concentrations exist in raw milk in many countries. Thus, the incidence of AFM1 in milk from dairy cows should not be underestimated. To further optimize the intervention strategies, it is necessary to better understand the metabolism of AFB1 and its biotransformation into AFM1 and the specific secretion pathways in lactating dairy cows. The metabolism of AFB1 and its biotransformation into AFM1 in lactating dairy cows are drawn in this review. Furthermore, recent data provide evidence that in the mammary tissue of lactating dairy cows, aflatoxins significantly increase the activity of a protein, ATP-binding cassette super-family G member 2 (ABCG2), an efflux transporter known to facilitate the excretion of various xenobiotics and veterinary drugs into milk. Further research should focus on identifying and understanding the factors that affect the expression of ABCG2 in the mammary gland of cows.

Exposure to aflatoxins and fumonisins and linear growth of children in rural Ethiopia: a longitudinal study

Objective:

We hypothesise that exposure to aflatoxins and fumonisins, measured in serum, alters protein synthesis, reducing serum protein and insulin-like growth factor 1 (IGF-1), increasing inflammation and infection, leading to child’s linear growth failure.

Design:

Children 6–35 months, stratified by baseline stunting, were subsampled from an intervention trial on quality protein maize consumption and evaluated at two time-points.

Setting:

Blood samples and anthropometric data were collected in the pre-harvest (August–September 2015) and post-harvest (February 2016) seasons in rural Ethiopia.

Participants:

102 children (50 stunted and 52 non-stunted).

Results:

Proportions of children exposed to aflatoxin G1, aflatoxin G2 and aflatoxin M1 were higher in the pre-harvest (8, 33 and 7, respectively) compared to post-harvest season (4, 28 and 4, respectively). The proportion of children exposed to any aflatoxin was higher in the pre-harvest than post-harvest season (51 % v. 41 %). Fumonisin exposure ranged from 0 % to 11 %. In joint statistical tests, aflatoxin exposure was associated with serum biomarkers of inflammation (C-reactive protein, α-1-glycoprotein) and protein status (transthyretin, lysine, tryptophan), IGF-1 and linear growth (all P < 0·01). However, exposure to specific aflatoxins was not significantly associated with any biomarkers or outcomes (all P > 0·05).

Conclusions:

Aflatoxin exposure among rural Ethiopian children was high, with large variation between seasons and individual aflatoxins. Fumonisin exposure was low. There was no clear association between aflatoxin exposure and protein status, inflammation or linear growth. A larger study may be needed to examine the potential biological interactions, and the assessment of aflatoxins in food is needed to determine sources of high exposure.

Efficient Aflatoxin B1 Sequestration by Yeast Cell Wall Extract and Hydrated Sodium Calcium Aluminosilicate Evaluated Using a Multimodal In-Vitro and Ex-Vivo Methodology

In this work, adsorption of the carcinogenic mycotoxin aflatoxin B1 (AFB1) by two sequestrants-a yeast cell wall-based adsorbent (YCW) and a hydrated sodium calcium aluminosilicate (HSCAS)-was studied across four laboratory models: (1) an in vitro model from a reference method was employed to quantify the sorption capabilities of both sequestrants under buffer conditions at two pH values using liquid chromatography with fluorescence detection (LC-FLD); (2) in a second in vitro model, the influence of the upper gastrointestinal environment on the mycotoxin sorption capacity of the same two sequestrants was studied using a chronic AFB1 level commonly encountered in the field (10 µg/L and in the presence of feed); (3) the third model used a novel ex vivo approach to measure the absorption of 3H-labelled AFB1 in the intestinal tissue and the ability of the sequestrants to offset this process; and (4) a second previously developed ex vivo model readapted to AFB1 was used to measure the transfer of 3H-labelled AFB1 through live intestinal tissue, and the influence of sequestrants on its bioavailability by means of an Ussing chamber system. Despite some sorption effects caused by the feed itself studied in the second model, both in vitro models established that the adsorption capacity of both YCW and HSCAS is promoted at a low acidic pH. Ex vivo Models 3 and 4 showed that the same tested material formed a protective barrier on the epithelial mucosa and that they significantly reduced the transfer of AFB1 through live intestinal tissue. The results indicate that, by reducing the transmembrane transfer rate and reducing over 60% of the concentration of free AFB1, both products are able to significantly limit the bioavailability of AFB1. Moreover, there were limited differences between YCW and HSCAS in their sorption capacities. The inclusion of YCW in the dietary ration could have a positive influence in reducing AFB1's physiological bioavailability.

Ruminant Mycotoxicosis: An Update

This review focuses on factors associated with mold production in feedstuffs and major mycotoxins affecting ruminants in North America. Ruminants are often considered less sensitive to mycotoxins owing to rumen microflora metabolism to less toxic compounds. However, ruminants occupy wide agricultural niches that expose animals to diverse toxins under widely different environmental and nutritional conditions. Often the moldy and potentially highly contaminated feeds end up at feedlots. Less than optimal feedstuffs creating suboptimal rumen microbial flora could result in decreased ruminal capacity to detoxify certain mycotoxins and adverse effects. Numerous mycotoxins and clinical effects in ruminants are discussed.

Calcination Improves the In Vivo Efficacy of a Montmorillonite Clay to Bind Aflatoxin G1 in Broiler Chickens: A Toxicokinetic Approach

The goal of this study was to investigate the toxicokinetic characteristics of aflatoxin G1 (AFG1) in broiler chickens and the effect of calcination of a Tunisian montmorillonite clay on the in vivo absorption of AFG1. In this study, broiler chickens were randomly distributed into four groups of 10 animals. Group 1 was administered AFG1 (2 mg/kg body weight (BW)) by single intravenous injection (IV), group 2 received an intra-crop bolus (PO) of AFG1 without any clay, group 3 was dosed AFG1 PO together with an oral bolus of purified clay (CP), and group 4 received AFG1 PO with an oral bolus of calcined clay. A significant difference in the area under the curve (AUC_0-t) was observed for group 4 (6.78 ± 4.24 h*ng/mL) in comparison with group 2 (12.83 ± 4.19 h*ng/mL). A significant reduction of the oral bioavailability of AFG1 was observed for group 4 (7.61 ± 4.76%) compared with group 2 (14.40 ± 4.70%), while no significant effect was observed of CP. In this experiment, no phase I nor phase II metabolites of AFG1 were observed. These findings confirm that calcination of the purified montmorillonite clay enhances the adsorption of AFG1 in the gastrointestinal tract after oral administration, thereby reducing its bioavailability, thus reducing its toxic effects.

Aflatoxin compromises development of the preimplantation bovine embryo through mechanisms independent of reactive oxygen production

Aflatoxin is a potent carcinogen often found in animal feedstuffs. Although it reportedly impairs development of the preimplantation pig embryo, it is not known whether it adversely affects development of the preimplantation bovine embryo. We conducted 3 experiments to investigate this possibility and determine whether deleterious effects of aflatoxin were caused by increased production of reactive oxygen species (ROS). Experiments were conducted with embryos produced in vitro and cultured after fertilization with various concentrations of aflatoxin. For experiment 1, embryos were treated with 0 (control), 40, 400, or 4,000 µg/L of aflatoxin B₁ (AFB₁). Treatment at all concentrations of AFB₁ tended to reduce cleavage rate, with the 2 highest concentrations having significant effects. As compared with the control, 40 µg/L AFB₁ reduced the percentage of oocytes becoming blastocysts and the percentage of cleaved embryos becoming blastocysts (19.7 vs. 8.1% and 30.3 vs. 14.3%, respectively). Complete inhibition of blastocyst formation occurred at concentrations of 400 and 4,000 µg/L of AFB₁. Experiments 2 and 3 involved a 2 × 2 factorial design with effects of AFB₁ (0 and 40 µg/L), the antioxidant Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid, a water-soluble analog of vitamin E; 0 and 5 µM), and their interaction on production of ROS in putative zygotes (experiment 2) and development to the blastocyst stage (experiment 3). Production of ROS was increased by AFB₁, and this effect was reversed by Trolox. However, Trolox did not prevent the reduction in development to the blastocyst stage caused by AFB₁. Thus, the anti-developmental effects of AFB₁ are not caused solely by increased ROS production. Rather, other underlying mechanisms exist for the adverse effects of aflatoxin on embryonic development. Overall, results indicate the potential for feeding aflatoxin-contaminated feed to cause embryonic loss in cattle.

Feed additives containing sequestrant clay minerals and inactivated yeast reduce aflatoxin excretion in milk of dairy cows

The objective was to evaluate the efficacy of 2 dietary mycotoxin sequestrants, Toxy-Nil (TN) or Unike Plus (UP), in reducing aflatoxin (AF) M₁ concentrations in milk of dairy cows challenged with dietary AF. Thirty-two mid-lactation Holstein cows were blocked by parity, days in milk, and milk yield and were randomly assigned within block to receive one of the following treatments: (1) 2.8 mg of AF/cow per d (positive control, PC), (2) 2.8 mg of AF + 100 g of TN/cow per d, (3) 2.8 mg of AF + 100 g of UP/cow per d, or (4) no AF and no additives (negative control, NC). For 7 d, treatments, dispersed in 150 g of sweet feed carrier, were top-dressed twice daily by mixing into the top portion of the TMR at each feeding. After the experimental period, cows were fed the NC diet and clearance of AFM₁ via milk was monitored for 7 d. Feed and water were available ad libitum throughout the trial. Treatments had no effect on feed intake, milk yield, milk composition, or milk somatic cell count. Relative intake of AF was similar among PC, TN, and UP, averaging 106.5, 107.6, and 102.5 ± 2.9 μg/kg of diet dry matter, respectively. Relative intake of mycotoxin sequestrants was similar between TN and UP, averaging 0.4 and 0.4 ± 0.1% of diet dry matter, respectively. Concentration and mass of AFM₁ secreted in milk and in urine were similar between TN and UP, but were lower than PC; concentrations in milk averaged 0.2, 0.3, and 0.6 ± 0.1 μg/kg, respectively, and mass secreted in milk averaged 8.1, 9.8, and 20.5 ± 1.7 μg/d. Concentrations in urine averaged 6.9, 7.4, and 14.2 ± 1.5 μg/L, respectively, and mass secreted in urine averaged 225.7, 250.8, and 521.6 ± 53.1 μg/d. Likewise, concentration and mass of free AF excreted in feces were similar between TN and UP, but were lower than PC; concentrations averaged 7.7, 8.9, and 12.4 ± 0.6 μg/kg, respectively, and mass excreted averaged 57.8, 69.6, and 95.6 ± 4.8 μg/d. Transfer of AF from feed to AFM₁ in milk was reduced by 63 and 52%, and in urine, by 57 and 52% for TN and UP, respectively. Transfer of AF from feed to free AF in feces was reduced by 38 and 26% for TN and UP, respectively. The clearance rate of AFM₁ in milk did not differ among PC, TN, and UP (46.1, 66.5, and 50.0 ± 6.7%/d, respectively). Results indicate that dietary inclusion of 100 g of TN or UP significantly reduced AFM₁ in milk of cows consuming TMR containing approximately 105 μg of AF/kg of diet dry matter. Results also suggest that both TN and UP reduced absorption of AF.

Lactobacillus rhamnosus GG modulates gastrointestinal absorption, excretion patterns, and toxicity in Holstein calves fed a single dose of aflatoxin B1

The aim of the present study was to evaluate the effects of Lactobacillus rhamnosus GG (LGG; ATCC 53013) on growth performance and hepatotoxicity in calves fed a single dose of aflatoxin B₁ (AFB₁) and to investigate the absorption, distribution, and elimination of AFB₁ and the hydroxylated metabolite aflatoxin M₁ (AFM₁) in rumen fluid, blood, and excretions. Twenty-four male Holstein calves were blocked for body weight and age and were randomly assigned to 1 of 3 treatment groups: (1) untreated control, (2) treated with 4.80 mg of AFB₁ (AFB₁ only), or (3) treated with 1 × 10¹⁰ cfu of LGG suspension and 4.80 mg of AFB₁ (AFB₁ plus LGG). The calves received LGG suspension in 50 mL of phosphate-buffered saline daily via oral administration for 14 d before and on the day they received a single oral dose of AFB₁. Body weight was recorded at the beginning of the study (before LGG administration), at the day of AFB₁ administration, and at the end of the trial. Rumen fluid, blood, urine, and feces samples were collected continuously for 96 h after AFB₁ administration. Average daily gain (ADG) and plasma biochemical parameters were analyzed, and concentrations of AFB₁ and AFM₁ in the samples were determined for monitoring excretion pattern and toxicokinetics. The results showed that ADG was lower in AFB₁-treated animals; LGG administration partially mitigated the decrease in ADG (0.85 ± 0.08 vs. 0.76 ± 0.18 kg of gain/d). The AFB₁ treatment increased plasma aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase levels. Administration of LGG alleviated the AFB₁-induced increase in plasma enzymes activity. The excretion patterns of AFB₁ and AFM₁ were surprisingly regular; toxins were rapidly detected in all samples after a single oral dose of AFB₁, and the peak of toxins concentrations was sequentially reached in rumen fluid, plasma, urine, and feces (except AFM₁ in rumen fluid), followed by an exponential decrease. The excretion curves showed that AFB₁ and AFM₁ concentrations were the highest in feces and urine, respectively. Administration of LGG decreased the concentrations of free AFB₁ and AFM₁ in rumen fluid and reduced the release of toxins into plasma and urine. Toxicokinetic parameters (except for the time of maximum concentration and the terminal half-life) were reduced by LGG administration. In conclusion, the absorption, distribution, and excretion of AFB₁ and AFM₁ were rapid in calves fed a single dose of AFB₁. Urine was the main route for the excretion of AFM₁, and the clearance pattern from the peak of concentration was well fitted by exponential decreasing function. Administration of LGG reduced the absorption of AFB₁ in the gastrointestinal tract by increasing the excretion via the feces, thus alleviating the hepatotoxic effect of AFB₁.

Bioluminescence-based detection of astrocytes apoptosis and ATP depletion induced by biologically relevant level aflatoxin B1

Although brain accumulation of aflatoxin B1 (AFB1) suggests potential impact on brain cells, including astrocytes, there still exists a scarcity of research on this issue within the literature. This research investigates the apoptosis effect of AFB1 on primary mouse astrocytes. To this aim, a MTT colorimetric assay on astrocytes was performed to measure the toxicity/LC50 of various concentrations (0-320,000 nM) of AFB1 for 24 h. Further, the astrocytes were exposed to concentrations of 8, 16 and 32 nM of AFB1 for 24, 48 and 72 h. Concentration of intracellular ATP) and caspase-3/7 activity was then determined by luciferase-dependent bioluminescence. Furthermore, the percentage of apoptotic cells was obtained using flow cytometry (annexin V+/propidium iodide (PI)−; cytochrome c release from mitochondria, a hallmark of cell damage, was carried out by Western blot as well. MTT assay at post-exposure hours (PEH) 24 revealed that the LC50 of AFB1 was ~80,000 nM. Though at PEH 48 only 32 nM of AFB1 resulted in a significant diminished intracellular ATP content, at PEH 72 both 8 and 32 nM of AFB1 led to a significant ATP depletion in astrocytes. Similar patterns of changes were observed in bioluminescence intensity of AFB1-treated astrocytes. Flow cytometry-based annexin V and PI staining of astrocytes at PEH 24, 48 and 72 showed that 32 nM of AFB1 significantly and time dependently increased the percentage of apoptotic astrocytes (annexin V+/PI−). With 32 nM of AFB1, caspase-3/7 activity in astrocytes was increased ~4-fold at PEH 72. A remarkable release of cytochrome c was only detected in astrocytes exposed to 32 nM AFB1 for PEH 72. The results indicated that a biologically relevant level of AFB1 (32 nM) induces apoptosis in astrocytes through ATP depletion and caspases activation.

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.

Seasonally Feed-Related Aflatoxins B1 and M1 Spread in Semiarid Industrial Dairy Herd and Its Deteriorating Impacts on Food and Immunity

To comparatively determine the levels of aflatoxin (AF) B1 in feedstuffs and of AFM1 in milk from semiarid industrial cattle farms in northeastern Iran during four seasons and to elucidate the effects of mixed AFB1 and AFM1 on bovine granulocytes, 72 feedstuffs (concentrate, silage, and totally mixed ration (TMR)) and 200 bulk milk samples were simultaneously collected for ELISA-based AFs detection. Isolated blood and milk neutrophils (n=8/treatment) were also preincubated with mix of 10 ng/ml AFB1 and 10 ng/ml AFM1 for 12 h; the impact was assessed on neutrophils functions. AFB1 levels in feedstuffs averaged 28 μg/kg (4–127 μg/kg), with TMR maximal (38±6.3 μg/kg), concentrate (32±6.5 μg/kg), and silage (16±1.5 μg/kg). The levels of AFB1 and AFM1 in feedstuffs and milk averaged 42±9.3, 27±2.8, 26±4.1, and 18.5±2.8 μg/kg and 85±7.3, 62±6.1, 46±6.2, and 41±6.5 ppb μg/kg in winter (maximal), autumn, spring, and summer, respectively. Mix of AFB1 and AFM1 weakened various functions of granulocytes. It adds new reason why during winter semiarid raised food-producing animals show more immune-incompetence.

Effects of calcium montmorillonite clay and aflatoxin exposure on dry matter intake, milk production, and milk composition

Fifteen primiparous crossbred dairy cows that were 114±14d in milk and weighed 533±56kg were used in a replicated 5×5 Latin square to test the efficacy of a calcium montmorillonite clay, NovaSil Plus (NSP; BASF Corp., Ludwigshaven, Germany), for the reduction of aflatoxin (AF) metabolite (AFM1) in milk and the effect of NSP on milk composition. Cows were housed in a freestall barn, fed once a day and milked twice a day. The experiment consisted of five 14-d periods: d 1 through 7 were considered for data collection, and d 8 through 14 were considered a wash-out phase. In each period, cows were randomly assigned to 1 of 5 dietary treatments: (1) control (CON), consisting of a basal total mixed ration (TMR); (2) high-dose NSP diet (NSP-1%), consisting of TMR plus 230 g of NSP; (3) aflatoxin diet (AFD), consisting of the TMR plus AF challenge; (4) low-dose NSP with AF (NSP-0.5%+AFD), composed of TMR plus 115 g of NSP and AF challenge; and (5) high-dose NSP with AF (NSP-1%+AFD), consisting of TMR plus 230 g of NSP and AF challenge. The AF challenge consisted of top dressing a daily dose of 100 µg/kg estimated dry matter intake (DMI); similarly, NSP was fed at 1.0 or 0.5% of estimated DMI. Milk yield and DMI were similar across treatments averaging 21.1±1.33 kg/d and 19.7±0.56 kg/d, respectively. Concentration of milk fat, protein, and lactose were similar across treatments with averages of 4.91±0.20%, 3.85±0.10%, and 4.70±0.06%, respectively. Concentration of vitamin A averaged 0.28±0.03 µg/mL and riboflavin concentration averaged 1.57±0.13 µg/mL across treatments. The concentration of minerals in milk were similar for all treatments. Cows fed CON and NSP-1% yielded the lowest concentration of AFM1 in milk with 0.03 and 0.01±0.06 µg/L. Addition of NSP reduced milk AFM1 from 1.10±0.06 µg/L with the AF diet to 0.58 and 0.32±0.06 µg/L with the NSP-0.5%+AF and NSP-1%+AF diets, respectively. Excretion of AFM1 was reduced by NSP; mean values were 24.38, 11.86, 7.38, 0.64, and 0.23, ± 1.71 µg/d, for AFD, NSP-0.5%+AFD, NSP-1%+AFD, NSP-1%, and CON, respectively. More specifically, 1.07±0.08% of the daily AF intake was transferred to the milk of cows consuming the AFD, whereas the AF transfer rates in milk from cows that consumed the NSP-0.5%+AFD and NSP-1%+AFD were 0.52 and 0.32±0.08%. Results from this research demonstrate that feeding NSP to lactating cows is an effective method to reduce the transfer and excretion of AFM1 in milk with no negative effects on dry matter intake, milk production, and composition.

Review on Mycotoxin Issues in Ruminants: Occurrence in Forages, Effects of Mycotoxin Ingestion on Health Status and Animal Performance and Practical Strategies to Counteract Their Negative Effects

Ruminant diets include cereals, protein feeds, their by-products as well as hay and grass, grass/legume, whole-crop maize, small grain or sorghum silages. Furthermore, ruminants are annually or seasonally fed with grazed forage in many parts of the World. All these forages could be contaminated by several exometabolites of mycotoxigenic fungi that increase and diversify the risk of mycotoxin exposure in ruminants compared to swine and poultry that have less varied diets. Evidence suggests the greatest exposure for ruminants to some regulated mycotoxins (aflatoxins, trichothecenes, ochratoxin A, fumonisins and zearalenone) and to many other secondary metabolites produced by different species of Alternaria spp. (e.g., AAL toxins, alternariols, tenuazonic acid or 4Z-infectopyrone), Aspergillus flavus (e.g., kojic acid, cyclopiazonic acid or β-nitropropionic acid), Aspergillus fuminatus (e.g., gliotoxin, agroclavine, festuclavines or fumagillin), Penicillium roqueforti and P. paneum (e.g., mycophenolic acid, roquefortines, PR toxin or marcfortines) or Monascus ruber (citrinin and monacolins) could be mainly related to forage contamination. This review includes the knowledge of mycotoxin occurrence reported in the last 15 years, with special emphasis on mycotoxins detected in forages, and animal toxicological issues due to their ingestion. Strategies for preventing the problem of mycotoxin feed contamination under farm conditions are discussed.

Ability of Lactobacillus plantarum MON03 to mitigate aflatoxins (B1 and M1) immunotoxicities in mice

Aflatoxin B1 (AFB1) and M1 (AFM1) are mycotoxins produced by numerous Aspergillus species in pre- or post-harvest cereals and milk. AFB1 and AFM1 display a potent economic loss in livestock and also cause severe immunological problems. The aims of this study were to: evaluate a new AFB1 and AFM1-binding/degrading micro-organism for biological detoxification; examine its ability to degrade AFB1 and AFM1 in liquid medium; and evaluate its potential for in vivo preventative effects against AFB1- and AFM1-induced immunomodulation in mice. Lactobacillus plantarum MON03 (LP) isolated from Tunisian artisanal butter was found to display significant binding ability to AFB1 and AFM1 in PBS (i.e. 82% and 89%, respectively) within 24 h of incubation and able to tolerate gastric acidity, have strongly hydrophilic cells surface properties, and adhere efficacy to Caco-3 cells in vitro. The in vivo study was conducted using Balb/c mice that received by oral gavage vehicle (control), LP only (2 × 10(9) CFU/L, ~2 g/kg BW), AFB1 or AFM1 alone (0.25 and 0.27 mg/kg, respectively), or AFB1 + LP or AFM1 + LP daily for 15 days. Compared to in control mice, treatments with AFB1 and AFM1 led to significantly decreased body weight gains, histopathological changes, and decrements in all hematologic and immune parameters assessed. Co-treatment with LP strongly reduced the adverse effects of each mycotoxin. In fact, the mice receiving AFB1 + LP or AFM1 + LP co-treatment displayed no significant differences in the assayed parameters as compared to the control mice. By itself, the bacteria alone had no adverse effects in the mice. From these data, it is concluded that the tested bacteria could be beneficial in biotechnology detoxification of contaminated food and feed for humans and animals.

Filamentous Fungi and Mycotoxins in Cheese: A Review

Important fungi growing on cheese include Penicillium, Aspergillus, Cladosporium, Geotrichum, Mucor, and Trichoderma. For some cheeses, such as Camembert, Roquefort, molds are intentionally added. However, some contaminating or technological fungal species have the potential to produce undesirable metabolites such as mycotoxins. The most hazardous mycotoxins found in cheese, ochratoxin A and aflatoxin M1, are produced by unwanted fungal species either via direct cheese contamination or indirect milk contamination (animal feed contamination), respectively. To date, no human food poisoning cases have been associated with contaminated cheese consumption. However, although some studies state that cheese is an unfavorable matrix for mycotoxin production; these metabolites are actually detected in cheeses at various concentrations. In this context, questions can be raised concerning mycotoxin production in cheese, the biotic and abiotic factors influencing their production, mycotoxin relative toxicity as well as the methods used for detection and quantification. This review emphasizes future challenges that need to be addressed by the scientific community, fungal culture manufacturers, and artisanal and industrial cheese producers.

Excretion pattern of aflatoxin M1 in milk of goats fed a single dose of aflatoxin B1

The feedstuffs used in dairy animals must be able to give consumers confidence about the wholesomeness of milk with regard to aflatoxin contamination. The aim of this study was to determine the excretion patterns of aflatoxin M(1) (AFM1) in the milk of dairy goats fed a single dose of pure aflatoxin B(1) (AFB1), which can occasionally occur if feeds are infected by hot-spot growth of molds that produce aflatoxins. Five dairy goats in midlactation were administered 0.8 mg of AFB1 orally. Individual milk samples were collected for 84 h after AFB1 dosage. Aflatoxin M(1) was found in milk in the highest concentration. In all goats, AFM1 was not detected in milk before AFB1 administration, but was detected in the first milking following AFB1 administration. The excretion pattern of AFM1 concentration in milk was very similar in all goats even if the values of the concentration differed between animals. The peak values for AFM1 concentration in milk was observed in milk collected during the milking at 3 and 6h. After the peak, the AFM1 in milk disappeared with a trend that fitted well a monoexponential decreasing function, and the toxin was not detected after 84 h. Only about 0.17% of the amount of AFB1 administered was detected as AFM1 in milk, and about 50% of this was excreted in the first liter of milk yielded after AFB1 intake. Correct procedures to prevent growth of molds, and consequent AFB1 contamination, on the feedstuffs for lactating goats represent the key to providing consumers a guarantee that milk is not contaminated by AFM1.

Natural occurrence of aflatoxins (B₁ and M₁) in feed, plasma and raw milk of lactating dairy cows in Beja, Tunisia, using ELISA

Beja is an agricultural area in northwest Tunisia. It contributes to national needs by offering cereals and milk to the market for human and animal consumption. A small number of studies on mycotoxin occurrence in feedstuffs and raw milk from lactating dairy cows in this region are available. Therefore, 226 samples were collected from farms and local markets during November 2008 until April 2010. Samples consisted of 112 raw cow milk, 56 blood from lactating cows and 58 feed destined for dairy cows. Plasma and feed were analysed for aflatoxin B₁ (AFB₁). Milk samples were analysed for aflatoxin M₁ (AFM₁). All samples were treated using a simultaneous methanolic-aqueous extraction, followed by immunoaffinity column clean-ups and were investigated by competitive enzyme-linked immunoabsorbent assay (ELISA). Recoveries were 80%-95% and 81%-92% for AFB₁ and AFM₁, respectively, while the limit of detection (LOD) was 0.01 µg/kg or µg/l for both mycotoxins. Results revealed the presence of AFB₁ in 84.4% of the feed samples (mean 18.7 ± 1.4 µg/kg), and 39.2% of the plasma-examined samples (median 7.1 ± 1.0 µg/l) were found to be contaminated at levels higher than the Tunisian and the European Union (EU) limit for dairy animals, which are 20 and 5 µg/kg in animal feed, respectively. AFM₁ was detected in 60.7% of the cow raw milk samples examined (median 13.6 ± 1.4 µg/l). Contaminated levels were higher than the EU limit of 0.05 µg/l. It was concluded that more precaution should be taken on hygiene controls in order to prevent fungal contamination.

Effect of oral supplementation of Lactobacillus reuteri in reduction of intestinal absorption of aflatoxin B(1) in rats

The goals of this work were to assess the ability of Lactobacillus reuteri to bind aflatoxin B(1) in the intestinal tract and determine its effect on intestinal absorption of the toxin dispensed in either single or multiple doses in a murine model. Male Wistar rats were used, and two experiments were conducted after bacteria were implanted. Experiment one involved a single-oral dose of toxin, and the subsequent flow cytometric analysis of bacteria isolated from the small intestine and treated with specific FITC-labeled AFB(1) antibodies. The second experiment was carried out supplying the toxin in 7 oral sub-doses, and the later quantification of AFB(1)-Lys adducts in blood samples by ELISA assay. The results demonstrated that L. reuteri was able to bind AFB(1) in the intestinal tract, mostly in the duodenum. Furthermore, the AFB(1)-Lys adducts were present at significantly lower levels in those animals receiving AFB(1) plus bacteria than in those receiving only AFB(1). Our findings confirm that probiotic bacteria could act as biological barriers in normal intestinal conditions thereby reducing the bioavailability of AFB(1) ingested orally in a single or multiple doses, thus avoiding its toxic effects.

Toxicokinetics of aflatoxin in pregnant mice

Our objective was to study the toxicokinetics of aflatoxin (AF) in pregnant mice. Aflatoxin B1 (AFB1) was administered intraperitoneally (IP) to groups of pregnant mice in single doses of 20 mg/kg on gestation day (GD) 13 and orally at the same gestational age. Controls received (IP and oral) a proportionate volume of solvent only. Maternal blood was collected at 15, 30, 45, 60, 90, 120, and 150 minutes posttreatment. Their AFB1 contents were determined. Aflatoxin B1 concentrations following maternal exposure to AFB1 were highly correlated with time after exposure. The serum concentrations were predictable and the highest serum levels were seen immediately at 15 minutes in mice given AFs IP and at 30 minutes in those given it orally. The absorption was 5.0 microg/min and elimination was 3.0 microg/min. The toxicokinetics of AFB1 have been delineated. Aflatoxins are easily and rapidly absorbed both from the gastrointestinal tract (GI) tract and through the peritoneum.

Effect of the inclusion of adsorbents on aflatoxin B1 quantification in animal feedstuffs

The extraction efficiency of aflatoxin B1 (AFB1) in cattle feed containing nine adsorbents (ADSs) was investigated using two organic/aqueous solvents composed of methanol/water (80/20 v/v; MeOH) and acetone/water (85/15 v/v; AC). Samples were obtained including a highly AFB1-contaminated (HC) and a low-level AFB(1)-contaminated (LC) feedstuff (15.33 and 7.57 microg kg(-1), respectively), nine ADSs (four clay minerals; one yeast cell wall-based product; one activated carbon and three commercial ADS products) at two different levels of inclusion (10 and 20 g kg(-1)). After solvent extraction and immunoaffinity column clean-up, all samples were analysed for AFB1 by high-performance liquid chromatography (HPLC) with fluorescence detection. For each contamination level (HC and LC), the data obtained were analysed using a factorial arrangement in a completely randomized design. Means were compared with the correspondent controls using the Dunnett's test. No statistical difference was found in AFB1 levels of feedstuffs not containing ADSs when extracted with AC or MeOH, even if numerically higher values were obtained with AC. A dose-dependent effect (p < 0.01) of ADSs inclusion was observed on AFB1 recoveries that were lower when the higher ADS level (20 g kg(-1)) was included in the HC and LC feedstuffs. Higher AFB(1) recoveries were obtained using AC compared with MeOH, both in HC (75.0% versus 12.0%, respectively) and in LC (84.0% versus 22.8%, respectively) ADSs containing feedstuffs. However, when the activated carbon and the sodium bentonite were included in feeds, lower AFB1 concentrations with respect to control values (p < 0.001 and <0.05, respectively) were obtained also using AC. The data obtained in this study indicate that routine use of the MeOH solvent for AFB1 analysis of unknown feedstuffs, can produce misleading results if they contain an ADS.