In vitromodels to evaluate the capacity of different sequestering agents to adsorb aflatoxins

Review: Strategies and technologies in preventing regulated and emerging mycotoxin co-contamination in forage for safeguarding ruminant health

Ruminants are often considered less susceptible to mycotoxins than monogastrics, owing to rumen microflora converting mycotoxins to less toxic compounds or several compounds present in the rumen-reticulum compartment, being able to bind the mycotoxin "mother" molecule that make them unavailable for absorption process in the gastro-intestinal tract of host animals. However, if ruminants consume feed contaminated by mycotoxins for long periods, their growth, development, and fertility can be compromised. Among regulated mycotoxins, the most studied and known for their effects are aflatoxins (AFs) AFB1, AFB2, AFG1 and AFG2, as well as the AFM1 for its high importance in dairy sector, deoxynivalenol (DON) and its metabolites 3/15 acetyl-DON and 3-glucoside DON, T-2 and HT-2 toxins, zearalenone, fumonisins, in particular that belong to the B class, and ochratoxin A. Furthermore, because of the emergence of multiple emerging mycotoxins that are detectable in feed utilised in ruminant diets, such as ensiled forage, there is now a growing focus on investigating these compounds by the scientific community to deepen their toxicity for animal health. Despite the enhancement of research, it is remarkable that there is a paucity of in vivo trials, as well as limited studies on nutrient digestibility and the impact of these molecules on rumen and intestinal functions or milk yield and quality. In this review, recent findings regarding the occurrence of regulated and emerging mycotoxins in forage and their possible adverse effects on dairy cattle are described, with special emphasis on animal performance and on rumen functionality.

In vitro aflatoxins recovery after changing buffer or protozoa concentrations in the rumen fermentation fluid

This study simulates in vitro the effects of (i) rumen acidity and (ii) change in rumen protozoa numbers on the recovery of aflatoxins (AFs). Two 24-h fermentation experiments were carried out using the same batch in vitro fermentation systems and substrate (dried corn meal) containing 11.42, 2.42, 7.65 and 1.70 µg/kg of AFB1, AFB2, AFG1 and AFG2 respectively. In Experiment 1, two buffer concentrations (normal salts dosage or lowered to 25%) were tested. Buffer reduction decreased gas production (730 vs. 1101 mL, p < 0.05), volatile fatty acids (VFA) and NH3 concentrations in the fermentation liquid (39.8 vs. 46.3 mmol/L, and 31.7 vs. 46.5 mg/dL respectively, p < 0.01). Recovery of all four AFs types was higher (p < 0.01) in the reduced buffer fermentation fluid, both as a percentage of total AF incubated (73.6% vs. 62.5%, 45.9% vs. 38.1%, 33.6% vs. 17.9% and 18.9% vs. 6.24% for AFB1, AFB2, AFG1 and AFG2 respectively) and as amounts relative to VFA production (163.4 vs. 123.5, 22.1 vs. 15.7, 48.8 vs. 22.5 and 6.16 vs. 1.86 ng/100 mmol of VFA, for AFB1, AFB2, AFG1 and AFG2 respectively). In Experiment 2, Stevia rebaudiana Bertoni extracts (S) or a Camphor essential oil (Cam) were added to fermenters and compared to the control (no additives, C). S and Cam addition resulted in a 25% reduction (p < 0.05) and a 15% increase (p < 0.05) in protozoa counts respectively, when compared to C. Both plant additives slightly reduced (p < 0.05) AFB1 recovery as a percentage of total AFB1 incubated (68.5% and 67.7% vs. 74.9% for S, Cam and C respectively). Recoveries of all other AFs were unaffected by the additives. In conclusion, the rumen in vitro AFB1 recovery (63%-75%) was higher than other AFs (3%-46%) and the acidic fermentation environment increased it. In our conditions, changes in protozoa numbers did not affect AFs recovery.

Pathological Role of Oxidative Stress in Aflatoxin-Induced Toxicity in Different Experimental Models and Protective Effect of Phytochemicals: A Review

Aflatoxin B1 is a secondary metabolite with a potentially devastating effect in causing liver damage in broiler chickens, and this is mainly facilitated through the generation of oxidative stress and malonaldehyde build-up. In the past few years, significant progress has been made in controlling the invasion of aflatoxins. Phytochemicals are some of the commonly used molecules endowed with potential therapeutic effects to ameliorate aflatoxin, by inhibiting the production of reactive oxygen species and enhancing intracellular antioxidant enzymes. Experimental models involving cell cultures and broiler chickens exposed to aflatoxin or contaminated diet have been used to investigate the ameliorative effects of phytochemicals against aflatoxin toxicity. Electronic databases such as PubMed, Science Direct, and Google Scholar were used to identify relevant data sources. The retrieved information reported on the link between aflatoxin B1-included cytotoxicity and the ameliorative potential/role of phytochemicals in chickens. Importantly, retrieved data showed that phytochemicals may potentially protect against aflatoxin B1-induced cytotoxicity by ameliorating oxidative stress and enhancing intracellular antioxidants. Preclinical data indicate that activation of nuclear factor erythroid 2-related factor 2 (Nrf2), together with its downstream antioxidant genes, may be a potential therapeutic mechanism by which phytochemicals neutralize oxidative stress. This highlights the need for more research to determine whether phytochemicals can be considered a useful therapeutic intervention in controlling mycotoxins to improve broiler health and productivity.

Occurrence of aflatoxins in water and decontamination strategies: A review

Aflatoxins are highly carcinogenic metabolites produced by some Aspergillus species and are the most prevalent mycotoxins. Although aflatoxins are commonly synthesized during fungal colonization in preharvest maize, cereals, and nuts, they can be transported by rainfall to surface water and are a common toxin found in wastewater from some food industries. Here, the occurrence of aflatoxins in bodies of water is reviewed for the first time, along with the decontamination methods. Aflatoxins have been detected in surface, wastewater and drinking water, including tap and bottled water. The specific sources of water contamination remain unclear, which is an important gap that must be addressed in future research. Two main kinds of decontamination methods have been reported, including degradation and adsorption. The best degradation rates were observed using gamma and UV irradiations, oxidoreductases and ozone, while the best adsorption abilities were observed with minerals, polyvinyl alcohol, durian peel and activated carbon. Synthetic polymers could be used as membranes in pipes to remove aflatoxins in water flows. Although most decontamination methods were screened using AFB₁, the other commonly found aflatoxins were not used in the screenings. Overall, the occurrence of aflatoxins in water could be a significant emerging public health concern largely ignored by local and international legislation. Numerous advances have been reported for the decontamination of aflatoxins in water; however, there is still a long way to go to put them into practice.

The efficacy of mycotoxin binders to control mycotoxins in feeds and the potential risk of interactions with nutrient: a review

Mycotoxicosis are a common problem in livestock, where a group of six major mycotoxins represents a high risk for animal health and production profits. Mycotoxin binders (MTB) can reduce the mycotoxin burden in the gastrointestinal tract of the animal. Mycotoxin binders are classified in inorganic, as clays and activated carbon (AC), and organic, as yeast cell wall (YCW) and micro-ionized fibers. The adsorption of mycotoxins into MTB is due to: 1) chemical interactions where the cation exchange capacity involves different types of bounds like ion-dipole, Van der Walls forces, or hydrogen bonds; and 2) to physical characteristics of MTB like pore size, or mycotoxin structure and shape. The adsorption capacity of MTB is determined using different in vitro tests that mimic the gastrointestinal tract of the animals. A literature search was conducted to identify in vitro research where the efficacy of adsorption of MTB was determined. The search was based on 8 MTB [AC, bentonite, clinoptilolite, hydrated sodium calcium aluminosilicate (HSCAS), montmorillonite (MMT), sepiolite, YCW and zeolite] and 6 mycotoxins [aflatoxin (AF), deoxynivalenol (DON), fumonisin (FUM), ochratoxin (OTA), T-2 toxin and zearalenone (ZEA)]. Sixty-eight papers with 1842 data were selected and analyzed with the PROC MIXED of SAS. The response variable was the percentage mycotoxins adsorption by MTB, and the model included the fixed effects of MTB, mycotoxins, incubation media, pH and their interactions, and the random effect of the study. Differences were considered significant when P < 0.05 and with tendency when 0.05 < P < 0.10. The mycotoxins adsorption capacity was 83% ± 1.0 for AC, 76% ± 3.1 for MMT, 62% ± 1.0 for bentonite, 55% ± 1.9 for HSCAS, 52% ± 9.1 for sepiolite, 52% ± 4.3 for clinoptilolite and 44% ± 0.4 for YCW. For mycotoxins, the adsorption of AF was 76% ± 0.6, for FUM was 50% ± 1.8, for OTA was 42% ± 1.0, for ZEA was 48% ± 1.1, for DON was 35% ± 1.6, and for T-2 was 27% ± 2.8. The pH affected the adsorption capacity of YCW with higher adsorption at low pH, and the adsorption of OTA and ZEA, where OTA adsorption tended to be lower at intermediate pH, and adsorption of ZEA tended to be higher at the two-steps pH. The potential adsorption of some essential nutrients, including amino acids and vitamins, should also be considered. Results should be used as a guide in the selection of the appropriate mycotoxin binder based on the predominant mycotoxin in feeds.

Industrial-Scale Production of Mycotoxin Binder from the Red Yeast Sporidiobolus pararoseus KM281507

Red yeast Sporidiobolus pararoseus KM281507 has been recognized as a potential feed additive. Beyond their nutritional value (carotenoids and lipids), red yeast cells (RYCs) containing high levels of β-glucan can bind mycotoxins. This study investigated the industrial feasibility of the large-scale production of RYCs, along with their ability to act as a mycotoxin binder. Under a semi-controlled pH condition in a 300 L bioreactor, 28.70-g/L biomass, 8.67-g/L lipids, and 96.10-mg/L total carotenoids were obtained, and the RYCs were found to contain 5.73% (w/w) β-glucan. The encapsulated RYC was in vitro tested for its mycotoxin adsorption capacity, including for aflatoxin B1 (AFB1), zearalenone (ZEA), ochratoxin A (OTA), T-2 toxin (T-2) and deoxynivalenol (DON). The RYCs had the highest binding capacity for OTA and T-2 at concentrations of 0.31–1.25 and 0.31–2.5 µg/mL, respectively. The mycotoxin adsorption capacity was further tested using a gastrointestinal poultry model. The adsorption capacities of the RYCs and a commercial mycotoxin binder (CMB) were comparable. The RYCs not only are rich in lipids and carotenoids but also play an important role in mycotoxin binding. Since the industrial-scale production and downstream processing of RYCs were successfully demonstrated, RYCs could be applied as possible feed additives.

An In Vitro Study on the Efficacy of Mycotoxin Sequestering Agents for Aflatoxin B1, Deoxynivalenol, and Zearalenone

Simple Summary

Mycotoxins in feeds can cause detrimental effects on the growth performance and health of pigs. One of the methods used to overcome the negative effects of mycotoxins in animal feeds is to add toxin sequestering agents to feed. The present work was conducted to determine the efficacy of mycotoxin sequestering agents using an in vitro method. All mycotoxin sequestering agents effectively bound to aflatoxin B1; only activated charcoal effectively sequestered deoxynivalenol; and a bentonite product, an aluminosilicate product, and activated charcoal effectively sequestered zearalenone.

Abstract

The objective of this study was to determine the efficacy of mycotoxin sequestering agents for aflatoxin B1 (AFB1), deoxynivalenol (DON), and zearalenone (ZEA) using an in vitro method. The twelve toxin sequestering agents tested were seven bentonite products (bentonite A, B, C, D, E, F, and G), two aluminosilicate products (aluminosilicate A and B), a heulandite product, an activated charcoal product, and a yeast cell wall product. A two-step in vitro procedure was employed to mimic the conditions of temperature, pH, and digestive enzymes in the stomach and small intestine of pigs. All mycotoxin sequestering agents tested were able to bind to AFB1 with a high efficacy (>92%). The DON sequestering rate of activated charcoal (99.1%) was greater (p < 0.05) than that of other products. The ZEA sequestering rate of bentonite F (97.0%), aluminosilicate A (99.6%), and activated charcoal (100.0%) was the greatest (p < 0.05) among the tested mycotoxin sequestering agents. Overall, most mycotoxin sequestering agents had the ability to bind to AFB1, but most products, except activated charcoal, failed to sequester DON and ZEA.

Combating immunotoxicity of aflatoxin B1 by dietary carbon supplementation in broiler chickens

Aflatoxin B1 (AFB1) is a secondary metabolite of some Aspergillus species that contaminate the agricultural commodities intended for animal and human consumption. The present in vivo study aimed to evaluate activated charcoal (AC) for its ability to reduce AFB1-induced immune suppressive effects in broiler chickens. One-day-old broiler chicks were divided into 12 groups (n = 30) and raised until 42 days of age. One control group was offered basal broiler feed. Three AFB1 groups were kept on AFB1-contaminated basal broiler feed (0.1, 0.2, and 0.6 mg/kg AFB1, respectively), whereas two AC groups were offered AC-added basal broiler feed (2.5 and 5.0 g/kg AC, respectively). Six combination groups were maintained on a combination of different doses of AFB1 and AC. The immune protective efficacy of AC was assessed by anti-sheep RBC's antibodies, phagocytic activity of the reticuloendothelial system, phytohemagglutinin-P (PHA-P)-induced cutaneous basophil response, and histopathological and morphometric analysis of lymphoid organs. Dietary exposure to AFB1 alone resulted in dose-dependent suppression of immune responses and degenerative and necrotic changes in the bursa of Fabricius and thymus. The dietary addition of AC reduced the toxic effects of 0.1 and 0.2 mg/kg dietary AFB1 on immune responses and histological lesion on lymphoid organs; however, at higher dietary level of AFB1 (0.6 mg AFB1/kg), the dietary addition of AC was not effective to prevent the immunotoxic effects. The results of this study suggested that dietary inclusion of AC has the ability to prevent immunotoxic effects induced by AFB1 at lower dietary contaminations levels in broiler chickens.

Short Communication: Quantification of the Effect of Mycotoxin Binders on the Bioavailability of Fat-Soluble Vitamins In Vitro

The aim of this study was to determine the capacity of six mycotoxin binders (MTBs) to adsorb vitamins A, D and E in an in vitro system that simulates gastric and intestinal digestion. Experiment 1 evaluated the recovery rate of vitamins A, D and E in the incubation conditions. In Experiment 2, the main factors were the MTB (bentonite, clinoptilolite, sepiolite, montmorillonite, active carbon and yeast cell walls), vitamins (A, D and E) and incubation type (vitamins incubated separately or together). The recovery was high for vitamin D (83%) and E (93%), but low for vitamin A (23%), for which no further analyses were conducted. When incubated separately, vitamin D was only adsorbed by yeast cell wall (20.2%). Vitamin E adsorption was highest with bentonite (54.5%) and montmorillonite (46.3%) and lowest with sepiolite (16.6%) and active carbon (18.5%). When incubated together, vitamin D was not adsorbed by any MTB. Vitamin E adsorption was highest in bentonite (61.8%) and montmorillonite (50.7%) and lowest in sepiolite (15.4%). Results indicate that the bioavailability of vitamin E, but not that of vitamin D, may be reduced in the presence of MTBs.

Physical and Chemical Methods for Reduction in Aflatoxin Content of Feed and Food

Aflatoxins (AFs) are among the most harmful fungal secondary metabolites imposing serious health risks on both household animals and humans. The more frequent occurrence of aflatoxins in the feed and food chain is clearly foreseeable as a consequence of the extreme weather conditions recorded most recently worldwide. Furthermore, production parameters, such as unadjusted variety use and improper cultural practices, can also increase the incidence of contamination. In current aflatoxin control measures, emphasis is put on prevention including a plethora of pre-harvest methods, introduced to control Aspergillus infestations and to avoid the deleterious effects of aflatoxins on public health. Nevertheless, the continuous evaluation and improvement of post-harvest methods to combat these hazardous secondary metabolites are also required. Already in-use and emerging physical methods, such as pulsed electric fields and other nonthermal treatments as well as interventions with chemical agents such as acids, enzymes, gases, and absorbents in animal husbandry have been demonstrated as effective in reducing mycotoxins in feed and food. Although most of them have no disadvantageous effect either on nutritional properties or food safety, further research is needed to ensure the expected efficacy. Nevertheless, we can envisage the rapid spread of these easy-to-use, cost-effective, and safe post-harvest tools during storage and food processing.

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.

Development of an in vitro gastro-intestinal pig model to screen potential detoxifying agents for the mycotoxin deoxynivalenol

Deoxynivalenol (DON) is a type B trichothecene mycotoxin with worldwide high incidence in feed which is produced by Fusarium species. Strategies are needed to eliminate its health risk for livestock and to minimise its economic impact on production. In order to assess the efficacy of potential physical, chemical and biological DON detoxifying agents, a good in vitro model is necessary to perform a fast and high-throughput screening of new compounds before in vivo trials are set up. In this paper, an in vitro model was developed to screen potential commercial products for DON degradation and detoxification. Contaminated feed with potential detoxifying agents are first applied to a simulated gastrointestinal tract (GIT) of a pig, after which detoxification is assessed through a robust, inexpensive and readily applicable Lemna minor L. aquatic plant bioassay which enables evaluation of the residual toxicity of possible metabolites formed by DON detoxifying agents. The GIT simulation enables taking matrix and incubation parameters into account as they can affect the binding, removal or degradation of DON. One product could reduce DON in feed in the GIT model for almost 100% after 6 h. DON metabolites were tentatively identified with LC-MS/MS. This GIT simulation coupled to a detoxification bioassay is a valuable model for in vitro screening and assessing compounds for DON detoxification, and could be expanded towards other mycotoxins.

Mycotoxin and Gut Microbiota Interactions

The interactions between mycotoxins and gut microbiota were discovered early in animals and explained part of the differences in susceptibility to mycotoxins among species. Isolation of microbes present in the gut responsible for biotransformation of mycotoxins into less toxic metabolites and for binding mycotoxins led to the development of probiotics, enzymes, and cell extracts that are used to prevent mycotoxin toxicity in animals. More recently, bioactivation of mycotoxins into toxic compounds, notably through the hydrolysis of masked mycotoxins, revealed that the health benefits of the effect of the gut microbiota on mycotoxins can vary strongly depending on the mycotoxin and the microbe concerned. Interactions between mycotoxins and gut microbiota can also be observed through the effect of mycotoxins on the gut microbiota. Changes of gut microbiota secondary to mycotoxin exposure may be the consequence of the antimicrobial properties of mycotoxins or the toxic effect of mycotoxins on epithelial and immune cells in the gut, and liberation of antimicrobial peptides by these cells. Whatever the mechanism involved, exposure to mycotoxins leads to changes in the gut microbiota composition at the phylum, genus, and species level. These changes can lead to disruption of the gut barrier function and bacterial translocation. Changes in the gut microbiota composition can also modulate the toxicity of toxic compounds, such as bacterial toxins and of mycotoxins themselves. A last consequence for health of the change in the gut microbiota secondary to exposure to mycotoxins is suspected through variations observed in the amount and composition of the volatile fatty acids and sphingolipids that are normally present in the digesta, and that can contribute to the occurrence of chronic diseases in human. The purpose of this work is to review what is known about mycotoxin and gut microbiota interactions, the mechanisms involved in these interactions, and their practical application, and to identify knowledge gaps and future research needs.

Evaluation of berberine efficacy in reducing the effects of aflatoxin B1 and ochratoxin A added to male broiler rations

Many types of mycotoxins are found in food sources contaminated with fungi, and if these are ingested in large quantities or over a long period, they can affect the health of humans and domestic animals. Berberine (BBR) is a plant alkaloid with multiple pharmacological functions. This study aimed to investigate the effect of different levels of the plant alkaloid BBR on reducing toxic effects of aflatoxin B1 (AFB) and ochratoxin A (OTA) in broilers by examining performance characteristics, blood biochemistry, antioxidant systems, ileum morphology, and histopathology of the liver. The experiment was performed with 288 Ross 308 broilers reared in floor pens for 42 d in a randomized design with 9 treatments. Each treatment was replicated 4 times, and each replicate contained 8 chicks. Experimental treatments included (1) negative control diet with no additives (NC); (2) NC + 2 ppm AFB (positive control AFB; PCAFB); (3) NC + 2 ppm OTA (positive control OTA; PCOTA); (4) PCAFB + 200 mg/kg BBR; (5) PCAFB + 400 mg/kg BBR; (6) PCAFB + 600 mg/kg BBR; (7) PCOTA + 200 mg/kg BBR; (8) PCOTA + 400 mg/kg BBR; and (9) PCOTA + 600 mg/kg BBR. Compared with NC, feeding PCAFB and PCOTA diets reduced average daily feed intake, weight gain, serum concentrations of superoxide dismutase, glutathione peroxidase, and the length and width of ileum villi (P < 0.05). At the same time, these parameters increased in birds fed PCAFB or PCOTA diets supplemented with 600 mg/kg of BBR (P < 0.05). Feeding PCAFB and PCOTA diets increased feed conversion ratio (FCR), serum aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and gamma-glutamyl transferase (GGT) activities, serum urea, and liver lesions compared with NC. By contrast, compared with PCAFB and PCOTA, adding 600 mg/kg BBR decreased FCR, AST, LDH, ALT, and GGT activities, urea, and liver lesions (P < 0.05). Overall, supplementation with 600 mg/kg BBR may improve growth performance, liver function, and antioxidant status of broilers fed diets contaminated with AFB and OTA.

Evaluation of the Efficacy of Mycotoxin Modifiers and Mycotoxin Binders by Using an In Vitro Rumen Model as a First Screening Tool

Ruminal microbiota of cattle are not able to detoxify all mycotoxins. In addition, detoxification can be hampered by adverse ruminal conditions (e.g., low ruminal pH). Hence, in the cattle husbandry, mycotoxin binders and modifiers could be used to prevent animal exposure to mycotoxins. In this study, an in vitro rumen model, including feed matrix, was established as first screening tool to test the efficacy of five products claiming to detoxify mycotoxins. The detoxifiers had different modes of action: (a) binding (three products); (b) enzymatic detoxification of zearalenone (ZEN; one product, ZenA); and (c) bacterial transformation of trichothecenes (one product, BBSH 797). For the mycotoxin binders, the binding to the mycotoxins enniatin B (ENN B), roquefortine C (ROQ-C), mycophenolic acid (MPA), deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEN) were tested at a dose recommended by the manufacturers. The in vitro model demonstrated that all binders adsorbed ENN B to a certain extent, while only one of the binders also partially adsorbed ROQ-C. The binders did not change the concentrations of the other mycotoxins in the ruminal fluid. The enzyme ZenA detoxified ZEN very quickly and prevented the formation of the more toxic metabolite α-zearalenol (α-ZEL), both at normal (6.8) and low ruminal pH (5.8). The addition of BBSH 797 enhanced detoxification of DON and NIV, both at normal and low ruminal pH. The in vitro rumen model demonstrated that the addition of ZenA seems to be a very promising strategy to prevent estrogenic effects of ZEN contaminated feed, and BBSH 797 is efficient in the detoxification of trichothecenes.

In Vitro Rumen Simulations Show a Reduced Disappearance of Deoxynivalenol, Nivalenol and Enniatin B at Conditions of Rumen Acidosis and Lower Microbial Activity

Ruminants are generally considered to be less susceptible to the effects of mycotoxins than monogastric animals as the rumen microbiota are capable of detoxifying some of these toxins. Despite this potential degradation, mycotoxin-associated subclinical health problems are seen in dairy cows. In this research, the disappearance of several mycotoxins was determined in an in vitro rumen model and the effect of realistic concentrations of those mycotoxins on fermentation was assessed by volatile fatty acid production. In addition, two hypotheses were tested: (1) a lower rumen pH leads to a decreased degradation of mycotoxins and (2) rumen fluid of lactating cows degrade mycotoxins better than rumen fluid of non-lactating cows. Maize silage was spiked with a mixture of deoxynivalenol (DON), nivalenol (NIV), enniatin B (ENN B), mycophenolic acid (MPA), roquefortine C (ROQ-C) and zearalenone (ZEN). Fresh rumen fluid of two lactating cows (L) and two non-lactating cows (N) was added to a buffer of normal pH (6.8) and low pH (5.8), leading to four combinations (L6.8, L5.8, N6.8, N5.8), which were added to the spiked maize substrate. In this study, mycotoxins had no effect on volatile fatty acid production. However, not all mycotoxins fully disappeared during incubation. ENN B and ROQ-C disappeared only partially, whereas MPA showed almost no disappearance. The disappearance of DON, NIV, and ENN B was hampered when pH was low, especially when the inoculum of non-lactating cows was used. For ZEN, a limited transformation of ZEN to α-ZEL and β-ZEL was observed, but only at pH 6.8. In conclusion, based on the type of mycotoxin and the ruminal conditions, mycotoxins can stay intact in the rumen.

Toxicopathological effects of feeding aflatoxins B1 in broilers and its ameliosration with indigenous mycotoxin binder

Mycotoxicosis is the second most important problem faced by the Pakistan poultry industry, after high feed prices. The present experimental study was designed to investigate the toxicopathological effects of aflatoxin B1 (AFB1) in commercial broiler chicks and its amelioration with locally produced mycotoxin binder. Total of 125 broiler chicks was divided into five equal groups (A-E). Group A served as negative control, group B (300 μg AFB1/kg feed) as positive control, group C (300 μg AFB1/kg + Local Mycotoxin Binder (LMB), 1 g/kg feed), group D (300 μg AFB1/kg + 2 g LMB/kg feed), and group E (300 μg AFB1/kg + Commercial Mycotoxin Binder (CMB), 2 g/kg of feed). Parameters studied included mortality, feed intake, bodyweights, absolute and relative organ weights, and gross and microscopic lesions in visceral organs. Clinical signs including alertness, fecal consistency, and feather shine were significantly lower in group B compared with control group A. The feed intake of 2 g/kg LMB treated group was significantly higher than that of the positive control group B. Also mean bodyweights of group D birds was higher than that of group B birds indicating an ameliorative effect of LMB. Histopathological results showed that moldy feed produced necrotic changes in the liver and kidneys in group B birds. However, in group D and E birds, the hepatic and renal parenchyma was normal, showing a protective effect of LMB. In the present study, a higher dose of LMB (2 g/kg) in group D showed higher bodyweights and feed intake. In group D, birds hepatic and renal parenchyma was also normal. The results suggested that local mycotoxin binder ameliorated the toxicopathological effects of AFB1 in mortality, feed intake, bodyweights, organ weights and, gross and microscopic lesions in visceral organs. These ameliorative effects of LMB were dose-dependent. The results of the present study concluded that AFB1 intoxication leads to decrease in bodyweights, feed intake in dose-related manner. The mortality was also dose-dependent. Gross and microscopic changes in the aflatoxin groups were more pronounced, however, all these deleterious effects were ameliorated in higher dose of LMB (group D) and CMB (group E). In group C, these deleterious effects were partially ameliorated. Local mycotoxin binder is an economical solution for aflatoxicosis problem, making poultry production more cost-effective.

Occurrence of Aflatoxin M1 in Raw Milk Marketed in Italy: Exposure Assessment and Risk Characterization

The current study is based on the AFM1 contamination of milk determined from April 2013 to December 2018 in the framework of a self-control plan of six milk processing plants in Italy. These data - together with the consumption data of milk consumers - were evaluated and used for the calculation of the Estimated Daily Intake (EDI), the Hazard Index (HI), and the fraction of hepatocarcinoma cases (HCC) due to AFM1 exposure in different population groups. Altogether a total of 31,702 milk samples were analyzed, representing 556,413 tons of milk, which is an outstanding amount compared to published studies. The results indicate the monthly fluctuation of AFM1 levels through a period of nearly 6 years. The EDI of AFM1 in different population groups was in the range of 0.025-0.328 ng kg-1 body weight (bw) per day, based on the average consumption levels and weighted mean contamination of the milk in the study period. Considering average consumptions, in the groups of infants and toddlers, the HI calculation resulted in 1.64 and 1.4, respectively, while for older age groups, it was <1. The estimated fractions of HCC incidences attributable to the AFM1 intakes were 0.005 and 0.004 cases per 100,000 individuals in the 0-0.9 and 1-2.9-year age groups, respectively, and below 0.004 cases in the other age categories. The monthly average AFM1 contamination of tested milk consignments ranged between 7.19 and 22.53 ng kg-1. Although the results of this extensive investigation showed a low risk of HCC, the variability of climatic conditions throughout years that influence AFB1 contamination of feed and consequently AFM1 contamination of milk justifies their continuous monitoring and update of the risk assessment.

Development of an UPLC-MS/MS Method for the Analysis of Mycotoxins in Rumen Fluid with and without Maize Silage Emphasizes the Importance of Using Matrix-Matched Calibration

Ruminants are less susceptible to the effects of mycotoxins than monogastric animals as their rumen microbiota are claimed to degrade and/or deactivate at least some of these toxic compounds. However, the mycotoxin degradation is not well-known yet. For this, a sensitive, specific, and accurate analytical method is needed to determine mycotoxins in the rumen fluid. This study aims to develop and thoroughly validate an ultra-performance liquid chromatography tandem mass spectrometry method for the quantitative determination in the rumen fluid of some of the most relevant mycotoxins found in maize silage in Western Europe: deoxynivalenol (DON), nivalenol (NIV), zearalenone (ZEN), mycophenolic acid (MPA), roquefortine C (ROQ-C) and enniatin B (ENN B), as well as their metabolites deepoxy-deoxynivalenol (DOM-1), α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), zearalanone (ZAN), α-zearalanol (α-ZAL) and β-zearalanol (β-ZAL). As feed is often present in the rumen fluid samples, the potential interaction of feed particles with the mycotoxin extraction and analysis was investigated. Extraction recovery and matrix effects were determined in the rumen fluid with and without maize silage. Differences in those parameters between rumen fluid alone and rumen fluid with maize silage highlight the importance of using matrix-matched calibration curves for the quantification of mycotoxins in rumen fluid samples. A cross-validation of the method with rumen fluid and maize silage demonstrates that this analytical method can be applied in research on rumen fluid samples to investigate the degradation of the reported mycotoxins by rumen microbiota if matrix-matched calibration is performed.

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.

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.

Effects of two different blends of naturally mycotoxin-contaminated maize meal on growth and metabolic profile in replacement heifers

The aim of this trial was to assess the effects of the administration of different combinations of mycotoxins in naturally contaminated maize grains on dairy heifer growth, blood measurements and puberty onset. A total of 35 Friesian female heifers were randomly allotted to three experimental groups from 18-21 to 42-45 weeks of age. During the 24-week experimental period (EP), heifers were fed the same diet, but with maize meal derived from three differently contaminated lots: very low contamination, as control (C); medium-low aflatoxin-contaminated (A); and mixed aflatoxin-fumonisin contaminated (A-F). At the end of the EP, they returned to a common diet without contaminated maize, and they were monitored for an additional period of 12 weeks (post-experimental period, PEP). BW, wither height, hip height, body length and heart girth were measured every 4 weeks from the beginning of EP to the end of PEP. At the same time, body condition score was evaluated and blood samples were taken from the jugular vein to be analysed for haematological, serum protein and metabolic profiles. Age at puberty was assessed by measuring weekly plasma progesterone levels from 40 to 52 weeks of age. Body growth measurements were processed both by ANOVA of average daily gain of EP and PEP separately, and by the analysis of growth curve parameters. Haematological, serum protein and metabolic profile were evaluated using a mixed model, taking into account the repeated measurements in time on each animal. Heifers' growth was delayed both in A and A-F groups during EP, as evidenced by the different linear coefficients of the BW growth curve in the three groups. Differently contaminated diets did not affect the haematological profile, so that it can be concluded that these levels of mycotoxin contamination do not determine any specific effect on haematopoiesis and immunity in growing heifers. The main blood marker of mycotoxin chronic toxicity was the γ-glutamyl transferase activity level in plasma, which appeared to be altered even after the removal of mycotoxins. During EP, plasma glucose was lower in the groups fed contaminated diet compared with C. The joint actions of an altered nutritional status and a long-lasting liver damage were probably the causes of the delay in puberty attainment in A and, particularly, in the A-F group. The results from this trial evidenced that a chronic aflatoxin-fumonisin contamination in diets of dairy heifers can determine an important delay in the reproductive career of these animals.

Capability of different non-nutritive feed additives on improving productive and physiological traits of broiler chicks fed diets with or without aflatoxin during the first 3 weeks of life

An experiment was conducted to determine whether some non-nutritive feed additives (NNFA) could block the adverse effects of aflatoxin (AF) on growth performance and physiological parameters of Cobb broilers throughout the period from 1 to 21 day of age. There were eight treatments consisting of two levels of AF at 0 and 200 ppb and four NNFA within each AF level. These additives included mannan oligosaccharides (MOS) at 2 g/kg diet, hydrated sodium calcium aluminosilicate (HSCAS) at 2 g/kg diet and Lactobacillus acidophilus (Lac) at 2 g/kg diet. At 21 day of age, five chickens of each treatment were slaughtered to study dressing percentage and relative weight of inner organs and glands. AF had a significant negative effect on body weight gain (BWG), and feed intake, while impairing feed conversion ratio (FCR). Aflatoxin significantly increased percentage liver, lymphocyte (%), monocyte (%), serum triglyceride level, and the aspartate aminotransferase (AST), and alanine aminotransferase (ALT), concentrations while decreasing dressing percentage, intestinal percentage, white blood cells (WBCs), red blood cells (RBCs), haemoglobin (Hgb), packed cell volume (PCV), heterophil (%), heterophil/lymphocyte ratio, total serum protein and serum albumin. Aflatoxin adversely affected the morphology of the liver, bursa and the thymus. There was a significant interaction between AF and NNFA on the relative weights of liver, heart and intestine. Lac completely blocked the negative effects of AF on the percentage liver and the heart and partially on the intestine. In conclusion, Lac was most effective in reversing the adverse effects of AF on growth and FCR and on the percentage, functions and morphology of the liver. Hydrated sodium calcium aluminosilicate also improved the economic traits of broilers but was less effective than Lac and more effective than MOS.

Binding of zearalenone, aflatoxin B1, and ochratoxin A by yeast-based products: a method for quantification of adsorption performance

A methodology was developed to quantify the efficiency of yeast-based products for adsorption of three mycotoxins: zearalenone (ZEA), aflatoxin B(1) (AFB(1)), and ochratoxin A (OTA). Eight products were tested (yeast cell wall or inactivated yeast). The described experimental protocol based on in vitro tests provided reliable isotherms for each mycotoxin. The most suitable models were the Hill model for ZEA, the Langmuir model for AFB(1), and the Freundlich model for OTA. From these models, original mathematical affinity criteria were defined to quantify the product adsorption performances for each mycotoxin. The best yeast product, a yeast cell wall from baker's yeast, can adsorb up to 68% of ZEA, 29% of AFB(1), and 62% of OTA, depending on the mycotoxin concentrations. The adsorption capacity largely depended both on yeast composition and mycotoxin, but no direct correlation between yeast composition and adsorption capacity was found, confirming that adsorption of mycotoxin on yeast-based products involves complex phenomena. The results of this study are useful for comparing the adsorption efficiency of various yeast products and understanding the mechanisms involved in adsorption.