Aflatoxin B1 residues in eggs of laying hens fed a diet containing different levels of the mycotoxin

Level of aflatoxins in dairy feeds, poultry feeds, and feed ingredients produced by feed factories in Addis Ababa, Ethiopia

Aflatoxins are one of the major factors that affect the quality and safety of feeds. They can be transferred into livestock through contaminated feed and then onto humans via animal sources of food such as milk, meat, and eggs. The objective of this study was to detect and quantify the level of aflatoxins (B1, B2, G1, G2, and total aflatoxin) in dairy feeds, poultry (layer and broiler) feeds, and feed ingredients produced in Addis Ababa. A total of 42 feeds and feed ingredients consisting of dairy feeds (n = 5), poultry broiler feeds (n = 6), layer feeds (n = 6), and feed ingredients (n = 25) were collected from feed factories in the city and analyzed in fresh weigh basis. The aflatoxins were analyzed using high-performance liquid chromatography after clean-up with immunoaffinity columns. Aflatoxin B1 levels in feeds ranged from 51.66 to 370.51 µg/kg in dairy cattle feed, from 1.45 to 139.51 µg/kg in poultry layer feed, and from 16.49 to 148.86 µg/kg in broiler feed. Aflatoxin B1 levels in maize ranged from 2.64 to 46.74 µg/kg and in Niger seed cake from 110.93 to 438.86 µg/kg. Aflatoxin B1 levels in wheat bran, wheat middling, and soybean were below 5 µg/kg. 100% of dairy feeds, 67% of poultry layer, 67% of broiler feeds, and 24% of ingredients contained aflatoxin in levels higher than the maximum tolerable limit set by the US Food and Drug Administration and Ethiopian Standard Agency. This shows the need for strong regulatory monitoring and better feed management practices to prevent consumers of animal-source foods from significant health impacts associated with aflatoxins.

Effects of moldy corn on the performance, antioxidant capacity, immune function, metabolism and residues of mycotoxins in eggs, muscle, and edible viscera of laying hens

Mycotoxins, including aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON), are common contaminants of moldy feeds. Mycotoxins can cause deleterious effects on the health of chickens and can be carried over in poultry food products. This study was conducted to investigate the effects of moldy corn (containing AFB1, ZEN, and DON) on the performance, health, and mycotoxin residues of laying hens. One hundred and eighty 400-day-old laying hens were divided into 4 treatments: basal diet (Control), basal diet containing 20% moldy corn (MC20), 40% moldy corn (MC40) and 60% moldy corn (MC60). At d 20, 40, and 60, the performance, oxidative stress, immune function, metabolism, and mycotoxin residues in eggs were determined. At d 60, mycotoxin residues in muscle and edible viscera were measured. Results showed the average daily feed intake (ADFI) and laying performance of laying hens were decreased with moldy corn treatments. All the moldy corn treatments also induced significant oxidative stress and immunosuppression, reflected by decreased antioxidase activities, contents of cytokines, immunoglobulins, and increased malonaldehyde level. Moreover, the activities of aspartate aminotransferase and alanine transaminase were increased by moldy corn treatments. The lipid metabolism was influenced in laying hens receiving moldy corn, reflected by lowered levels of total protein, high density lipoprotein cholesterol, low density lipoprotein cholesterol, total cholesterol, and increased total triglyceride as well as uric acid. The above impairments were aggravated with the increase of mycotoxin levels. Furthermore, AFB1 and ZEN residues were found in eggs, muscle, and edible viscera with moldy corn treatments, but the residues were below the maximum residue limits. In conclusion, moldy corn impaired the performance, antioxidant capacity, immune function, liver function, and metabolism of laying hens at d 20, 40, and 60. Moldy corn also led to AFB1 residue in eggs at d 20, 40, and 60, and led to both AFB1 and ZEN residues in eggs at days 40 and 60, and in muscle and edible viscera at d 60. The toxic effects and mycotoxin residues were elevated with the increase of moldy corn levels in feed.

Development of High-Throughput Sample Preparation Procedures for the Quantitative Determination of Aflatoxins in Biological Matrices of Chickens and Cattle Using UHPLC-MS/MS

Aflatoxins (AFs) frequently contaminate food and animal feeds, especially in (sub) tropical countries. If animals consume contaminated feeds, AFs (mainly aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2) and their major metabolites aflatoxin M1 (AFM1) and M2 (AFM2)) can be transferred to edible tissues and products, such as eggs, liver and muscle tissue and milk, which ultimately can reach the human food chain. Currently, the European Union has established a maximum level for AFM1 in milk (0.05 µg kg-1). Dietary adsorbents, such as bentonite clay, have been used to reduce AFs exposure in animal husbandry and carry over to edible tissues and products. To investigate the efficacy of adding bentonite clay to animal diets in reducing the concentration of AFB1, AFB2, AFG1, AFG2, and the metabolites AFM1 and AFM2 in animal-derived foods (chicken muscle and liver, eggs, and cattle milk), chicken and cattle plasma and cattle ruminal fluid, a sensitive and selective ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed. High-throughput sample preparation procedures were optimized, allowing the analysis of 96 samples per analytical batch and consisted of a liquid extraction using 1% formic acid in acetonitrile, followed by a further clean-up using QuEChERS (muscle tissue), QuEChERS in combination with Oasis® Ostro (liver tissue), Oasis® Ostro (egg, plasma), and Oasis® PRiME HLB (milk, ruminal fluid). The different procedures were validated in accordance with European guidelines. As a proof-of-concept, the final methods were used to successfully determine AFs concentrations in chicken and cattle samples collected during feeding trials for efficacy and safety evaluation of mycotoxin detoxifiers to protect against AFs as well as their carry-over to animal products.

Cellular immune response after vaccination with Salmonella Gallinarum 9R in laying hens and addition of aflatoxin and absorbent in the feed

Salmonella Gallinarum greatly impacts commercial flocks and vaccination with S. Gallinarum 9R (SG9R) is one of the most effective control strategies in some countries. However, mycotoxins can affect immunization success. Herein, we measured the cellular immune response in SG9R-vaccinated hens, quantified the impact of aflatoxins on the immune response, and determined whether the anti-mycotoxin additive (adsorbent) influences immunity after vaccination. One-day-old chicks of commercial laying hens were raised until 49 days of age and were assigned to six groups. T1 (control group): control diet (no detectable concentration of aflatoxin), no vaccine or adsorbent. T2: vaccine SG-9R at day 28, aflatoxins 2.5 ppm from day 1 to day 49, and adsorbent 2.5 Kg/ton. T3: control diet and vaccine. T4: aflatoxins and vaccine. T5: control diet and aflatoxins. T6: aflatoxins and adsorbent. Body weights were evaluated on days 1, 31, and 41. Cellular immune response was evaluated by flow cytometry at 31, 41, and 49 days of age. T lymphocytes, B lymphocytes, monocytes, phagocytic monocytes and heterophils were evaluated. Aflatoxins suppressed peripheral and mucosal helper T lymphocytes, and mucosal cytotoxic T lymphocytes in vaccinated birds (T2 and T4). However, inclusion of the adsorbent in the feed of vaccinated birds neutralized the effects of aflatoxin (T6). The concentration of immune cells may show differences after SG9R vaccination, particularly an increase in the monocyte concentration. The SG9R vaccine reduced the concentration of activated cytotoxic T lymphocytes, making this marker a good parameter to analyze before and three weeks after immunization.

Occurrence of Aflatoxins in Poultry Feed in Selected Chicken Rearing Villages of Bishoftu Ethiopia

Background

Aflatoxins (AFs) are major contaminants of feed used in the poultry industry that negatively affect animal and human health. In Ethiopia, previous studies on AFs mainly considered cattle feed and milk but scarce information exists for poultry feeds.

Methods

The aim of this study was to determine the occurrence of AFs in poultry feed in selected chicken rearing villages of Bishoftu. The study was conducted from December 2018 to May 2019. Thirty-three compound poultry feed samples were collected and analyzed for aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2) and total AFs (AFT) using high performance liquid chromatography (HPLC). The moisture content of the samples was also determined.

Results

The result indicated that 31 (94%) from a total of 33 samples were contaminated with AFs. The mean levels of AFB1, AFB2, AFG1, AFG2 and AFT were 70.11 µg/kg, 13.50 µg/kg, 88.55 µg/kg, 18.00 µg/kg and 190.18 µg/kg, respectively. This study found AFs at a level above the limit of FDA regulatory levels of 20 µg/kg in 25 (72.75%) samples for AFT and 22 (66.67%) samples for AFB1. The analysis of moisture content of the samples, ranges from 7.33% to 11.17%, indicating all were at optimal value (<12%).

Conclusion

The study showed the high contamination of AFs in poultry feeds with optimal moisture content and hence further investigations are needed to address the cause. The study also supports the need for preventive strategies of AFs contamination in poultry feeds in Bishoftu.

Assessment of mycotoxins (deoxynivalenol, zearalenone, aflatoxin B1 and fumonisin B1) in hen's eggs in Jordan

The present study was carried out to evaluate the prevalence of mycotoxins (Deoxynivalenol (DON), Zearalenone (ZEA), Aflatoxin B₁ (AFB₁) and Fumonisin B₁ (FB₁)) in local hen's table eggs (white and yolk) as well as their stability upon refrigeration. Two hundred and fifty of fresh table eggs samples collected from Jordan governorates were analyzed using Liquid Chromatography- Mass Spectrophotometry (LC– MS/MS) More than half (67%) of the tested samples were positive for mycotoxins. The mean concentration of AFB_1, FB₁ and ZEA was 0.5 ± 0.4, 0.5 ± 0.2 and 3.2 ± 1.5 μg/kg, respectively. The overall prevalence of AFB₁, ZEA, FB₁ was 56.8, 16.0 and 7.6%, respectively. DON was not found in any of the samples. The highest prevalence was observed in Amman (85.7%) followed by Mafraq (78.6%), Karak (75.0%) and Zarqa'a (66.6%). None of the investigated mycotoxins were detected in egg whites. However, the prevalence of AFB₁, ZEA, FB₁ in egg yolk was 21.3, 16 and 7.6%, respectively. Refrigeration up to 4 weeks did not decrease the mycotoxin concentration significantly. Mycotoxin concentration in all investigated samples in this study were well below both the International and Jordanian acceptable limits. However, continuous exposure may lead to bioaccumulation over a long term and pose a threat to health.

Aflatoxin B1 in the egg chain: monitoring with specific indirect competitive ELISA in northern Paraná, Brazil

An indirect competitive immunoassay (ic-ELISA) was developed using monoclonal antibody produced by hybridoma AF4, which showed high specificity and reactivity with aflatoxin B1 (AFB1) and aflatoxicol, but low cross-reactivity to other analogs. This low cost reliable method was applied for AFB1 monitoring in the poultry chain of a high agribusiness potential region (northern Paraná state, Brazil). Maize, laying hens feed and egg samples were collected from two poultry farms (with production above 200,000 eggs/day) and evaluated by intralaboratory validated ic-ELISA. The sensitivity of such a validated assay, detecting picogram levels of aflatoxins, demonstrated to be proper for surveying daily ingested cumulative toxins and estimating risks. Additionally, more than 61.00% of positive egg samples ranged between the limit of quantification (LOQ – 0.035 ng/g) and 1.00 ng/g, values commonly not covered by commercial kits. Positive data (>LOQ) occurred in 22 maize (56.40%), 34 feed (85.00%) and 192 (48.00%) egg samples. Mean contamination in maize was 1.51±0.94 ng/g (range 0.11-3.91 ng/g), 1.26±0.96 ng/g in feed (0.10-3.58 ng/g), and 1.01±0.77 ng/g in egg (0.05-3.85 ng/g). No statistical difference was observed between farms (P>0.05) for any of the matrices analysed. However, the difference between median values in maize (0.98 ng/g – Farm A; 1.76 ng/g – Farm B) indicated a higher contamination trend in farm B, possibly due to inadequate local storage. Although there is no limit stipulated for AFB1 contamination in eggs, the levels detected in samples were low and do not represent an immediate risk to animal production or human consumption. Nevertheless, the high frequency of positive maize and feed samples in this field of agribusiness should be highlighted. Sensitive aflatoxin monitoring procedures must be strategically carried out from raw materials to animal derived products, aiming harmless production, which also assures human health.

Prevalence, level and health risk assessment of mycotoxins in the fried poultry eggs from Jordan

In the current study, level and prevalence of deoxynivalenol (DON), aflatoxin B1 (AFB1), zearalenone (ZEN), and ochratoxin A (OTA) in fried poultry eggs in Jordan was investigated. Poultry egg samples (n = 250) were collected from March to September 2017. The level of DON, AFB1, ZEN and OTA in the white and yolk of poultry eggs was measured using LC-MS-MS. The health risk assessment was calculated using Margin of Exposures (MOEs) for AFB1 and OTA and hazard index (HI) for ZEN and DON. The highest prevalence in yolk and white of eggs was related to ZEN (96.56 %) and OTA (97.44 %), respectively. Also, the highest level in white and yolk was related to DON (1.07 μg/kg) and DON (1.65 μg/kg), respectively. Level of DON in the yolk of eggs was significantly higher than white of eggs (P-value < 0.05). Risk assessment indicated that exposed population are at high risk of AFB1 (MOEs < 10,000) in fried poultry eggs.

The Protective Role of Selenium Against AFB1-Induced Liver Apoptosis by Death Receptor Pathway in Broilers

Aflatoxin B1 (AFB₁) is the most toxic among the mycotoxins and causes detrimental health effects on the liver of human and animals. Selenium (Se) plays an important role in protection of various animal species against numerous notorious toxic agents. The present study is designed to explore the protective effects of Se against AFB₁-induced liver pathogenesis by the methods of histopathology, flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR), and biochemical analysis. A total of 312, 1-day-old healthy Cobb-500 broilers were randomly divided into four groups and fed with basal diet (control group), 0.6 mg/kg AFB₁ (AFB₁ group), 0.4 mg/kg Se (+ Se group), and 0.6 mg/kg AFB₁ + 0.4 mg/kg Se (AFB₁ + Se group) for 21 days, respectively. Our results showed that 0.4 mg/kg Se supplement in broiler's diets could alleviate the AFB₁-induced histological lesions in the liver. The apoptosis analysis by flow cytometry showed that 0.4 mg/kg Se ameliorated the AFB₁-induced apoptosis in the liver. Moreover, the mRNA expression levels of Fas, TNF-α, FAS-associated death domain, TNF receptor-associated death domain, TNF receptor-associated factor 2, caspase 10, caspase 8, B cell lymphoma 2, IκB kinase, X-linked inhibitor of apoptosis protein, caspase 9, and caspase 3 analyzed by qRT-PCR demonstrated that 0.4 mg/kg Se could relieve the impact caused by AFB₁ to these parameters. The biochemical analyses of activities of CAT, GSH-Px and SOD, hydroxyl ion scavenging and contents of MDA and GSH in liver cells also indicated that 0.4 mg/kg Se has positive effect on AFB₁-induced oxidative stress in the liver. In conclusion, Se could relieve AFB₁-induced apoptosis by the molecular regulation of death receptors pathway in the liver of broilers. The outcomes from the present study may lead to a better understanding of the nature of selenium's essentiality and its protective roles against AFB₁.

Protective and Detoxifying Effects Conferred by Dietary Selenium and Curcumin against AFB1-Mediated Toxicity in Livestock: A Review

Aflatoxin B1 (AFB1), among other aflatoxins of the aflatoxin family, is the most carcinogenic and hazardous mycotoxin to animals and human beings with very high potency leading to aflatoxicosis. Selenium is an essential trace mineral possessing powerful antioxidant functions. Selenium is widely reported as an effective antioxidant against aflatoxicosis. By preventing oxidative liver damage, suppressing pro-apoptotic proteins and improving immune status in AFB1 affected animals; selenium confers specific protection against AFB1 toxicity. Meticulous supplementation of animal feed by elemental selenium in the organic and inorganic forms has proven to be effective to ameliorate AFB1 toxicity. Curcumin is another dietary agent of importance in tackling aflatoxicosis. Curcumin is one of the major active ingredients in the tubers of a spice Curcuma longa L., a widely reported antioxidant, anticarcinogenic agent with reported protective potential against aflatoxin-mediated liver damage. Curcumin restricts the aflatoxigenic potential of Aspergillusflavus. Curcumin inhibits cytochrome P450 isoenzymes, particularly CYP2A6 isoform; thereby reducing the formation of AFB1-8, 9-epoxide and other toxic metabolites causing aflatoxicosis. In this review, we have briefly reviewed important aflatoxicosis symptoms among animals. With the main focus on curcumin and selenium, we have reviewed their underlying protective mechanisms in different animals along with their extraction and production methods for feed applications.

Validation of a liquid chromatography/tandem mass spectrometry method for the detection of aflatoxin B1 residues in broiler liver

Aflatoxin B₁ is a carcinogenic and mutagenic mycotoxin produced mainly by Aspergillus flavus and Aspergillus parasiticus. It is the predominant mycotoxin found in raw materials used for the manufacture of broiler feeds. The aim of the present study was to develop a new and optimized method for the detection and quantification of aflatoxin B₁ (AFB₁) residues in broiler liver using solid phase extraction (SPE) clean-up and liquid chromatography-electrospray ionization/tandem mass spectrometry (LC-ESI-MS/MS) detection. The method was validated for linearity, accuracy, precision, limit of detection (LOD) and limit of quantification (LOQ). The validation parameters indicated satisfactory linearity (r²>0.99), accuracy and precision (4.57% intra-day RSD; 14.65% inter-day RSD) a very high recovery (99±13%) and high sensitivity achieved for AFB₁ in animal samples (LOD=0.017 and LOQ=0.050ng/g). The method was effective for the detection and quantification of AFB₁ residues in broiler liver and could also be potentially used for detecting AFB₁ in other edible animal tissues after natural or experimental AFB₁ exposure with high sensitivity and precision.

Kinetics of aflatoxin degradation during peanut roasting

This study investigated aflatoxin degradation during peanut roasting. First, peanuts contaminated with three initial aflatoxin concentrations (35, 332 and 695μg/kg) were roasted at 180°C for up to 20min. The percentage of aflatoxin degradation after 20min were 55, 64 and 81% for peanuts contaminated with aflatoxin at 35, 332 and 695μg/kg, respectively. This difference was statistically significant (p<0.05), showing that initial concentration influences aflatoxin reduction. Thereafter, peanut samples contaminated with an initial aflatoxin concentration of 85μg/kg were roasted at 160, 180 and 200°C for 5, 10, 15, 20 and 25min, then residual concentrations of aflatoxin were determined. Roasting at 160, 180 and 200°C resulted in an aflatoxin reduction of 61.6, 83.6 and 89.7%, respectively. This study has provided quantitative data reinforcing the fact that roasting alone is not enough to control aflatoxins in peanuts.

The toxic effects of combined aflatoxins and zearalenone in naturally contaminated diets on laying performance, egg quality and mycotoxins residues in eggs of layers and the protective effect of Bacillus subtilis biodegradation product

The toxic effect of aflatoxins (AF) and zearalenone (ZEA) and their combination on laying performance, egg quality and toxins residues in eggs, as well as the efficacy of Bacillus subtilis biodegradation product (BDP) for ameliorating these effects in layers were evaluated. Layers were submitted to a two phase experiment. The first phase was an intoxication period (18-23 wk) with birds fed 7 (3 × 2 + 1) diets (3 treatments with mycotoxins: AF (123.0 μg/kg), ZEA (260.2 μg/kg), or AF + ZEA (123.0 + 260.2 μg/kg); 2 treatments with or without BDP (1000 g/t); and a control group contained no toxins nor BDP). The next phase was a recovery period (24-29 wk) in which birds were fed a toxin-free diet. In the intoxication period, AF and AF + ZEA groups exhibited lower egg production, feed intake and shell thickness, and higher AFB1, AFB2 and AFM1 residues as compared with the control group. In addition, AF and ZEA exerted synergistic effects on egg production and feed intake. Moreover, AF alone or combined with ZEA had a continuous toxic effect on laying performance in the recovery phase. Addition of BDP offset these negative effects, showing that BDP has a protective effect on layers fed contaminated diets.

Hepatic Transcriptome Responses of Domesticated and Wild Turkey Embryos to Aflatoxin B₁

The mycotoxin, aflatoxin B₁ (AFB₁) is a hepatotoxic, immunotoxic, and mutagenic contaminant of food and animal feeds. In poultry, AFB₁ can be maternally transferred to embryonated eggs, affecting development, viability and performance after hatch. Domesticated turkeys (Meleagris gallopavo) are especially sensitive to aflatoxicosis, while Eastern wild turkeys (M. g. silvestris) are likely more resistant. In ovo exposure provided a controlled AFB₁ challenge and comparison of domesticated and wild turkeys. Gene expression responses to AFB₁ in the embryonic hepatic transcriptome were examined using RNA-sequencing (RNA-seq). Eggs were injected with AFB₁ (1 μg) or sham control and dissected for liver tissue after 1 day or 5 days of exposure. Libraries from domesticated turkey (n = 24) and wild turkey (n = 15) produced 89.2 Gb of sequence. Approximately 670 M reads were mapped to a turkey gene set. Differential expression analysis identified 1535 significant genes with |log₂ fold change| ≥ 1.0 in at least one pair-wise comparison. AFB₁ effects were dependent on exposure time and turkey type, occurred more rapidly in domesticated turkeys, and led to notable up-regulation in cell cycle regulators, NRF2-mediated response genes and coagulation factors. Further investigation of NRF2-response genes may identify targets to improve poultry resistance.

A simple sample pretreatment method for multi-mycotoxin determination in eggs by liquid chromatography tandem mass spectrometry

In this study, a reliable and fast method using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction procedure without any clean-up step was developed for simultaneous extraction of 15 mycotoxins, i.e., aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, aflatoxin M1, aflatoxin M2, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, de-epoxy-DON, zearalenone, α-zearalenol, β-zearalenol, α-zearalanol, and β-zearalanol, from eggs. High-performance liquid chromatography tandem mass spectrometry was used to separate and detect all of the analytes. Electrospray ionization at both negative and positive modes and multiple reaction-monitoring mode were applied to detect these analytes. The main factors, such as extraction time, extraction solvent, evaporation temperature, and pH of the solvent, were carefully optimized to improve the extraction efficiency. The coefficients of determination of the calibration curves ranged from 0.9884 to 0.9998. The recoveries of most of the analytes were between 71.3% and 105.4% at three concentration levels, except for AFB1 that showed recovery rates of not more than 67.5% in all concentrations. The repeatability and intra-lab reproducibility of this method were both lower than 15% and 25%, respectively. The limit of quantification ranged from 0.2 μg/kg to 5 μg/kg. The matrix effect was evaluated and reduced by the use of matrix-matched calibration curves. The validated method was applied in a pilot study to analyze mycotoxin contamination in 12 eggs, and trace amounts of deoxynivalenol, 15-acetyldeoxynivalenol, aflatoxin B1, aflatoxin G2, zearalenone and β-zearalenol were detected in these samples.

Aflatoxin B1 in eggs and chicken livers by dispersive liquid-liquid microextraction and HPLC

A rapid, low-cost and simple technique has been developed for the determination of aflatoxin B1 (AFB1) in eggs and livers using high-performance liquid chromatography (HPLC) with UV detection. In this study, the presence of AFB1 was investigated in 150 eggs and 50 chicken livers from the local market of Tabriz, Iran. AFB1 was extracted with a mixture of acetonitrile:water (80:20) and cleaned up by dispersive liquid-liquid microextraction which is a very economical, fast and sensitive method. AFB1 was quantified by HPLC-UV without need for any complex derivatisation in samples to enhance the detection. The results showed that 72% of the liver and 58% of the egg samples were contaminated with AFB1 ranging from 0.30 to 16.36 µg kg (̶1). limit of detection and limit of quantification for AFB1 were 0.08 and 0.28 µg kg (̶ 1), respectively. The proposed method is suitable for fast analysing of AFB1 in egg and liver samples.

Role of Adhatoda vasica (L.) Nees leaf extract in the prevention of aflatoxin-induced toxicity in Wistar rats

BACKGROUND

Aflatoxin contamination of various foodstuffs and agricultural commodities is a major problem worldwide. Several strategies have been reported for the detoxification of aflatoxins in contaminated foods and feeds, but all these methods have their own shortcomings. Traditional medicinal plants are potential sources of aflatoxin-detoxifying compounds. In this study a spray-dried formulation of Adhatoda vasica (L.) Nees leaf extract was prepared and its chemopreventive effect on aflatoxin B1 (AFB1)-induced biochemical changes in the liver and serum of Wistar rats was investigated.

RESULTS

Administration of AFB1 (1.5 mg kg(-1) body weight (BW) intraperitoneally) to rats significantly reduced the activities of superoxide dismutase and catalase in liver tissues and increased the activities of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase and the levels of very-low-density lipoprotein, low-density lipoprotein and cholesterol in blood serum. However, pre-feeding of rats with A. vasica formulation (500 mg kg(-1) BW for 7 days) protected the animals from AFB1-induced biochemical changes during subsequent exposure to AFB1.

CONCLUSION

Pre-feeding of rats with A. vasica formulation counteracted the hepatic dysfunction induced by subsequent treatment with AFB1. This formulated A. vasica extract offers a biologically safe alternative to detoxify aflatoxin and has huge potential to be used in the poultry industry to reduce aflatoxicosis.

Assessment of aflatoxin contamination of maize, peanut meal and poultry feed mixtures from different agroecological zones in Cameroon

Mycotoxins affect poultry production by being present in the feed and directly causing a negative impact on bird performance. Carry-over rates of mycotoxins in animal products are, in general, small (except for aflatoxins in milk and eggs) therefore representing a small source of mycotoxins for humans. Mycotoxins present directly in human food represent a much higher risk. The contamination of poultry feed by aflatoxins was determined as a first assessment of this risk in Cameroon. A total of 201 samples of maize, peanut meal, broiler and layer feeds were collected directly at poultry farms, poultry production sites and poultry feed dealers in three agroecological zones (AEZs) of Cameroon and analyzed for moisture content and aflatoxin levels. The results indicate that the mean of the moisture content of maize (14.1%) was significantly (P < 0.05) higher than all other commodities (10.0%–12.7%). Approximately 9% of maize samples were positive for aflatoxin, with concentrations overall ranging from <2 to 42 µg/kg. Most of the samples of peanut meal (100%), broiler (93.3%) and layer feeds (83.0%) were positive with concentrations of positive samples ranging from 39 to 950 µg/kg for peanut meal, 2 to 52 µg/kg for broiler feed and 2 to 23 µg/kg for layer feed. The aflatoxin content of layer feed did not vary by AEZ, while the highest (16.8 µg/kg) and the lowest (8.2 µg/kg) aflatoxin content of broiler feed were respectively recorded in Western High Plateau and in Rainforest agroecological zones. These results suggest that peanut meal is likely to be a high risk feed, and further investigation is needed to guide promotion of safe feeds for poultry in Cameroon.

Mycotoxin-contaminated diets and deactivating compound in laying hens: 1. effects on performance characteristics and relative organ weight

The current experiment was conducted to determine the effect of mycotoxin-contaminated diets with aflatoxin (AFLA) and deoxynivalenol (DON) and dietary inclusion of deactivation compound on layer hen performance during a 10-wk trial. The experimental design consisted of a 4 × 2 factorial with 4 toxin levels: control, low (0.5 mg/kg AFLA + 1.0 mg/kg DON), medium (1.5 mg/kg AFLA + 1.5 mg/kg DON), and high (2.0 mg/kg AFLA + 2.0 mg/kg DON) with or without the inclusion of deactivation compound. Three hundred eighty-four 25-wk-old laying hens were randomly assigned to 1 of the 8 treatment groups. Birds were fed contaminated diets for a 6-wk phase of toxin administration followed by a 4-wk recovery phase, when all birds were fed mycotoxin-free diets. Twelve hens from each treatment were subjected to necropsy following each phase. Relative liver and kidney weights were increased (P < 0.05) at the medium and high toxin levels following the toxin phase, but the deactivation compound reduced (P < 0.05) relative liver and kidney weights following the recovery period. The high toxin level decreased (P < 0.05) feed consumption and egg production during the toxin period, whereas the deactivation compound increased (P < 0.05) egg production during the first 2 wk of the toxin phase. Egg weights were reduced (P < 0.05) in hens fed medium and high levels of toxin. An interaction existed between toxin level and deactivation compound inclusion with regard to feed conversion (g of feed/g of egg). High inclusion level of toxins increased feed conversion compared with the control diet, whereas deactivation compound inclusion reduced feed conversion to a level comparable with the control. These data indicate that deactivation compound can reduce or eliminate adverse effects of mycotoxicoses in peak-performing laying hens.

Effects of individual and combined administration of ochratoxin A and aflatoxin B1 in tissues and eggs of White Leghorn breeder hens

BACKGROUND

Mycotoxins, the secondary fungal metabolites, are unavoidable contaminants of human and animal food and feeds. The objectives of this study were to evaluate the effect of concurrent feeding of ochratoxin A (OTA) and aflatoxin B(1) (AFB(1) ) to breeder hens, upon their deposition in different tissues and eggs.

RESULTS

Residues of OTA and AFB(1) in (ng g(-1) ) were significantly higher in liver followed by kidneys and breast muscles by 22.54 ± 1.48, 4.22 ± 0.93 and 0.56 ± 0.06 for OTA (group fed OTA at 5 mg kg(-1) diet) and 1.44 ± 0.21, 0.25 ± 0.01 and 0.03 ± 0.01 for AFB(1) (group fed AFB(1) at 5 mg kg(-1) diet), respectively. Residues of OTA and AFB(1) in eggs appeared at days 3 and 5 of toxin feeding and disappeared at days 5 and 6 of withdrawal of mycotoxins contaminated feed, respectively. The residues of OTA and AFB(1) were significantly lower in the tissues of hens fed these toxins concurrently compared with the groups fed OTA and AFB(1) independently.

CONCLUSIONS

Residues of OTA and AFB(1) appeared in the tissues and eggs of laying hens kept on OTA- and AFB(1) -contaminated diets. Concurrent feeding of OTA and AFB(1) to hens significantly decreased the concentration of OTA and AFB(1) residues in the tissues and eggs.

Effect of low levels of aflatoxin B₁ on performance, biochemical parameters, and aflatoxin B₁ in broiler liver tissues in the presence of monensin and sodium bentonite

Aflatoxins (AF) are a major problem in broiler production and are significant economic and public health burdens worldwide. A commercial sodium bentonite (Na-B) adsorbent was used to prevent the effect of AF [50 µg of aflatoxin B₁ (AFB₁)/kg of feed] in broiler productivity, biochemical parameters, macroscopic and microscopic liver changes, and AFB₁ liver residues. The influence of Na-B (0.3%) and monensin (MON, 100 mg/kg), alone or in combination, was investigated in depth. The dietary treatments were as follows: treatment (T) 1: basal diet (B); T2: B + MON; T3: B + Na-B; T4: B + Na-B + MON; T5: B + AFB₁; T6: B + AFB₁ + Na-B + MON; T7: B + AFB₁ + MON; T8: B + AFB₁ + Na-B. Birds were fed dietary treatments for 28 d (d 18 to 46). No significant differences (P < 0.05) were observed among treatments with respect to broiler performance, biochemical parameters, or relative liver weights. With the exception of T8, all livers showed histopathological alterations, with accumulation of fat vacuoles. The normal appearance of livers from T8 showed the protective effect of Na-B against aflatoxicosis. The residual AFB₁ levels in livers from T5 to T8 ranged from 0.2 to 1.0 ng/g and were higher in livers from T6 (P < 0.05). Results of this study indicate a competition between AFB₁ and MON for adsorption sites on Na-B when feed contains low levels of the toxin, indicating a nonselective adsorption capacity of this particular Na-B. In addition, significant levels of AFB₁ in livers indicate that this determination is an important technique not only for diagnosis of aflatoxicosis in broilers, but also for quality control of avian products.

Identification and quantification of aflatoxins and aflatoxicol from poultry feed and their recovery in poultry litter

Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to animals and humans. Poultry litter is frequently used as a food supplement for ruminants, and when poultry feed contains AF, the litter becomes contaminated as well, thus having an effect on livestock health. This study identified and quantified AF (AFB(1), AFB(2), AFG(1), and AFG(2)) from poultry feed and their recovery, together with their metabolites (AFM(1), AFM(2), AFP(1), and aflatoxicol) in litter. An experiment with 25 Hy-Line W-36 hens, in their second production stage, 121 wk old, was carried out. Hens were distributed in 3 groups placed in individual cages and 1 ration of 250 g of feed was given to each hen daily. Nine hens of the control group were fed with clean feed, without AFB(1); the other 2 experimental groups, with 8 hens each, were fed with 2 AFB(1) concentrations: 30 and 500 microg.kg(-1). The feed was replaced and weighed daily throughout a 7-d period to register the amount of feed consumed by the hens. Litter from each hen was collected, weighed, and dried individually. The chemical analysis of 40 g of each one of the 200 feed and 200 litter samples was chemically extracted and concentrated with immunoaffinity columns for total AF. To quantify AF, calibration curves for each AF were done by HPLC. Feed samples of the 3 groups presented significant difference with AFB(2) and AFG(2), whereas in litter samples, there were significant differences for AFG(2) in the 500 microg.kg(-1) group. Poultry litter had traces of AFM(1), AFM(2), AFP(1), and AFL with no significant differences among treatments. Aflatoxin B(1) prevalence in litter samples can cause damages in livestock because this mycotoxin reduces the digestibility of ruminant feed up to 67%.

Effects of dietary AflaDetox on performance, serum biochemistry, histopathological changes, and aflatoxin residues in broilers exposed to aflatoxin B(1)

The aim of this study was to evaluate the ability of AflaDetox (Adiveter, Agro-Reus, Reus, Tarragona, Spain) in counteracting the deleterious effects of aflatoxin B(1) (AFB(1)) in broiler chicks. A total of 120 Ross 308 one-day-old male broiler chicks were assigned to 8 treatments for 42 d. The experiment had a 2 x 4 factorial arrangement of treatments involving 0 and 1 mg of AFB(1)/kg feed and 0, 1, 2, and 5 g of AflaDetox/kg feed. Chicks were fed on the ground during the first 7 d and in cages (3 chicks/cage; 5 cages/treatment) from 7 to 42 d. Growth performance was measured from d 7 to 42 and whole-tract digestibility of gross energy and protein on d 40 to 41. Serum biochemical parameters, organ weights, histopathological examination of liver, and AFB(1) residues in liver and breast muscle tissues were determined on d 42. Aflatoxin B(1) significantly decreased the BW gain, feed intake, and impaired feed conversion rate (P < 0.05). The addition of AflaDetox in the contaminated diets significantly diminished the inhibitory effects of dietary AFB(1) (P < 0.05) on the growth performance with no differences compared to the control diet. Feeding AFB(1) alone decreased serum protein concentration, increased the serum activity of alkaline phosphatase, and caused significant increases in the relative weights of livers. Treatment with AflaDetox significantly alleviated the negative effects of AFB(1) on these parameters (P < 0.05) with no effect on uncontaminated diets. Liver tissue of broilers receiving AFB(1) alone had perilobular inflammation and vacuolar degeneration of hepatocytes as compared with the tissue from the control group (P < 0.05). Residues of AFB(1) were detected in the liver tissues of broilers fed on the AFB(1) diet (0.166 microg/kg). Supplementation of AflaDetox reduced the incidence and severity of the hepatic histopathology changes associated with aflatoxicosis and the amount of AFB(1) residue in liver. In conclusion, our results showed that addition of AflaDetox may reduce the adverse effects produced by the presence of AFB(1) in broiler chickens diets.

An overview of conventional and emerging analytical methods for the determination of mycotoxins

Mycotoxins are a group of compounds produced by various fungi and excreted into the matrices on which they grow, often food intended for human consumption or animal feed. The high toxicity and carcinogenicity of these compounds and their ability to cause various pathological conditions has led to widespread screening of foods and feeds potentially polluted with them. Maximum permissible levels in different matrices have also been established for some toxins. As these are quite low, analytical methods for determination of mycotoxins have to be both sensitive and specific. In addition, an appropriate sample preparation and pre-concentration method is needed to isolate analytes from rather complicated samples. In this article, an overview of methods for analysis and sample preparation published in the last ten years is given for the most often encountered mycotoxins in different samples, mainly in food. Special emphasis is on liquid chromatography with fluorescence and mass spectrometric detection, while in the field of sample preparation various solid-phase extraction approaches are discussed. However, an overview of other analytical and sample preparation methods less often used is also given. Finally, different matrices where mycotoxins have to be determined are discussed with the emphasis on their specific characteristics important for the analysis (human food and beverages, animal feed, biological samples, environmental samples). Various issues important for accurate qualitative and quantitative analyses are critically discussed: sampling and choice of representative sample, sample preparation and possible bias associated with it, specificity of the analytical method and critical evaluation of results.

Mannanoligosaccharides and aflatoxin B1 in feed for laying hens: effects on egg quality, aflatoxins B1 and M1 residues in eggs, and aflatoxin B1 levels in liver

Ninety-six laying hens were allocated to 4 groups and fed diets (control diet (0-0), diet supplemented with 2.5 ppm aflatoxin B1 (0-AF); diet supplemented with 0.11% mannanoligosaccharide (MOS-0); diet supplemented with 0.11% MOS and 2.5 ppm aflatoxin B1 (MOS-AF) for 4 wk to evaluate the effect of aflatoxin B1 (AFB1), mannanoligosaccharide (MOS), or both on egg quality and the in vivo efficacy of MOS to interact with an oral administration of AFB1. After 2 and 3 wk, egg weight decreased (P < 0.05) in the group fed MOS-0 versus groups on 0-0 and 0-AF. Egg shell weight was lower (P < 0.05) in the group fed 0-AF. Aflatoxin influenced color parameters, which were probably related to interference of AFB1 with lipid metabolism and pigmentary substances deposition in yolk. MOS appeared to increase protein percentage in albumen. No AFB1 or aflatoxin M1 (AFM1; a polar metabolite of AFB1) residues were found in eggs of the experimental groups. Livers from groups 0-0 and MOS-0 always tested negative for AFB1 and AFM1. Differences (P < 0.01) were found between AFB1 hepatic levels of group 0-AF (mean +/- SD: 4.13 +/- 1.95 ppb) and group MOS-AF (mean +/- SD: 2.21 +/- 1.37 ppb). The data demonstrated the ability of MOS to adsorb and degrade AFB1, reducing gastrointestinal absorption of AFB1 and its levels in tissues.

Toxicological effects of chronic low doses of aflatoxin B(1) and fumonisin B(1)-containing Fusarium moniliforme culture material in weaned piglets

The effects of chronic oral exposure (28 days) to aflatoxin B(1) (AFB(1)) and fumonisin B(1) (FB(1)) were studied in weaned piglets. Six experimental groups, each comprising two neutered males and two females, were fed ad libitum with rations containing: (A) 0 mg of FB(1) and 0 mg of AFB(1)/kg of feed (control); (B) 10 mg of FB(1)/kg of feed; (C) 30 mg of FB(1)/kg of feed; (D) 50 microg of AFB(1)/kg of feed; (E) 10 mg of FB(1) plus 50 microg of AFB(1)/kg of feed; (F) 30 mg of FB(1) plus 50 microg of AFB(1)/kg of feed. The animals were inspected twice daily and their body weight and feed consumption were recorded weekly and daily, respectively. Samples of feces and urine were collected 24 h after the start of the experiment, to check for fumonisin residues by HPLC analysis. Blood samples were drawn at the start of the experiment and after 28 days for quantification of hematological and biochemical parameters. Necropsies were performed after 28 days; at necropsy, the organs were weighed, inspected macroscopically and processed for histopathological and toxicological analyses. All piglets from groups C and F presented typical signs of pulmonary edema, with reduced feed consumption and body weight gain as well as pathological alterations. FB(1) was detected in feces and urine at 24 h of intoxication and in liver after 28 days of intoxication. Increases were detected regarding the following hematological and biochemical parameters in animals from treatments C and F: erythrocyte number; hematocrit; total bilirubin; total protein; activity of serum alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase. Cholesterol levels were significantly aumented only in animals from groups C and F, whereas albumin concentrations increased in groups C, F, B and E. The average organ/body weight ratio of piglets (hearth, liver and lung) were significantly greater in groups C and F. The only joint effects of FB(1) and AFB(1) detected (group F) were a decrease in feed consumption during the last week of intoxication and in feed conversion throughout the 28 days of intoxication. Chronic intoxication of piglets with AFB(1) and FB(1) leads to important losses of productivity.

Aflatoxin residues in eggs of laying Japanese quail after long-term administration of rations containing low levels of aflatoxin B1

The aim was to evaluate the excretion of residues of aflatoxin B(1) (AFB(1)), aflatoxin M(1) (AFM(1)), aflatoxin B(2a) (AFB(2a)) and aflatoxicol (AFL) in eggs of laying Japanese quail fed rations with low levels of aflatoxin B(1) for 90 days. The quail were randomly assigned into four experimental groups and given prepared rations containing either 0 (controls), 25, 50 or 100 microg AFB(1) kg(-1) feed. Thirty-two eggs per treatment were collected on days 1-7, 10, 20, 30, 60 and 90 of the aflatoxin treatment period, and submitted to aflatoxin analysis by high-performance liquid chromatography. Average egg production and feed consumption were not affected ( p > 0.05) by AFB(1). Egg weight was significantly lower ( p<0.05) only for groups exposed to 100 microg AFB(1) kg(-1). Residues of aflatoxins were detected in eggs at levels that ranged from 0.01 to 0.08 microg kg(-1) (AFB(1)), 0.03-0.37 microg kg(-1) (AFM(1)), 0.01-1.03 microg kg(-1)(AFB(2a)) and 0.01-0.03 microg kg(-1) (AFL). Results indicate that the excretion of aflatoxin residues in quail eggs might occur at relatively low concentrations under conditions of long-term exposure of quail to low levels of AFB(1).

Occurrence of aflatoxins in layer feed and corn samples in Konya province, Turkey

The natural occurrence of aflatoxin was investigated in layer feed and corn samples brought to Konya Veterinary Control and Research Institute Laboratory between 15 April and 15 December 2002. Seventy-eight samples (52 feeds, 26 corn samples) were analysed for total aflatoxin (B1 + B2 + G1 + G2) by an ELISA screening method. Aflatoxin contamination was deter-mined in 37 feed samples (71.1%) and 15 corn samples (57.7%), with a range of 1.5-133 microg kg(-1). However, a majority of the aflatoxin contamination was less than 5 microg kg(-1) (50% within the positive samples). Two feed samples and two corn samples exceeded the maximum tolerated levels in feed (20 microg kg(-1)) and feedstuffs (50 microg kg(-1)) for total flatoxin.

Aflatoxin B1 and clinoptilolite in feed for laying hens: effects on egg quality, mycotoxin residues in livers, and hepatic mixed-function oxygenase activities

Ninety-six laying hens were allocated to four groups administered different diets (group 0-0 received a complete diet, group 0-AF received a diet supplemented with 2.5 ppm of aflatoxin B1 [AFB1], group 2-0 received a diet supplemented with 2% clinoptilolite [CPL], and group 2-AF received a diet supplemented with 2% CPL and 2.5 ppm of AFB1) for 4 weeks to evaluate the effect of AFBI and/or CPL on egg quality and the ability of CPL to interact with the oral administration of AFB1. The possible effects of AFB1 on cytochrome P450-dependent hepatic mixed-function oxygenase (MFO) activities were also evaluated. Mycotoxin reduced yolk weight, while CPL influenced albumen percentage relative to that of eggs laid by chickens in group 0-AF Eggs laid by chickens in groups 0-AF and 2-AF had stronger shells and weighed less than the eggs of other groups. The eggs of treated groups were lighter in color than those of the control group (P < 0.01), and the tendency to yellowness in eggs was increased by CPL, probably through the affinity of red pigments for adsorbents and a consequent prevalence of yellow tonality. Color parameters might be connected with AFB1's interference with lipid metabolism and pigment deposition. The livers of hens in groups 0-AF and 2-AF showed very low mycotoxin concentrations that were significantly different (P < 0.01). The highest levels observed were those in the livers of the hens receiving the diet supplemented with the mycotoxin alone. AFB1 did not exert any significant effects on the hepatic MFO activities examined.

Residues of aflatoxins in the liver, muscle and eggs of domestic fowls

The residue of aflatoxins in the liver, muscle and eggs of laying ducks, hens and quails and in broiler chickens was examined by conducting 7-day feeding experiments with a diet containing 3 ppm Aflatoxin B1 (AFB1). Birds were sacrificed on the 8th or 11th day of AFB1 feeding. AFB1 and its metabolites in the tissues and eggs were determined by HPLC. The tissue levels of AFB1 and its metabolites were higher in quail than in the other birds. The levels of AFB1 and its metabolites, including acid-hydrolyzable metabolites, were more than 10-fold higher in the liver than in the muscle in all the species. The ratio of AFB1 in the feed to the residual level in the liver was 383 in quail, but was > or = 5769 in the other birds. The corresponding ratios in the egg yolk and albumen of AFB1 were 4615 and 3846, respectively, in chicken hens, and these values were higher than those in the other birds.