Different Levels Of Aflatoxin B1 Research Articles

The effects of probiotic-based additives on aflatoxin intoxication in Piaractus mesopotamicus: a study of liver histology and metabolic performance.

Mycotoxins, produced by fungi, can contaminate fish food and harm their health. Probiotics enhance immune balance and primarily function in the animal intestine. This study aimed to assess aflatoxin's impact on Piaractus mesopotamicus and explore probiotic-based additive (PBA) benefits in mitigating these effects, focusing on antioxidant activity, biochemical indices, and hepatic histopathology. Two experiments were conducted using P. mesopotamicus fry. The first experimental assay tested various levels of aflatoxin B1 (0.0, 25.0, 50.0, 100.0, 200.0, and 400.0µg kg-1) over a 10-day period. The second experimental assay examined the efficacy of the probiotic (supplemented at 0.20%) in diets with different levels of aflatoxin B1 (0.0, 25.0, and 400.0µg kg-1) for 15 days. At the end of each assay, the fish underwent a 24-hour fasting period, and the survival rate was recorded. Six liver specimens from each treatment group were randomly selected for metabolic indicator assays, including superoxide dismutase, catalase, alanine aminotransferase, aspartate aminotransferase, and albumin. Additionally, histopathological analysis was performed on six specimens. The initial study discovered that inclusion rates above 25.0µg kg-1 resulted in decreased activity of AST (aspartate aminotransferase), ALT (alanine aminotransferase), ALB (albumin), CAT (catalase), and SOD (superoxide dismutase), accompanied by liver histopathological lesions. In the second study, the inclusion of PBA in diets contaminated with AFB1 improved the activity of AST and ALT up to 25.0µg kg-1 of AFB1, with no histopathological lesions observed. The study demonstrated the hepatoprotective effects of PBA in diets contaminated with AFB1. The enzyme activity and hepatic histopathology were maintained, indicating a reduction in damage caused by high concentrations of AFB1 (400.0µg kg-1 of AFB1). The adverse effects of AFB1 on biochemical and histopathological parameters were observed from 25.0µg kg-1 onwards. Notably, PBA supplementation enhanced enzymatic activity at a concentration of 25µg kg-1 of AFB1 and mitigated the effects at 400.0µg kg-1 of AFB1. The use of PBAs in pacu diets is highly recommended as they effectively neutralize the toxic effects of AFB1 when added to diets containing 25.0µg kg-1 AFB1. Dietary inclusion of aflatoxin B1 at a concentration of 25.0µg kg-1 adversely affects the liver of Piaractus mesopotamicus (Pacu). However, the addition of a probiotic-based additive (PBA) to the diets containing this concentration of aflatoxin neutralized its toxic effects. Therefore, the study recommends the use of PBAs in Pacu diets to mitigate the adverse effects of aflatoxin contamination.

Effect of Different Levels of Aflatoxin B1 in Concentrated Livestock Diets on Some Characteristics of Rumen Fluid in Laboratory with Sodium Bentonite

This study was conducted in the nutrition laboratory of the Department of Animal Production in the College of Agricultural Engineering Sciences at the University of Baghdad, Al-Jadriya. The experiment lasted for 90 days to investigate the effects of adding sodium bentonite (SB) to a concentrated diet contaminated with aflatoxin B1 on some characteristics of rumen fluid in a laboratory setting. Four diets were prepared, each contaminated with different concentrations of aflatoxin B1 (0, 20, 40, 60 ppb), and four different percentages of sodium bentonite (0, 3, 5, 7%) were added to each ration. The results showed a significant increase in pH values among the different treatments, with the diet contaminated with 40 ppb aflatoxin B1 (T3) recording the highest acidity compared to the control treatment at 0% concentration. However, there were no significant differences in pH rates between the treatments. The pH rates of 7% sodium bentonite addition did not differ significantly from 5% and 0%, while 3% had the lowest pH rate. Regarding volatile fatty acids (VFA), there was a significant increase in their percentage with the increase in sodium bentonite concentrations. The second treatment contaminated with 20 ppb aflatoxin B1 recorded the highest VFA percentage among the treatments, while the fourth treatment (T4) at 0% concentration recorded the lowest VFA percentage. Significant differences in VFA percentages were observed among all the treatments, with the highest VFA percentage in T2, followed by T3 and T1, while T4 recorded the lowest percentage. The analysis of ammonia nitrogen values showed a significant increase among the different treatments, with T2 recording the highest value among the treatments, and T4 at 0% concentration recording the lowest ammonia nitrogen value. Significant differences in the average percentage of ammonia nitrogen were observed among all the experimental treatments, with the highest value in T2, followed by T1 and T3, while T4 recorded the lowest percentage. The total number of microorganisms showed a significant increase with the increase in sodium bentonite concentrations, with T2 at 7% concentration having the highest number of microorganisms, while T4 at 0% concentration recorded the lowest number. Significant differences in the average total number of microorganisms were observed among all the experimental treatments, with T2 having the highest number, followed by T1 and T3, while T4 had the lowest number.

Extraction and determination of aflatoxin B1 in cereal samples using pH-switchable hydrophobic deep eutectic solvents followed by HPLC-FL analysis.

A quick, simple and environmentally friendly liquid phase microextraction (LPME) sample pretreatment procedure was proposed based on pH-switchable hydrophobic deep eutectic solvents (HDESs) and high performance liquid chromatography coupled with a fluorescence detector (HPLC-FL). This method was used for the quantitative study of aflatoxin B1 (AFB1) and applied to eight widely consumed cereal samples. In this method, six different DESs were synthesized and then their pH-switchability was investigated. DESs that could be switched with pH were employed for separation and preconcentration of AFB1 in cereal samples. In this method, dispersing the extractant phase in the aqueous solution and subsequent phase separation are performed only by changing the pH. Important parameters affecting extraction, such as the type of DES and its volume, concentration of KOH, volume of HCL, effect of salt and extraction time were investigated and optimum conditions were obtained. Under the optimum conditions, relative standard deviation (RSD) values for intra-day and inter-day of the method based on seven replicate measurements of 5.0 μg kg-1 of AFB1 in cereal samples were 3.3 and 5.2%, respectively. The calibration graphs were linear in the range of 0.007-20 μg kg-1 and limit of detection (LOD) was 0.002 μg kg-1. The relative recoveries of real cereal samples which have been spiked with different levels of AFB1 were 90.8-107.5%.

Effects of Aflatoxin B1 on growth performance, carcass traits, organ index, blood biochemistry and oxidative status in Chinese yellow chickens.

In this study, the effects of different levels of aflatoxin B1 (AFB1) on the growth performance, carcass traits, organ index, blood biochemistry, and antioxidant capacity of yellow-feathered broilers were investigated to provide a reference for the application of AFB1-containing feed ingredients. In this test, yellow-feathered broilers were chosen as the research objects and divided into five treatment groups, with seven replicates in each group and 75 broilers in each replicate. The AFB1 concentration in the diets of groups 1 to 5 were 1.5 μg/kg, 15 μg/kg, 30 μg/kg, 45 μg/kg, and 60 μg/kg, respectively. The results showed that when dietary AFB1 levels were greater than 45 μg/kg, the feed conversion ratios of broilers of 1-21, 22-42, and 43-63 days of age increased (P<0.05). When dietary AFB1 levels were 30 μg/kg, liver glutathione peroxidase (GPx) activity was decreased (P<0.05), and serum transaminase (AST) activity was increased (P<0.05). Overall, dietary AFB1 levels had negative effects on growth performance, antioxidant capacity, blood biochemistry, and liver metabolism in yellow-feathered broilers. Based on using growth performance as the effect index, AFB1 levels in the diets of yellow-feathered broilers should not exceed 45 μg/kg. Based on using antioxidant capacity, liver function, and blood biochemistry as effect indexes, AFB1 levels in the diets of yellow-feathered broilers should not exceed 30 μg/kg.

Effects of Dietary Aflatoxin B1 on Hybrid Striped Bass (Morone chrysops × M. saxatilis) and Assessment of Supplemental Arginine as a Potential Aflatoxicosis Alleviator

Aflatoxin contamination of feeds poses a significant threat to aquaculture. This six-week study was conducted to evaluate the impact of aflatoxin B1 (AFB1) in diets with and without supplemental arginine (Arg) on the production performance, somatic indices, body composition, and immune responses of hybrid striped bass (HSB). Six experimental diets were formulated to contain different levels of AFB1 (0, 1, or 2 mg/kg) and supplemental Arg (0 or 2%) following a 3 × 2 factorial arrangement. Triplicate groups of HSB (~5.44 g/fish) stocked in 18 glass aquaria were randomly assigned each diet and fed at a rate approaching apparent satiation twice daily. At the conclusion of the feeding trial, no interactions among dietary AFB1 and Arg were found. However, both medium (~1 mg/kg) and high (~2 mg/kg) levels of dietary AFB1 caused severe toxic effects on HSB directly affecting performance. Relative to control groups without AFB1 supplementation, steep reductions in weight gain (from 553% to 120% of initial weight), feed efficiency ratio (from 0.96 to 0.36), and protein retention (from 43% to 12%) were found in fish fed diets containing medium AFB1, and further reductions were observed in groups exposed to high AFB1. Dietary AFB1 also negatively affected condition factor and somatic indices and reduced whole-body protein and lipid contents relative to control groups. Significantly lower plasma hemolytic and lysozyme activities were found in fish exposed to dietary AFB1. Despite no significant protective effect of supplemental Arg being observed for most response parameters, reduced levels of Arg in plasma and muscle of AFB1-fed HSB indicated increased catabolism under nutritional stress. In conclusion, this study demonstrated that exposure to dietary AFB1 concentrations of ~1 and 2 mg/kg severely affected HSB and that supplemental Arg above requirement levels may be ineffective in alleviating aflatoxicosis.

Laser induced fluorescence spectroscopy for detection of Aflatoxin B1 contamination in peanut oil

The Aflatoxin B1 (AFB1) contamination in peanut oil is harmful and widespread. In this study, a laser induced fluorescence spectroscopy (LIF) system was developed for rapid and non-invasive screening of four varieties of peanut oils contaminated with different levels of AFB1. Discriminant analysis was conducted to classify the four varieties of peanut oils into acceptable (AFB1 < 20 μg kg−1) and contaminated (AFB1 ≥ 20 μg kg−1) levels. The results of single-step modelling, which directly classify the whole 540 peanut oils into acceptable and contaminated levels, could achieve an accuracy of 95% and 93% for calibration and validation sets respectively. Considering the fluorescence spectra could easily be influenced by the difference of physicochemical properties of different varieties of peanut oils, two-steps modelling method was conducted. In the first step, the total 540 peanut oils were classified into four varieties with all accuracy of 100% based on 600–800 nm, by using LDA algorithm. In the second step, the AFB1 contamination levels of each variety were discriminated. The classification accuracy was increased by at least 5% by conducting two-steps modelling. The results of quantitative analysis showed that for single variety, PLSR based on 400–600 nm could achieve accurate quantitative prediction. The feasibility of LIF technique for the rapid and nondestructive detection of AFB1 contamination in different varieties of edible oils was proved in this study. Further research will focus on the detection of naturally infected oils.

Evaluation of growth performance, hematological, biochemical and histopathological parameters of Rhamdia quelen fed with a feed artificially contaminated with aflatoxin B1

Contamination by aflatoxin B1 (AFB1) in fish is related to several non-specific signs, including immunosuppression, inadequate growth, histological and behavioral changes. Hematological, biochemical and histopathological parameters can be important diagnostic tools to evaluate metabolic and cellular processes in fish. The objective of this study was to determine the effects of diets containing different levels of AFB1 fed to silver catfish (Rhamdia quelen). A total of 624 silver catfish juveniles (mean weight of 7.44 g ± 2.18) were distributed into 4 different treatments (T1, T2, T3 and T4 containing 0, 45, 90 and 180 μg.kg−1 AFB1, respectively). Fish were randomly divided into 24 aquaria (n = 26 per aquarium) and fed for 56 consecutive days with pelleted feed. Growth, hematological, serum biochemistry and histopathological parameters were evaluated on days 28, 42 and 56 of the experimental period. There were no significant differences (p > 0.05) in the growth parameters when comparing the treatments exposed to AFB1 with the control treatment. AFB1 was able to induce hematological and biochemical changes consistent with metabolic disorders in the silver catfish and these were found in liver, gill and renal tissue. Different concentrations of dietary AFB1 had no effect on growth performance of silver catfish in a linear way, nor do they cause histological alterations in the evaluated organs. Nonetheless, fish fed AFB1 containing diets showed hematological and biochemical changes consistent with immunosuppression and hepatoxicity, which are commonly reported in animals exposed to AFB1.

English

The aim of this study was to measure aflatoxin B1 in granola sold in stores in the city of Teresina, Piau&iacute;. Sixty samples of granola sold in four supermarkets were used. The mycological evaluation was carried out immediately, and then the samples were stored at -4&deg;C, for later analysis of aflatoxin B1. Thirty-one strains of Aspergillus flavus were isolated. Two strains demonstrated capacity for aflatoxin production with aflatoxin B1 concentration of 2.30 and 3.90 &micro;g/g. Sixty percent of samples tested positive for aflatoxin. Granolas may have different levels of aflatoxin B1, a risk for the consumer. Therefore, there must be better control of the quality of raw materials used to make granola, because they may be the source of contamination by aflatoxins. Key words: Aspergillus flavus, cereals, fungi, grains, mycotoxins.

Effects of dietary aflatoxin B1on growth performance, body composition, haematological parameters and histopathology of juvenile Pacific white shrimp (Litopenaeus vannamei)

An 8-week feeding trial was conducted to evaluate the effects of dietary aflatoxin B1 (AFB1) on growth performance, haematological parameters and histological changes in juvenile Pacific white shrimp, Litopenaeus vannamei. Six practical diets (455 g kg-1 protein, 78 g kg-1 lipid) with different levels of AFB1 (0, 25, 50, 100, 500, 1000 μg kg−1) were formulated. Each diet was fed to triplicate groups of shrimps (initial weight: 0.52 g). The results showed that shrimp fed with control diet (0 μg kg−1 AFB1) had significant higher weight gain (WG) and specific growth rate (SGR) than other groups. However, there were no significant differences in feed efficiency (FE) or hepatosomatic index (HSI) among all groups. Compared to the control diet, AFB1 supplementation significantly changed the activities of shrimp serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total antioxidant capacity (T-AOC) and glutathione S-transferase (GST) and the content of cholesterol (CHO). Histological damages were identified in the hepatopancreas of shrimp when dietary AFB1 level was over 107.6 μg kg−1. Based on this study, it was concluded that the AFB1 level in Pacific white shrimp diet should be <38.1 μg kg−1.

Quality Evaluation of Five Commercial Enzyme Linked Immunosorbent Assay Kits for Detecting Aflatoxin B&lt;sub&gt;1&lt;/sub&gt; in Feedstuffs

The objective of this study was to evaluate the quality of five commercial enzyme linked immunosorbent assay (ELISA) kits (A, B, C, D, and E) from different suppliers for detecting aflatoxin B1 (AFB1). AFB1-free corn samples supplemented with different levels of AFB1 (5, 10, and 20 μg/kg) were used as positive controls and 6 replicates of each control sample were tested to evaluate the accuracy and precision of these kits. In addition, we also evaluated the performance of these ELISA kits for AFB1 in 30 feed samples, including corn, distillers dried grains with soluble, wheat samples, soybean meal, and poultry feed, which were verified by high performance liquid chromatography. Results showed that the coefficients of variation ranged from 1.18% to 16.22% in intra-plate and 2.85% to 18.04% in inter-plate for the determination of AFB1. The half maximal inhibitory concentration for five kits ranged from 3.72 to 7.22 μg/kg. The quantitation limits of AFB1 were all under the legal limit in China but somewhat inconsistent with kit instructions. Although the recovery rate of four of the five kits were either less than 90% or more than 110%, all these values were acceptable in practice. Two kits had high false positive rates (C and E). In conclusion, our results revealed that the qualities of five tested ELISA kits were significantly different.

Feasibility of detecting aflatoxin B1 on inoculated maize kernels surface using Vis/NIR hyperspectral imaging.

The feasibility of using a visible/near-infrared hyperspectral imaging system with a wavelength range between 400 and 1000 nm to detect and differentiate different levels of aflatoxin B1 (AFB1 ) artificially titrated on maize kernel surface was examined. To reduce the color effects of maize kernels, image analysis was limited to a subset of original spectra (600 to 1000 nm). Residual staining from the AFB1 on the kernels surface was selected as regions of interest for analysis. Principal components analysis (PCA) was applied to reduce the dimensionality of hyperspectral image data, and then a stepwise factorial discriminant analysis (FDA) was performed on latent PCA variables. The results indicated that discriminant factors F2 can be used to separate control samples from all of the other groups of kernels with AFB1 inoculated, whereas the discriminant factors F1 can be used to identify maize kernels with levels of AFB1 as low as 10 ppb. An overall classification accuracy of 98% was achieved. Finally, the peaks of β coefficients of the discrimination factors F1 and F2 were analyzed and several key wavelengths identified for differentiating maize kernels with and without AFB1 , as well as those with differing levels of AFB1 inoculation. Results indicated that Vis/NIR hyperspectral imaging technology combined with the PCA-FDA was a practical method to detect and differentiate different levels of AFB1 artificially inoculated on the maize kernels surface. However, indicated the potential to detect and differentiate naturally occurring toxins in maize kernel.

The Efficacy of Prebiotic (β-Glucan) as a Feed Additive against Toxicity of Aflatoxin B1 in Common Carp, Cyprinus Carpio L.

This study was undertaken to investigate the adverse effects of aflatoxin B1 (AFB1) on common carp (Cyprinus carpio L) and detoxifying these drastic effects by using prebiotics (β-glucan). A total of six treatments were used, including a control diet (G1) that had different combinations of AFB1 and/or 1% β-glucan. This included a diet with only β-glucan (G2), 4 mg AFB1 kg dw-1 diet with β-glucan (G3) or without (G5) and 6 mg AFB1 kg dw-1 diet with β-glucan (G4) or without (G6).These diets were offered 6 days a week at 3% daily of actual biomass in fiberglass aquaria in duplicate (2 aquaria treatment-1) for 60 days. Several endpoints at different levels of biological organisations were evaluated. These included DNA damage (using comet assay), haematological parameters, histopathological changes of the liver and kidney were also examined and growth performance. Results revealed significantly increase (P<0.05) of DNA damage in AFB1 groups (G5 and G6) compared to AFB1 plus β-glucan groups (G3 and G4). The haematological parameters showed significant differences between AFB1 groups (G5 and G6) and AFB1 plus β-glucan groups (G3 and G4). Histopathological changes revealed damage to liver and kidney tissues in AFB1 groups. Different levels of AFB1 significantly (P<0.05) affect the final average of fish weight in G5 and G6 compared to G3 and G4. Interestingly specific growth rate (%) of fish was lowered in AFB1 groups (G5 and G6) compared to AFB1 plus 1% β-glucan groups (G3 and G4). In conclusion, β-glucan, found to be a successful agent protected against the genotoxicity induced by AFB1 and effectively alleviate lesions of AFB1. Therefore, obtained results recommended adding 1% β-glucan as fish feed additives.

Pattern of partitioning of aflatoxins from feed to urine and its effect on serum chemistry in Nili-Ravi buffalo heifers

The objectives of the present study were (1) to monitor the pattern of excretion of aflatoxinM1 in urine after its conversion from aflatoxinB1 and (2) to observe the effects of different levels of aflatoxinB1 in feed on serum concentrations of key metabolites glucose, total protein, cholesterol and urea as indicators of metabolic status. Nili-Ravi buffalo heifers (n = 12) of similar age and weight were randomly distributed to four groups. Animals in Groups A, B and C were offered a contaminated cottonseed cake-based concentrate ration at 0.5%, 1.0% and 1.5% of bodyweight, respectively. Control animals in Group D were fed with aflatoxinB1-free green fodder. Based on the level of contamination of the concentrate ration with aflatoxinB1 (554 µg/kg), Groups A, B and C consumed 953, 2022, 3202 µg of aflatoxinB1 daily. Feed samples were analysed at Romer Laboratories Pty Ltd, Singapore by high performance liquid chromatography. AflatoxinM1 quantification in urine samples was conducted using a competitive enzyme-linked immunosorbent assay with kits supplied by Helica Biosystems, Inc., USA. Serum samples were analysed for concentrations of glucose, total protein, cholesterol and urea using clinical chemistry kits provided by Human diagnostics (HUMAN, Biochemica und Diagnostica mbH, Germany). Carry-over rate of aflatoxinM1 in urine for Groups A, B and C was 15.51%, 15.44% and 14.04% of aflatoxinB1 while there was no detectable aflatoxinM1 in the urine of the control group (D). There was no significant difference in the concentrations of serum glucose, total protein and cholesterol between treatment groups. However, the concentration of serum urea was significantly higher (P &lt; 0.05) in the group offered the highest level of aflatoxinB1-contaminated concentrate. This result suggests that mycotoxicosis may compromise protein metabolism and accretion in affected animals. This leaves open the possibility that high concentrations of aflatoxins in milk may ultimately affect the health status of human milk consumers.

Toxic effects of aflatoxin B 1 on growth performance, biochemical and hepatopancreas microstructure ofLitopanaeus vannamei

The toxic effects of aflatoxin B1 (AFB1) on Litopanaeus vannamei were examined in terms of growth indices, body composition, hepatopancreas microstructure and biochemical indexes of haemolymph and hepatopancreas. Six isonitrogenous purified diets were fed to shrimp [initial mean weight (0.3?0.02) g] for 8 weeks in triplicate tanks connected to recirculating system. Diets contained different levels of AFB1 (0, 400, 800, 1 200, 1 600, 2 000 μg/kg). Crude protein of whole shrimp had no significant differences (P 0.05). Body lipid tended to be higher within shrimp fed diets with higher AFB1 level (1 600 and 2 000 μg/kg). The lowest weight gain (304.67%) was found in shrimp fed with 1 200 μg/kg diet. However the shrimp fed with 2 000 μg AFB1/kg got the lowest survival rate (58.33%) and the highest weight gain. Enzyme activities generally indicated a downward trend. Total antioxidant capacity of hepatopancreas decreased significantly (P0.05) in 2 000 μg/kg diet. The activity of GST, Na+, K+-ATPase and SOD in hepatopancreas reached minimum in shrimp fed with 1 600 μg/kg AFB1 diet, but GST of haemolymph was significantly higher than others (P0.05). Histological study on shrimp fed more AFB1 exhibited histological changes. Besides, higher AFB1 residues in hepatopancreas were observed in shrimp fed with higher level AFB1. The most AFB1 residues in hepatopancreas were detected at 95.49 μg/kg in shrimp fed with 2 000 μg/kg. However, no AFB1 residue in muscle was detected in all groups.

Mycobiota and aflatoxin B1 contamination of rainbow trout (Oncorhinchus mykiss) feed with emphasis to Aspergillus section Flavi

In the present study, natural occurrence of fungi and aflatoxin B1 (AFB1) in trout pellet feed and feed ingredients randomly obtained from feed markets was investigated. The samples were cultured on the standard isolation media for 2 weeks at 28 oC. Identification of fungal isolates was implemented based on the macro- and microscopic morphological criteria. AFB1 was detected using high performance liquid chromatography (HPLC). Based on the results obtained, a total of 109 fungal isolates were identified of which Aspergillus was the prominent genus (57.0%), followed by Penicillium (12.84%), Absidia (11.01%) and Pseudallscheria (10.10%). The most frequent Aspergillus species was A. flavus (60.66%) isolated from all the feed ingredients as well as pellet feed. Among 37 A. flavus isolates, 19 (51.35%) were able to produce AFB1 on YES broth in the range of 10.2 to 612.8 µg/g fungal dry weight. HPLC analyses of trout feed showed that pellet feed and all feed ingredients tested except gluten were contaminated with different levels of AFB1 in the range of 1.83 to 67.35 µg/kg. Unacceptable levels of AFB1 were reported for feed including soybean, fish meal and wheat. These results indicate the importance of AF contamination of trout feed in amounts higher than the acceptable level as a risk factor for fish farming production.

Low levels of Aflatoxin B1 could cause mortalities in juvenile hybrid sturgeon, Acipenser ruthenus ♂×A. baeri♀

Toxicity of aflatoxin B1 (AFB1) was investigated in juvenile hybrid sturgeon Acipenser ruthenus ♂ × A. baeri♀, an important coldwater finfish farmed in China and other countries. Seven experimental diets (Diet A–G) containing different levels of AFB1 (0, 1, 5, 10, 20, 40 and 80 μg kg−1 diet) were fed to juvenile sturgeon weighing 10.53 ± 0.17 g kg−1 to determine its effect on survival, growth, feed consumption, hematocrit, liver histology as well as muscular and hepatic toxin accumulation. The experiment lasted for 35 days and was conducted in two periods of 25 and 10 days each. No external changes or unusual behaviour was observed in the fish fed diets with AFB1. Mortality was observed in fish fed with highest levels of AFB1 (80 μg kg−1– Diet G) from day 12 onwards. After 25 days, fish fed the diet of 80 μg AFB1 kg−1 showed significant lower survival (50 ± 5.77%) followed by those fed 40 μg AFB1 kg−1 diet (80 ± 5.77%) and 20 μg AFB1 kg−1 diet (86.66 ± 3.33%). No significant difference was observed in specific growth rate (SGR) or hepatosomatic index (HSI) between groups. Hematocrit was significantly higher in the fish fed the diet of highest AFB1. The fish were weighed at day 25 in some treatments (Diets F and G) because of high mortality. However, feeding was continued for another 10 days to observe mortality or behavioural changes if any in the other groups. After 35 days, survival in the fish fed Diet F (40 μg AFB1 kg−1) was 40% and those fed Diet E (20 μg AFB1 kg−1) was 36.2%. Significant histopathological changes including nuclear hypertrophy, hyperchromasia, extensive biliary hyperplasia, focal hepatocyte necrosis and presence of inflammatory cells were observed in the liver of fish fed high levels of aflatoxin (40 and 80 μg kg−1). AFB1 accumulation in fish muscle and liver increased with increased dietary AFB1 levels. It could be confirmed that 10 μg AFB1 kg−1 diet was the maximum allowable level in hybrid sturgeon diet.

Aflatoxin B1 and fumonisin B1 affect the oxidative status of bovine peripheral blood mononuclear cells

Mycotoxins are secondary metabolites having a high cytotoxic potential. They are produced by molds and released in food and feed. To date, the mechanisms underlying the mycotoxin-induced cytotoxicity have not been fully clarified. The induction of oxidative stress, as a possible mechanism, has been postulated. This in vitro study was focused on the effect of two widely occurring mycotoxins, aflatoxin B1 (AFB1) and fumonisin B1 (FB1), on the oxidative status of bovine peripheral blood mononuclear cells (PBMC) incubated for 2 and 7days at different levels of AFB1 (0, 5 and 20μg/ml) and FB1 (0, 35 and 70μg/ml). Reactive oxygen metabolites (ROM), intracellular thiols (SH), malondialdehyde (MDA) and gene expression of cytoplasmic superoxide dismutase (SOD) and glutathione peroxidase (GSHPX-1) were measured on PBMC after incubation. The highest concentration of AFB1 and all concentrations of FB1 caused an increase (p<0.05) of intracellular ROM without any time dependent effect. Intracellular SH decreased with 20μgAFB1/ml (p<0.05) and the effect was particularly marked after 7days of exposure. Intracellular SH were not affected by FB1 even though a lower (p<0.05) SH level after 2days exposure than after 7days was observed. MDA increased (p<0.05) in AFB1 or FB1 treated PBMC. The exposure to FB1 for 7days increased MDA (p<0.05) only in cells treated with 70μg/ml. Exposure of PBMC to AFB1 reduced SOD mRNA while FB1 decreased both SOD and GSHPX-1 mRNA abundance. These results demonstrate that, even though by different mechanisms, AFB1 and FB1 may induce cytotoxicity through an impairment of the oxidative status of PBMC.

Toxic effects and residue of aflatoxin B1 in tilapia ( Oreochromis niloticus × O. aureus ) during long-term dietary exposure

As a fish farmed widely in the tropical and subtropical regions where aflatoxin contamination has been generally detected, tilapia has been studied for aflatoxicosis evaluation in Asia. However, relatively short-term aflatoxin B1 (AFB1) exposure in previous studies resulted in some contradictory conclusions. Therefore, this work was designed to investigate the toxic effects and residue of AFB1 in tilapia during a long-term trial of 20 weeks, during which the tilapia obtained more than 1900% weight gain and grew to a commercial size (around 500 g). Tilapia were fed six diets containing different levels of AFB1 (19, 85, 245, 638, 793 and 1641 μg/kg), which were prepared with AFB1-contaminated peanut meal. AFB1-related physiological and toxicological properties in fish were determined during the 20-week period. The results indicated that dietary AFB1 led to aflatoxicosis effects in tilapia in a dose- and duration-dependent manner. No toxic effects of AFB1 were found during the first 10 weeks, but by 20 weeks, the diet with 245 μg AFB1/kg or higher doses reduced the growth and induced hepatic disorder, resulting in decreased lipid content, hepatosomatic index, cytochrome P450 A1 activity, elevated plasma alanine aminotransferase activity and abnormal hepatic morphology, but such dietary AFB1 doses did not affect the survival rate of experimental fish. The AFB1 residue was only detected in liver, in a dose-dependent manner, but not in edible flesh. Taken together, under good culture conditions, tilapia is a rather tolerant species for dietary AFB1 exposure up to 1641 μg/kg diet during 20 weeks. Long-term exposure for more than 15 weeks is necessary to evaluate aflatoxicosis in tilapia. Consuming only tilapia flesh would not increase the risk of exposure to AFB1 for human consumers.

Extraction and Thin Layer Chromatography of Aflatoxin Bi in Mixed Feeds

A method was developed for the determination of aflatoxin B1 in commercially prepared feeds. The method incorporates methylene chloride and citric acid solution extraction, cleanup on a small silica gel column, and thin layer chromatography for quantitation. Commercial turkey starter, catfish chow, medicated pig starter, broiler finisher, rabbit chow, horse feed, rat chow, and dog chow were investigated. The feeds were spiked with naturally contaminated corn at 4 different levels of aflatoxin B1 (16-130 microgram/kg). Three assays were run on each of the 32 combinations of feed and levels of aflatoxin. Mean recoveries were 85.9-92.8% at levels of 16.5, 32.9, 65.8, and 131.6 micrograms/kg. The relative standard deviation per assay was 18.6%. This method is more rapid and less involved than most previously published methods for mixed feeds.