Variation in sensitivity to aflatoxin B1 among several strains of Drosophila melanogaster (Diptera).

Eggs of five different wild-type strains of fruit flies, Drosophila melanogaster, were allowed to develop into adults on media containing 0.27 and 0.40 ppm of the toxic and carcinogenic mycotoxin, aflatoxin B₁ (AFB₁). Egg-to-adult viability and development time, adult sex ratio and size, and pupa case size were measured for each treatment and compared to control values for each strain. Adult size and pupa size were not affected significantly by the AFB₁ treatments, while egg-to-adult development time increased for strains grown on AFB₁-containing media. Strain-specific changes in egg-to-adult viability and adult sex ratio were observed. The most probable explanation for these differences is genetic variation among the strains. Crimea, Hikone-R, Lausanne-S, Oregon-R, and Swedish-C were the strains tested.     

Potential for aflatoxin B1 and B2 production by Aspergillus flavus strains isolated from rice samples

In this study, we investigated the potential for aflatoxin B₁ (AFB₁) and B₂ (AFB₂) production in rice grain by 127 strains of Aspergillus flavus isolated from rice grains collected from China. These strains were inoculated onto rice grains and incubated at 28 °C for 21 days. AFB₁ and AFB₂ were extracted and quantified by high-performance liquid chromatography coupled with fluorescence detection. Among the tested strains, 37% produced AFB₁ and AFB₂ with levels ranging from 175 to 124 101 μg kg⁻¹ for AFB₁ and from not detected to 10 329 μg kg⁻¹ for AFB₂. The mean yields of these isolates were 5884 μg kg⁻¹ for AFB₁ and 1968 μg kg⁻¹ for AFB₂. Overall, most of the aflatoxigenic strains produced higher levels of AFB₁ than AFB₂ in rice. The obtained information is useful for assessing the risk of aflatoxin contamination in rice samples.     

Reduced aflatoxin toxicity in hybrid crosses of aflatoxin B1 sensitive and resistant strains of Drosophila melanogaster (Diptera)

Toxicity studies on four different wild-type strains of Drosophila melanogaster (Lausanne-S, Canton-S, Florida-9, and Swedish-C) and a hybrid strain produced by intercrossing these four strains are reported. The Lausanne-S and hybrid strains exhibited resistance to aflatoxin B₁ above 0.35 ppm. The resistant strains did show decreasing egg-to-adult viabilities with increasing concentrations of the toxin in the media. No adults eclosed at or above 0.35 ppm in the Canton-S, Florida-9, or Swedish-C strain, all of which we classify as aflatoxin-sensitive. The genetic control of the degree of sensitivity to AFB₁ displayed by a strain is discussed briefly.     

Mutagenicity and cytotoxicity of the carcinogen-mutagen aflatoxin B1 in Streptococcus pneumoniae (Pneumococcus) and Salmonella typhimurium: dependence on DNA repair functions

Strains R6, R6x and R6uvr-1 of Streptococcus pneumoniae (Pneumococcus) are sensitive to the cytotoxic effects of the mutagen/carcinogen aflatoxin B₁ (AFB₁). R6uvr-1 is more prone to the cytotoxic effects of AFB₁ than the repair-proficient parental strain, R6. The same differential susceptibility of strains R6, R6x and R6uvr-1 was observed when UV light replaced metabolically activated AFB₁. All pneumococcal strains were immutable by AFB₁. AFB₁ mutagenesis in Salmonella typhimurium strains was dependent on a functional RecA gene product. The enhancing effects of ΔuvrB and plasmid pKM101 were found to be additive. Data presented are consistent with the following: (i) AFB₁ toxic effects are due mainly to DNA binding of AFB₁; (ii) AFB₁ mutagenesis is dependent on error-prone DNA repair; (iii) Pneumococcus lacks an active error-prone (SOS) DNA-repair system.     

A comparative evaluation of aflatoxin B1 genotoxicity in fish models using the Comet assay

Aflatoxin B₁ (AFB₁) is classified as a Group I hepatocarcinogen in humans by the International Agency for Research on Cancer (IARC). The alkaline Comet assay is a simple and rapid method by which DNA damage can be demonstrated as a function of tail moment. The present work is the first to evaluate the genotoxicity of AFB₁ in fish using the Comet assay. Two different species of fish were selected as models due to previously established sensitivity to AFB₁: rainbow trout (sensitive) and channel catfish (resistant). Fish were i.p. injected with 0.5 mg AFB₁/1 ml DMSO/1 kg body weight. The Comet assay was performed after 4 and 24 h on whole blood, liver, and kidney cells of both species. Trout blood and kidney tissue tested displayed significant (p<0.05) and extensive DNA damage (shown by increased tail moment) after 4 h which then decreased by 24 h. In liver cells, damage progressively increased over time. Conversely, similarly treated catfish showed no elevation in DNA damage over controls at the same doses. These results suggest that the Comet assay is a useful tool for monitoring the genotoxicity of mycotoxins such as AFB₁ and for evaluating organ specific effects of these agents in different species.     

Effects of aflatoxin B, aflatoxin B, aflatoxin G and sterigmatocystin on viability, rates of development, and body length in two strains of Drosophila melanogaster (Diptera)

Two wild-type laboratory populations of Drosophila melanogaster, Florida-9 (sensitive to aflatoxin (AF) B₁-induced toxicity) and Lausanne-S (resistant to AFB₁-induced toxicity) were tested to determine relative degress of sensitivity to growth from the egg stage on media containing 0.2, 0.6, 2.0, and 4.0 ppm AFB₁, AFG₁, AFB₂, or sterigmatocystin (ST). Data indicate that strain Florida-9 is quite sensitive to AFG₁ toxicity at both the egg-pupa and egg-adult stages of development while Lausanne-S is quite resistant to such toxic effects. For Lausanne-S, AFB₁ > AFG₁ in relative toxicity, while for Florida-9, AFG₁ > AFB₁. The latter is noteworthy since vertebrate studies consistently show that AFB₁ is a significantly stronger carcinogen and mutagen than AFG₁. Possible explanations are discussed. Neither strain tested displayed toxic responses to the presence of AFB₂ or ST in the culture media; however, the 4.0-ppm Lausanne-S treatment displayed a significantly lower adult mortality rate than the control, indicating that Lausanne-S flies may benefit from the presence of ST in the culture medium.     

Effects of mycotoxin pretreatment on aflatoxin B1 post-treatment toxicity in Drosophila melanogaster (Diptera)

Two wild-type laboratory strains of Drosophila melanogaster were used in this study: strain Flordia-9, which is sensitive to aflatoxin B₁ (AFB₁)-induced toxicity, and strain Lausanne-S, which is resistant. Eggs of these strains were deposited on medium containing either low or high doses of dietary AFG₁, AFB₂, or sterigmatocystin (ST) and allowed to develop into second instar larvae. After this pretreatment, the larvae were transferred onto medium containing either high or low doses of dietary AFB₁ (post-treatment) and allowed to complete development and eclose as adults. Viability and development data were analyzed to determine the effects of the various pretreatments on the level of AFB₁-induced toxicity in the post-treatments. In no case did any of the pretreatments reduce the toxic effects of AFB₁ post-treatment responses. However, for strain Florida-9, all high-dose pretreatments resulted in enhanced post-treatment toxicity, and all low-dose pretreatments also enhanced toxicity of high-dose post-treatments. For strain Lausanne-S, high-dose AFB₂ pretreatment significantly enhanced toxicity of both high- and low-dose post-treatments. These results indicate that, in strain Florida-9, pretreatment with relatively less toxic mycotoxins (ST and AFB₂) has an enhancing effect on AFB₁-induced toxicity, whereas in strain Lausanne-S, a similar but smaller enhancing effect is seen only with AFB₂ pretratment.     

Comparative induction of unscheduled DNA synthesis by physical and chemical agents in non-proliferating primary cultures of rat hepatocytes

The incorporation of [³H]thymidine into DNA due to unscheduled DNA synthesis (UDS) induced by N-OH-2-acetylaminofluorene (N-OH-AAF), aflatoxin B₁ (AFB₁), ethyl methanesulfonate (EMS) and ultra-violet light was quantitated by autoradiography and by scintillation spectrometry on acid precipitable macromolecules or DNA insolated by isopycnic banding in cesium chloride (CsCl). Dose-dependent increases in UDS due to N-OH-AAF and AFB₁ treatment were found. Only 2-fold increases at the highest dose levels were found, however, when incorporated [³H]thymidine was quantitated by scintillation spectrometry. Seven, 11, and 25-fold increases in UDS induced by AFB₁, N-OH-AAF and ultra-violet light, respectively, were found when incorporated [³H]thymidine was quantitated by autoradiography, indicating a high sensitivity for detecting ‘long patch’ repair by this technique. Scintillation spectrometry was completely ineffective in detecting EMS-induced UDS, whereas autoradiography demonstrated a small, but significant induction in [³H]thymidine incorporation at high dose levels. The non-proliferative nature of the primary hepatocyte prohibits the uniform radioactive prelabeling of DNA, necessary in other techniques, for the detection of ‘short patch’ repair induced by compounds such as EMS. Therefore, the sensitivity of the primary cultured rat hepatocyte in conjunction with UDS for detecting DNA damage caused by mutagens and carcinogens which induce ‘short patch’ repair may be limited to the autoradiographic analysis of the unscheduled incorporation of [³H]thymidine.     

HPLC based method for the measurement of the reduction of aflatoxin B<Subscript>1</Subscript> by bacterial cultures isolated from different African foods

The consumption of fermented foods contaminated with aflatoxin B₁ is linked to aflatoxicosis. Aflatoxicosis is a serious problem in developing countries with environmental conditions appropriate for the biosynthesis of AFB₁ byAspergillus flavus andAspergillus parasiticus. In Africa, especially in Ghana and Nigeria, there is a very high risk of liver cancer which is caused by the consumption of AFB₁-intoxicated, traditionally fermented maize and sorghum products. It is suggested that one way to diminish this health risk might be the reduction of the AFB₁ concentration in foods by bacteria. Especially bacteria used for food fermentation processes are of great importance, with a special emphasis on lactic acid bacteria which are involved in traditionally fermented African foods based on maize and sorghum.Most publications dealing with aflatoxin degradation by microorganisms describe a phosphate buffer test system for the performance of degradation experiments. In contrast to that, a test system based on physiological active bacterial and yeast cells has been developed, to assess food fermentation organisms for their ability to reduce the AFB₁ concentration in vitro. The aflatoxin B₁ concentration in test samples was quatitatively determined by HPLC.The assessment of lactic acid bacteria originating from different German and other European culture collections only showed a very slight reduction of the AFB₁ concentration from 3% to 12%. Screening experiments in which other bacterial genera and lactic acid bacteria, isolated from different African foods have been assessed, in most cases showed the same results. However, some bacterial strains, e.g. strains of the genusBacillus derived from European culture collections and strains of the genusLactobacillus isolated from African foods, caused a release of AFB₁ which was chemically bound before to components of the test medium and which therefore could not be extracted with chloroform.A process quite similar to that may happen during food fermentations. Different experiments showed that e.g. cellulose can bind AFB₁ very effectively. Cellulose and different other food components are well known to absorb AFB₁. During fermentation the cellulose and other AFB₁-absorbing components may be degraded and the AFB₁ will be released again.The only bacterial strain known as yet which is able to reduce the AFB₁ concentration in vitro and in different food comodities isNocardia corynebacteroides (formerFlavobacterium aurantiacum). Nevertheless the mechanism of this AFB₁ reduction is actually not well understood, it still has to be investigated. In the meantime several other bacterial strains, presumably from the taxonomic group of theActinomycetes could be proved to be effective reducers of the AFB₁ concentration in our in vitro test system. Because as yet no food relevant microorganism could be found, which is able to degrade AFB₁, these new strains in general offer the possibility for a genetic modification of food relevant microorganisms. This seems to be the way to come to starter cultures which are able to degrade AFB₁ during food fermentations.     

Lactobacillus rhamnosus Strain GG Modulates Intestinal Absorption, Fecal Excretion, and Toxicity of Aflatoxin B1 in Rats

In this study, the modulation of aflatoxin B₁ (AFB₁) uptake in rats by administration of the probiotic Lactobacillus rhamnosus GG was demonstrated. Fecal AFB₁ excretion in GG-treated rats was increased via bacterial AFB₁ binding. Furthermore, AFB₁-associated growth faltering and liver injury were alleviated with GG treatment.     

Alpha-Class Glutathione S-Transferases in Wild Turkeys (Meleagris gallopavo): Characterization and Role in Resistance to the Carcinogenic Mycotoxin Aflatoxin B1

Domestic turkeys (Meleagris gallopavo) are one of the most susceptible animals known to the toxic effects of the mycotoxin aflatoxin B₁ (AFB₁), a potent human hepatocarcinogen, and universal maize contaminant. We have demonstrated that such susceptibility is associated with the inability of hepatic glutathione S-transferases (GSTs) to detoxify the reactive electrophilic metabolite exo-AFB₁-8,9-epoxide (AFBO). Unlike their domestic counterparts, wild turkeys, which are relatively AFB₁-resistant, possess hepatic GST-mediated AFBO conjugating activity_. Here, we characterized the molecular and functional properties of hepatic alpha-class GSTs (GSTAs) from wild and domestic turkeys to shed light on the differences in resistance between these closely related strains. Six alpha-class GST genes (GSTA) amplified from wild turkeys (Eastern and Rio Grande subspecies), heritage breed turkeys (Royal Palm) and modern domestic (Nicholas strain) turkeys were sequenced, and catalytic activities of heterologously-expressed recombinant enzymes determined. Alpha-class identity was affirmed by conserved GST domains and four signature motifs. All GSTAs contained single nucleotide polymorphisms (SNPs) in their coding regions: GSTA1.1 (5 SNPs), GSTA1.2 (7), GSTA1.3 (3), GSTA2 (3), GSTA3 (1) and GSTA4 (2). E. coli-expressed GSTAs possessed varying activities toward GST substrates 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), ethacrynic acid (ECA), cumene hydroperoxide (CHP). As predicted by their relative resistance, livers from domestic turkeys lacked detectable GST-mediated AFBO detoxification activity, whereas those from wild and heritage birds possessed this critical activity, suggesting that intensive breeding and selection resulted in loss of AFB₁-protective alleles during domestication. Our observation that recombinant tGSTAs detoxify AFBO, whereas their hepatic forms do not, implies that the hepatic forms of these enzymes are down-regulated, silenced, or otherwise modified by one or more mechanisms. These data may inform of possible molecular mechanisms of resistance to AFB₁, and may also have the benefit of identifying genetic markers which could be used to enhance AFB₁ resistance in modern domestic strains.     

Comparison of growth and aflatoxin B1 production profiles of Aspergillus flavus strains on conventional and isogenic GM-maize-based nutritional matrices

Maize grown in both North and South America are now predominantly genetically modified (GM) cultivars with some resistance to herbicide, pesticide, or both. There is little information on the relative colonisation and aflatoxin B₁ (AFB₁) production with maize meal-based nutritional matrices based on kernels of non-GM maize and isogenic GM-ones by strains of Aspergillus flavus. The objectives were to examine the effect of interacting conditions of temperature (25–35 °C) and water availability (0.99–0.90 water activity, a_w) on (a) mycelial growth, (b) AFB₁ production and (c) develop contour maps of optimum and marginal conditions of these parameters for four strains of A. flavus on three different non-GM and isogenic GM-maize based nutritional media. The growth of the four strains of A. flavus (three aflatoxigenic; one non-aflatoxigenic) was relatively similar in relation to the temperature × a_w conditions examined on both non-GM and GM-based matrices. Optimum growth overall was at 30–35 °C and 0.99 a_w for all four strains. Under water stress (0.90 a_w) growth was optimum at 35 °C. Statistically: non-GM, GM cultivars, temperature and a_w all significantly affected growth rates. For AFB₁ production, all single and interacting factors were statistically significant except for non-GM × GM cultivar. In conclusion, colonisation of GM- and non-GM nutritional sources was similar for the different A. flavus strains examined. The contour maps will be very useful for understanding the ecological niches for both toxigenic and non-toxigenic strains in the context of the competitive exclusion of those producing aflatoxins.     

Mycotoxin-Producing Ability and Chemotype Diversity of Aspergillus Section Flavi from Soils of Peanut-Growing Regions in Iran

Invasion of crops with Aspergillus flavus may result in contamination of food and feed with carcinogenic mycotoxins such as aflatoxins (AF) and cyclopiazonic acid (CPA). In the present study, distribution and toxigenicity of Aspergillus flavus and A. parasiticus in soils of five peanut fields located in Guilan province, Northern Iran was investigated. From a total of 30 soil samples, 53 strains were isolated which all of them were finally identified as A. flavus by a combination of colony morphology, microscopic criteria and mycotoxin profiles. Chromatographic analysis of fungal cultures on yeast extract sucrose broth by tip culture method showed that 45 of the 53 A. flavus isolates (84.9 %) were able to produce either CPA or AFB₁, while eight of the isolates (15.1 %) were non-toxigenic. The amounts of CPA and AFB₁ produced by the isolates were reported in the range of 18.2–403.8 μg/g and 53.3–7446.3 μg/g fungal dry weights, respectively. Chemotype classification of A. flavus isolates based on the ability for producing mycotoxins and sclerotia showed that 43.4 % were producers of CPA, AFB₁ and sclerotia (group I), 13.2 % of CPA and AFB₁ (group II), 9.4 % of AFB₁ and sclerotia (group III), 13.2 % of AFB₁ (group IV), 5.7 % of CPA and sclerotia (group V) and 15.1 % were non-toxigenic with no sclerotia (group VI). No strain was found as producer of only CPA or sclerotia. These results indicate different populations of mycotoxigenic A. flavus strains enable to produce hazardous amounts of AFB₁ and CPA are present in peanuts field soils which can be quite important regard to their potential to contaminate peanuts as a main crop consumed in human and animal nutrition.     

Survey of Aspergillus section Flavi and aflatoxin B1 in brewer’s grain used as pig feedstuff in Córdoba, Argentina

Brewing industry by-products are important animal feedstuff alternatives for local swine producers in Córdoba, Argentina. The high content of nutrients makes these by-products vulnerable to bacterial and fungal contamination. The objectives of the present study were (1) to determine the presence of Aspergillus section Flavi in brewer’s grain used to feed pigs and (2) to evaluate the incidence of aflatoxin B₁ in the substrate. Total fungal count of most samples exceeded the levels proposed as feed quality limits, and most Aspergillus section Flavi strains found were able to produce high amounts of AFB₁ in vitro. However, the incidence of AFB₁ was low. The presence of contamination by aflatoxicogenic species in feedstuff might affect the productivity of swine producers and indirectly represents a public health issue.     

Isolation of Bacillus spp. from Thai fermented soybean (Thua-nao): screening for aflatoxin B1 and ochratoxin A detoxification

Aims: To study the interaction between Bacillus spp. and contaminating Aspergillus flavus isolated strains from Thai fermented soybean in order to limit aflatoxin production. To study the detoxification of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) by Bacillus spp. in order to find an efficient strain to remove these toxins. Methods and Results: One A. flavus aflatoxin-producing strain and 23 isolates of Bacillus spp. were isolated from soybean and fresh Thua-nao collected from the north of Thailand. Inhibition studies of A. flavus and A. westerdijkiae NRRL 3174 (reference strain) growth by all isolates of Bacillus spp. were conducted by dual culture technique on agar plates. These isolates were also tested for AFB₁ and OTA detoxification ability on both solid and liquid media. Most of the strains were able to detoxify aflatoxin but only some of them could detoxify OTA. Conclusions: One Bacillus strain was able to inhibit growth of both Aspergillus strains and to remove both mycotoxins (decrease of 74% of AFB₁ and 92·5% of OTA). It was identified by ITS sequencing as Bacillus licheniformis. The OTA decrease was due to degradation in OTα. Another Bacillus strain inhibiting both Aspergillus growth and detoxifying 85% of AFB₁ was identified as B. subtilis. AFB₁ decrease has not been correlated to appearance of a degradation product. Significance and Impact of the Study: The possibility to reduce AFB₁ level by a strain from the natural flora is of great interest for the control of the quality of fermented soybean. Moreover, the same strain could be a source of efficient enzyme for OTA degradation in other food or feeds.     

Effect of aflatoxin B1 on the delayed type hypersensitivity and phagocytic activity of reticuloendothelial system in chickens

Efforts were made to see the effect of feeding aflatoxin B₁ at 0.3 ppm level on various aspects of the immune system in chickens. The birds were fed aflatoxin B₁ (AFB₁) mixed ration from 0 to 6 weeks of age and thereafter normal feed was given up to 12 weeks of age. The delayed type hypersensitivity reaction of these birds was assessed by contact sensitivity to Dinitrofluorobenzene. The dietary AFB₁ significantly suppressed the cell mediated immune response at all the three periods tested (30, 45 and 60 days of age). The toxin showed residual effect on immunity as the suppression of cell mediated immunity was maximum three days after the withdrawal of toxin from the feed. The effect of AFB₁ on the phagocytic status of reticulo endothelial system (RES) was assessed by colloidal carbon clearance test at various intervals. The residual effect of toxin was observed on RES too as phagocytic index of AFB₁ fed birds was significantly lowered up to 45 days of age.     

Evaluation of aflatoxin B1 and ochratoxin A in interacting mixed cultures of Aspergillus sections Flavi and Nigri on peanut grains

The influence of inoculum size on the colony-forming units, production of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) was determined when Aspergillus flavus and A. niger aggregate strains were cultured alone and in pairs on irradiated peanut grains at 28°C and 0.97 water activity (a_W). The results showed a marked influence of inoculum factor on fungal counts, AFB₁ and OTA production in single and paired cultures. Fungal counts of the A. niger aggregate strain in interacting cultures at 7, 14 and 21?days of incubation were significantly higher than those observed in the A. flavus strain, except in the mixed culture with 10² spores/ml of both strains. In all mixed culture assays, the AFB₁ production was significantly reduced in comparison with the accumulation of mycotoxin in single cultures. A total inhibition in AFB₁ production was observed in some interactions as 10² spores/ml of A. flavus and 10³ spores/ml of A. niger aggregate strain at 7 and 14?days, among others. With regard to OTA production, a stimulation in the interacting cultures was observed at all inoculum sizes and incubation period. The highest levels of OTA accumulation were observed at 14?days for all interacting cultures. The maximum level was reach in the culture 10³ spores/ml of A. niger aggregate and 10⁴ spores/ml of A. flavus (p?<?0.001). These results suggest that, under optimal environmental conditions in peanut grains, the interaction between A. flavus and A. niger aggregate strains could result in an inhibition of AFB₁ and in a stimulation of OTA production.     

Sex-determined differential mortality of milkweed bugs, Oncopeltus fasciatus (hemiptera), to aflatoxins

Studies on the aflatoxins, toxic metabolites of Aspergillus flavus and A. parasiticus, have involved test systems ranging from cell cultures to laboratory animals. This work reports on the differential response by sex of Oncopeltus fasciatus to aflatoxin B₁ (AFB₁). Young adult milkweed bugs were chosen randomly from our stock colony and housed in glass culture jars. Triplicate sets of experimental animals were fed 5 μg/ml of AFB₁ in their liquid diet. The first death for the experimental females occurred at day 4, and at 10 days for the experimental males. A 50% lethality level for experimental females developed by day 8. Males subjected to the same concentration achieved a 50% lethality level at day 24. For the females the LD₅₀ occurred after consuming 0.49 μg/ml of AFB₁. The results indicate that adult female milkweed bugs were hypersensitive to AFB₁ as compared to adult males. This organism is more sensitive than the American cockroach and less sensitive than the fruitfly, housefly, and honeybee to toxic aflatoxicosis. Even the female is not sufficiently sensitive to rate highly as a bioassay organism for AFB₁. The extreme difference in mortality between the sexes is significant, unusual, and unexplained.     

Use of yeast (<Emphasis Type="Italic">Pichia kudriavzevii</Emphasis>) as a novel feed additive to ameliorate the effects of aflatoxin B<Subscript>1</Subscript> on broiler chicken performance

The aim of this study was to evaluate the efficacy of autochthonous Pichia kudriavzevii as a novel bioadsorbent for aflatoxin B₁ (AFB₁). The selection of this yeast was based on the AFB₁ adsorption capacity previously demonstrated in vitro (Magnoli et al. 2016). One-day-old Cobb broilers (n = 160) were randomly assigned to four dietary treatments (T1: basal diet (B); T2: B + 0.1% yeast; T3: B + AFB₁, 100 μg/kg; T4: B + 0.1% yeast + AFB₁, 100 μg/kg). Performance parameters (average daily weight gain body, average daily consumption, feed conversion ratio, carcass weight, and dead weight), biochemical parameters (albumin, globulin, and albumin/globulin), liver pathological changes, and AFB₁ residual levels in the liver and excreta were evaluated. Significant differences (P < 0.05) in performance parameters were observed among treatments and controls: T3 group showed the lowest average daily body weight gain value while in T4 group, the value of this parameter increased significantly (P < 0.05). T3 and T4 groups showed the lowest and highest values for average daily feed consumption, respectively. The feed conversion ratio (FC) showed no significant differences among treatments. T3 group showed the lowest dead weight and carcass weight compared with T1 group. The biochemical parameters showed no significant differences among treatments. T3 group showed macroscopic and microscopic liver changes compared to the control. Aflatoxin B₁ levels (μg/g) were detected in broiler livers and showed significant differences among treatments (P < 0.05). In conclusion, native P. kudriavzevii incorporation (0.1%) in broiler diets containing AFB₁ was shown to be effective in ameliorating the adverse effects of AFB₁ on production.     

Effect of UV irradiation on aflatoxin reduction: a cytotoxicity evaluation study using human hepatoma cell line

In this proof-of-concept study, the efficacy of a medium-pressure UV (MPUV) lamp source to reduce the concentrations of aflatoxin B₁, aflatoxin B₂, and aflatoxin G₁ (AFB_1, AFB₂, and AFG₁) in pure water is investigated. Irradiation experiments were conducted using a collimated beam system operating between 200 to 360 nm. The optical absorbance of the solution and the irradiance of the lamp are considered in calculating the average fluence rate. Based on these factors, the UV dose was quantified as a product of average fluence rate and treatment time. Known concentrations of aflatoxins were spiked in water and irradiated at UV doses ranging from 0, 1.22, 2.44, 3.66, and 4.88 J cm^?2. The concentration of aflatoxins was determined by HPLC with fluorescence detection. LC-MS/MS product ion scans were used to identify and semi-quantify degraded products of AFB₁, AFB₂, and AFG₁. It was observed that UV irradiation significantly reduced aflatoxins in pure water (p < 0.05). Irradiation doses of 4.88 J cm^?2 reduced concentrations 67.22% for AFG₁, 29.77% for AFB₂, and 98.25% for AFB₁ (p < 0.05). Using this technique, an overall reduction of total aflatoxin content of ≈95% (p < 0.05) was achieved. We hypothesize that the formation of ˙OH radicals initiated by UV light may have caused photolysis of AFB₁, AFB₂, and AFG₁ molecules. In cell culture studies, our results demonstrated that the increase of UV dosage decreased the aflatoxin-induced cytotoxicity in HepG₂ cells. Therefore, our research finding suggests that UV irradiation can be used as an effective technique for the reduction of aflatoxins.