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ABSTRACT. 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 ≥ 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. KEY WORDS: aflatoxin B1, domestic fowl, residue.J. Vet. Med. Sci. 64(11): 1037-1039, 2002 Aflatoxins are toxic, carcinogenic secondary metabolites of Aspergillus flavus and A. parasiticus, aflatoxin B1 (AFB1) being the most toxic and frequently produced metabolite. There have been many observations of aflatoxin residues in the tissues and eggs of broiler chickens and laying hens [1-3, 7, 10, 11, 13], but little is known about aflatoxin residues in ducks and quails. In this study, we investigated the aflatoxin residue in the liver, muscle and eggs of laying ducks, hens and quails and in broiler chickens by conducting short-term feeding experiments, with an emphasis on comparison between species.The cultures of Aspergillus flavus (a local strain of the Department of Agriculture, Ministry of Agriculture and Cooperatives, Thailand) on potato dextrose agar were dissolved in distilled water, mixed with 30% moisture-commercial corn and kept in gunny sacks for 1-2 weeks to allow aflatoxin production. After being dried and ground, the contaminated corn was mixed with feed to give 3 ppm aflatoxin B1 concentration, and then kept in a refrigerator until used.Eighteen each 6-month-old Kaki Campbell laying ducks, 6-month-old laying hens that were cross-breed of Rhode Island Red (cock) and Bar Premutroc (hen) chickens and 40-day-old Arbor Acor broiler chickens (Bang-Pa-Kong 1 Breed from the Department of Livestock Development, Thailand), and sixty 2-month-old laying Japanese quails (Coturnix Coturnix Japonica) were purchased from farmers around Bangkok. For control groups, 6 laying ducks, laying hens and broiler chickens, and 20 laying quails, were given conventional feed free of aflatoxins. The other birds were fed a diet containing 3 ppm AFB1 for 7 days, from the morning of the first day until the evenng of the 8th day. In preliminary experiments, no birds died and AFB1 was detected in the livers of the birds with this feeding regime.Half of the control and aflatoxin-fed groups were sacrificed on the 8th day, and the remaining birds were sacrified on the 11th day, 3 days after withdrawal of the contaminated feed.The liver and muscle we...

One hundred fifty samples of shrimp feed were collected from the eastern and southern regions of Thailand, and aflatoxins B1, B2, G1, and G2 (AFB1, AFB2, AFG1, and AFG2) in them were analyzed. AFB1 contamination ranged from a nondetectable level (< 0.003 ppb) to 0.651 ppb. Metabolites of AFB1 were less abundant than AFB1. To study the effects of aflatoxin in feed on shrimp production, black tiger shrimp were divided into four groups of 30 shrimp per group, tested in triplicate, and fed diets containing 0 (control), 5, 10, or 20 ppb of AFB1 for 10 consecutive days. After 7 or 10 days of consumption on each diet, the shrimp were weighed and sacrificed for laboratory examination. AFB1 and its metabolites were not detected in shrimp muscle. The mortality rate was slightly higher in the AFB1-treated groups than in the control group. The body weight of the surviving shrimp was decreased to 46 to 59% of the initial body weight in the AFB1-treated groups but not in the control group. Histopathological findings indicated hepatopancreatic damage by AFB1 with biochemical changes of the hemolymph. These results show that aflatoxin contamination in shrimp feed may cause economic losses by lowering the production of shrimp. Feed contaminated at the level of 20 ppb or lower (i.e., at the observed natural contamination level) may pose a very low risk, if any, to human health.

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Aflatoxin B1 (AFB1) is produced by Aspergillus flavus growing in feedstuffs. Early detection of maize contamination by aflatoxigenic fungi is advantageous since aflatoxins exert adverse health effects. In this study, we report the development of an optimized conventional PCR for AFB1 detection and a rapid, sensitive and simple screening Real-time PCR (qPCR) with SYBR Green and two pairs of primers targeting the aflR genes which involved aflatoxin biosynthesis. AFB1 contaminated maize samples were divided into three groups by the toxin concentration. Genomic DNA was extracted from those samples. The target genes for A. flavus were tested by conventional PCR and the PCR products were analyzed by electrophoresis. A conventional PCR was carried out as nested PCR to verify the gene amplicon sizes. PCR-RFLP patterns, obtained with Hinc II and Pvu II enzyme analysis showed the differences to distinguish aflatoxin-producing fungi. However, they are not quantitative and need a separation of the products on gel and their visualization under UV light. On the other hand, qPCR facilitates the monitoring of the reaction as it progresses. It does not require post-PCR handling, which reduces the risk of cross-contamination and handling errors. It results in a much faster throughout. We found that the optimal primer annealing temperature was 65°C. The optimized template and primer concentration were 1.5 μL (50 ng/μL) and 3 μL (10 μM/μL) respectively. SYBR Green qPCR of four genes demonstrated amplification curves and melting peaks for tub1, afIM, afIR, and afID genes are at 88.0°C, 87.5°C, 83.5°C, and 89.5°C respectively. Consequently, it was found that the four primers had elevated annealing temperatures, nevertheless it is desirable since it enhances the DNA binding specificity of the dye. New qPCR protocol could be employed for the determination of aflatoxin content in feedstuff samples.