• Asian-Australasian Journal of Animal Sciences
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• 제24권12호
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• pp.1757-1762
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• 2011

Aflatoxins are natural contaminants of poultry feeds and feed ingredients and cause liver damage, immunosuppression, reduction in performance and mortality in broilers. A number of studies have been carried out to study the effects of aflatoxin on feed conversion ratio in broilers. The results on feed conversion ratio of 10 research articles in broilers fed with aflatoxin from first day of age to six weeks of age were compiled and were subjected to meta-analysis. Chi-square test and $Tau^2$ (heterogeneity co-efficient) were applied to test for significance of heterogeneity of studies. To integrate results, fixed effect model by Inverse Variance method (IV method) was used when heterogeneity was insignificant and otherwise random effect model by DerSimonian and Laird Method (DL method) was used. The results of meta-analysis showed that the adverse effect of aflatoxin on feed conversion ratio at the end of first week was negligible, second week was medium and third to six weeks was very large.

• Journal of Microbiology and Biotechnology
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• 제10권2호
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• pp.154-160
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• 2000

Aflatoxin B1 is known as the most potent mycotoxin produced by several fungi. It has been demonstrated to be not only carcinogenic but teratogenic and mutagenic as well in humans. To prevent or inactivate aflatoxins, several chemical of physical methods were tested for ammoniation, using insecticides as an wxample, but they were unsuitable for food products. On the contrary, biological control by antagonistic microorgani는 is and ideal method. In order to control aflatoxin B1 biologically, the antagonists #07, #63, #75, #74, and #61 were separated from various samples by using the antagonistic activity test. Among them, culture filtrate part A (non heat-treated) of #63 and #74 on aflatoxin B1 produced by Aspergillus fkavus were shown to be 95% and 75%, respectively. Based on the morphological characteristics, #63 was deduced as an Azospirillum sp.

• Asian-Australasian Journal of Animal Sciences
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• 제8권4호
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• pp.379-385
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• 1995

Ninety Wistar male rats were used to study the effects of vitamin E and Se supplementation to diets containing aflatoxin $B_1$ on the contents of liver lipids and various blood parameters. Two levels of dietary aflatoxin (0 and 1 ppm), 3 levels of vitamin E (30, 60 and 120 IU/kg), and 3 levels of Se (0.1, 1 and 2 ppm) were used to design a $2{\times}3{\times}3$ factorial experiment. Rats, weighing about 200 g, were randomly allotted to 18 cages, 5 rats per cage. The aflatoxin significantly (p < .05) decreased growth rate, feed intake and feed efficiency. Aflatoxin increased the glucose level and decreased the cholesterol level in blood significantly. Levels of blood triglyceride, total protein, and albumin were not affected by aflatoxin, vitamin E or Se. Activities of blood alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly increased by aflatoxin; however, the glutathione peroxidase (GSH-Px) activity in the blood was decreased by aflatoxin even in the presence of Se. The vitamin E supplementation decreased the AST activity significantly, while GSH-Px activity increased significantly as the levels of dietary Se increased. The levels of total cholesterol and free cholesterol in the liver were significantly lower in rats receiving aflatoxin, while the extra vitamin E supplementation increased these hepatic cholesterol levels. It was concluded that the extra dietary vitamin E or Se supplementation might partially alleviate some of the harmful effects of aflatoxin in rats.

• 한국식품위생안전성학회지
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• 제13권2호
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• pp.164-170
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• 1998

발효식품이 유해곰팡이에 의한 발암물질(aflatoxin)생성에 미치는 억제 효과에 관한 연구의 일환으로 유산균 및 유산균 발효유가 Asperillus Parasiticus ATCC 15517의 성장과 aflatoxin 생성에 미치는 영향을 실험하였다. 발효유를 일정 농도별로 첨가한 YES 배지에서 Asperillus Parasiticus를 배양말기에 대조군에 비하여 건조 균체량, 배양물의 pH, 그리고 alftoxin 생성량 등이 낮게 나타났다(p<0.05). Aflatoxin B1은 48.6~58.1% 각 감소되었으며 G1은 29.8~34.2%가 감소되었다. 이 발효유의 발효에 사용된 유산간균(lactobacillus casei)과 Asperillus Parasiticus를 변형 APT 배지에 혼합 배양한 결과 Asperillus Parasiticus 단독 배양의 경우에 비하여 균체량이 배양 5일째까지는 현저하게 억제되었으나 배양 말기에는 유의한 차이를 보이지 않았다. 또한 배양 말기에 단독 배양의 경우보다 pH가 훨씬 감소되고 (p<0.05) aflatoxin의 생성량도 감소되었다. 이로부터 발효유는 유해곰팡이인 Asperillus Parasiticus의 성장과 aflatoxin 생성을 억제시키는 효과를 가짐을 알 수 있으며, 이는 발효에 관여한 미생물의 경쟁뿐만 뿐만아니라 유산균의 대사산물에 의한 영향으로 보여진다.

• Applied Biological Chemistry
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• 제31권2호
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• pp.182-186
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• 1988

A. flavus ATTC 15517를 A. awamori var. fumeus와 함께 혼합배양 하였을 때 단독배양과 비교하여 aflatoxin의 생성시기는 변하지 않았으나 최대생산량은 $B_1$이 $97\;{\mu}g/50ml$ 및 $G_1$이 $21\;{\mu}g/50ml$로서, 이는 각각 98% 및 99% 감소한 것이었다. 이는 A. awamori var. fumeus가 균사 성장중 aflatoxin을 분해하는 물질을 배지로 분비하기 때문이다. 또한 이 물질은 유안($0{\sim}80%)$포화)에 의하여 침전되었다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2006년도 추계학술대회 및 정기총회
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• pp.32-44
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• 2006

To investigate non-aflatoxin-production of A. oryzae at the molecular level, an aflatoxin biosynthesis gene homolog cluster of RIB 40 was analyzed. Although most genes in the corresponding cluster exhibited from 97 to 99 % similarity to those of Aspergillus flavus, three genes shared 93 % similarity or less. In addition, although slight expression of aflR, positive transcriptional regulator gene, was detected in some A. oryzae strains having seven aflatoxin biosynthesis homologous genes, other genes related to aflatoxin production were not detected. RIB strains were mainly divided into group 1, having seven aflatoxin biosynthesis homologous genes (aflT, nor-i, aflR, norA, avnA, verB, and vbs), and group 2, having three homologous (avnA, verB, and vbs). Partial aflatoxin homologous gene cluster of RIB62 from group 2 was sequenced and compared with that of RIB40 from group 1. RIB62 showed a large deletion upstream of ver-1 with more than half of the aflatoxin homologous gene cluster missing including aflR, a positive transcriptional regulatory gene. Adjacent to the deletion of the aflatoxin homologous gene cluster, RIB62 has a unique sequence of about 8kb and a telomere. Southern analysis of A. oryzae RIB strains with four kinds of probe derived from the unique sequence of RIB62 showed that all group 2 strains have identical hybridizing signals. Polymerase chain reaction with specific primer set designed to amplify the junction between ver-1 and the unique sequence of RIB62 resulted in the same size of DNA fragment only from group 2 strains. Based on these results, we developed a useful genetic tool that distinguishes A. oryzae group 2 strains from the other groups' strains and propose that it might have differentiated from the ancestral strains due to chromosomal breakage.

• Mycobiology
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• 제44권2호
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• pp.67-78
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• 2016

Rice contaminated with fungal species during storage is not only of poor quality and low economic value, but may also have harmful effects on human and animal health. The predominant fungal species isolated from rice grains during storage belong to the genera Aspergillus and Penicillium. Some of these fungal species produce mycotoxins; they are responsible for adverse health effects in humans and animals, particularly Aspergillus flavus, which produces the extremely carcinogenic aflatoxins. Not surprisingly, there have been numerous attempts to devise safety procedure for the control of such harmful fungi and production of mycotoxins, including aflatoxins. This review provides information about fungal and mycotoxin contamination of stored rice grains, and microbe-based (biological) strategies to control grain fungi and mycotoxins. The latter will include information regarding attempts undertaken for mycotoxin (especially aflatoxin) bio-detoxification and microbial interference with the aflatoxin-biosynthetic pathway in the toxin-producing fungi.

• Biomolecules & Therapeutics
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• 제4권2호
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• pp.190-195
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• 1996

Aflatoxin B1 (AFB1) has been reported to directly suppress the immune responses. In the present study, the effect of AFB1 on immune functions was investigated. Splenic lymphocytes were treated with various doses of the mitogens (lipopolysaccharide, concanavalin A) in the presence of AFB1. AFB1 pretretment decreased the number of plaque forming cells (PFC) in a dose-dependent manner. Antibody production of IgM and IgG class was significantly decreased in AFB1-treated splenic cells. In addition, when animals were exposed to AFB1, the susceptibility of bacterial infection as well as the growth of tumor cells was increased. These data suggest that AFB1 affected the immune function and humoral immunity impaired by AFB1 treatment contributed to pathological process.

• Toxicological Research
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• 제32권1호
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• pp.81-87
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• 2016

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 $65^{\circ}C$. The optimized template and primer concentration were $1.5{\mu}L\;(50ng/{\mu}L)$ and $3{\mu}L\;(10{\mu}M/{\mu}L)$ respectively. SYBR Green qPCR of four genes demonstrated amplification curves and melting peaks for tub1, afIM, afIR, and afID genes are at $88.0^{\circ}C$, $87.5^{\circ}C$, $83.5^{\circ}C$, and $89.5^{\circ}C$ 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.

• 생명과학회지
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• 제19권1호
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• pp.65-74
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• 2009

본 연구는 미국산 옥수수와 인도산 옥수수의 steam flaking 처리가 in vtro 가스발생량과 미생물 성장량 그리고 곰팡이 독소 aflatoxin $B_1$과 ochratoxin A의 농도에 미치는 영향을 구명하기 위하여 수행되었다. 실험 설계는 4개의 처리구, (1) USCW (미국산 무처리 옥수수), (2) USCF (미국산 steam flaking 옥수수 ), (3) IDCW (인도산 무처리 옥수수) 그리고 (4) IDCF (인도산 steam flaking 옥수수), 처리구당 4반복으로 6개의 발효시간대(3, 6, 9, 12, 18 및 24)를 두고 in vitro 실험을 수행하였다. 공시한 옥수수중 aflatoxin $B_1$이나 ochratoxin A와 같은 곰팡이 독소의 함량은 항구, hopper, 사일로 그리고 가공 전까지 보관기간이 길어짐에 따라 증가하는 경향을 보였다. 공정라인별로 곰팡이 독소를 측정한 결과 입고 시 인도산 옥수수(IDCW)와 미국산 옥수수 (USCW)의 aflatoxin $B_1$ 수치는 각각 11.71 ppb와 1.78 ppb으로 나타났지만 steam flaking 후의 aflatoxin $B_1$ 함량은 USCW 구와 IDCW구에서 전혀 검출되지 않아(0.00 ppb) steam flaking 처리가 곰팡이 Aspergillus flavus를 감소시킬 수 있는 것으로 조사되었다. 그러나 이러한 경향은 ochratoxin A 함량에서 관찰되지 않았다. In vitro 실험에서 gas 발생량은 원산지별로는 미국산 옥수수 (USCW & USCF)가 인도산 옥수수 (IDCW & IDCF) 보다 유의적으로 높았으며 가공 처리별로는 steam flaking 처리한 옥수수가 알곡 옥수수보다 발효 3시간대를 기준으로 $1.5{\sim}2%$ 정도 높았다. 배양액 중의 pH 는 $6.05{\sim}6.54$의 범위로서 미생물이 성장하기에 적정한 pH를 유지하였으며 처리 구간에 유의적인 차이는 찾아 볼 수 없었으나 USCF구의 pH가 다른구에 비해 다소 낮았다. pH는 배양 12 시간까지 감소하였으며 이 시간 중에 가스 발생량은 급격히 증가하였다. In vitro 미생물 성장량도 발효 18시간까지 증가하다가 그 이후 시간대에서는 성장량이 증체를 보이거나 오히려 감소하는 경향이었다. 결론적으로 원산지별로는 in vitro 실험결과와 곰팡이 독소 함량을 기준으로, 미국산 옥수수가 인도산 옥수수보다는 품질이 훨씬 높았으며, 수입산 옥수수의 steam flaking 처리는 invitro 가스발생량 및 미생물 성장량을 개선 시킬 뿐만 아니라, aflatoxin $B_1$이나 ochratoxin A와 같은 곰팡이 독소를 감소시키는 역할을 하였다.