兰州大学机构库 >草地农业科技学院
饲料源寄生曲霉和纯绿青霉菌落生长及产毒的调控研究
Alternative TitleStudy on the regulation of colony growth and mycotoxins production of Aspergillus parasiticus and Penicillium viridicatum from feed sources
高晶
Subtype博士
Thesis Advisor王静
2023-05-19
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name农学博士
Degree Discipline草学
Keyword饲料 feed 黄曲霉毒素 aflatoxin 赭曲霉毒素 ochratoxin 环境因素 environmental factors 营养成分 nutrients 化学农药 chemical pesticides 响应面法 response surface methodology
Abstract

       黄曲霉毒素(aflatoxin,AF)和赭曲霉毒素(ochratoxin)是饲料中最常见的真菌毒素。黄曲霉毒素家族中的AFB1、AFB2、AFG1和AFG2以及赭曲霉毒素家族中的赭曲霉毒素A(ochratoxin A,OTA)毒性最强、危害最大,对动物健康和畜牧业发展造成严重威胁。目前,大量研究仅关注饲料中的AFB1,然而四种黄曲霉毒素通常在饲料中被同时检测到,寄生曲霉(Aspergillus parasiticus)可同时产生四种毒素。OTA的毒性仅次于黄曲霉毒素,纯绿青霉(Penicillium viridicatum)是OTA的主要产毒菌株。已有的大多数研究主要致力于黄曲霉毒素和赭曲霉毒素化学和生物解毒策略;然而,由于两类真菌毒素化学性质的强稳定性,使其在饲料中很难被去除,目前尚未有安全有效去除被污染饲料中这两类真菌毒素的方法。因此,如何从源头抑制寄生曲霉和纯绿青霉的生长和产毒是防止其污染饲料的关键问题。本研究以寄生曲霉和纯绿青霉为对象,选择在饲用作物田间管理阶段和贮藏阶段导致饲料发生霉变的主要因素(pH、温度、湿度、饲料养分和施用的化学农药等),以合成培养基为基质,调节其pH、温度和湿度,添加饲料中的主要养分和田间常施用的化学农药,监测两种真菌菌落的生长状况,测定培养基中黄曲霉毒素和赭曲霉毒素的含量;基于单因素试验结果,采用响应面设计交互试验,建立各因素交互作用对两种真菌生长和产毒影响的模型,以获取在田间管理和贮藏条件下抑制饲用作物中两种真菌生长和产毒的最佳条件。该研究结果将为有效防控饲料中的黄曲霉毒素和赭曲霉毒素污染提供理论依据,并为保障饲料安全、家畜和人类健康以及国家经济安全提供实践参考。主要研究结果如下:

    (1)在饲用作物田间管理因素中,环境pH和化学农药的施用可影响寄生曲霉的菌落生长。弱碱性(pH = 8)环境可显著抑制寄生曲霉的菌落生长。化学农药中,杀菌剂苯醚甲环唑、戊唑醇和代森锰锌在田间推荐浓度(R)下对寄生曲霉菌落生长的抑制率分别为59.89%、100%和100%。然而,代森锰锌与杀虫剂氯虫苯甲酰胺在R浓度下的同时添加使菌落生长抑制率降低了8.81%;戊唑醇与氯虫苯甲酰胺在R浓度下的同时添加使菌落生长抑制率降低了56.32%;戊唑醇与植物生长调节剂赤·吲哚·芸苔在R浓度下的同时添加使菌落生长抑制率降低了41.24%。

    (2)在饲料的贮藏管理因素中,环境条件、饲料养分和化学农药残留均可影响寄生曲霉的生长和产毒。当温度和水活度(water activity)分别降至10℃和0.85 aw及以下时,寄生曲霉的生长及产毒皆受到显著抑制。饲料养分中的葡萄糖、果糖、蔗糖、天冬氨酸和脯氨酸均可显著促进寄生曲霉的生长和产毒,且寄生曲霉优先利用糖类作为产毒的初始底物。化学农药中,杀菌剂百菌清的残留量低于中国农药最大残留限量时,仍可显著促进寄生曲霉的生长及产毒;残留的杀菌剂戊唑醇与植物生长调节剂胺鲜·乙烯利的交互作用可显著降低寄生曲霉菌落生长的抑制率。

    (3)在饲用作物田间管理因素中,环境pH和化学农药的施用可影响纯绿青霉的菌落生长。弱碱性(pH = 8)环境可显著抑制纯绿青霉的菌落生长。化学农药中,杀菌剂咪鲜胺在R浓度下对纯绿青霉菌落生长的抑制率为100%。然而,咪鲜胺与除草剂二甲四氯钠在R浓度下的同时添加使菌落生长抑制率降低了26.48%;咪鲜胺与植物生长调节剂赤·吲哚·芸苔在R浓度下的同时添加使菌落生长抑制率降低了22.97%。

    (4)在饲料的贮藏管理因素中,饲料养分和化学农药残留均可影响纯绿青霉的生长和产毒。纯绿青霉在低温4℃和低水活度0.8 aw的交互作用下仍可生长,较难通过控制温度和湿度的方法预防其生长。饲料养分中的淀粉、葡萄糖、果糖和蔗糖可显著促进纯绿青霉生长和产毒,且纯绿青霉优先利用粗脂肪和糖类作为其产毒的初始底物,最后利用淀粉,然而在高淀粉含量的作物中,纯绿青霉则会同时利用淀粉与其他碳源作为其产毒的初始底物。化学农药中,杀菌剂戊唑醇的残留量低于中国农药最大残留限量时,仍可显著促进纯绿青霉的生长和产毒;残留的杀菌剂咪鲜胺、除草剂苯磺隆和植物生长调节剂多唑甲哌鎓的两两交互作用均有促进纯绿青霉生长和产毒的风险。

       综上所述,饲用作物田间管理期,在保障作物健康生长的基础上,适时调节环境pH、合理配施不同种类的化学农药可有效抑制寄生曲霉和纯绿青霉的生长及产毒;在饲料贮藏期间,控制环境温度和湿度、密切关注易被真菌毒素污染的饲料类型且对养分种类和含量差异较大的饲料进行分类施策、实时监测饲料中的化学农药残留均可有效预防寄生曲霉和纯绿青霉的生长及产毒。该研究结果将为从源头上防控饲料中真菌毒素的污染提供新思路,并对于保障饲料安全、促进畜牧业和国家经济发展具有重要意义。

Other Abstract

    Aflatoxin and ochratoxin are the most common mycotoxins found in feed around the world. aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) in the aflatoxin family and ochratoxin A (OTA) in the ochratoxin family are the most toxic and harmful, posing a serious threat to animal health and animal husbandry development. At present, a large number of studies have only focused on AFB1 in feed, but four aflatoxins are usually detected simultaneously in feed, and the Aspergillus parasiticus (A. parasiticus) can produce four aflatoxins at the same time. OTA is second only to aflatoxin in toxicity, and Penicillium viridicatum (P. viridicatum) is the main toxin-producing strain of OTA. Most of the available research has focused on chemical and biological detoxin production strategies for aflatoxin and ochratoxin. However, due to the strong chemical stability of aflatoxin and ochratoxin, they are difficult to eradicate in feed, and there is no safe and effective way to remove these two types of mycotoxins from contaminated feed. Therefore, how to inhibit the growth and toxin production of A. parasiticus and P. viridicatum from the source is the key issue to prevent their contamination of feed. This study focused on the A. parasiticus and P. viridicatum. The main factors (pH, temperature, humidity, feed nutrients and chemical pesticides applied, etc.) leading to mildew in the field management and storage stage of feed were selected, and the pH, temperature and humidity were adjusted with synthetic medium as the matrix, the main nutrients in the feed and the chemical pesticides commonly applied in the field were added, the growth status of the two fungal colonies was monitored, and the content of aflatoxin and ochratoxin in the medium was determined. Based on the results of univariate experiments, the response surface methodology was used to design the interaction test, and a model of the interaction of each factor on the growth and toxin production of the two fungi was established, so as to obtain the optimal conditions for inhibiting the growth and toxin production of the two fungi. The results of this study can provide a theoretical basis for effective prevention and control of aflatoxin and ochratoxin pollution in feed, and provide practical reference for ensuring forage safety, livestock and human health, and national economic security. The main findings are as follows:

    (1) Among the field management factors of forage crops, environmental pH and chemical pesticide application can affect the colony growth of A. parasiticus. The weakly alkaline (pH = 8) environment can significantly inhibit the colony growth of A. parasiticus. Among chemical pesticides, the fungicides difenoconazole, tebuconazole and mancozeb had inhibition rates of 59.89%, 100% and 100% on the colony growth of A. parasiticus at the recommended concentration (R) in the field. However, the simultaneous addition of mancozeb and the insecticide chlorantraniliprole at R concentration reduced the inhibition rate of colony growth by 8.81%. The simultaneous addition of tebuconazole and chlorantraniliprole at R concentration reduced the inhibition rate of colony growth by 56.32%. The simultaneous addition of tebuconazole and the plant growth regulator gibberellin-indoleacetate-brassinolide at R concentration reduced the inhibition rate of colony growth by 41.24%.

    (2) Among the storage management factors of feed, environmental conditions, feed nutrients and chemical pesticide residues can affect the growth and toxin production of A. parasiticus. When the temperature and water activity dropped to 10°C and 0.85 aw and below, respectively, the growth and toxin production of A. parasiticus were significantly inhibited. Glucose, fructose, sucrose, aspartic acid and proline in feed nutrients can significantly promote the growth and toxin production of A. parasiticus, and A. parasiticus preferentially uses carbohydrates as the initial substrate for toxification. Among chemical pesticides, when the residue of the fungicide chlorothalonil is lower than the maximum residue limit of pesticides in China, it can still significantly promote the growth and toxin production of A. parasiticus. The interaction between the residual fungicide tebuconazole and the plant growth regulator amine fresh fat-ethephon significantly reduced the inhibition rate of A. parasiticus colony growth.

    (3) Among the field management factors of forage crops, environmental pH and chemical pesticide application can affect the colony growth of P. viridicatum. A weakly alkaline (pH = 8) environment significantly inhibits colony growth of P. viridicatum. Among the chemical pesticides, the fungicide prochloraz inhibited the colony growth of P. viridicatum at R concentration of 100%. However, the simultaneous addition of prochloraz and herbicide chipton at R concentration reduced the inhibition rate of colony growth by 26.48%. The simultaneous addition of prochloraz and plant growth regulator gibberellin-indoleacetate-brassinolide at R concentration reduced the inhibition rate of colony growth by 22.97%.

    (4) Among the storage management factors of feed, feed nutrients and chemical pesticide residues can affect the growth and toxin production of P. viridicatum. P. viridicatum can still grow under the interaction of low temperature 4°C and low water activity of 0.8 aw, and it is difficult to prevent its growth by controlling temperature and humidity. Starch, glucose, fructose and sucrose in feed nutrients can significantly promote the growth and toxin production of P. viridicatum, and P. viridicatum preferentially uses crude fat and sugar as the initial substrate for its toxicity, and finally uses starch, but in crops with high starch content, P. viridicatum will use starch and other carbon sources as the initial substrate for its toxicity. Among chemical pesticides, when the residue of the fungicide tebuconazole is lower than the maximum residue limit of pesticides in China, it can still significantly promote the growth and toxin production of P. viridicatum. The interaction of the residual fungicide prochloraz, the herbicide tribenuron-methyl and the plant growth regulator paclobutrazole-methylpiperium all promoted the growth and toxin production of P. viridicatum.

    In summary, during the field management period of feed crops, on the basis of ensuring the healthy growth of crops, timely adjustment of environmental pH and reasonable application of different types of chemical pesticides can effectively inhibit the growth and toxin production of A. parasiticus and P. viridicatum. During feed storage, controlling the ambient temperature and humidity, paying close attention to the feed types that are easily contaminated by mycotoxins, classifying feed with large differences in nutrient types and contents, and monitoring chemical pesticide residues in feed in real time can effectively prevent the growth and toxin production of A. parasiticus and P. viridicatum. The results of this study will provide new ideas for the prevention and control of mycotoxin pollution in feed from the source, and are of great significance for ensuring feed safety, promoting animal husbandry and national economic development.

MOST Discipline Catalogue农学 - 草学
URL查看原文
Language中文
Other Code262010_120170900060
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/537932
Collection草地农业科技学院
Affiliation
兰州大学草地农业科技学院
Recommended Citation
GB/T 7714
高晶. 饲料源寄生曲霉和纯绿青霉菌落生长及产毒的调控研究[D]. 兰州. 兰州大学,2023.
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