饲料原料基质中不同营养成分对黄曲霉毒素B1合成关键基因表达影响的研究

The effects of nutrients in feed ingredients on key genes expression for aflatoxin B1 synthesis

通过研究饲料基质中不同营养成分对黄曲霉毒素B1(aflatoxin B1,AFB1)合成关键基因的影响,探讨营养元素影响AFB1合成的作用机制,为饲料生产中AFB1污染的防治提供一定的科学依据。在课题组前期研究的不同饲料原料营养成分组成的差异以及不同营养成分对黄曲霉生长和产毒作用的基础上,进一步研究营养成分对AFB1合成中关键基因(aflR、aflS、aflD、aflM和aflP)表达量的影响。结果显示:①相比于1.0%的蔗糖、葡萄糖、麦芽糖和水苏糖,3.0%的可溶性糖均能明显促进aflS、aflD、aflM和aflP基因表达,且葡萄糖(P<0.01)和水苏糖(P<0.001)也能促进了aflR基因的表达。②天冬氨酸、谷氨酸和精氨酸都可以不同程度地促进关键基因aflR、aflS、aflD、aflM和aflP的表达。③当培养3 d时,锌能够显著地促进基因aflR、aflS、aflD、aflM和aflP的表达(P<0.001);培养5 d时,铜明显抑制了这5个关键基因的表达。综上所述,可溶性糖、氨基酸和微量元素均可通过对黄曲霉毒素(aflatoxin,AF)合成关键基因(aflR、aflS、aflD、aflM、aflP)不同程度的上调,从而促进AFB1合成,来影响黄曲霉在饲料原料中产生AFB1,可以通过物理、化学或生物的方法,抑制AF合成调节基因(aflR、aflS)的表达,从而控制AF的污染。

The aim was to study the effects of nutrients on AFB1 relative mRNA expression to identify the nutrients responsible for the different AFB1 contamination in feed ingredients.Based on the early research that the differences in nutritional composition of feed ingredients and the effects of different nutrients on the Aspergillus flavus growth and AFB1 production to further study the effect of nutrients on the key genes(aflR,aflS,aflD,aflM,andaflP)expression in AFB1 synthesis.The results showed that:①Compared to 1.0%sucrose,glucose,maltose and stachyose,3.0%soluble sugars significantly promoted aflS,aflD,aflM and aflP gene expression,and 3.0%glucose(P<0.01)and stachyose(P<0.001)promotedaflR expression.②Aspartic acid,glutamic acid and arginine were varying degrees to promote these five key genes expression.③In 3 days,zinc can significantly increase the expression of the 5 key genes(P<0.001)and on 5 days,copper inhibited the five key genes expression significantly.In conclusion,these nutrients promote the synthesis of AFB1 possibly by up-regulating key genes expression.And these results will provide new concepts for antifungal methods to protect feed from AFB1 contamination.