假丝酵母ZD-3与黑曲霉ZD-8复合固体发酵对棉籽饼脱毒及营养价值的影响研究

Effect of Solid Substrate Fermentation with Mixed Cultured C.tropicalis ZD-3 and A.niger ZD-8 on Nutritional Value and Detoxification of Cottonseed Meal

研究目的为研究热带假丝酵母ZD-3与黑曲霉ZD-8复合固体发酵对棉籽饼粕脱毒效果、蛋白质营养价值及显微形态结构等的影响。利用热带假丝酵母ZD-3和黑曲霉ZD-8对棉籽饼进行单菌及复合固体发酵,然后测定发酵底物中游离棉酚(FG)、氨基酸含量,体外法测定饲料蛋白质氨基酸消失率,用环境扫描电镜拍摄底物发酵后的显微形态结构变化等。试验结果:复合发酵可极显著(P<0.01)地降低棉籽饼底物游离棉酚含量,脱毒率为91.64%;棉籽饼底物粗蛋白、总氨基酸、必需氨基酸含量分别提高27.83%、18.15%、19.18%;提高粗蛋白、总氨基酸及必需氨基酸体外消化率分别为20.90%、26.16%、24.47%,赖氨酸和蛋氨酸分别增加20.24%、66.29%。环境扫描电镜图片表明,复合发酵处理棉籽饼底物后,黑曲霉形态结构发生变化,其菌丝变细,未观察到孢子头,只见光秃秃的顶囊。酵母菌形态未发现有明显变化。试验结果表明,复合发酵效果明显优于单菌发酵棉籽饼底物的效果,不但达到棉酚脱毒的目的,而且发酵饲料营养价值显著提高。复合发酵时,热带假丝酵母ZD-3对黑曲霉ZD-8的形态变化有显著影响。

Cottonseed meal was fermented with C. tropicalis ZD - 3 and/or A. niger ZD - 8 ; then the free gossypol and amino acids in the cottonseed meal substrate were determined; their in vitro digestibility of crude protein and amino acids were analyzed; and a morphology observation for the fermented cottonseed meal was conducted under environmental scanning electron microscope （ESEM）. The following are the results： The mixed culture fermentation significantly （ P 〈 0.05 ） decreases free gossypol content in the fermented cottonseed meal with detoxification efficiency up to 91.64%. Crude protein, total amino acids and essential amino acids in the fermented cottonseed meal are increased by 27.83% , 18. 15% , 19. 18% , respectively, and their in vitro digestibilities are also increased by 20.90% , 26.16% , 24.47% , respectively. Lysine and methionine levels of the fermented cottonseed meal are im- proved by 20.24% and 66.29% respectively. Morphology change of A. niger ZD - 8 under ESEM is obvious, mycelium becoming thin and sporangium not being seen, only sporangiophore being seen, but morphology observation shows no transform of C. tropicalis ZD -3. It is indicated that the mixed culture fermentation is superior to that of single strain fermentation, which not only decreases gossypol, but also increases the nutritional value of the fermented cottonseed meal. It is found that morphology character of A. niger ZD - 8 is transformed significantly by C. tropicalis ZD -3 during the mixed culture fermentation.