摘要
本试验旨在揭示不同培养基质、培养时间和处理方式对真菌处理小麦秸秆的营养指标、霉菌毒素含量和碳水化合物二级分子结构的影响,并探究营养指标与碳水化合物二级分子结构之间的相关关系,进一步采用体外法评价处理后小麦秸秆在奶牛瘤胃内的发酵效果.试验以Pleurotus eryngii为试验菌株,将高粱和小麦作为培养基质,按处理方法分为常规组、灭菌组和微贮组,发酵时间分别为5、8、11周.结果表明:培养基质为小麦组的中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、木质素较高粱组分别降低了3.71％、4.32％、18.45％;灭菌组在11周时酸性洗涤木质素(ADL)和木质素含量最低,相较于8周分别降低了74.90％、31.16％,粗蛋白质(CP)含量极显著升高(P＜0.01),而微贮组在8周时NDF、ADF、CF含量最低.NDF、ADL与总碳水化合物第一亚峰和第三亚峰的峰高、峰面积,结构性碳水化合物峰高、峰面积呈负相关,ADF与它们存在显著负相关(P＜0.05),NDF、ADL含量与纤维性碳水化合物峰高、峰面积均呈正相关.微贮组的乙酸和总挥发性脂肪酸(TVFA)含量最高,灭菌组的乙酸:丙酸值最低,且灭菌组样品的氨态氮(NH3-N)和异丁酸、丁酸、异戊酸和戊酸的含量降低,30 h产气量(GP30)提高(P＜0.01).由此可见,Pleurotus eryngii真菌处理小麦秸秆通过改变总碳水化合物、结构性碳水化合物和纤维性碳水化物的结构来影响秸秆纤维成分含量和营养指标.相较于常规组,灭菌组发酵培养11周、微贮组培养8周效果最佳,且在该培养时间5种霉菌毒素含量均低于限量标准.
Abstract
This paper was conducted to investigate the effects of different culture substrates,culture time and treatment methods on nutritional indices,mycotoxin content and secondary molecular structure of carbohydrates in wheat straw treated with fungi,and to explore the correlation between nutritional indices and secondary molecular structure of carbohydrates,and to further evaluate the fermentation effect of wheat straw treated in rumen of dairy cows by in vitro method.Pleurotus eryngii was used as the test strain,sorghum and wheat were used as the culture substrates,respectively.The treatment methods were divided into conventional group,sterilization group and microstorage group,and the fermentation time was 5,8,11 weeks.The results showed that the neutral detergent fiber(NDF),acid detergent fiber(ADF)and lignin in the wheat group decreased by 3.71％,4.32％and 18.45％compared with the sorghum group,respectively;The contents of acid detergent lignin(ADL)and lignin in the sterilization group at 11 weeks were the lowest,which decreased by 74.90％and 31.16％compared with that at 8 weeks,respectively,and the contents of crude protein(CP)were significantly increased(P＜0.01),while the contents of NDF,ADF and CF in the micro-storage group were the lowest at 8 weeks.NDF and ADL were negatively correlated with the peak height and peak area of the first subpeak and the third subpeak of total carbohydrate,and the peak height and peak area of structural carbohydrate,among which ADF was significantly negatively correlated with them(P＜0.05),the contents of NDF and ADL were positively correlated with the peak height and peak area of fibrous carbohydrate.The contents of total volatile fatty acids(TVFA)were the highest in the microstorage group,and the contents of acetic acid:propionate were the lowest in the sterilization group.In the sterilization group,the contents of ammonia nitrogen(NH3-N),isobutyric acid,butyric acid,isovaleric acid and valeric acid of the samples were decreased,and the 30-hour gas production(GP30)was increased(P＜0.01).It could be seen that Pleurotus eryngii fungus affected the fiber content and nutritional indices of wheat straw by changing the structure of total carbohydrate,structural carbohydrate and fibrous carbohydrate.Compared with the conventional group,the sterilization group had the best effect of fermentation culture for 11 weeks,the micro-storage group for 8 weeks,and the contents of five mycotoxins were lower than the limit standard at this culture time.
维普
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