Effects of different culture substrates,culture time and treatment methods on nutrient value and rumen fermentation effect of wheat straw treated with fungi
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.
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维普
