Study On The Dynamic Variation Of Mycotoxins During The Fermentation And Aerobic Stability Of Whole Plant Corn Silage

This study was aimed to reveal the dynamic variation of the mycotoxins during the fermentation and aerobic stability of corn silage. And studyed the variation of whole plant corn silage nutritional quality at different compaction.The treatments used Xinsiyu 10 for silage material with five compaction degrees(350,400, 500, 600 and 700 kg·m-3). Dynamic monitored the nutritional and fermentation quality and the changes of major mycotoxins, as well as the impact on the aerobic stability of silages was done on the 1 st,3rd, 5th, 7th, 9th, 15 th, 30 th and 50 th day after ensiling. Simultaneous detected the 12 th, 24 th, 36 th, 60 th and 108 th hour after opened silo. Study the variation systematic of nutritional quality, the fermentation characteristics and mycotoxin of corn silage in different compaction treatments. To explore the correlation between the content of mycotoxins with fermentation characteristics, nutritional quality and microbial quantity of whole plant corn silage in the fermentation and oxygen exposure process.The main reached the following conclusions:1. Comprehensive comparison, increases silage compaction(350-600 kg·m-3), the silage quality is improved,aerobic stability duration has been extended. When at the end of fermentation, compaction for 600 kg·m-3treatment p H value is 3.97, lactic acid content was 4.00%, dry matter of 19.65%, crude protein 7.71%,neutral detergent fiber is 50.45%, acid detergent fiber was 30.66%, water soluble carbohydrate content was4.61%, aerobic stability was the best, up to 100 hours.2. Number of lactic acid bacteria during the fermentation of compaction 600 and 700 kg·m-3 treatments were significantly higher than other treatments(P<0.05). At the end of fermentation compaction 600kg·m-3 degrees of lactic acid bacteria was the highest and reached 9.19 lg cfu·g-1 FW. Number of fungi,yeasts and aerobic bacteria of compaction 700 kg·m-3 was 2.42, 5.57 and 7.78 lg cfu·g-1 FW, respectively.And the content of aflatoxin aflatoxin B1(AFB1), zearalenone(Zea), deoxynivalenol(Don) and T-2 toxin and fumonisin B1(FB1) compaction for 600 kg·m-3 were the lowest. 4.60, 23.46, 116.38, 10.83 and17.37μg·kg-1 respectively and did not exceed the highest limited standard of China dairy cattle feed. The content of 350 kg·m-3 AFB1 reached 15.862 μg·kg-1 has exceeded the maximum limit standard Chinese cow feed AFB1(15μg·kg-1). At the same time separated 3 kinds main mold from silage: A. flavus, F.graminearum and F. moniliforme.3. When one after the end of the aerobic stability, amount of lactic acid bacteria of compaction 600 kg·m-3was the most 8.17 lg cfu·g-1 FW, molds and yeasts minimum number was 5.38 and 772 lg cfu·g-1 FW,respectively. The content of 5 kinds of mycotoxins in each treatment was accompanied with the increase of oxygen exposure time. Only AFB1 content of compactness for 400, 500, 600 and 700 kg·m-3 respectively after opened silo 24 h, 36 h, 108 h and 60 h beyond China dairy feed AFB1 highest limited standard(15μg·kg-1). The rest of the mycotoxins level did not exceed the maximum limits prescribed in the cow feed.4. Through the analysis of mold and yeast in the fermentation process and the number of p H, NH3-N, TN,NH3-N/TN, NDF, ADF and WSC content were positively correlated(P<0.01), was significantly negatively correlated with the content of lactic acid(P<0.01). After opened silo molds and yeasts and aerobic bacteria number and p H value, the content of NH3-N and ADF was significantly correlated(P<0.01); and TN, DM,CP, lactic acid and WSC content showed significant negative correlation(P<0.01).5. The content of fermentation in the process of AFB1, ZEA, DON and T-2 toxin and FB1 were with the number of yeast and TN, DM, CP, ADF and WSC content showed highly significant negative correlation(P<0.01); and the amount of lactic acid bacteria and NH3-N/TN content showed highly significant positive correlation(P<0.01); and mould number showed a significant negative correlation(P<0.05). After opened silo thies were with lactic acid bacteria quantity, lactic acid, TN, DM, CP, WSC content was very significant negative correlation(P<0.01); and the quantity of fungi and yeast and p H value and NH3-N,NH3-N/TN, NDF and ADF content were extremely significant positive correlation(P< 0.01).