Effects Of Additives On Quality Of Alfalfa Silage And The Content Of Aflatoxin

Alfalfa is a leguminosae perennial herbal, and named "the king of pasture"Tor the plenty of the contents of CP, victim and minerals, which make alfalfa the excellent grass to develope the livestock in our country. However, alfalfa is a difficult raw material directly silage with the less soluble carbohydrates, dry matter content and high value buffer. In order to improve the quality of silage fermentation and inhibit the activity of undesirable microorganisms in the silage process, often using additives to improve the efficiency of silage fermentation and the fermentation stability, and inhibit the secondary fermentation. Three experiments were conducted to determine the effect acetic acid, propionic acid, lactic acid bacterial, cellulose and urea additives on the fermentation quality and chemical component whole-plant alfalfa growth in the first year, aerobic stability and the dynamic of aflatoxin.In Expt.l, alfalfa from Zhangjiakou Agricultural Science Academy in Hebei was used as accessions to investigate the effects of different additives on the fermentation quality of different alfalfa varieties. Results showed, all additives except for urea significantly improved the fermentation quality of alfalfa and decreased pH and ammoniacal nitrogen content. The interaction of additives and varieties significantly affected all testing items for fermentation quality (p<0.01). Additives had a significant effect on pH and lactic acid bacterial content of different alfalfa varieties (p<0.01) and also affected NH3-N/TN (p<0.05). However, additives showed no significant effect on content of acetic acid, propionic acid and butyric acid. Among all varieties, God Empress had a superior silage quality with a lowest pH and highest lactic acid content and a relatively low NH3-N/TN.In Expt.2, the silage material of experiment 1 was used to test the effects of additives on the aerobic stability of different alfalfa silage at different time knots (0d, 3d and 7d). Results showed, treat of additives inhibited the silage secondary fermentation to a certain extent. All additives except for urea can inhibit the production of ammoniacal nitrogen, butyric acid and the decomposition of protein during silage secondary fermentation, but the effects on pH were differing. Variety God Empress and Zhongmu 1 had the superior aerobic stability which means they have a strong aerobic stability and can delay secondary fermentation. Variety OM was inferior.In Expt.3, aflatoxin is harmful to animal and humans because of its intense teratogenesis and mutagenicity. We used alfalfa and silage as materials to test aflatoxin content. Results showed, no aflatoxin was detected in alfalfa; minim aflatoxin was detected when opening, and control was the highest (1.63ppb), urea group was the lowest(0.72ppb); with an aerobic fermentation after it was opened, more aflatoxin was detected than when opening, and control was the highest (8.21ppb), urea group was the lowest(5.51ppb).The content was still within the security range and was safe to use(≤10μg/Kg). All additives can effectively inhibit the production of aflatoxin during aerobic process. Control barely inhibited aerobic microorganism due to a low lactic acid bacterial content, high pH value and low acidity which resulted the highest aflatoxin content. Variety Aohan had a higher aflatoxin content than other varieties because the pH increased rapidly which resulted lower lactic acid bacterial content and acidity. Under aerobic condition, aflatoxin content increased slowly in other varieties.