| There are four experiments in this study. Using napier grass as silage raw materials and through adding additives to observe the fermentation dynamics of napier grass silage. The additives are formic acid (2.2ml kg-1,4.4ml kg-1,6.6ml kg-1FW), cellulase (50mg kg-1,250mg kg-1,500mg kg-1FW), hemicellulose (20mg kg-1,100mg kg-1,200mg kg-1FW), Cornzyme (0.22ml kg-1,1.1ml kg-1,2.2ml kg-1FW), glucose (3%FW) and xylan (3%FW).Experiment I:Effect of adding different leves of formic acid on fermentation quality of napier grass silageThe aim of this experiment was to evaluate formic acid (2.2ml kg-1,4.4ml kg-1,6.6ml kg-1FW) and storage time (0.5,1,2,3,5,7,14and30days) on fermentation quality of napier grass silage. The results were followed:Lactic acid content rapidly increased, pH value quickly lowered and NH3-N content was lower than60g kg-1TN, which indicated good fermentation quality of control group during ensiling30days. In30days ensiling process, compared with the control group, adding2.2,4.4and6.6ml kg-1formic acid slowed the declining rate of water soluble carbohydrates and the slowing effects of adding4.4and6.6ml kg-1formic acid were better than adding2.2ml kg-1(P<0.05). After ensiling3days, NH3-N and butyric acid content of adding2.2ml kg-1formic acid silages rapidly increased and the contents of them were higher than control group, adding4.4and6.6ml kg-1(P<0.05). Adding4.4and6.6ml kg-1formic acid prohibited silage to produce lactic, acetic, propionic and butyric acid, and made silages had lower NH3-N (<12g kg-1TN). In conclusion, after ensiling30days, without adding formic acid made napier grass silages had good fermentation quality while adding2.2ml kg-1formic acid lowered the fermentation quality. Adding4.4and6.6ml kg-1formic acid had the best effects on preserving napier grass. Experiment II:Effect of adding cell wall-degrading enzymes at three different levels on fermentation quality of napier grass silageThe aim of this experiment was to evaluate the affection of cell enzymes at three different levels on fermentation quality of napier grass silage on30th day. The experiment setted ten treatments:control group, the recommended level of cellulase group (50mg kg-1), five times the recommended level of cellulase group (250mg kg-1), ten times the recommended level of cellulase group (500mg kg-1), The recommended level of hemicellulose group (20mg kg-1), five times the recommended level of hemicellulose group (100mg kg-1), ten times the recommended level of hemicellulose group (200mg kg-1), the recommended level of the cornzyme enzyme group (0.22ml kg-1), five times the recommended level of the cornzyme enzyme group (1.1ml kg-1), and ten times the recommended level of the cornzyme enzyme group (2.2ml kg-1). The results showed that: compared with the control group, pH value, NH3-N/TN value, the total volatile fatty acids and cellulase contents of adding cellulase and cornzyme enzyme group to be significant (P<0.05) lower, and lactic acid/acetic acid value, lactic acid and water soluble carbohydrate contents increased significantly (P<0.05), the higher adding, the effect was more significant, all the indicators of the hemicellulose group compared with the control group had no significant difference (P>0.05). In summary, adding cornzyme and cellulase enzyme higher, the fermentation was better, the hemicellulose group had no significantiy improving on fermentation quality of napier grass silage.Experiment â…¢:Comparative study the effect of three kinds of cell wall degrading enzymes on fermentation quality of napier grass silageThe aim of this experiment was to evaluate three kinds of cell wall degrading enzymes and storage time (0.5,1,2,3,5,7,14and30days) on fermentation quality of napier grass silage. The experiment setted four treatments:control group, the cellulase group (500mg kg-1), hemicellulose (200mg kg-1) group and cornzyme enzyme group (2.2ml kg-1). The results showed that:in the fermentation process, pH value of the control group decreased slowly, low lactic acid production, fermentation quality was poor. After ensiling1day, pH values of all treatment groups reduced significantly (P<0.05) lower than the control group, the lactic acid content was significant (P<0.05) higher than the control group. Cellulase and cornzyme enzyme groups reduced significantly (P<0.05) NH3-N/TN value, the total volatile fatty acid and cellulase contents, and significantly (P<0.05) increased LA/AA value and water soluble carbohydrates content. Compared with the control group, hemicellulose enzyme group had no different significant (P>0.05). In summary, that addding cornzyme and cellulase can increase the fermentation substrate, resulting in improved fermentation quality of napier grass silage, adding hemicellulose had no improving fermentation quality of napier grass silage.Experiment IV:Effect of adding monosaccharide on fermentation characteristics of napier grass silageThe aim of this experiment was to evaluate monosaccharide and storage time (0.5,1,2,3,5,7,14and30days) on fermentation quality of napier grass silage. This experiment setted three treatments:control group, glucose group (3%FW) and xylose group (3%FW). The results showed that:in the silage fermentation process, the pH value of the control group decreased slowly, low lactic acid production, fermentation quality was poor. Compared with the control group, glucose and xylose groups had significantly (P<0.05) lower pH value (less than4.20), NH3-N/TN (less than100g kg-1) value, and improved the lactic acid production and saved more of water soluble carbohydrates content in the silage, but after ensiling2days, the total volatile fatty acids content of xylose group was significant (P<0.05) higher than the control group. In summary, adding glucose and xylose can improve fermentation quality of napier grass silage, and glucose better. |
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