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不同吸收剂对甜菜渣青贮的发酵品质与有氧稳定性的影响

Effect of Adding Different Absorbent on Beet Silage Quality and Aerobic Stability

【作者】 张微微

【导师】 张永根;

【作者基本信息】 东北农业大学 , 动物营养与饲料科学, 2010, 硕士

【摘要】 本试验研究高水分甜菜渣添加吸收剂对于青贮发酵品质和有氧稳定性的影响,从而寻找一种来源广泛、价格低廉和容易获得的吸收剂,以期改善高水分甜菜渣青贮的发酵品质和营养价值。试验1:甜菜渣原料的碳水化合物组分的测定甜菜渣的碳水化合物存在细胞内容物和细胞壁中,通过测定,得出细胞内容物中含有机酸0.48%、糖4.82%、淀粉2.98%,而细胞壁由中性洗涤纤维(NDF)组成,达49.62%,间质部分如果胶(14.17%),与细胞内容物中的果聚糖一起组成中洗可溶性纤维(达30.28%)。由此可以看出,甜菜渣中非淀粉多糖含量极高,达到79.90%。试验2:添加不同来源吸收剂的甜菜渣青贮本试验采用单因素设计,一共五个处理组,每个处理18个重复(其中15个重复用于青贮过程中的5个阶段的品质测定)。将豆荚、稻秸、玉米秸和麸皮按照4:1比例分别和甜菜渣混合,使得其水分调节到70%左右。对照组甜菜渣不添加任何的辅料,然后按照正常的青贮方法进行青贮。试验结果表明:在发酵过程中,各处理组pH值的变化不是很大。氨态氮一直处于增长状态,尤其是甜菜渣组,增长迅速,且和其它处理组差异显著(P<0.05)。发酵完成后,从青贮的发酵品质方面来看:往甜菜渣添加吸收剂之后,可以减缓蛋白的降解速度,且与甜菜渣组间差异显著(P<0.05),其中麸皮组氨态氮占总氮(VBN/TN)的比例最小。各处理组间的乳酸(LA)和乙酸(AA)的含量差异显著(P<0.05)。丙酸(PA)含量各个处理组间差异不显著(P>0.05),甜菜渣组与玉米秸组和麸皮组的丁酸(BA)含量差异不显著(P>0.05),其中稻秸组和豆荚组没有检测到丁酸。另一方面从青贮的流失损失来看:添加吸收剂之后,各处理组的干物质损失率(DML)差异极显著(P<0.01),甜菜渣组干物质损失率达到20.76%,而麸皮处理组只有1.59%。同时甜菜渣直接青贮组可溶性碳水化合物损失率最为严重,高达92%,且处理组间差异显著(P<0.05)。试验3:添加不同来源吸收剂的甜菜渣青贮的有氧稳定性青贮70天后进行有氧稳定性试验,结果表明,直接青贮的甜菜渣组暴露在空气中的第2天就开始升温,在第4天,即96小时就处于不稳定状态。玉米秸组延迟一天。豆荚组的有氧稳定性是最高的,达216小时。试验4:添加不同来源吸收剂的甜菜渣青贮不同时间点的瘤胃DM、CP、NDF的降解率的测定本试验用尼龙袋法测定了这5种不同处理的甜菜渣青贮的瘤胃DM、CP和NDF的降解率。试验结果表明:甜菜渣组DM的有效降解率最高,为65%,其次是麸皮组(58.27%);甜菜渣组的NDF的有效降解率仍旧处于最高,为55.82%,其次是麸皮组(44.59%),稻秸组、玉米秸组和豆荚组的降解率依次为19.87%、33.03%、20.70%;而CP的有效降解率,麸皮组的为最高,达到了74.30%。甜菜渣组和豆荚组的蛋白降解率依次为55.86%和57.66%。本试验得出以下结论:(1)从原料甜菜渣的碳水化合物组分可以得出甜菜渣的营养特点:纤维含量高,但是大部分是可溶性纤维,同时从甜菜渣青贮的瘤胃降解试验可以得出甜菜渣是易降解物质。(2)从甜菜渣青贮来看,甜菜渣直接青贮发酵品质不佳,而且青贮渗出液比较多。添加不同来源吸收剂(稻秸、玉米秸、豆荚和麸皮)之后,能更好的提高青贮品质。在一定程度上降低了氨态氮的产生,保留DM和CP的含量,减少WSC随着汁液的流失。在另一方面来说,吸收剂的添加延缓了青贮料的二次发酵。(3)从发酵品质、营养成分、二次发酵和吸收剂的来源与经济方面综合考虑,本研究以添加20%的粉碎干稻秸的甜菜渣青贮为最佳,其次是添加20%干豆荚。

【Abstract】 The study was to evaluate the effect of adding different absorbents on the fermentation quality and aerobic stability of beet silage. The purpose is to find a suitable absorbent,which is too low and easy to get , to improve the beet silage fermentation quality and nutrition value.Test 1 Carbohydrate composition of the fresh beet pulpThe carbohydrate contents of the beet pulp are consisted of cell wall and cell contents. Among the cell contents, the organic acids accouted for 0.48%, sugar was 4.82% and starch was 2.98%. In the cell wall, which was consisted of the NDF, was 49.62%, and the rest such as the pectic substances, which was 14.17%, and fructans were composed as neutral detergent soluble fiber (up to 30.28%). It can be seen that beet pulp was rich in the non starch polysaccharide, up to 79.90%.Test 2 The beet pulp silages with different absorbentsThis study was adopted by Single factor design. There were five treatments, and each of them had 18 repeats (15 of them repeats were for the 5 stages to quality testing during silage.). The pods, rice straw, corn stovers and wheat bran were in accordance with the 4:1 ratio to beet pulp, making its water 70%. The control did not add anything to silage.The results showed that: duiring the silage, all the treatments had not a big change in pH value. But the NH3-N was always increasing, especially the control, which was significant difference between treatments (P < 0.05). After silage, adding the absorbents could slow down the degradation rate of protein, and were significant with the control (P < 0.05). Ammonia nitrogen in the bran was the smallest proportion. Among all these, the content of lactic acid and acetic acid were significant seperatly (P < 0.05). Acid content in each treatment was not significant (P > 0.05). The rice straw and pods were not detected in acid, and others were not significant (P > 0.05).On the other hand, adding the absorbents to the beet pulp silage could reduce the dry matter loss. The dry matter loss were significantly different (P < 0.01), when the dry matter loss in control loss was 20.76%, the bran treatment was only 1.59%. Similarly, the five treatments could have a significantly different in the loss rate of WSC (P < 0.05). The control was the most serious, up to 92%.Test 3 The aerobic stability of the beet pulp silage with different absorbentsAfter 70 days, all the treatments were exposed to the air. It was shown that the control was in the unaerobic stability state after three days, that was to say, it was only 96 hours. The corn stalks delayed one day. The aerobic stability of the pod was the highest, up to 216 hours.Test 4 Determination of the degradation rate of DM, CP, NDF at different time points in the rumen This study was to determination these five different beet silages in the rumen DM, CPand NDF degradation rate by nylon bag method. The results showed that, the controlhad ahighest effective degradation of DM at 65%, followed by wheat bran (58.27%); the control of NDF degradation rate was still at the highestwhich was 55.82%, followed by wheat bran (44.59%). And the rate were 19.87%, 33.03%, 20.70% in turn in rice straw, corn stalks and the pod; the CP degradation in the bran was the highest(74.30%).This experiment showed the following conclusions:(1)The nutritional characteristics of the beet pulp: the high soluble fiber. From the rumen degradation, it also could be thought as a easily degradable substance.(2)It showen that beet pulp which was at low dry matter was in poor fermentation quality and had more effluents. Adding absorbents (such as rice straw, corn stover, pods and wheat bran) to the beet pulp silage couls better improve the quality. It can to some extent reduce NH3-N and the loss of WSC and reserve the dry matter and CP content. In the other hand, it also delayed absorbent secondary fermentation of silage.(3)Considing all the aspects, especially the econoimy, this study pointed out that the beet pulp silage with 20% dry rice straw as the best, followed by adding 20% dry pods.

【关键词】 甜菜渣吸收剂青贮品质有氧稳定性
【Key words】 beet pulpabsorbentsilage qualityaerobic stability
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