Effects of addition of malic or citric acids on fermentation quality and chemical characteristics of alfalfa silage
Effects of addition of malic or citric acids on fermentation quality and chemical characteristics of alfalfa silage
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添加苹果酸和柠檬酸对苜蓿青贮饲料发酵品质和化学特性的影响
DOI：
10.3168/jds.2017-12875
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发表时间：
2017-11-01
影响因子：
3.5
通讯作者：
Guo, X. S.
中科院分区：
文献类型：
--
作者：
Ke, W. C.;Ding, W. R.;Guo, X. S.
研究了青贮时添加不同水平的苹果酸和柠檬酸对苜蓿保鲜效果和化学成分的影响，以及发酵后这2种有机酸的利用率。在初花期收获苜蓿。在萎蔫至干物质含量约为40%后，将苜蓿切成1- 2cm的小块用于青贮。四个层次在青贮苜蓿时，分别用0、0.1、0.5和1%鲜重的苹果酸或柠檬酸处理苜蓿碎料，每个处理4个重复，并将处理后的苜蓿粗料在真空密封的聚乙烯袋中青贮60 d（尺寸：200 mm x 300 mm），每个小型筒仓填充200至230 g新鲜苜蓿，初始密度为0.534 g/cm（3）。苹果酸或柠檬酸在青贮60天的应用导致青贮饲料的pH值低于观察到的控制青贮饲料（0%的苹果酸或柠檬酸）。除1%鲜重外，添加2种有机酸的苜蓿青贮料中乳酸含量均高于对照青贮料。用两种有机酸处理的青贮饲料的非蛋白氮浓度低于对照青贮饲料，青贮饲料中的非蛋白氮浓度随着苹果酸或柠檬酸施用量的增加而降低。2种有机酸添加剂的应用导致青贮苜蓿中饱和脂肪酸比例较低，多不饱和脂肪酸比例较高。苜蓿青贮过程中苹果酸和柠檬酸的降解量分别为1.45和0.63 g。在0.5%鲜重的施用量下，苜蓿青贮中苹果酸和柠檬酸的残留量分别为11.1和13.6g/kg干物质。这些结果表明，包括苹果酸或柠檬酸在苜蓿青贮有效地提高青贮发酵质量，限制蛋白质水解，改善青贮饲料的脂肪酸组成，并可以提供动物的额外的饲料添加剂证明，以促进动物的生产性能。但当两种有机酸的添加量均达到1%时，青贮饲料中乳酸含量显著降低。此外，0.5%和1%的施用量也增加了青贮苜蓿中的酵母计数。
We studied the effects on alfalfa preservation and chemical composition of the addition of different levels of malic acid and citric acid at ensiling as well as the utilization efficiency of these 2 organic acids after fermentation. Alfalfa was harvested at early bloom stage. After wilting to a dry matter content of approximately 40%, the alfalfa was chopped into 1- to 2-cm pieces for ensiling. Four levels (0, 0.1, 0.5, and 1% of fresh weight) of malic acid or citric acid were applied to chopped alfalfa at ensiling with 4 replicates for each treatment, and the treated alfalfa forages were ensiled for 60 d in vacuum-sealed polyethylene bags (dimensions: 200 mm x 300 mm) packed with 200 to 230 g of fresh alfalfa per mini silo and an initial density of 0.534 g/cm(3). The application of malic or citric acids at ensiling for 60 d led to lower silage pH than was observed in the control silage (0% of malic or citric acids). Application of the 2 organic acids led to higher lactic acid concentration in alfalfa silage than in the control silage except with the application rate of 1% of fresh weight. Silages treated with both organic acids had lower nonprotein nitrogen concentrations than the control silages, and the nonprotein nitrogen concentrations in ensiled forages decreased with the increase in malic or citric acid application rates. The application of the 2 organic acid additives led to lower saturated fatty acid proportions and higher polyunsaturated fatty acid proportions in ensiled alfalfa than in the control silage. The amount of malic and citric acids degraded during ensiling of alfalfa was 1.45 and 0.63 g, respectively. At the application rate of 0.5% of fresh weight, residues of malic acid and citric acid in alfalfa silage were 11.1 and 13.6 g/kg of dry matter. These results indicate that including malic or citric acids at the ensiling of alfalfa effectively improved silage fermentation quality, limited proteolysis, improved fatty acid composition of the ensiled forage, and could provide animals with additional feed additives proven to promote animal performance. However, when the application rate of both organic acids reached 1%, the concentration of lactic acid in silages decreased notably. Additionally, 0.5 and 1% application rates also increased the yeast count in ensiled alfalfa.