不同牧草青贮对发酵品质的影响

Effects of herbage silage on fermentation quality

本研究旨在评估3种牧草在不同青贮发酵和需氧变质时期下对其青贮品质的影响。将收割的黑麦草、羊草和全珠玉米在不添加任何添加剂的条件下直接切段,在实验仓中青贮发酵3、7、14、28、56和112 d,分别测定活菌数和发酵产物含量。结果:丁二醇和乙醇是黑麦草青贮的主要发酵产物。青贮3 d时,丁二醇和乙醇的含量分别为58.2和27.7 g/kg,3~7 d时再增加约10 g/kg,而乙醇含量变化不大。在青贮过程中,乳酸含量从青贮第3天的低水平升高到28 d的最大值(P<0.05)。无论青贮期如何,乳酸菌计数均在107 cfu/g。在羊草青贮饲料中,乙酸是主要产物。其中青贮3 d时为26.0 g/kg,青贮112 d时为57.8 g/kg。在青贮初期,乳酸含量仅次于乙酸,但在第14天显著下降(P<0.05)。全珠玉米青贮饲料发酵初期乳酸产量显著提高(P<0.05),其中青贮3 d乳酸含量为50.4 g/kg,在青贮28 d时达到峰值。虽然乙酸含量保持在乳酸含量的1/3以下,但在青贮56 d后显著增加(P<0.05),在112 d时达到最大值。结论:在本试验条件下,丁二醇和乙醇是黑麦草青贮的主要发酵产物,乙酸是羊草青贮的主要产物,全珠玉米青贮饲料发酵初期乳酸产量显著提高。

The purpose of this study was to evaluate the effects of three herbage species on their silage quality during different silage fermentation and aerobic metamorphism.The ryegrass,leymus chinensis and whole corn crop were cut into sections without any additives and fermented in silage for 3,7,14,28,56 and 112 days in the experiment bin.Results:butanediol and ethanol were the main fermentation products of ryegrass silage.The contents of butanediol and ethanol were 58.2 and 27.7 g/kg at 3 d of silage,and increased by about 10 g/kg at 3~7 d.During silage,the lactic acid content increased from the low level on day 3 to the maximum value on day 28(P<0.05).The lactobacillus count was 107 cfu/g regardless of silage stage.Acetic acid is the main product in leymus chinensis silage.Among them,the silage was 26.0g/kg in 3d and 57.8g/kg in 112d.At the early stage of silage,lactic acid content was second only to acetic acid,but decreased significantly at the 14th day(P<0.05).The lactic acid yield of whole corn crop silage was significantly increased in the early stage of fermentation(P<0.05),and the lactic acid content of silage was 50.4g/kg on day 3,which reached the peak on day 28.Although the acetic acid content remained below 1/3 of the lactic acid content,it increased significantly after 56 days of silage(P<0.05)and reached its maximum value at 112 days.Conclusion:under the conditions of this experiment,butanediol and ethanol were the main fermentation products of ryegrass silage,acetic acid was the main product of leymus chinensis silage,and the yield of lactic acid was significantly increased in the early stage of whole corn crop silage.