添加初花期骆驼刺改善苜蓿青贮品质

    Improve alfalfa silage quality by adding alhagi sparsifolia shap in initial bloom stage

    • 摘要: 为改善苜蓿的发酵品质,软化初花期骆驼刺的刺状花梗,确定二者的适宜混贮比例。采用初花期骆驼刺、紫花苜蓿及其二者不同比例混合料为青贮原料,共5个处理,青贮90 d后,通过分析青贮前、后的化学成分、乳酸菌和酵母菌数量变化;鉴定青贮饲料感官品质和发酵品质,研究骆驼刺与苜蓿混合青贮对青贮品质的影响。结果表明,2种豆科牧草混合后,干物质、可溶性碳水化合物含量、乳酸菌数量和酵母菌数量较苜蓿显著提高(P<0.05);青贮90 d后的所有青贮饲料,乳酸菌数量明显上升,酵母菌数量明显下降;混贮饲料的pH值、氨态氮/总氮、乙酸、丙酸、丁酸、戊酸和甲醇、乙醇、丙醇含量显著低于苜蓿青贮(P<0.05或P<0.01),乳酸含量显著高于苜蓿青贮(P<0.01);混贮饲料的乙酸、丙酸含量显著高于骆驼刺(P<0.01),混贮饲料有氧稳定性好,感官品质优良。骆驼刺占混贮料的30%及以上时,均能改善苜蓿青贮品质。研究结果为骆驼刺资源开发利用,寻找无添加剂高水分苜蓿青贮方法提供理论依据。

       

      Abstract: Abstract: The objectives of this work were to evaluate the effects of mixed silage of Alhagi sparsifolia Shap in initial bloom stage and alfalfa on silage quality, investigate a way of the silage of juicy alfalfa without additive, and provide a theoretical basis for the development and utilization of A. sparsifolia Shap. 100% of alfalfa (Ⅰ, as a control group) , 100% of A. sparsifolia Shap in initial bloom stage (Ⅱ) , or mixtures of their different percentages (Ⅲ: 30% of A. sparsifolia Shap + 70% of alfalfa, Ⅳ: 50% of A. sparsifolia Shap + 50% of alfalfa, Ⅴ: 70% of A. sparsifolia Shap + 30% of alfalfa) were used in this experiment and each treatment had three replicates. After 90 d of ensiling, silages were sampled, and sensory quality and fermented products (pH, lactic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, isovaleric, methanol, ethanol, propanol and ammonia nitrogen) were evaluated. Chemical components (dry matter, crude protein, water soluble carbohydrate, neutral detergent fiber, acid detergent fiber), lactobacillus and yeast living cells were determinated for both fresh forages and silages.The results showed that the contents of dry matter (DM), water soluble carbohydrate (WSC) in mixed forages (as raw material to make silage) were higher than in alfalfa (P<0.05); the maximum of DM content was 26.48% in mixed forages and the minimum was 19.52% in alfalfa; and the maximum of WSC content was 6.27% in mixed forages and the minimum was 4.60% in alfalfa. The numbers of lactic acid bacteria living cells in mixed forages were higher than in alfalfa (P<0.05); the maximum in mixed forages was 7.2×105 (Ⅴ), and the minimum was 3.3×104 in alfalfa (Ⅰ). The quantities of yeast living cells in mixed forages were lower than in alfalfa (P<0.05); the maximum was 5.0×1011 in alfalfa (Ⅰ) , and the minimum of yeast living cells was 2.5×1010 in mixed forages (Ⅲ). After 90 d of ensiling, the lactobacillus living cells in silage was more than in forage at harvest (P<0.05); the numbers of lactobacillus in the silage of different treatments were 5.1×105 (Ⅰ), 1.5×1011 (Ⅱ), 3.5×106 (Ⅲ), 3.5×107 (Ⅳ), and 6.5×107 (Ⅴ), respectively, and those in forage at harvest were 3.3×104, 5.5×106, 6.5×104, 7.3×104, and 7.2×105, respectively. The numbers of yeast living cells in silage were 3.3×104 (Ⅰ), 5.5×106 (Ⅱ), 6.5×104 (Ⅲ), 7.3×104 (Ⅳ) and 7.2×105 (Ⅴ), respectively, while those in forage at harvest (P<0.05) were 3.5×105, 6.5×103, 4.5×105, 1.5×105 and 6.5×104, respectively. The pH values of the groupⅡwas minimum (3.72); compared with that of the control group (4.32), adding A. sparsifolia Shap could significantly reduce the pH value. Lactic acid (LA) contents were higher in mix-silage (Ⅲ, Ⅳ, and Ⅴ were 4.70 %, 5.25 %and 6.12 %, respectively) than in alfalfa silage (Ⅰwas 3.73%, P<0.01). The contents of propionic acid (PA), butyric acid (BA), isovaleric, methanol, ethanol, propanol were lower in mixed silage than in alfalfa silage (P<0.05); PA and BA contents in alfalfa silage were 0.43% and 1.347%, respectively, and the minimums of PA and BA contents in mixed silage were 0.26% (Ⅳ) and 0.357% (Ⅴ), respectively. Meanwhile, PA and BA contents were higher in mixed silage than in A. sparsifolia Shap silage (it's traces). The maximum of isolaleric content was 0.42% inⅠ and the minimum was 0.20% in Ⅴ. The contents of methanol, ethanol, propanol in mixed silage (Ⅲ, Ⅳ, Ⅴ) were at trace level or not detectable. The ammonia nitrogen contents of mixed silage were significantly decreased compared with that of alfalfa silage (P<0.05), the maximum was 10.16% and the minimum was 4.76% of ratio of ammonia nitrogen to total nitrogen in Ⅰ and Ⅲ, respectively.In conclusion, mixed silage improves silage quality of alfalfa, and also softens camel thorn spiny of A. sparsifolia Shap in initial bloom stage. Mixed silages are excellent in sensory and fermented quality. To improve the quality of the silage, A. sparsifolia Shap should account for no less than 30% of mixed silage.

       

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