Effect of microbial inoculants on the fermentation characteristics,nutritive value,and in vitro digestibility of various forages

This study was aimed to examine the characteristics of three isolated lactic acid bacteria (LAB) strains (HG24, M1, and TG1), and to evaluate their effects on fermentation characteristics, nutritive value, and in vitro digestibility in a variety of substrates. The experiments were conducted with Italian ryegrass (Lolium multiflorum Lam.), tall fescue (Festuca arundinacea Schred.), and oat (Avena sativa L.) in laboratory silo (1 L) for ensiling 30 days. All the treated silages had significantly (p < 0.05) higher in vitro dry matter digestibility (IVDMD), and lower undesirable microorganism populations compared with controls. In Italian ryegrass and oat silages, all the inoculants improved the fermentation quality, evidenced by distinctly (p < 0.05) higher LA contents and ratios of LA to acetic acid, and lower pH, butyric acid and ammonia nitrogen contents. Strains HG24 and commercial inoculant G (Lactobacillus plantarum MTD‐1) performed better than strains M1 and TG1, indicated by obviously (p < 0.05) higher LA contents, LAB numbers, and IVDMD. In tall fescue silage, all the isolated LAB strains (HG24, M1 and TG1) markedly (p < 0.05) increased IVDMD compared with strain G. Strain HG24 is recommended as a good LAB inoculant for ensiling in various forages.     

Silage fermentation and ruminal degradation of stylo prepared with lactic acid bacteria and cellulase

In order to improve the silage fermentation of stylo (Stylosanthes guianensis ) in tropical areas, stylo silages were prepared with commercial additives Lactobacillus plantarum Chikuso‐1 (CH 1), L. rhamnasus Snow Lact L (SN ), Acremonium cellulase (CE ) and their combination as SN +CE or CH 1 + CE , and the fermentation quality, chemical composition and ruminal degradation of these silages were studied. Stylo silages treated with lactic acid bacteria (LAB ) or cellulase, the pH value and NH ₃‐N ? total‐N were significantly (P  <  0.05) decreased while the ruminal degradability of dry matter (DM ), crude protein (CP ), neutral detergent fiber (aNDF om) and acid detergent fiber (ADF om) were significantly (P  <  0.05) increased compared to control. Compared to LAB or cellulase‐treated silages, the DM , CP contents and relative feed value (RFV ), and the ruminal degradability in LAB plus cellulase‐treated silages were significantly (P  <  0.05) higher, but the aNDF om content was significantly (P  <  0.05) lower. CH 1 + CE treatment was more effective in silage fermentation and ruminal degradation than SN +CE treatment. The results confirmed that LAB or LAB plus cellulase treatment could improve the fermentation quality, chemical composition and ruminal degradation of stylo silage. Moreover, the combined treatment with LAB and cellulase may have beneficial synergistic effects on ruminal degradation.     

冬闲田种植大麦不同生育期的营养价值和青贮品质

利用冬闲田种植一年生饲草或饲料作物,是解决南方粗饲料不足的有效途径。本研究利用冬闲田种植大麦(Hordeum vulgare),分析其不同刈割期的产量、营养价值和青贮发酵品质。主要研究结果如下,1)大麦的干物质产量随生育期的推进逐渐提高,但乳熟期相对饲用价值和干物质消化率显著高于其它生育期(P0.05),分别为107.19和63.84%。2)随着生育期的推进,全株大麦青贮发酵品质显著提高(P0.05)。3)添加乳酸菌Lactobacillus plantarum CCZZ1可以显著增加各生育期大麦青贮饲料的乳酸含量,降低pH、丁酸和氨态氮含量(P0.05),显著提高青贮发酵品质(P0.05),但开窖后容易引起有氧变质;添加乳酸菌L.parafarraqinis ZH1能有效改善各生育期大麦青贮饲料的有氧稳定性。因此,冬闲田种植大麦宜在乳熟期至蜡熟早期收割青贮,并有益南方畜牧业发展。     

Effect of ensiling whole crop oat with lucerne in different ratios on fermentation quality,aerobic stability and in vitro digestibility on the Tibetan plateau

The objective of this study was to determine the effect of ensiling different ratios of whole crop oat to lucerne on fermentation quality, aerobic stability and in vitro digestibility of silage on the Tibetan plateau. Four experimental treatments were produced varying in the ratio of forages on a fresh matter (FM) basis: 1) 100% oat (control, dry matter (DM) content: 317 g/kg), 2) 90% oat + 10% lucerne (OL10, DM content: 316 g/kg), 3) 80% oat+ 20% lucerne (OL20, DM content: 317 g/kg) and 4) 70% oat+ 30% lucerne (OL30, DM content: 318 g/kg). All treatments were packed into laboratory‐scale silos and ensiled for 60 days and then subjected to an aerobic stability test for 15 days. Further, the four experimental treatments were incubated in vitro with buffered rumen fluid to study the nutrient digestibility. All silages were well preserved with low pH and NH₃‐N contents, and high lactic acid contents and V‐scores (evaluation of silage quality). Increasing the lucerne proportion increased (p < 0.05) crude protein (CP) content of silage, whereas neutral (NDF) and acid (ADF) detergent fibre contents were not affected. Under aerobic conditions, the control silage showed higher (p < 0.05) yeast counts (>10⁵ cfu/g FM) followed by OL10 silage, and OL10 silage improved aerobic stability for 74 h. OL20 and OL30 silages showed fewer (p < 0.05) yeasts (<10⁵ cfu/g FM) and markedly (p < 0.05) improved the aerobic stability (>360 h). After 48‐h incubation, OL30 silage increased (p < 0.05) in vitro dry matter digestibility (IVDMD) and neutral detergent fibre digestibility (IVNDFD) compared with the control silage. These results suggest that replacing oat with lucerne had no unfavourable effects on fermentation quality of silage, but improved CP content, aerobic stability IVDMD and IVNDFD. OL30 silage was the best among the three mixed silages.     

乳酸菌及丙酸钙对全株玉米和燕麦青贮饲料发酵品质和霉菌毒素含量的影响

为研究乳酸菌及丙酸钙对全株玉米和燕麦青贮饲料发酵品质、营养品质、微生物数量、霉菌毒素含量及有氧稳定性的影响,利用蒸馏水(CK组)、复合乳酸菌(LAB组,添加量为5×10⁵CFU·g^-1鲜样)、丙酸钙(PACA组,添加量为鲜草重的0.4%)以及乳酸菌和丙酸钙复合(LAB+PACA)分别添加进全株玉米和燕麦原料中青贮120 d。结果表明:全株玉米青贮饲料发酵品质优良而萎蔫后的燕麦青贮丁酸和氨态氮含量较高。添加剂在不同青贮饲料中表现不同。所有添加剂均显著提高了燕麦青贮饲料的乳酸和乙酸含量,降低了pH值、氨态氮、丁酸含量和酵母菌数量(P<0.05)。而PACA和LAB+PACA组则显著提高了玉米青贮饲料中的淀粉和可溶性碳水化合物含量和有氧稳定性并且降低了霉菌和酵母菌数量(P<0.05)。LAB和LAB+PACA的使用有效降低了玉米青贮饲料中的黄曲霉毒素B1含量(P<0.05)。在两种青贮饲料中丙酸含量只有PACA和LAB+PACA组能够显著增加。因此,添加剂尤其是LAB+PACA的复合添加对于提高玉米和燕麦青贮饲料的青贮品质和安全性...     

不同温度下添加乳酸菌对油莎草青贮品质及体外干物质消失率的影响

为研究不同乳酸菌添加剂及贮藏温度对油莎草青贮品质及体外干物质消失率的影响,试验采用双因素完全随机设计,将采集的油莎草原料分为3组,分别进行副干酪乳杆菌(AC组)和植物乳杆菌添加(LP组)及无添加处理(对照组),每组设10个重复。将以上处理的样品200 g装入食品级聚乙烯袋中进行真空密封,各取5袋分别置于常温(20±2)℃和低温4℃贮藏35 d。结果表明:1)常温处理下,LP组油莎草青贮有机物含量,AC组和LP组粗蛋白质、粗脂肪含量,乳酸菌数量及体外产气量,干物质消失率,丙酸含量均显著高于对照组(P<0.05);AC组和LP组油莎草青贮pH,氨态氮/总氮,酵母菌、好氧菌数量及体外pH,乙酸含量均显著低于对照组(P<0.05)。2)低温处理下,AC组和LP组油莎草青贮乳酸含量,乳酸菌、芽孢杆菌数量,粗蛋白质含量及体外产气量,干物质消失率均显著高于对照组(P<0.05);AC组和LP组油莎草青贮酵母菌、好氧菌数量及体外氨态氮含量均显著低于对照组(P<0.05)。3)乳酸菌添加和温度处理在油莎草青贮pH,乳酸菌、酵母菌、好氧菌及芽孢杆菌数量,有机物、粗蛋白质、粗脂肪含量,氨态氮/总氮及体外发酵产气量,干物质消失率,乳酸、乙酸和丙酸含量方面表现出极显著的交互作用(P<0.01)。本试验条件下,2种乳酸菌添加均能有效改善油莎草青贮品质,提高营养价值,添加植物乳杆菌可以改善低温环境下油莎草的青贮品质。     

旋扭山绿豆的营养成分及青贮发酵品质

旋扭山绿豆(Desmodium intortum)是一种优良的多年生热带豆科牧草,本研究分析了其营养成分和乳酸菌、葡萄糖添加对其青贮发酵品质的改善效果。青贮试验设有6个处理,即对照(无添加),添加乳酸菌(LAB)、1%葡萄糖(1%G)、2%葡萄糖(2%G)、乳酸菌+1%葡萄糖(LAB+1%G)和乳酸菌+2%葡萄糖(LAB+2%G)。结果显示:旋扭山绿豆的粗蛋白含量(20.75%)和水溶性碳水化合物含量(7.19%)较高;青贮60 d后,对照处理发酵品质较差,pH在4.7以上;单独添加乳酸菌显著降低了pH和氨态氮含量,增加了乳酸含量(P <0.05);而单独添加葡萄糖的两个处理pH与对照差异均不显著(P> 0.05),但均显著降低了氨态氮含量(P <0.05);乳酸菌和葡萄糖混合添加处理均使pH降至4.1以下,乳酸含量超过6%,显著优于其他处理(P <0.05),但两混合添加处理间无显著差异(P> 0.05),因此添加乳酸菌和1%葡萄糖是改善旋扭山绿豆青贮发酵品质的有效措施。     

Characteristics of isolated lactic acid bacteria and their effectiveness to improve stylo (Stylosanthes guianensis Sw.) silage quality at various temperatures

Two lactic acid bacteria (LAB) strains, Pediococcus pentosaceus SC1 and Lactobacillus paraplantarum SC2 isolated from king grass silage, were characterized and their effectiveness to improve the silage fermentation quality of stylo (Stylosanthes guianensis Sw.) was studied. Strain SC1 was able to grow at a high temperature of 45°C, while SC2 did not. SC2 normally grew at a low pH of 4.0, while SC1 could not. These two strains and a commercial inoculant of LAB (L. plantarum, LP) were used as additives to stylo silage preparation at various temperatures (20°C, 30°C and 40°C). All LAB inoculants significantly (P < 0.05) reduced the pH value and ammonia-N content, and increased the ratio of lactic acid to acetic acid and quality score compared with the control. In addition, inoculating LAB strains markedly (P < 0.05) reduced butyric acid content at the temperatures of 30°C and 40°C. Compared to SC2 and LP strains, strain SC1 was the most effective for improving stylo silage quality at 20°C, indicated by the increase in lactic acid, ratio of lactic acid to acetic acid and quality score. At 30°C and 40°C, there were no significant differences among SC1, SC2 and LP treatments in pH values, contents of acetic acid, butyric acid and ammonia-N (P > 0.05).     

不同燕麦品种在甘肃中部的营养价值及青贮发酵品质综合评价

为筛选适宜在甘肃省二阴地区种植的优质青贮燕麦品种,采用随机区组设计方法,在甘肃省定西市通渭县华家岭乡研究了7个燕麦品种(陇燕1号、陇燕3号、定莜7号、坝莜9号、坝莜3号、白燕2号和晋燕17号)的产量表现和青贮发酵品质。于燕麦乳熟期刈割,分析鲜草的营养成分和微生物组成,切短至2 cm后直接青贮。60 d后开封取样,测定其营养指标、发酵指标,并进行发酵品质评定。结果表明:1)品种间鲜草产量和干物质含量差异显著(P<0.01),陇燕3号鲜草产量最高,达45257 kg·hm^-2,比定莜7号(35320 kg·hm^-2)高出28.13%。供试品种的干物质含量为31.35%~35.36%。尽管在同一块地上生长,但不同品种植株上附着的微生物组成差异显著(P<0.01),定莜7号的乳酸菌数达10⁵ cfu·g^-1 FM,高于其他品种,有害微生物数量较少。2)青贮60 d后,品种间营养成分差异显著(P<0.01),陇燕3号和定莜7号的干物质含量最高,粗蛋白含量显著(P<0.01)高于其他品种,分别为10.12%和11.09%。坝莜3号(55.78%)、陇燕3号(54.27%)和定莜7号(52.16%)的中性洗涤纤维含量显著(P<0.01)高于其他各品种,陇燕3号的酸性洗涤纤维含量低于坝莜3号和定莜7号,半纤维素含量最高。3)不同品种的发酵品质差异也极显著(P<0.01)。定莜7号的pH值最低(4.13),陇燕3号次之(4.20),晋燕17号为最高(4.53)。定莜7号、陇燕3号和坝莜3号拥有较高的乳酸含量,较低的总挥发性脂肪酸和氨态氮含量,发酵品质良好。坝莜9号和晋燕17号表现较差。4)感官评定和V-Score评分结果基本一致,以陇燕3号和定莜7号的发酵品质最优,感官评定结果为1级,V-Score评分为优。综合考虑产量、营养成分和青贮发酵品质,陇燕3号适宜作为青贮燕麦品种在通渭县及类似的二阴地区种植。     

Effect of lactic acid bacteria,molasses, and their combination on the fermentation quality and bacterial community of cassava foliage silage

This study investigated the effects of LAB inoculants (L) and molasses (M) on the microbial community and fermentation quality of cassava foliage (CF). The small segments (about 2–3 cm) CF were ensiled in plastic bags and incubated at normal temperature (25°C). Four treatments were carried out as follows: control (no additives, CK), LAB inoculants (Lactobacillus plantarum, L), molasses (M), and LAB in combination with molasses (LM). The LAB and molasses obviously altered the bacterial community structure of the CF silage and enhanced the fermentation quality. The combination addition could increase the abundance of Lactobacillus and reduce the Pseudomonas. The LAB and molasses also significantly elevated the lactic acid concentration (P < 0.001) and decreased the pH (P < 0.001), as well as the concentrations of acetic acid, propionic acid, butyric acid, and ammonia-N (P < 0.05). In addition, the combination treatment displayed more effective results on silage fermentation. The LAB and molasses improved the fermentation quality of the CF silage by altering the bacterial community structure. Furthermore, the bacterial community was significantly correlated with fermentation indexes.     

不同粗饲料分级指数混合粗饲料与不同比例精饲料混合日粮体外有机物消化率研究

本试验通过体外连续培养分析了高、低分级指数混合粗饲料日粮24h连续培养中不同时间点培养液中的有机物消化率的动态变化。试验结果表明,高分级指数混合粗饲料日粮不需提高精饲料的比例就有较高的有机物体外消化率(IVOMD),且提高精饲料水平未必能提高其IVOMD,而低分级指数混合粗饲料日粮只有提高精饲料水平才能达到高分级指数混合粗饲料日粮的效果。     

全株青贮玉米品种对其发酵品质及营养价值的影响

试验旨在比较不同品种青贮专用型玉米全株青贮发酵品质及营养价值的差异,以郑青贮1号、金岭青贮17号和京科青贮516为试验材料,于1/2~3/4乳线期刈割,使用聚乙烯发酵袋(50 cm×80 cm)在实验室条件下发酵60 d,开袋后进行感官评价,测定发酵品质,风干样粉碎后用于常规化学成分及消化率的测定。结果表明:不同品种感官评分等级均为良好级,其中,籽粒含量和总评分差异极显著(P<0.01),色泽及气味差异显著(P<0.05)。品种间各项发酵参数差异极显著(P<0.01),费氏评分≥110.00分,发酵品质均为优级。各品种青贮后干物质、粗蛋白、粗脂肪、水溶性碳水化合物、淀粉、中性洗涤纤维、酸性洗涤纤维、酸性洗涤木质素、粗灰分含量及相对饲喂价值差异极显著(P<0.01),且相对饲喂价值>121.00。品种间青贮产量及能量价值均存在极显著差异(P<0.01),郑青贮1号的奶吨指数、总可消化养分及各项能值极显著高于其他品种(P<0.01),干物质产量及奶亩指数极显著低于其他品种(P<0.01),金岭青贮17号的干物质产量显著较高(P<0.01),奶吨指数、总可消化养分及各项能值均极显著高于京科青贮516(P<0.01),奶亩指数极显著高于其他品种(P<0.01)。各品种碳水化合物组分剖分及体外干物质、中性洗涤纤维消化率均存在极显著差异(P<0.01),金岭青贮17号的体外干物质及中性洗涤纤维消化率均极显著高于京科青贮516和郑青贮1号(P<0.01),京科青贮516的体外干物质消化率极显著高于郑青贮1号(P<0.01),郑青贮1号的体外中性洗涤纤维消化率极显著高于京科青贮516(P<0.01)。综上所述,金岭青贮17号为优异的青贮专用型玉米品种,其次为京科青贮516。     

体外法研究不同磷添加水平对奶牛瘤胃发酵的影响

本试验采用体外法研究无机磷对瘤胃发酵的影响。无机磷在培养液中设0、30、60、90、120、150、200、250、300、350 mg/L 10个水平。体外培养发酵48 h终止培养,测定培养液的产气量和干物质降解率。结果表明:无机磷添加水平对48 h总产气量和干物质降解率影响显著(P<0.05),随着无机磷添加水平的提高,48 h总产气量和干物质降解率显著提高(P<0.05),添加水平为200 mg/L时达到最大值,分别为44.30 mL和54.80%,随后下降。在本试验条件下,无机磷的适宜添加水平为200 mg/L。     

Effect of organic acids on the microbial quality of Taiwanese-style sausages

The effects of organic acids on the microbial quality of Taiwanese‐style sausages were studied. Pork meat from a Taiwan retail market was decontaminated with various organic acids (citric, lactic and tartaric acid), then, the raw meat was used to make Taiwanese‐style sausages and stored from 0 to 40 days at 4°C. The total plate counts, lactic acid bacteria, Micrococcus, Listeria monocytogenes, Hunter‐L and Hunter‐a values were determined. The total plate counts of the control group were initially greater than those of the treated groups. Higher incidence rates of L. monocytogenes in the products were obtained from the control group, but were not detected in the treated groups during storage. Lactic acid bacteria counts following the lactic acid treatment were lower than those of the other groups. Micrococcus counts of the controls increased by 0.6–1.2 log₁₀ colony‐forming unit (CFU)/g greater than those of treated groups throughout storage at 4°C. The light color (L‐value) of the control group gradually decreased during storage. Pork meat dipped in various organic acids was found to be suitable to extend the shelf‐life and improve the microbiological quality of Taiwanese‐style sausages.     

Effect of crushing unhulled rice and the addition of fermented juice of epiphytic lactic acid bacteria on the fermentation quality of whole crop rice silage, and its digestibility and rumen fermentation status in sheep

This experiment was carried out to examine the effect of crushing unhulled rice and the addition of fermented juice of epiphytic lactic acid bacteria (FJLB) on the fermentation quality of whole crop rice silage, and its digestibility and rumen fermentation in sheep. After whole rice plants (Oryza sativa L. cv. Haenuki) were harvested between the yellow and full‐ripened period of maturity, and cut at a length of 2 cm, four silage treatments were set: (i) non‐treatment; (ii) crushing treatment of unhulled rice division (crushing); (iii) addition of 1% FJLB; and (iv) crushing + addition of 1% FJLB. Lactic acid content increased with the addition of FJLB, and was highest in the crushing + FJLB treatment. Digestibilities of crude fiber, acid detergent fiber and neutral detergent fiber were significantly higher during the crushing + FJLB treatment. There were no differences among treatments in the volatile fatty acid concentrations before and after feeding. At 4 h after feeding, however, the ratio of acetic acid : propionic acid was significantly lower with the addition of FJLB. It was proven that the fermented quality of silage was improved when FJLB was added to rice plants and then ensilaged, and the digestibility of the fibrous component was raised when unhulled rice division was crushed and FJLB was supplemented.     

短芒大麦草青贮微生物特性研究及优良乳酸菌筛选

以短芒大麦草为研究对象,利用传统培养法从叶围和青贮发酵体系中分离出乳酸菌、大肠杆菌、好氧细菌、酵母菌和霉菌,并计数;结合细菌形态学、生理生化特征及16S rDNA序列分析鉴定分离出的乳酸菌菌株;通过研究乳酸菌的生长曲线、产酸特性及耐酸性,筛选优质乳酸菌。以期探明短芒大麦草叶围及青贮发酵体系中微生物菌群特性及青贮料中乳酸菌多样性,筛选出具有促发酵效果的乳酸菌菌株,为有益微生物饲料研发奠定基础。试验结果表明,短芒大麦草经青贮发酵后各微生物菌群数量发生不同程度变化,乳酸菌数量由0 cfu/g FM增加到4.00×10⁸ cfu/g FM,酵母菌数量由8.50×10⁵ cfu/g FM增加到1.02×10⁸ cfu/g FM,而好氧细菌、大肠杆菌和霉菌数量变化不明显;从短芒大麦草青贮发酵体系分离得到4株乳酸菌,经鉴定Lx36为Lactobacillus pentosus,Lx37为Lactobacillus brevis,Lx53为Pediococcus pentosaceus,Lx54为Lactobacillus parabuchneri;筛选得到1株益于青贮的乳酸菌株Lx36,约在20 h后进入稳定生长期,OD值达到4.21,且发酵12 h的pH仅为4.08,并可以在pH=3.0环境条件下生长。综上所述,青贮发酵是体系中各种微生物相互作用的过程,微生物菌群的数量及变化直接影响青贮饲料发酵品质。短芒大麦草青贮饲料中乳酸菌种类较丰富,筛选得到的戊糖乳杆菌繁殖速度快、产酸能力强同时表现出了较强的耐酸性,具有潜在的生产应用价值,适宜用作促发酵的青贮添加剂菌种。     

不同温度条件下添加剂对青贮苜蓿细胞壁成分和体外干物质消化率的影响

用第2茬紫花苜蓿草,采用交叉分组设计调制了青贮。试验设20℃、30℃和40℃3个贮藏温度区,设对照(CON)、添加0.0004%乳酸菌(LAB)、添加0.005%纤维素酶(CEL)和添加0.0004%乳酸菌 0.005%纤维素酶(MIX)4个添加处理。贮存55d开封后测定青贮的细胞壁成分(总纤维-OCW、低消化性纤维-Ob、高消化性纤维-Oa)含量和体外干物质消化率(IVDMD)。结果有以下几种倾向:添加CEL和MIX可使青贮的OCW和Ob含量减少;添加LAB和MIX可提高青贮的IVDMD;添加CEL可降低青贮的IVDMD;在20℃~40℃,随贮藏温度的升高,青贮的Oa含量和IVDMD提高,Ob含量降低。     

The effects of continuous and rotational grazing of sourveld on the quality of herbage selected by Simmentaler heifers

A grazing trial was conducted at the Kokstad Agricultural Station to compare the dry matter digestibility (DMD) and crude protein content (CP) of diets selected by four fistulated cattle which were continuously and rotationally grazing sourveld. Two stocking rates of 1,0 and 2,3 animals/ha (0,5 and 1,2 LSU/ha) were applied under each grazing method. The mean DMD and CP values of diets selected in the continuous and rotational grazing treatments, respectively, were: DMD=64,3%, 62,3%; CP=6,63%, 6,88%. The effect of stocking rate on the quality of the diet selected varied between the two grazing methods. DMD and CP of diets selected under rotational grazing decreased with time during the week‐long period of stay in each paddock. On average, DMD and CP values on the first and sixth day respectively, were: DMD=66,6%, 60,5%; CP=8,37%, 6,01%. These differences were more pronounced at the higher than at the lower stocking rate. It was concluded that, although some of the treatment differences were small, grazing method differences in the DMD of diets might at least partially account for observed differences in livemass gains under the two grazing systems.     

添加丙酸和乳酸菌对杂交狼尾草青贮发酵品质的影响

研究丙酸、乳酸菌和两者组合不同添加水平对杂交狼尾草（Pennisetum americanum×P.purpereum）青贮发酵品质的影响。试验设对照(无添加)、乳酸菌(LAB)、0.2%丙酸、0.3%丙酸、0.4%丙酸、0.5%丙酸、0.2%丙酸+乳酸菌、0.3%丙酸+乳酸菌、0.4%丙酸+乳酸菌、0.5%丙酸+乳酸菌（占鲜质量比例）处理,青贮45 d后开袋分析。结果表明,添加丙酸可以有效改善杂交狼尾草的青贮品质,最佳添加量为0.3%;添加乳酸菌有助于提高杂交狼尾草的有氧稳定性。     

Effects of inoculants and environmental temperature on fermentation quality and bacterial diversity of alfalfa silage

To investigate the effects of inoculants and environmental temperature on fermentation quality and bacterial diversity of alfalfa silage, first‐cut alfalfa was ensiled with or without two screened lactic acid bacteria (LAB) strains, Lactobacillus plantarum, LP, and Lactobacillus casei, LC. Each treatment was divided into three parts and stored at 20°C, 30°C, 40°C, respectively. After 60 days ensiling, fermentation characteristics were measured and bacterial diversity was investigated by 16S ribosomal RNA gene sequencing using Illumina MiSeq platform. LP and LC decreased pH, coliform bacteria counts and increased lactic acid content at 20°C, and the two strains decreased pH, ammonia‐N concentration, coliform bacteria counts at 30°C. When the environmental temperature was 40°C, silage treated with LC showed lower LAB and coliform bacteria counts and higher lactic acid content than the untreated and LP treated silages. Butyric acid mainly appeared in silages stored at 40°C. The relative abundance of Lactobacillus in alfalfa silages stored at 20°C and 30°C was highest and increased after LP and LC were added. Garciella was another dominant genus in silages stored at 40°C. In conclusion, LP and LC improved fermentation quality of alfalfa silage by increasing Lactobacillus proportions at 20°C and 30°C; ensiling alfalfa at 40°C was difficult because of Garciella.