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.     

Effect of total mixed ration silage containing agricultural by-products with the fermented juice of epiphytic lactic acid bacteria on rumen fermentation and nitrogen balance in ewes

The goal of this study was to determine the effects of the fermented juice of epiphytic lactic acid bacteria (FJLB) on the quality of total mixed ration (TMR) silage containing agricultural by-products, its digestibility, rumen fermentation, and nitrogen balance in ewes. TMR was prepared from rice straw, corn stover silage, brewer grain, tofu waste, steam-flaked corn, and a mineral mixture. The treatments consisted of silage additives added to TMR: CON (no silage additive), FJLB, COM (commercial additive), and MIX (FJLB + COM). Four cannulated ewes were assigned to the 4 × 4 Latin square design. The MIX treatment produced a lower (P < 0.01) pH than did the CON and FJLB treatments and a higher (P < 0.01) lactic acid concentration than did the other treatments. The fiber content in the COM treatment was lower (P < 0.05) than that in the other treatments. The FJLB treatment had similar fermentation quality and chemical composition to those of the CON and COM treatments in all parameters observed. Although the silage quality index (Fleig point) was higher in the MIX and COM treatments than in the CON treatment, all silages had good quality. No silage additives affected intake, digestibility, rumen fermentation, or nitrogen balance. In conclusion, the TMR silage prepared from agricultural by-products mixed with wet-type food by-products with or without FJLB added resulted in well-preserved fermentation, and this product might be used as a ruminant feed.

     

单宁酸和乳酸菌对紫花苜蓿青贮品质和体外瘤胃发酵的影响

为评价单宁酸和乳酸菌单独以及组合添加对紫花苜蓿（Medicago sativa L.）青贮品质和体外瘤胃发酵的影响,本试验以晾晒至含水量约为55%的初花期紫花苜蓿为青贮原料,设无添加剂为对照组（CK）,单宁酸（Tannic acid,TC）、乳酸菌（Lactic acid bacteria,L）和单宁酸+乳酸菌（Tannic acid+Lactic acid bacteria,TL）为添加剂处理组。青贮60 d后开袋取样,测定相关指标。结果表明：添加剂处理组均显著降低了青贮饲料的pH值、乙酸和非蛋白氮含量（P<0.05）,干物质和真蛋白含量显著增加（P<0.05）;添加剂处理组均能促进瘤胃丙酸生成,提高微生物蛋白产量（P<0.05）;与TC处理组相比,TL处理组能够减轻TC处理组对青贮饲料干物质降解的抑制作用。综上,单宁酸和乳酸菌组合添加对紫花苜蓿青贮饲料品质的调控作用效果最好。     

添加绿汁发酵液、乳酸菌制剂和葡萄糖对象草青贮发酵品质的影响

为评价添加绿汁发酵液、乳酸菌制剂和葡萄糖对象草青贮发酵品质的影响,试验设6个处理组:即对照组(无添加剂),绿汁发酵液组(FJLB),乳酸菌制剂组(LAB),葡萄糖组(G),绿汁发酵液＋葡萄糖组(FJLB+G),乳酸菌制剂＋葡萄糖组(LAB+G);在青贮第3,7,14,30天开窖,取样分析发酵品质。结果表明,与对照组相比,LAB处理对发酵品质影响不大,FJLB处理显著(P<0.05)降低了乳酸和水溶性碳水化合物含量,显著(P<0.05)提高了pH值、乙酸、丁酸和氨态氮含量,使发酵品质变差,而G、LAB+G和FJLB+G处理均显著(P<0.05)提高了青贮早期的乳酸含量,在整个青贮过程中保持较高的乳酸/乙酸值,并显著(P<0.05)降低了最终青贮饲料的pH和氨态氮含量,但与G处理相比,LAB+G和FJLB+G处理没有显示出更优的效果。综上所述,添加葡萄糖可促进同型乳酸发酵,对象草青贮发酵品质的改善效果优于接种乳酸菌。     

不同添加剂对陇东紫花苜蓿青贮品质的影响

生物添加剂在促进牧草青贮发酵过程中有益菌和酶的活性、提高消化率和改善发酵品质等方面发挥着重要作用。本研究以初花期刈割的第1茬陇东紫花苜蓿(Medicago sativa)为原料,分析不同添加剂(甲酸、蔗糖、EM菌液和纤维素酶)对青贮发酵品质的影响。结果表明,4种添加剂处理组苜蓿青贮饲料感官评定得分均高于无添加剂对照组,pH、乙酸和氨态氮(NH₃-N)/总氮(TN)含量均显著(P<0.05)低于对照组,乳酸含量均显著(P<0.05)高于对照组,且未检测到丁酸和丙酸。4种添加剂处理组的粗蛋白质含量均显著(P<0.05)高于对照组,酸性洗涤纤维含量均显著(P<0.05)低于对照组。蔗糖组、EM菌液组和纤维素酶组的中性洗涤纤维含量均显著(P<0.05)低于甲酸组和对照组。粗灰分含量各组间无显著差异(P>0.05)。4种添加剂处理组的有氧稳定性均显著(P<0.05)高于对照组。上述结果说明,4种添加剂都可以提高陇东紫花苜蓿青贮的发酵品质、营养价值,延长有氧稳定性。但以纤维素酶组pH、乙酸和NH₃-N/TN含量最低,乳酸含量最高,青贮发酵品质最佳,建议在生产实践中大量推广应用。     

昆明优质本土乳酸菌的筛选及其对全株玉米青贮品质的影响

为筛选出适用昆明地区全株玉米青贮发酵的优质乳酸菌菌株,探求其青贮效果,本研究以自然发酵60 d的全株玉米(Zea mays)、紫花苜蓿(Medicago sativa)、鸭茅(Dactylis glomerata)为试验材料,将继代培养、菌株分离和形态及基因序列鉴定等方式筛选的3株优质菌株制成菌液,单独或2种菌液按1∶1配比添加到全株玉米中,检测其对全株玉米发酵品质、营养品质及有氧稳定性的提升效果。结果表明：短乳杆菌B10、植物乳杆菌B16及戊糖片球菌C23是昆明地区3种青贮饲料中的优质本土乳酸菌;与自然发酵相比,同型发酵乳酸菌B16,C23单独添加或与异型发酵乳酸菌B10配合添加可显著提高青贮饲料中乳酸菌的数量(P＜0.05);与商用复合乳酸菌相比,优质本土乳酸菌单一菌液或复合菌液的添加可更好的保存青贮饲料的DM及CP含量,但对青贮饲料有氧稳定性的提升效果相对较差。因此,添加本土优质乳酸菌可改善全株玉米青贮品质。     

绿汁发酵液中的微生物多样性及其对菌糠发酵品质的影响

本试验旨在通过高通量测序技术,测定分析5种不同原料制备的绿汁发酵液的微生物分布情况,通过Alpha多样性、主成分分析等解明其微生物群落结构。同时,为探究其微生物与发酵品质的关联性,本试验调制了对照组（无添加）和添加2%绿汁发酵液的5个菌糠青贮处理组,每个处理5个重复。结果表明：5种材料制作的绿汁发酵液样本通过Illumina Miseq测序平台共获得548 266条高质量有效序列,经分类学鉴定分属23门,129属,其中丰度大于1%的有9属。聚类分析结果表明甘蔗梢、玉米秸秆和葛藤绿汁发酵液归为一类,红象草和菌糠绿汁发酵液各自单独一类。5种绿汁发酵液处理组的菌糠青贮料乳酸含量显著（P<0.05）升高,丁酸含量显著（P<0.05）降低,能够提高青贮料的发酵品质。其中,红象草绿汁发酵液处理菌糠的发酵效果最佳,原因是象草绿汁发酵液中与青贮发酵密切相关菌属的分布比例最高。     

不同乳酸菌添加剂对青贮黑麦草和青贮玉米发酵产物和有氧稳定性的影响

在青贮黑麦草(Lolium perenne)和青贮玉米(Zea mays)中添加鼠李糖乳杆菌和布氏乳杆菌,研究其对发酵产物与有氧稳定性的影响.青贮饲料贮藏时间为14,56和120 d.无添加青贮黑麦草发酵产物中乙醇含量较多,在14 d开封时,乙醇和2,3-丁二醇含量为乳酸和挥发性脂肪酸总和的7倍.添加鼠李糖乳杆菌与布氏乳杆菌可以抑制乙醇型发酵,使乳酸型与乙酸型发酵占主导.无添加青贮黑麦草与添加鼠李糖乳杆菌的黑麦草发生了有氧腐败,但是添加布氏乳杆菌的黑麦草保持了有氧稳定.在青贮玉米中,添加鼠李糖乳杆菌未影响发酵品质,但添加布氏乳杆菌增加了发酵产物中乙酸含量,降低了乳酸含量.添加布氏乳杆菌的青贮玉米从56 d开封开始保持了有氧稳定,其它组在120 d开封时保持了有氧稳定,所有组乙酸含量都增加.     

Effect of applying lactic acid bacteria and propionic acid on fermentation quality and aerobic stability of oats‐common vetch mixed silage on the Tibetan plateau

The objective of this study was to evaluate effects of lactic acid bacteria and propionic acid on the fermentation quality and aerobic stability of oats‐common vetch mixed silage by using a small‐scale fermentation system on the Tibetan plateau. (i) An inoculant (Lactobacillus plantarum) (L) or (ii) propionic acid (P) or (iii) inoculant + propionic acid (PL) were used as additives. After fermenting for 60 days, silos were opened and the aerobic stability was tested for the following 15 days. The results showed that all silages were well preserved with low pH and NH₃‐N, and high lactic acid content and V‐scores. L and PL silages showed higher (P < 0.05) lactic acid and crude protein content than the control silage. P silage inhibited lactic acid production. Under aerobic conditions, L silage had similar yeast counts as the control silage (> 10⁵ cfu/g fresh matter (FM)); however, it numerically reduced aerobic stability for 6 h. P and PL silages showed fewer yeasts (< 10⁵ cfu/g FM) (P < 0.05) and markedly improved the aerobic stability (> 360 h). The result suggested that PL is the best additive as it could not only improved fermentation quality, but also aerobic stability of oats‐common vetch mixed silage on the Tibetan plateau.     

添加乳酸菌和菠萝皮对柱花草青贮品质的影响

柱花草是热带、亚热带的优质豆科牧草,蛋白含量高、营养品质好,为促进柱花草的加工利用,本试验研究了添加不同乳酸菌和菠萝皮对其青贮发酵品质和有氧稳定性的影响。青贮处理为CK(对照)、LQ(青贮宝)、LF(发酵乳杆菌)、LP(植物乳杆菌)、LS(鼠李糖乳杆菌)、B(20%菠萝皮)、BLQ(B+LQ)、BLF(B+LF)、BLP(B+LP)、BLS(B+LS)。添加处理后青贮60 d进行分析。结果表明,柱花草含有较少的可溶性碳水化合物和乳酸菌,自然青贮其pH超过5.0,发酵品质差;所有添加物都显著降低pH、增加乳酸含量(P＜0.05),明显改善了柱花草青贮料的发酵品质。单独添加菠萝皮的丁酸和NH₃-N含量显著高于所有单独添加乳酸菌(P＜0.05),pH与LP以外的其他3种乳酸菌差异不显著(P＞0.05)。除LP的乙酸含量较高,丁酸含量较低外,4种乳酸菌对其他各个发酵指标的影响没有显著差异(P＞0.05)。本试验所用4种乳酸菌与菠萝皮混合添加,都进一步改善了柱花草青贮料的发酵品质,特别是BLP的青贮效果最佳,其pH值、乙酸和NH₃-N含量低,乳酸含量及乳酸与乙酸比高。青贮袋开封后,包括对照在内的所有青贮料的有氧稳定性均较佳。     

Microbial Diversity of Fermented Juice Using Epiphytic Lactic Acid Bacteria and Their Effects of on the Fermentation Quality of Fungus Chaff Silage北大核心CSCD

The objective of this experiment was to analyze microbial diversity of fermented juice using epiphytic lactic acid bacteria (FJLB). There were 5 kinds of FJLB in this experiment including corn stalk FJLB, red elephant grass FJLB, fungus chaff FJLB, kudzu FJLB and sugarcane top FJLB. Alpha diversity and principal component analysis were carried out to investigate the microbial diversity of 5 kinds of FJLB. In order to investigate the fermentation effect of 5 kinds of FJLB, the control group (without adding) and adding 5 kinds of 2% FJLB to fungus chaff silage treatments were made. Each treatment had 5 repeats. The results showed that a total of 548 266 high-quality effective sequences were obtained by Illumina Miseq sequencing platform, and totally 23 phyla, 129 genera of bacteria were identified in samples of 5 kinds of FJLB. And there were 9 genera with abundance greater than 1%. Cluster analysis results showed that sugarcane FJLB, corn stalk FJLB and kudzu FJLB were classified into one group, red elephant grass FJLB and fungus chaff FJLB fell into one category separately. The lactic acid was significantly increased (P< 0.05), the butyric was significantly decreased (P < 0. 05) when treated with 5 kinds of FJLB. What's more, the lowest pH value and the highest lactic acid content were achieved by treated with red elephant grass FJLB. By Miseq high-throughput sequencing technology, we found out that the highest proportion of genera of bacteria which were closely related to silage fermentation quality were red elephant grass FJLB. © 2019 China Agricultural University. All rights reserved.     

乳酸菌对苜蓿青贮发酵品质和细菌菌群的影响

为探究乳酸菌作为青贮添加剂对苜蓿青贮发酵品质和细菌菌群的影响,试验选取萎焉苜蓿为原料分为三个处理组,分别为无添加剂对照组(CK组)和分别添加1×106cfu/g乳酸菌YX(LPI组)、乳酸菌ZZU A341(LPA组)。结果表明:LPI或LPA组乳酸积累量显著高于CK组(P<0.05),pH和氨态氮含量显著低于CK组(P<0.05),且pH均降至5.00以下;CK组或LPI组的优势菌属为Pediococcus属(56.40%、98.63%),LPA组为Lactobacillus属(98.88%)。综上所述,乳酸菌作为青贮添加剂可通过调控青贮环境中细菌菌群的组成或相对丰度,从而提高青贮苜蓿的发酵品质。     

添加剂和混合比例对裸燕麦和紫花苜蓿混贮品质的影响

探讨添加剂和不同混合比例对裸燕麦和紫花苜蓿混贮饲料品质的影响,为开展牧草混播及调制高质量的混合青贮饲料提供参考。以裸燕麦和紫花苜蓿为原料,按质量比1∶1、2∶1和1∶2进行混合青贮,并分别加入0.4% 甲酸(formic acid,FA)或2%蔗糖(sucrose,S),青贮60 d后测定混合青贮饲料的发酵品质和营养物质含量。结果显示,裸燕麦与苜蓿混合比例为2∶1时青贮饲料的感官评价上均优于其余2种混合比例,添加0.4%甲酸或者2%蔗糖,感官评定为优并显著高于对照组(P<0.05)。混合青贮饲料的发酵品质随裸燕麦比例增加而不同程度提高。其中,pH值随裸燕麦比例增加而逐渐降低;在裸燕麦与苜蓿混合比例在2∶1时,添加2%蔗糖组乳酸(lactic acid,LA)含量显著高于对照及0.4%甲酸处理组(P<0.05),且与另外2种混合比例的处理组相比差异均显著(P<0.05);此混合比例下添加0.4%甲酸处理组pH值和氨态氮/总氮(AN/TN)较低,乙酸(acetic acid,AA)和总挥发性脂肪酸(total VFA,TVFAs)含量最低,乳酸含量及乳酸/乙酸(LA/AA)较高,丙酸(propionic acid,PA)和丁酸(butyrate acid,BA)含量极低未检出,V-Score评分最高,总体发酵品质最佳。随苜蓿比例增加,混贮饲料CP含量提高,纤维组分(NDF、ADF和HC)含量降低,青贮饲料养分更加均衡,但添加剂对青贮饲料营养成分影响不大。裸燕麦与紫花苜蓿混合青贮可形成养分互补,提高营养价值;加入适量甲酸或蔗糖有助于抑制不良发酵,提高发酵品质。     

添加剂对紫花苜蓿青贮品质及小肠可吸收氨基酸的影响

为研究添加复合乳酸菌和葡萄籽单宁对紫花苜蓿(Medicago sativa L.)青贮品质及小肠可吸收氨基酸的影响，选用凋萎后二茬现蕾期紫花苜蓿为材料，设置对照(CK)，葡萄籽单宁(G)、复合乳酸菌(戊糖乳杆菌+戊糖片球菌+乳酸片球菌，L)和复合乳酸菌+葡萄籽单宁(LG)组，青贮60 d后测定其品质，并采用体外三步法测定其小肠可吸收氨基酸含量。结果表明：与CK组相比，G和LG组青贮饲料乳酸、乙酸、丁酸、总挥发性脂肪酸和氨态氮含量均显著降低(P<0.05)；L和G组粗蛋白含量显著提高(P<0.05)。与其他三组相比，G组青贮饲料的Ile，Leu，Lys，His，Arg，Tyr和总氨基酸含量显著提高，菌体蛋白以及小肠可吸收Ile，Lys，His，Arg，Ser和总氨基酸含量显著提高(P<0.05)。因此，添加葡萄籽单宁对紫花苜蓿青贮品质有一定改善作用，明显提高青贮饲料中Lys，His和Arg以及总氨基酸的小肠可吸收量。     

添加剂对温湿生境青贮玉米发酵品质及有氧稳定性的影响

为探讨不同添加剂对贵州温暖湿润气候环境下生长的全株玉米（Zea mays L.）青贮饲料发酵品质及有氧稳定性的影响,试验选用贵州本土常见的玉米品种进行全株青贮,设对照组和添加剂组（乳酸菌制剂、食盐、丙酸）。青贮60 d后开封,测定青贮饲料的发酵品质、化学成分和有氧稳定性。结果表明：各组发酵品质均较好,感官评价能达到一级优良,有机酸评分均为满分。有氧稳定性表现最好的为丙酸组,为110.5 h,显著高于除食盐处理组之外其它组（P<0.05）。各添加剂处理组均能改善全株玉米青贮饲料的营养水平,采用模糊数学隶属函数法对营养水平进行评价排名,结果表现为：丙酸组 > 乳酸菌制剂组 > 食盐组 > 对照组。因此,全株玉米青贮时不使用添加剂也能获得发酵品质较好的青贮料;综合考虑营养水平和有氧稳定性,在贵州温暖湿润气候环境下,选用丙酸为全株玉米青贮添加剂最适宜。     

添加剂对苜蓿青贮料品质和乳酸菌群的影响

以紫花苜蓿（Medicago sativa）为原料,分别添加植物乳杆菌WN5（Lactobacillus plantarum WN5,保藏号为CGMCC NO.7469）和干酪乳杆菌SN3（L.casei SN3,CGMCC NO.7470）的菌液,以及菌液与蔗糖、纤维素酶的混合液后青贮,探讨添加剂对苜蓿青贮料品质和乳酸菌群的影响。结果表明：苜蓿直接青贮发酵品质差;添加剂可改善苜蓿青贮料的发酵品质;添加乳酸菌和蔗糖对于苜蓿青贮饲料的营养价值和乳酸菌群有更明显的改善,青贮饲料中乳酸菌群占绝对优势,植物乳杆菌WN5和其他乳酸菌存活,但乳酸菌种类因蔗糖浓度不同而有差异;添加10 mL乳酸菌和2.0 g蔗糖的效果最好,其苜蓿青贮饲料的pH最低,粗蛋白、甲酸、乙酸和丙酸的含量最高,乳酸菌群的遗传差异大。乳酸菌和蔗糖作为优质添加剂,在苜蓿青贮发酵过程中可以保留大量不同种类的乳酸菌群,从而有利于形成品质良好的青贮苜蓿。     

Effects of chlorpyrifos and chlorantraniliprole on fermentation quality of alfalfa (Medicago sativa L.) silage inoculated with or without Lactobacillus plantarum LP

The effects of pesticides and Lactobacillus plantarum (LP) on fermentation quality of alfalfa (Medicago sativa L.) silage were investigated. Chlorpyrifos and chlorantraniliprole were sprayed on the surface of alfalfa plants at 658.6 and 45.0 g active ingredient/ha, respectively. Alfalfa plants were harvested on day 5 post‐application and ensiled with or without LP. Chlorpyrifos and chlorantraniliprole decreased the yeast count of alfalfa material (P < 0.05). Both pesticides increased the butyric acid content of alfalfa silage (P < 0.001). Chlorpyrifos increased pH and decreased lactic acid, acetic acid and short‐chain fatty acid contents (P < 0.05). LP decreased pH and butyric acid content, and increased lactic acid and short‐chain fatty acid contents of alfalfa silage treated with pesticides (P < 0.05). LP increased the concentration of chlorpyrifos residue in alfalfa silage (P < 0.05). Chlorpyrifos and chlorantraniliprole affected the microbial communities of the material before ensiling, especially coliform bacteria and yeast; the two pesticide residues were reduced after the fermentation of alfalfa silage and affected the fermentation process, whereas LP improved the fermentation quality of pesticides‐contaminated alfalfa silage and slowed down the dissipation of chlorpyrifos.     

添加剂对全株燕麦青贮饲料发酵品质和有氧稳定性的影响

为了提高全株燕麦（Avena sativa L.）的饲料化程度,本研究以无添加剂组为对照,探究了添加植物乳杆菌（LP,1×10^-5 cfu·g^-1）、糖蜜（ML,0.4%）、食用油（OL,1%）、丙酸（PA,0.4%）、茶多酚（TP,0.4%）以及茶多酚和糖蜜组合（TP+ML,0.4%+0.4%）对全株燕麦贮饲料发酵品质和有氧稳定性的影响。结果表明,与对照组相比,LP,ML,PA以及TP+ML添加组增加了乳酸含量（P<0.05）,减少了好氧性细菌数量（P<0.05）,提高了发酵品质。有氧暴露阶段,TP+ML添加组的有氧稳定性最佳,超过48 h。综上所述,TP+ML添加组提高了发酵品质和有氧稳定性,可作为青贮添加剂生产优质全株燕麦青贮饲料。     

紧实度对青贮玉米有氧稳定期发酵品质、微生物数量的效应研究

本研究旨在分析不同紧实度对全株玉米青贮有氧暴露期间发酵品质和微生物变化的影响,为生产实践选择适宜的青贮紧实度提供参考。以新饲玉10号青贮玉米为材料,发酵装料密度设计为5个梯度(350,400,500,600,700 kg/m³),发酵期为50 d,检测开窖后各紧实度处理第12,24,36,60,108 h青贮发酵品质和主要微生物的变化,并用多通道温度记录仪监测温度变化。结果表明,有氧暴露时间与紧实度的交互作用对pH、乳酸、乙酸和氨态氮含量以及乳酸菌、霉菌、酵母菌和好氧细菌数量产生极显著影响(P<0.01)。开窖108 h后,紧实度为600 kg/m³青贮饲料的乳酸菌数量最多,达到8.17 lg cfu/g FW,其pH值和氨态氮含量最低,霉菌和酵母菌数量最少,分别为5.38和7.72 lg cfu/g FW;且紧实度600 kg/m³有氧暴露后稳定的时间显著高于其他处理(P<0.05),达到100 h。通过综合评价,在有氧暴露后紧实度为600 kg/m³的全株玉米青贮发酵品质及有氧稳定性最好,建议600 kg/m³为全株玉米最佳青贮紧实度。     

刈割期和添加剂对苜蓿青贮发酵品质和 CNCPS蛋白组分的影响

为研究刈割时期及添加剂对苜蓿(Medicago sativa)青贮品质的影响,本试验选择2个茬次,现蕾、初花、盛花3个时期刈割,并以无添加(CK)、丙酸钠(SP,0.5%)、乳酸菌(LD,106 cfu·g~(-1))3种处理进行苜蓿青贮制作,在贮存45d后取样,分析其发酵品质及营养价值。结果发现,随着收获时期的延迟,青贮苜蓿pH值呈下降的趋势;丙酸钠及乳酸菌添加剂的添加对苜蓿青贮饲料的发酵品质有显著的改善作用;随着同一茬次生育期的延长,青贮苜蓿中的粗蛋白(CP)含量显著降低(P0.05);刈割时期可显著降低苜蓿青贮饲料的pH值并明显提高乳酸含量(P0.05),对乙酸及丙酸含量影响不显著(P0.05)。而添加剂可显著增加乙酸含量(P0.05),两者存在显著互作效应(P0.05)。添加乳酸菌的现蕾期苜蓿青贮品质最佳。应用康奈尔净碳水化合物-蛋白质体系(CNCPS)提出的方法测定表明,第1茬盛花期的苜蓿青贮饲料的非蛋白氮(PA)含量较高,苜蓿青贮饲料各处理中的中速降解蛋白质(PB2)含量均是占可降解蛋白质(PB)含量的最大比例。