混合乳酸菌发酵生产玉米秸秆青贮饲料的研究

采用正交试验的方法,向青绿玉米秸秆中添加不同配比的乳酸菌,进行厌氧发酵,20天后检测pH值,分析得出青贮饲料最佳的乳酸菌组合,即明串珠球菌1×104 cfu/g、植物乳杆菌1 × 104 cfu/g、短乳杆菌1×106 cfu/g.在此基础上添加纤维素酶和亚硝酸钠作为发酵促进荆,进行优化试验,得到pH值3.65,氨态氮与总氮的比值7.5,乳酸含量1.21%.     

玉米秸秆青贮添加剂的研究与应用

筛选得到高产乳酸菌株WGY-3,利用正交试验法确定出WGY-3菌株液体发酵的培养基配方为:葡萄糖20 g/L、豆粕26 g/L、西红柿汁20 g/L、K:HPO41 g/L、Na2HPO4 2g/L.最佳液体发酵条件:pH值6～7,温度为38℃,接种量为4%,发酵时间15h,WGY-3菌株的最佳添加量为188 ml/(100 g玉米秸秆).     

复合酶和乳酸菌制剂对玉米秸秆青贮发酵品质的影响

为研究复合酶和乳酸菌制剂对玉米秸秆青贮发酵品质的影响,共设2个处理组,试验组:玉米秸秆+1kg/t复合酶制剂+20g/t乳酸菌制剂;对照组:玉米秸秆。结果表明:试验组干物质和粗蛋白质含量都显著高于对照组(P0.05),而中性洗涤纤维和酸性洗涤纤维含量均显著低于对照组(P0.05)。试验组乳酸、乙酸和丙酸水平均显著高于对照组(P0.05),而pH值、丁酸和氨态氮浓度都显著低于对照组(P0.05)。综合分析得出,添加复合酶和乳酸菌制剂可使玉米秸秆青贮发酵品质得以明显改善。     

球磨预处理和固态发酵对玉米秸秆饲用品质的影响

玉米秸秆经球磨预处理后物理空间结构和化学物质结构改变,更容易被相应的酶降解,进而被微生物利用,其饲用品质提高,从而可能替代饲料中的部分粮食。研究表明,球磨预处理后的玉米秸秆粒径大小均匀,约90%的颗粒集中在10~100μm,酸性洗涤纤维下降3.5%,可溶性总糖提高2.0倍,对其单糖组成分析发现:可溶性总糖的增加主要来自半纤维素和纤维素的分子断裂。用木聚糖酶和纤维素酶酶解球磨预处理后的玉米秸秆,可溶性总糖和还原糖含量比酶解前分别提高了3.3倍和9.7倍,球磨预处理后酶解效率大大提高。球磨预处理的玉米秸秆经固态酶解、发酵后,总酸质量分数达26.3 mg/g,纤维素和半纤维素质量分数分别下降9.1%和4.9%,乳酸菌含量达到1.5×109CFU/g,饲用品质显著提高。     

微生物发酵对玉米秸秆多糖产量及基本结构特征影响

为了进一步探索玉米秸秆的资源化利用途径,本研究以秸秆为唯一碳源进行发酵,并监测了发酵过程中多糖的含量变化。实验组与对照组经Sevage法除蛋白后通过醇沉得到多糖产品FFSP和FFSP0,利用气相色谱(GC)、傅里叶变化红外光谱(FT-IR)和扫描电子显微镜(SEM)对两种多糖产品的基本结构和表面形貌进行了分析对比。结果表明,实验组中发酵液多糖含量比对照组增加了677.54 mg/L;虽然FFSP和FFSP0均主要由鼠李糖、阿拉伯糖、木糖、葡萄糖、甘露糖和半乳糖组成,但其摩尔比由FFSP0的1:4.6:6.5:1.4:2.9:2.5变为1:13.4:16.8:3:2.7:8.4,微生物的存在增加了多糖的含量,并改变了多糖产品的单糖组成;SEM显示FFSP0为粒径小的粗糙的球体,而FFSP为粒径大的较光滑球体。上述实验结果表明,微生物的加入对秸秆多糖的产量与基本结构产生了一定的影响,这为秸秆的综合利用提供了一个新的途径和方向,也为以后的进一步研究提供了实验依据。     

不同长度玉米秸秆青贮对奶牛生产性能的影响

将玉米秸秆以10、26 mm两种不同长度切碎后青贮,分别以直接和全混合日粮(TMR)揉碎两种形式饲喂奶牛进行比较研究.结果表明:两种切碎长度对玉米秸秆青贮质量无明显影响;但无论采用何种饲喂方法,将切碎长度为26 mm的青贮玉米秸秆饲喂给奶牛,奶牛产奶量提高,胎衣不下减少,空怀母牛降低,各种疾病发生减少;同时切碎长度增加还可以提高青贮劳动效率.     

玉米秸秆发酵法生产燃料酒精的研究进展

玉米秸秆是丰富的、可再生的资源,主要由纤维素、半纤维素和木质素组成。玉米秸秆经过预处理,水解和发酵可生成酒精。介绍了玉米秸秆生产酒精几个关键工艺的最新进展。      

玉米秸秆稀酸预处理对发酵抑制物产生的影响

研究了稀硫酸预处理玉米秸秆过程中,硫酸浓度、温度与时间对发酵抑制物甲酸、乙酸、糠醛、羟甲基糠醛以及乙酰丙酸产生的影响.结果表明,发酵抑制物甲酸、乙酸、糠醛、羟甲基糠醛与乙酰丙酸最大量分别为0.60、8.75、4.93、1.02、0.41g/L.随着硫酸浓度增大、温度升高、时间延长,各抑制物生成量增加.正交试验结果表明,影响乙酸生成的因素主次大小依次为硫酸浓度,温度,时间;而影响糠醛生成的因素主次大小依次是温度,硫酸浓度,时间.     

生物处理玉米秸秆的研究进展

本文主要对近十年来,玉米秸秆生物处理方面的研究与利用作了综述。     

玉米秸秆发酵生产燃料乙醇的研究进展

玉米秸秆是丰富的可再生资源,主要由纤维素、半纤维素和木质素组成。秸秆经过预处理,水解和发酵可生成乙醇。秸秆生产乙醇的工艺包括预处理、水解和发酵。介绍了玉米秸秆生产酒精几个关键工艺的最新进展。     

Effects of 8 chemical and bacterial additives on the quality of corn silage

This project aimed to evaluate the effects 8 additives on the fermentation, dry matter (DM) losses, nutritive value, and aerobic stability of corn silage. Corn forage harvested at 31% DM was chopped (10 mm) and treated with (1) deionized water (control); (2) Buchneri 500 (BUC; 1 × 10⁵ cfu/g of Pediococcus pentosaceus 12455 and 4 × 10⁵ cfu/g of Lactobacillus buchneri 40788; Lallemand Animal Nutrition, Milwaukee, WI); (3) sodium benzoate (BEN; 0.1% of fresh forage); (4) Silage Savor acid mixture (SAV: 0.1% of fresh forage; Kemin Industries Inc., Des Moines, IA); (5) 1 × 10⁶ cfu/g of Acetobacter pasteurianus-ATCC 9323; (6) 1 × 10⁶ cfu/g of Gluconobacter oxydans-ATCC 621; (7) Ecosyl 200T (1 × 10⁵ cfu/g of Lactobacillus plantarum MTD/1; Ecosyl Products Inc., Byron, IL); (8) Silo-King WS (1.5 × 10⁵ cfu/g of L. plantarum, P. pentosaceus and Enterococcus faecium; Agri-King, Fulton, IL); and (9) Biomax 5 (BIO; 1 × 10⁵ cfu/g of L. plantarum PA-28 and K-270; Chr. Hansen Animal Health and Nutrition, Milwaukee, WI). Treated forage was ensiled in quadruplicate in mini silos at a density of 172 kg of DM/m³ for 3 and 120 d. After 3 d of ensiling, the pH of all silages was below 4 but ethanol concentrations were least in BEN silage (2.03 vs. 3.24% DM) and lactic acid was greatest in SAV silage (2.97 vs. 2.51% DM). Among 120-d silages, additives did not affect DM recovery (mean = 89.8% ± 2.27) or in vitro DM digestibility (mean = 71.5% ± 0.63). The SAV silage had greater ammonia-N (0.85 g/kg of DM) and butyric acid (0.22 vs. 0.0% DM) than other treatments. In contrast, BEN and Silo-King silages had the least ammonia-N concentration and had no butyric acid. The BEN and A. pasteurianus silages had the lowest pH (3.69) and BEN silage had the least ethanol (1.04% DM) and ammonia nitrogen (0.64 g/kg DM) concentrations, suggesting that fermentation was more extensive and protein degradation was less in BEN silages. The BUC and BIO silages had greater acetic acid concentrations than control silages (3.19 and 3.19 vs. 2.78% DM), but yeast counts did not differ. Aerobic stability was increased by 64% by BUC (44.30 h) and by 35% by BEN (36.49 h), but other silages had similar values (27.0 ± 1.13 h).     

Effect of supplemental tallow on performance of dairy cows fed diets with different corn silage:alfalfa silage ratios

A study was conducted to investigate the response to supplemental tallow of lactating cows fed basal diets with different alfalfa silage:corn silage ratios. We postulated that supplemental tallow will have decreasing negative effects on rumen fermentation, dry matter intake (DMI), and milk fat percentage as the dietary ratio of alfalfa silage:corn silage is increased. Eighteen Holstein cows averaging 134 +/- 14 d in milk were used in a replicated 6 x 6 Latin square design with 21-d periods. Treatments were arranged as a 2 x 3 factorial with 0 or 2% tallow (DM basis) and three forage treatments: 1) 50% of diet DM as corn silage, 2) 37.5% corn silage and 12.5% alfalfa silage, and 3) 25% corn silage and 25% alfalfa silage. Cows were allowed ad libitum consumption of a total mixed ration. Diets were formulated to contain 18% crude protein and 32% neutral detergent fiber. No fat x forage treatment interactions were observed. Fat supplemented cows had lower DMI and produced more milk with less milk fat content relative to non-supplemented cows. Concentration of trans-octadecenoic acids was higher in milk fat of tallow-supplemented cows. Tallow supplementation had no effect on ruminal pH and acetate:propionate ratio, but tended to decrease total volatile fatty acid (VFA) concentration in the rumen. Increasing the proportion of alfalfa silage increased DMI, milk fat percentage, and milk fat yield regardless of the fat content of the diet. Total VFA concentration and acetate:propionate ratio in the rumen were increased in response to higher levels of alfalfa in the diets. These results suggest that replacing corn silage with alfalfa silage did not alleviate the negative response of dairy cows to tallow supplementation at 2% of diet DM.     

The effects of various antifungal additives on the fermentation and aerobic stability of corn silage

In 2 consecutive years, whole plant corn was ensiled in laboratory silos to investigate the effects of various silage additives on fermentation, dry matter (DM) recovery and aerobic stability. In yr 1, chopped forage was treated with 1) no additive (untreated, U), 2) Lactobacillus buchneri40788, 4 × 10⁵ cfu/g of fresh forage (LLB4), 3) L. buchneri 11A44, 1 × 10⁵ cfu/g (PLB), 4) Biomax 5 (Lactobacillus plantarum PA-28 and K-270), 1 × 10⁵ cfu/g (B5), 5) Silo Guard II (sodium metabisulfite and amylase), 0.05% of fresh forage weight (SG), 6) a buffered propionic acid-based additive, 0.1% (Ki-112), 7), sodium benzoate, 0.1% of fresh weight (SB), or 8) potassium sorbate:EDTA (1:1), 0.1% of fresh weight (PSE). Silage treated with LLB4 had the highest concentration of acetic acid compared with other treatments, and yeasts were undetectable in LLB4 (<log₂ cfu/g). Silages treated with SB and PSE had the highest concentrations of water-soluble carbohydrates, the greatest recoveries of DM, and the lowest concentrations of ethanol. Silages treated with B5, SG, and Ki-112 had no effects on fermentation, DM recovery, or aerobic stability. The aerobic stabilities of silages treated with LLB4, SB, and PSE were greatest among all treatments. In yr 2, treatments were: 1) U, 2) LLB4, 3) PLB, 4) PLB at 4 × 10⁵ cfu/g (PLB4), and 5) B5. Silages treated with L. buchneri had greater concentrations of acetic acid but lower concentrations of ethanol than did U- and B5-treated silages. Yeasts were undetected in all silages except in silage treated with B5, which had the poorest aerobic stability of all treatments. Treatments had no effect on DM recovery. Silages treated with PLB, PLB4, and LLB4 remained stable for >210 h.     

Performance of dairy cows fed annual ryegrass silage and corn silage with steam-flaked or ground corn

Twenty-four lactating Holstein cows were used in a 6-wk randomized block design trial with a 2 × 2 factorial arrangement of treatments to determine the effects of feeding ground corn (GC) or steam-flaked corn (SFC) in diets based on either annual ryegrass silage (RS) or a 50:50 blend of annual ryegrass and corn silages (BLEND). Experimental diets contained 49.6% forage and were fed as a total mixed ration once daily for 4 wk after a 2-wk preliminary period. No interactions were observed among treatments. Cows fed BLEND consumed more dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) than those fed RS, but total-tract digestibility of OM, NDF, and ADF was greater for RS than for BLEND. No differences in nutrient intake were observed among treatments during wk 4 when nutrient digestibility was measured, but digestibility of DM and OM was greater for SFC than for GC. Cows fed BLEND tended to produce more energy-corrected milk than those fed RS, resulting in improved efficiency (kg of milk per kg of DM intake). When diets were supplemented with SFC, cows consumed less DM and produced more milk that tended to have lower milk fat percentage. Yield of milk protein and efficiency was greatest with SFC compared with GC. Blood glucose and milk urea nitrogen concentrations were similar among treatments, but blood urea nitrogen was greater for cows fed GC compared with those fed SFC. Results of this trial indicate that feeding a blend of annual ryegrass and corn silage is more desirable than feeding diets based on RS as the sole forage. Supplementing diets with SFC improved performance and efficiency compared with GC across forage sources.     

The effects of Lactobacillus buchneri 40788 and Pediococcus pentosaceus R1094 on the fermentation of corn silage

The effect of inoculating whole-plant corn at the time of harvest with Lactobacillus buchneri 40788 (4 × 10⁵ cfu/g of fresh forage) combined with Pediococcus pentosaceus R1094 (1 × 10⁵ cfu/g) on the fermentation and aerobic stability of corn silage (37% dry matter) through 361 d of ensiling was investigated. Dry matter recovery was similar between treatments throughout the study except at one early time point (14 d), when treated silage had a lower recovery than untreated silage. The concentration of lactic acid was unaffected by inoculation but inoculated silages had greater concentrations of 1,2-propanediol and acetic acid from 56 to 361 d of storage. In general, inoculation decreased the concentration of water-soluble carbohydrates but increased the concentration of ethanol. The numbers of yeasts was lower in inoculated silage at 42, 56, 70, and 282 d of ensiling. However, inoculation did not consistently improve the aerobic stability of silage, suggesting that microbes other than yeasts may have been responsible for aerobic instability in this study. Even after prolonged storage (361 d), silage treated with L. buchneri 40788 and P. pentosaceus R1094 had normal silage fermentation characteristics.     

Performance of lactating dairy cows fed ryegrass silage and corn silage with ground corn, steam-flaked corn, or hominy feed

Forty-eight mid-lactation Holstein cows were used in a 6-wk completely randomized block design trial with a 4 × 3 factorial arrangement of treatments to determine the effects of feeding different proportions of corn silage and ryegrass silage with supplemental ground corn (GC), steam-flaked corn (SFC), and hominy feed (HF) on the performance of lactating dairy cows. Forage provided 49% of the dietary dry matter in the experimental diets, which were formulated to meet National Research Council requirements. Ryegrass silage provided 100, 75, 50, or 25% of the total forage dry matter, with corn silage supplying the remainder. There were no interactions between the proportion of forage provided by ryegrass silage and energy supplement. Dry matter intake and milk protein percentage decreased linearly with increasing proportions of ryegrass silage, but milk protein yield was similar among forage treatments. There were no differences among forage treatments in milk yield, milk fat percentage and yield, and energy-corrected milk yield. Dry matter intake was higher and there was a tendency for increased milk fat percentage for GC compared with SFC or HF. No other differences were observed in milk yield or composition among energy supplements. Plasma urea nitrogen and glucose concentrations were similar among treatments. Under the conditions of this trial, our results indicate that feeding a combination of corn silage and ryegrass silage is more desirable than feeding ryegrass silage alone, whereas supplementation with GC, SFC, or HF supports similar levels of milk production.     

不同微生物青贮剂对全株玉米青贮饲料的影响

选用两种不同的青贮发酵剂对全株玉米进行发酵,观察发酵8 d、10 d、20 d、40 d两种青贮发酵剂对全株玉米微生物消长及营养品质的影响。结果表明,经两种青贮发酵剂处理后,全株玉米青贮饲料均有酒香味;发酵前期（8 d、10 d）乳酸菌生长迅速,酵母菌生长相对缓慢。两种发酵剂对全株玉米青贮饲料的pH值、水分、粗蛋白、粗脂肪、粗灰分和粗纤维含量的影响差异不大,但对总酸、中性洗涤纤维和酸性洗涤纤维含量影响差异较大,青贮发酵剂B适合短期发酵使用,而青贮发酵剂A适合长期发酵保藏使用。两种青贮发酵剂处理的全株玉米青贮饲料中的限制因子（挥发性盐基氮、霉菌、黄曲霉毒素B1、玉米赤霉烯酮、呕吐毒素）均符合相关标准要求。     

Effect of re-ensiling on the quality of sorghum silage

The commercialization of silage in many countries, including Brazil, has increased in recent years. Re-ensiling of previously ensiled forage occurs when silage is relocated from one farm to another, where it will be compacted and sealed again. During this process, silage is exposed to oxygen before being ensiled, which may affect its quality. We exposed sorghum silage to air during the anaerobic storage phase to simulate the transportation of silages between farms. Experimental treatments included silage exposed to air for 0 or 12 h, with or without the use of an inoculant containing a mixture of Lactobacillus plantarum and the propionic bacteria Propionibacterium acidipropionici (1 × 10⁶ cfu/g of forage; Biomax corn, Lallemand, Saint-Simon, France), totaling 4 treatments: conventional silage, conventional silage with inoculant use, re-ensilage after exposure to air, and re-ensilage after exposure to air with use of an inoculant. The sorghum was stored in experimental silos containing about 9.0 kg of fresh forage per replicate. Treatments were tested in a factorial 2 × 2 design with 5 replicates each. Chemical composition, in vitro dry matter digestibility, fermentative characteristics, losses (due to gas, effluents, and total dry matter), microorganism counts, and aerobic stability of sorghum silage were evaluated. Dry matter content of sorghum before ensiling was 273.12 g/kg. The 12-h re-ensiling process increased the effluent loss of the silage when compared with conventional silage (456.42 vs. 201.19 g/kg of FM, respectively). In addition, re-ensiled silages presented lower concentrations of lactic acid and higher concentrations of propionic acid than the silages that had not been opened during storage. The aerobic stability of silage was not affected by the re-ensiling process and the use of inoculant. The use of inoculant increased the pH and loss of dry matter of the silages (4.23 vs. 3.98 and 14.05 vs. 7.82%, respectively) and therefore did not provide any benefits in this study.     

Evaluation of two biodegradable coatings on corn silage quality

This experiment was performed to assess two different biodegradable coating formulations for the preservation of corn silage quality. Soy‐ and casein‐based biodegradable coatings were evaluated for their ability to exclude oxygen and preserve corn silage. Experiments were conducted under natural conditions outdoors. The effect of the coating composition on silage quality was compared with the quality of silage covered with a plastic (0.15 mm) (positive control) and uncovered (negative control) after 4 and 8 week periods. The results showed that the two biodegradable coatings offered the same level of silage protection during the overall experiment (8 weeks). As compared with the negative control, the two formulations prevented deterioration associated with air infiltration (heating, mold growth and dry matter losses) and limited the decrease in nutritive value. Also, the pH of the coated silage was significantly lower (P ≤ 0.05) than the negative control after 4 weeks of storage. Silage coated with the biodegradable coatings was able to maintain the pH below 4.5 during the first 4 weeks of storage. The decline in lactic acid concentration seems to have been initiated by the lactate‐utilizing yeasts, responsible for the increase in the silage pH. No visual growth of mold was observed in silage sealed with biodegradable coatings. This study showed that biodegradable coatings were able to protect the quality of silage during 4 weeks but the biodegradable coatings were not as good as plastic at preserving silage after 8 weeks of storage. Copyright © 2005 Society of Chemical Industry