A review of okara (soybean curd residue) utilization as animal feed: Nutritive value and animal performance aspects

Year by year, huge quantities of by-products are generated during the manufacturing process of soybean-based products. Okara is one of the by-products, and it is an insoluble portion of the soybean. It consists of high moisture (8.4–22.9%); on dry matter basis, it contains high metabolizable energy (9.0–14.2 MJ/kg) and other components that include crude protein (20.9–39.1%), crude fiber (12.2–61.3%), crude fat (4.9–21.5%), and ash (3.4–5.3%). Fermentation of okara improves its nutritional quality and reduces its anti-nutrient contents. Due to animals' palatability, okara can be used to replace the soybean meal/concentrate feed partially or completely in ruminant's diet and partially in nonruminant's diet. Okara feeding does not depress the intake, digestibility, growth, milk production, blood metabolic profiles, and meat quality of animals. However, this by-product decays quickly due to its high moisture content, and its heavy weight and sticky nature make it difficult to process and expensive to dry using conventional methods. This paper thoroughly summarizes the utilization of okara as animal feed in the cause of developing a general guideline with favorable levels of inclusion in the diets of animals for its exploitation and valorization. This review will encourage further research to develop eco-friendly and value added feed for animals.     

颗粒大小和几种预处理方法对浒苔厌氧发酵产沼气的影响

近年来,由于生态环境变化和人为等因素,我国东部沿海遭受大规模浒苔侵袭的现象时有发生。开展浒苔的沼气发酵研究,一方面可以使这种优质的大型海藻类生物质原料被合理高效地利用,变废为宝;另一方面可以丰富沼气发酵原材料的种类,达到可再生能源开发的目的。该实验研究了不同颗粒大小（粗粒0.30~0.85 mm、中粒0.15~0.30 mm、细粒0.075~0.15 mm）和碱预处理法、热预处理法、酸预处理法对浒苔在高温条件下发酵产沼气的影响。研究表明,当温度为50 ℃、初始pH为7、接种率为10%、料液总固形物（TS）质量分数为8%的条件下厌氧发酵浒苔,粗粒组、中粒组和细粒组的浒苔挥发性固体（VS）产气率分别为386.9 mL/g、434.4 mL/g、436.5 mL/g。其中,中粒组比粗粒组产气总量提高了12.26%,细粒组比中粒组产气总量提高了0.49%。这说明粒度越小越有利于提高浒苔沼气发酵的利用率;在相同发酵条件下（同上试验）,碱、热、酸预处理组分别比未预处理组产气总量提高13.14%、11.39%和3.63%。其中,碱预处理组的VS产气率最高,为493.3 mL/g,发酵过程中pH也较为稳定。因此,碱预处理法在提高浒苔厌氧发酵的沼气产量方面效果最佳。该研究的成果可为厌氧发酵浒苔生产沼气的工艺研究及生产提供参考。     

人工瘤胃评价屎肠球菌对瘤胃发酵的影响

【目的】探讨屎肠球菌对瘤胃发酵的影响,以此评价屎肠球菌能否作为直接饲用微生物用于反刍动物的生产。【方法】利用持续动态人工瘤胃装置,采用完全随机试验设计,以不添加屎肠球菌发酵液为对照,研究了添加1.25×106和6.25×106mL-1屎肠球菌发酵液对瘤胃液pH、微生物蛋白(MCP)、氨态氮(NH3-N)、乙酸、丙酸、丁酸和总挥发性脂肪酸(TVFA)浓度的影响。【结果】添加屎肠球菌对瘤胃pH值和MCP无显著影响(P>0.05),但能显著提高瘤胃NH3-N浓度(P<0.01);与对照组相比,1.25×106mL-1屎肠球菌液添加组显著提高了瘤胃液的乙酸与总挥发性脂肪酸浓度(P<0.05),而添加屎肠球菌对瘤胃丙酸和丁酸浓度及乙酸与丙酸的比例没有显著影响(P>0.05)。【结论】添加一定量的屎肠球菌,可在不改变瘤胃发酵类型的情况下促进饲料中碳水化合物的消化。     

蔬菜残株沼气发酵液对薄皮甜瓜幼苗生长的影响

[目的]分析不同浓度沼气发酵液两种喷施方式对甜瓜幼苗生长发育的影响.[方法]以薄皮甜瓜(Cucumis melo)“京蜜11号”为试材、蔬菜残株为材料制作沼气发酵液,进行喷施和浇灌两种施用方式后,利用测量法观察株高、茎粗、地上部干重和地下部干重的变化.[结果]喷施沼气发酵液可以提高甜瓜幼苗株高和茎粗,促进真叶生长,增加地上部和地下部的干重,以300倍液沼气发酵液表现最明显,株高、茎粗、地上部和地下部的干重比对照分别增加31％、38％、57％,54％;浇灌不同浓度的沼气发酵液,株高、茎粗、地上部和地下部的干重比对照也有不同程度的增加.[结论]整体来看,喷施和浇灌沼气发酵液都能促进甜瓜幼苗生长,且喷施效果优于浇灌且以300倍液沼气发酵液为最优.     

长寿老人源双歧杆菌的鉴定及发酵胡萝卜饮品的研制

为研究新型益生菌产品,开发研制多功能发酵饮料,通过生理生化鉴定、16S rRNA结合tuf基因鉴定确定一株分离自广西巴马长寿老人肠道的菌株为长双歧杆菌长亚种（Bifidobacterium longum subsp. longum Blm)。采用该菌株发酵胡萝卜汁,通过L9(34)正交试验分别对培养成分和发酵条件进行优化,得到最佳发酵工艺为胡萝卜与水的质量比为1∶3,脱脂牛乳添加量为5%,蔗糖添加量为2%,接种量5%,发酵温度37℃,起始pH为6.8,在此最优条件发酵获得的双歧杆菌发酵饮品,活双歧杆菌菌数高达1010 CFU/mL。发酵后饮料中维生素B1、B2、B6、B12的含量较发酵前显著增加,分别为264 μg/g、10.3 μg/g、220 μg/g和21.4 μg/g。长双歧杆菌Blm发酵胡萝卜汁饮料活菌数高,维生素和氨基酸含量丰富,感官品质良好,具有开发为活菌饮品的潜质。     

紫丁香蘑菌丝体液体发酵培养基的筛选

[目的]选出适合紫丁香蘑(Lepista nuda)菌丝生长的液体发酵培养基。[方法]以紫丁香蘑菌丝体干重和胞外糖含量为评价指标,通过正交试验筛选出最适合紫丁香蘑菌丝生长的液体发酵培养基。[结果]碳源对菌丝体生长的影响最大,其次是KH_2PO_4和氮源,最后是MgSO_4。[结论]最适液体发酵培养基为:可溶性淀粉2%(w/V),酵母浸粉0.5%(w/V),KH_2PO_40.3%(w/V),MgSO_40.05%,CaCl_20.001%,VB10.001%(w/V),pH 7。     

红萍发酵过程中一些营养及理化特性的变化

红萍干萍、米糠等按C∶N比为25~30进行堆肥发酵,利用微生物分解红萍制作红萍有机肥。红萍发酵过程中温度迅速上升直至最高温度,然后开始下降;此时进行适时翻堆,当翻堆后温度又开始升高,然后再次下降;再次进行翻堆,温度又重复如此变化,但每次变化程度都有所不同,呈现不断加剧现象。pH值则呈不断上升趋势。不同营养成分发生了不同的变化,全N、P、K和速效P、K呈下降然后再上升趋势,速效N呈上升趋势,其含量得到了大大的提高。由此可见采用此方法可以制成优质的红萍有机肥。     

The effects of fermentation and adsorption using lactic acid bacteria culture broth on the feed quality of rice straw

To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution(50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula) kg–1 straw dry matter, or spraying a large amount of culture broth(1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth) on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter(DM) and crude protein(CP) concentrations, lower neutral detergent fiber(NDF), acid detergent fiber(ADF) and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM(IVDMD). The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.     

海洋氧化短杆菌15E产碱性蛋白酶的发酵条件

对氧化短杆菌15E菌株(Brevibacterium oxydans)产碱性蛋白酶的发酵条件进行研究,结果表明,培养基初始pH值9.0、培养温度28℃、摇床转速200.rmin-1条件下培养40 h,菌体生长最适且总酶活力达到最大;菌株在添加5 g.L-1牛肉膏、1 g.L-1葡萄糖的酪蛋白培养基中生长和产酶均达到最佳;人工海水中的K+、Ca2+和Mg2+浓度较为适合15E菌株生长和产酶,其中K+对菌株产酶起关键作用.     

梅林青霉液态发酵生产纤维素酶条件的研究

研究不同培养条件对梅林青霉液体发酵产纤维素酶的影响,为此对不同碳源、氮源、pH、培养温度、摇瓶转速和摇瓶装量、发酵时间培养条件下羧甲基纤维素酶、滤纸酶、β-葡萄糖苷酶活力进行了测定.结果表明,碳源麦麸诱导效果好于稻草、玉米秸、羊草;氮源中尿素明显降低β-葡萄糖苷酶活力,豆饼、硝酸钠和蛋白胨之间影响不明显;28℃和pH5.0是产纤维素酶最佳温度与酸碱度;通过响应面与等值线分析可知,在摇床转速170～180 r·min-1,摇瓶装量30～40 mL时,羧甲基纤维素酶、β-葡萄糖苷酶显示较高活性;摇床转速140～150 r·min-1,摇瓶装量40～50 mL时,滤纸酶显示较高活性;梅林青霉在Bioengineering的NLF19生物反应器液体发酵大约11 d时3种酶活力达到最高.