| 摘要: |
| 【目的】筛选生氰糖苷（CGs）降解菌株并探究其对亚麻籽饼的发酵效果。【方法】采用七叶苷柠檬酸铁平板法从绵羊瘤胃初筛CGs降解菌株，然后用复筛发酵培养基进行复筛，并对筛选所得的菌株进行鉴定。以CGs降解率为指标，对菌液接种量(体积分数5%，10%，15%，20%和25%)、发酵培养基含水量(40%，45%，50%，55%和60%)、发酵温度(20，25，30，35和40 ℃)、发酵时间(24，48，72，96和120 h)进行单因素试验。在单因素试验的基础上采用L9(34)正交试验优化接种量（8%，10%，12%）、发酵培养基含水量（42%，45%，48%）、发酵温度（33，35，37 ℃）、发酵时间（36，48，60 h），最终确定最佳发酵条件。在最佳发酵条件下对亚麻籽饼进行发酵，测定发酵前后亚麻籽饼的干物质、粗灰分、粗蛋白、粗脂肪、粗纤维和氨基酸含量，比较亚麻籽饼发酵前后营养成分的变化。【结果】从绵羊瘤胃液中筛选出1株CGs降解菌，其对CGs的降解率为66.55%，经形态学和分子生物学鉴定该菌为枯草芽孢杆菌（Bacillus subtilis）。枯草芽孢杆菌固态发酵亚麻籽饼的最佳发酵条件：接种量12%，发酵培养基含水量42%，发酵温度37 ℃，发酵时间48 h，在最佳发酵条件该菌株对CGs的降解率达78.21%。与发酵前相比，发酵后亚麻籽饼中粗蛋白、粗灰分含量显著提高（P＜0.05），粗纤维含量显著降低（P＜0.05），干物质和粗脂肪含量无显著变化；谷氨酸、丙氨酸、缬氨酸、异亮氨酸、亮氨酸、苯丙氨酸、赖氨酸、脯氨酸含量均显著提高（P＜0.05），精氨酸含量显著降低（P＜0.05），其他氨基酸含量均无显著变化。【结论】筛选出的枯草芽孢杆菌可以降解CGs，改善亚麻籽饼的营养价值。 |
| 关键词: 亚麻籽饼 生氰糖苷降解菌 发酵工艺 营养成分 抗营养因子 |
| DOI：10.13207/j.cnki.jnwafu.2025.05.003 |
| 分类号: |
| 基金项目:河南省青年科学基金项目（212300410136） |
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| Screening of cyanogenic glycoside-degrading strains in flaxseed cake |
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JIA Hanfang1, HE Wanling1, LI Xiaoli1, DING Xiaowei2, WANG Pengfei1
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1.College of Animal Science and Technology，Henan University of Science and Technology，Luoyang，Henan 471023，China;2.Henan Qibo Industrial Co.，Ltd.，Hebi，Henan 456250，China
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| Abstract: |
| 【Objective】This research aimed to screen cyanogenic glycosides (CGs) degrading strains and explore their effect on fermentation of flaxseed cake.【Method】The CGs degraded strains were initially screened from sheep rumen by escin ferric citrate plate method，and rescreened with rescreened fermentation medium,and the selected strains were identified. With the degradation rate of CGs as the index,single factor tests were performed on inoculation amount (5%,10%,15%,20% and 25%),water content (40%,45%,50%,55% and 60%)，fermentation temperature (20,25,30,35 and 40 ℃) and fermentation time (24,48,72,96 and 120 h).On the basis of single factor tests,L9(34) orthogonal experiment was used to optimize the inoculation amount (8%,10%,12%),water content (42%,45%,48%),fermentation temperature (33,35,37 ℃) and fermentation time (36,48,60 h) to finally determine the optimal fermentation conditions.The contents of dry matter,crude ash,crude protein,crude fat,crude fiber and amino acid of flaxseed cake before and after fermentation were determined under the optimal fermentation conditions,and the changes of nutritional components of flaxseed cake before and after fermentation were compared.【Result】A strain of CGs degrading bacteria was screened from rumen fluid of sheep,and its CGs degrading rate was 66.55%.The strain was identified as Bacillus subtilis by morphology and molecular biology analysis.The optimum fermentation conditions for solid fermentation of flaxseed cake were as follows inoculation amount of 12%,water content of 42%,fermentation temperature of 37 ℃ and fermentation time of 48 hours.The degradation rate of CGs by Bacillus subtilis reached 78.21% under the optimum fermentation conditions. Compared with those before fermentation,the contents of crude protein and crude ash in flaxseed cake after fermentation were significantly increased (P＜0.05),the content of crude fiber was significantly decreased (P＜0.05),and no significant difference was observed in the contents of dry matter and crude fat.The contents of glutamic acid,alanine,valine,isoleucine,leucine,phenylalanine,lysine and proline were significantly increased (P＜0.05)，the content of arginine was significantly decreased (P＜0.05)，and no significant difference was observed in the contents of other amino acids.【Conclusion】The selected Bacillus subtilis can degrade CGs and improve the nutritional value of flaxseed cake. |
| Key words: flaxseed cake cyanogenic glycosides-degrading strain fermentation process nutrients anti-nutritional factors |
