体外发酵法评定不同茬次和生长年限苜蓿的营养价值

本试验采用瘤胃体外发酵技术比较研究了不同茬次和生长年限紫花苜蓿的营养价值及体外发酵特性。试验以3头装有永久性瘤胃瘘管的荷斯坦奶牛为瘤胃液供体,称量1 g苜蓿样品于含有10 mL瘤胃液和90 mL培养基的发酵瓶内,39℃体外发酵96 h,分别于24、48、72及96 h冰浴终止发酵,采样。结果显示:茬次、生长年限对苜蓿体外发酵产气量、氨态氮(NH3-N)和菌体蛋白(MCP)浓度均有显著影响(P0.05),茬次对苜蓿体外发酵营养物质降解率有显著影响(P0.05),且茬次与生长在苜蓿体外发酵产气量、营养物质降解率上均存在交互作用(P0.05)。发酵结束后,苜蓿的产气量,营养物质降解率及挥发性脂肪酸(VFA)、NH3-N和MCP浓度在第3茬最高。产气量、营养物质降解率、NH3-N浓度在1和4年龄较高,3年龄较低。综上,以1年龄第3茬和4年龄第3茬苜蓿营养价值较高,3年龄第2茬较低。     

半地下带保温夹套发酵罐的应用

通过对半地下带保温夹套的发酵罐与普通发酵罐24 h的温度变化和6 d的产气量的对比试验分析,结果表明:采用半地下带保温夹套发酵罐发酵,24 h的温度变化缓慢,受外界温度变化影响小,高温持续的时间较长,利于微生物发酵;产气总量多,持续时间长。     

固态发酵在真菌除草剂规模化生产中的应用及展望

本文就固态发酵在真菌除草剂规模化生产中的应用现状、实例及如何控制发酵条件进行了综述,并对其应用前景进行了展望。     

利用甜高粱秸秆汁产单细胞蛋白的分批补料发酵研究

本文以甜高粱秸秆汁为主要的发酵原料,对热带假丝酵母SG-1在15-L罐上产单细胞蛋白(SCP)的分批补料发酵过程进行研究。首先对分批发酵模式下的菌体代谢过程变化进行研究。研究发现,接种后菌体快速进入繁殖阶段,但是总糖在12 h处于耗竭状态,使得菌体量和SCP产量过早的在18 h就达到峰值。基于此,在15-L罐上建立了热带假丝酵母SG-1产SCP的分批补料发酵模式。结果表明:菌体代谢因基质的补加而得到进一步的延续,放罐时(42 h)其菌体干重和SCP产量分别达19.86 g/L和9.93 g/L,显著高于分批发酵模式的10.45 g/L和4.70 g/L。     

Effect of hay type on cecal and fecal microbiome and fermentation parameters in horses

The effect of hay type on the microbiome of the equine gastrointestinal tract is relatively unexplored. Our objective was to characterize the cecal and fecal microbiome of mature horses consuming alfalfa or Smooth Bromegrass (brome) hay. Six cecally cannulated horses were used in a split-plot design run as a crossover in two periods. The whole plot treatment was ad libitum access to brome or alfalfa hay fed over two 21-d acclimation periods with subplots of sampling location (cecum and rectum) and sampling hour. Each acclimation period was followed by a 24-h collection period where cecal and fecal samples were collected every 3 h for analysis of pH and volatile fatty acids (VFA). Fecal and cecal samples were pooled and sent to a commercial lab (MR DNA, Shallowater, TX) for the amplification of the V4 region of the 16S rRNA gene and sequenced using Illumina HiSeq. The main effects of hay on VFA, pH, and taxonomic abundances were analyzed using the MIXED procedure of SAS 9.4 with fixed effects of hay, hour, location, period, and all possible interactions and random effect of horse. Alpha and beta diversities were analyzed using the R Dame package. Horses fed alfalfa had greater fecal than cecal pH (P ≤ 0.05), whereas horses fed brome had greater cecal than fecal pH (P ≤ 0.05). Regardless of hay type, total VFA concentrations were greater (P ≤ 0.05) in the cecum than in feces, and alfalfa resulted in greater (P ≤ 0.05) VFA concentrations than brome in both sampling locations. Alpha diversity was greater (P ≤ 0.05) in fecal compared with cecal samples. Microbial community structure within each sampling location and hay type differed from one another (P ≤ 0.05). Bacteroidetes were greater (P ≤ 0.05) in the cecum compared with the rectum, regardless of hay type. Firmicutes and Firmicutes:Bacteroidetes were greater (P ≤ 0.05) in the feces compared with cecal samples of alfalfa-fed horses. In all, fermentation parameters and bacterial abundances were impacted by hay type and sampling location in the hindgut.     

Nutritive value of sorghum silage for sheep

This study compared ensiled sorghum (ES) from two varieties (first and second cuts) with corn silage (CS) for chemical analysis, total-tract nutrient digestibility, ruminal variables and blood biochemistry metabolites in sheep. Five experimental silages representing first cut ES var. Pegah (PS1), second cut ES var. Pegah (PS2), first cut ES var. Speedfeed (SS1), second cut ES var. Speedfeed (SS2) and CS were assessed for chemical analysis, silage fermentation and anti-quality compounds. Diets consisted of lucerne hay, silage and a premix (at the ratio of 53.5:46:0.5 on a dry matter [DM] basis). Feed consumption, total-tract nutrient digestibility, microbial nitrogen supply (MNS), ruminal variables and blood biochemistry metabolites were determined in a Latin square design of five periods with five male sheep. Compared to sorghum, CS had lower (p < 0.01) concentrations of ash, water-soluble carbohydrates and crude protein, but higher starch, lignin (sa), non-structural carbohydrates and apparent nutrient digestibility. The measurements of pH, lactic acid, NH₃-N and volatile fatty acids (VFA) confirmed that all silages were well-preserved. The anti-quality compound levels in the silages were below the safe limits for ruminants. No differences were observed in feed consumption (p > 0.05) and total-tract digestibility of DM and nutrients (p > 0.05). Rumen pH, NH₃-N, VFA concentrations and acetate to propionate ratio showed no difference among treatments (p > 0.05). Sheep fed on sorghum silage showed a decrease (p < 0.01) in total protozoa, and particularly in the Entodiniae population. There were no differences in cellulolytic bacteria counts (p > 0.05) among treatments. Urinary N, MNS and blood biochemistry metabolites showed no difference among treatments (p > 0.05). Silages from both cuts of sorghum had comparable total-tract nutrient digestibility to CS, therefore, these varieties could be used as a more drought resilient silage source in the feeding of sheep.     

不同氨基酸对泰万菌素发酵影响的研究

通过单因素试验考察了泰万菌素发酵培养基中不同氨基酸种类对其发酵过程的影响,并利用正交试验对发酵培养基中3种主要氨基酸的用量配比进行了优化,结果表明发酵培养基加入0.2%亮氨酸、0.1%色氨酸、0.1%甘氨酸对泰万菌素发酵转化率影响显著,发酵摇瓶效价从14000μ/mL提高到18000μ/mL,效价提高了28.5%,完成了对泰万菌素提高发酵转化率和发酵单位的目的,并为大规模商业化生产泰万菌素奠定了良好的基础。     

日粮添加不同油脂原料对肉牛生长性能、养分消化及瘤胃发酵性能的影响

文章旨在探讨日粮添加不同油脂原料对肉牛生长性能、养分消化及瘤胃发酵性能的影响。试验选择平均初始体重（296±32.33）kg、带有瘤胃瘘管的肉牛48头,随机分为4组,每组4个重复,每个重复3头。对照组肉牛饲喂不含油脂的日粮,处理组肉牛分别饲喂含有5%棕榈油、亚麻油和包被脂肪的日粮。在为期10周的饲养试验后测定相关指标。结果：对照组与包被脂肪组干物质、有机物和氮摄入量及干物质、有机物表观消化率显著高于棕榈油和亚麻油组（P＜0.05）,而包被脂肪组与亚麻油组粗脂肪摄入量显著高于对照组和棕榈油组（P＜0.05）。对照组粗脂肪表观消化率较其他组分别显著降低31.94%、32.17%和33.56%（P＜0.05）,而亚麻油组中性洗涤纤维表观消化率较其他组分别显著降低18.61%、17.10%和19.68%（P＜0.05）。包被脂肪组瘤胃不饱和脂肪酸流量较对照组和棕榈油组分别显著提高152.26%和240%（P＜0.05）。对照组与包被脂肪组瘤胃氨氮浓度显著高于棕榈油组和亚麻油组（P＜0.05）。结论：包被脂肪降低了脂肪对瘤胃发酵的影响,其对瘤胃饱和脂肪酸流量的影响与亚麻油相似,但棕榈油降低了瘤胃氨氮浓度,不能有效向瘤胃提供不饱和脂肪酸。 [关键词]油脂原料|肉牛|生长性能|养分消化|瘤胃发酵     

青贮蘑菇渣的营养品质及体外发酵特性评价

本文旨在评估蘑菇渣青贮料的营养品质、发酵特性及其与常规饲料原料的体外降解差异性。试验将收集的蘑菇渣作为原料,与米糠、糖蜜、垫料和菌种混合后青贮4周。分别在青贮0、7、14和28d时收集样品,用于评估营养品质、体外发酵特性,同时对比青贮蘑菇渣饲料与水稻秸秆和大麦秸秆的体外降解特性。结果:随着蘑菇渣青贮时间的升高,干物质含量显著降低(P<0.05),同时青贮7d后有机物含量也显著降低(P<0.05)。蘑菇渣青贮后,粗蛋白质和粗脂肪含量显著升高(P<0.05)。青贮7d后,粗灰分含量显著升高(P<0.05),而青贮7和28d后酸性洗涤纤维含量显著高于青贮0和14d(P<0.05)。蘑菇渣青贮7d后,pH显著升高(P<0.05),随后又显著降低(P<0.05),同时乙酸和丙酸含量显著降低,随后又升高(P<0.05)。蘑菇渣青贮后,乳酸和氨氮浓度显著升高(P<0.05),而水溶性碳水化物浓度显著降低(P<0.05)。青贮蘑菇渣的干物质组分中,水溶降解部分显著高于水稻秸秆和大麦秸秆(P<0.05),但不溶降解部分显著降低(P<0.05)且非降解部分显著低于水稻秸秆(P<0.05)。针对蛋白组分,青贮蘑菇渣水溶降解部分也显著高于其他两种原料(P<0.05),但不溶降解和非降解部分显著降低(P<0.05)。蘑菇渣青贮料中性洗涤纤维可消化部分显著低于水稻和大麦秸秆(P<0.05),不可消化部分则显著提高(P<0.05)。结论:以蘑菇渣为基础的青贮料发酵良好,可保存至第4周。以蘑菇渣为基础的青贮料干物质和粗蛋白质降解率远高于水稻、大麦和黑秸秆,中性洗涤纤维的降解率则相反。     

添加亚油酸条件下不同剂量硝酸钠对水牛瘤胃体外发酵脂肪酸组成及相关微生物数量的影响

为了探究添加亚油酸条件下不同剂量硝酸钠对水牛瘤胃体外发酵脂肪酸组成及相关微生物数量的影响,本试验选用3头装有永久性瘤胃瘘管的母水牛,以精粗比40∶60为底物进行瘤胃液体外发酵试验。试验组硝酸钠的浓度分别为1、2、3 mg·mL^-1,对照组不加硝酸钠,每组均添加0.25 mg·mL^-1的亚油酸,每组各5个重复。在体外培养3、6、9、12、24 h时测定产气量和甲烷产量,24 h结束培养,测定瘤胃体外发酵参数、脂肪酸含量及瘤胃微生物数量。结果表明：1）添加硝酸钠显著降低了总产气量和甲烷产量（P<0.05）;2）添加硝酸钠pH值和氨态氮（NH₃-N）含量显著升高（P<0.05）,异丁酸和异戊酸含量显著降低（P<0.05）,而对总挥发性脂肪酸（TVFA）含量无显著性影响（P>0.05）;3）添加1 mg·mL^-1硝酸钠,C18：2cis-9,trans-11、C18：2trans-10,cis-12含量和不饱和脂肪酸/饱和脂肪酸（UFA/SFA）显著高于其他组（P<0.05）,且C20：5n3 （EPA）含量显著高于添加3 mg·mL^-1硝酸钠组（P<0.05）,添加2 mg·mL^-1硝酸钠C22：6n3 （DHA）含量显著高于其他组（P<0.05）;4）添加硝酸钠组原虫数量显著低于对照组（P<0.05）,添加2、3 mg·mL^-1硝酸钠产甲烷菌数量显著低于添加1 mg·mL^-1硝酸钠组（P<0.05）,添加1 mg·mL^-1硝酸钠总细菌、真菌、溶纤维丁酸弧菌、蛋白分解丁酸弧菌、非典型丁酸弧菌、亨氏丁酸弧菌数量显著高于其他组（P<0.05）。由此可得,体外法添加1~3 mg·mL^-1硝酸钠和0.25 mg·mL^-1亚油酸在维持水牛TVFA含量不变的情况下显著降低了甲烷含量,且1 mg·mL^-1硝酸钠能促进亚油酸生成共轭亚油酸（CLA）,优化脂肪酸组成,并能增加大多数瘤胃微生物的数量。