An efficient cofactor regeneration system has been developed to provide a hydride source for the preparation of optically pure alcohols by carbonyl reductase-catalyzed asymmetric reduction. This system employed a novel glucose dehydrogenase (BcGDH90) from Bacillus cereus HBL-AI. The gene encoding BcGDH90 was found through the genome-wide functional annotation. Homology-built model study revealed that BcGDH90 was a homo-tetramer, and each subunit was composed of βD-αE-αF-αG-βG motif, which was responsible for substrate binding and tetramer formation. The gene of BcGDH90 was cloned and expressed in Escherichia coli. The recombinant BcGDH90 exhibited maximum activity of 45.3 U/mg at pH 9.0 and 40 °C. BcGDH90 showed high stability in a wide pH range of 4.0–10.0 and was stable after the incubation at 55 °C for 5 h. BcGDH90 was not a metal ion-dependent enzyme, but Zn2+ could seriously inhibit its activity. BcGDH90 displayed excellent tolerance to 90% of acetone, methanol, ethanol, n-propanol, and isopropanol. Furthermore, BcGDH90 was applied to regenerate NADPH for the asymmetric biosynthesis of (S)-(+)-1-phenyl-1,2-ethanediol ((S)-PED) from hydroxyacetophenone (2-HAP) with high concentration, which increased the final efficiency by 59.4%. These results suggest that BcGDH90 is potentially useful for coenzyme regeneration in the biological reduction.

Amphiphilic protein has lipophilic and hydrophilic domains, displaying the potential for development as a biosurfactant. The polyhydroxyalkanoate (PHA) surface binding protein derived from Bacillus is a type of protein that has not been studied for its emulsifying properties. In this study, PHA granule-associated protein (PhaP), PHA regulatory protein (PhaQ), and PHA synthase subunit (PhaR) derived from an alkali-tolerant PHA-producing Bacillus cereus HBL-AI were found and heterologously expressed in E. coli and purified to investigate their application as biosurfactants. It showed that the emulsification ability and stability of three amphiphilic proteins were higher than those of widely used chemical surfactants in diesel oil, vegetable oil, and lubricating oil. In particular, the PhaQ protein studied for the first time can form a stable emulsion layer in vegetable oil at a lower concentration (50 µg/mL), which greatly reduced the amount of protein used in emulsification. This clearly demonstrated that the PHA-binding protein of HBL-AI can be well applied as an environmentally friendly biosurfactants.

筛选出具有产脲酶抑制剂功能的芽孢杆菌菌株并验证其对鸡粪便氨减排的效果.采用以硫酸铵为唯一氮源的培养基,从鸡粪便中富集、分离高效利用氨氮的芽孢杆菌.利用尿素酚红培养基平板与尿素培养基摇瓶培养相结合,筛选不能利用尿素生长的菌株.通过比较各菌株发酵液对大豆脲酶的抑制率,获得对大豆脲酶抑制活性最高的菌株.分析该菌株的16SrRNA基因序列,观察其菌落菌体形态,测定其生理生化特征,以鉴定其种属.将该菌株以1.0×107 CFU/g的接种量接入新鲜鸡粪,30℃静置5d,评价对鸡粪中芽孢杆菌含量、脲酶活性、氨氮、尿素、尿酸含量、pH、氨气释放量的影响.结果 表明,筛选到氨氮利用芽孢杆菌菌株共562个,其中氨氮利用率85％以上的菌株218个;初筛得到不产脲酶菌株23个;复筛得到对大豆脲酶活性抑制较强的菌株(抑制率＞50％)6个,其中J530菌株抑制率达99.3％.经鉴定菌株J530为枯草芽孢杆菌(Bacillus subtilis).该菌株5d内可使鸡粪便中芽孢含量增加50.83倍(P＜0.01),使鸡粪中脲酶的活性和氨氮含量分别降低83.86％ (P＜0.01)和44.41％(P＜0.01),尿素含量和尿酸含量分别提高28.80％ (P＜0.05)和1.51％(P＞0.05),pH降低1.15(P＜0.05),5d氨气释放量减少67.88％ (P＜0.01).筛选得到了产脲酶抑制剂的枯草芽孢杆菌J530菌株,该菌株可显著降低鸡粪便氨排放.

芽孢杆菌科来源的脂肽(Bacillaceae-derived lipopeptides,BLP)具有抗细菌、抗真菌、抗炎症等活性,因其具有低毒、高效、可生物降解等优点而被认为是抗生素的理想替代物之一,被广泛应用于医药、生物修复、植物病害防治、食品添加剂和化妆品等领域,而其在动物生产中的应用研究尚处于起步阶段.文章综述了BLP的生物合成调控及其在动物生产中的应用,指出了其中存在的问题,提出将发酵饲料技术与BLP应用相结合的发展方向,以期促进BLP在动物生产中的应用.

为提高产脲酶抑制剂枯草芽孢杆菌J530菌株摇瓶发酵时的产芽孢量,并探索J530菌株制备的菌剂对鸡粪便的氨减排效果,利用单因素和正交试验对该菌株摇瓶发酵条件进行优化,将该菌剂活化后接入新鲜鸡粪,测定发酵5 d后芽孢杆菌浓度、脲酶活性、氨气释放量、氨氮含量、pH值、尿素含量、尿酸含量和总氮含量的变化.结果表明,J530菌株摇瓶发酵产芽孢的最优条件:玉米粉1.5％、黄豆饼粉1.5％、MgSO4·7H2O 0.3％、Na2HPO40.2％、KH2PO40.2％、装液量50 mL(250 mL锥形瓶)、初始pH值8.0、接种量4.0％、培养温度37℃、摇床转速150 r/min、发酵时间36 h.优化后,发酵液芽孢浓度提高了20.32倍.鸡粪应用试验中,与未接种菌剂的对照组相比,试验组的芽孢杆菌浓度提高了60.29倍(P<0.01);脲酶活性、氨气释放量和氨氮含量分别降低了80.78％(P<0.01)、67.78％(P<0.01)和48.57％(P<0.01);pH值降低了1.35(P<0.05);尿素含量、尿酸含量和总氮含量分别提高了24.79％(P<0.05)、0.91％(P>0.05)和8.53％(P>0.05).综上,研究确定了J530菌株摇瓶发酵产芽孢的最优条件,并证明J530菌剂具有显著的降低鸡粪便氨排放的效果.

为了确定甲基营养型芽孢杆菌(Bacillus methylotrophicus)SD48菌株液体发酵豆粕产大豆肽的最优培养基组成和最佳发酵条件,以大豆肽含量为指标,通过单因素试验确定最优碳源种类、无机盐种类和发酵温度;通过正交试验确定最适碳源、豆粕、硫酸铵和无机盐的含量,以及SD48菌株接种量、起始pH值、装瓶量和发酵时间.结果表明,最优培养基组成:可溶性淀粉含量为1.00％,豆粕含量为15.00％,硫酸铵含量为4.00％,硫酸锰含量为0.09％;最适发酵条件:起始pH值为6.00,装瓶量为40％,SD48菌株的接种量为6.00％,发酵温度为28℃,培养时间为72 h.由此获得的大豆肽含量为8.03％,相对含量为71.06％,抗氧化活性达到343.70μg AEAC/mL.综上,获得了SD48菌株液体发酵豆粕产大豆肽的最佳条件,提高了大豆肽的产量.

为验证微生态制剂Z-27(以下简称Z-27菌剂)对猪舍空气中有害气体减排的效果,选取400头50 kg左右健康杜长白三元杂交育肥猪,随机平均分为对照组和试验组,每组1栋猪舍,每栋20栏,每栏10头猪.对照组饲喂基础日粮,试验组在基础日粮中添加0.1％Z-27菌剂.试验共15 d,期间检测猪舍空气中NH3、H2 S浓度及细菌、大肠杆菌数量,测定猪粪和尿中总氮含量、氨态氮含量和pH值,检测粪尿混合物NH3、H2 S的48 h排放量;观察每组腹泻情况,计算腹泻率;每组分出3栏(30头)分别于试验开始和结束时空腹12 h称体质量并结算剩余料,计算均增质量和料质量比.试验结果表明,试验前期试验组各参数有一个渐变过程,7 d后方能达到稳定,故以第8天(含)后的数据将试验组和对照组进行比较.试验组猪舍空气中NH3、H2 S含量比对照组分别下降63.27％、54.61％,细菌、大肠杆菌总数比对照组分别下降46.68％、59.89％;试验组猪粪总氮含量和氨氮含量比对照组分别下降46.32％、65.83％,猪粪的pH值比对照组降低0.54;试验组猪尿总氮含量和氨氮含量分别降低26.47％、27.59％,尿液pH值比对照组降低0.86;试验组新鲜猪粪尿混合物的NH3、H2 S的48 h释放量比对照组分别下降32.76％、35.69％;同时试验组均增质量比对照组提高10.38％,料质量比降低9.05％,腹泻率降低60.06％.表明该菌剂具有降低育肥猪氮素排泄的作用,可从源头降低猪排泄物NH3、H2 S等有害气体排放,还能够显著提高育肥猪的生长性能,防治腹泻.

为了获得贝莱斯芽孢杆菌(Bacillus velezensis)T-70-1菌株发酵产抗菌肽小试生产的最佳条件,试验考查了转速、通气量、装液量和罐压对发酵液抑菌活性的影响,设计正交试验优化5L发酵罐的发酵条件;在此基础上,以发酵通气率不变为原则,探索发酵时间对30 L发酵罐发酵效果的影响.结果 表明:当通气量为2.0 L/min,压强为0.05 MPa,转速为180 r/min,装液量为40％时,5L发酵罐相对应发酵上清液的抑菌效价为2 851.8 Au.当放大至30 L发酵罐时,对应的发酵条件为装液量20 L,通气量1.2 m3/h,压强0.05 MPa,转速180 r/min,对应的抑菌效价可达到6 159.2 Au,抗菌肽含量提高了1.16倍.说明通过优化条件实现了抗菌肽从5L发酵罐到30 L发酵罐的放大,使T-70-1菌株胞外抗菌肽含量得到了明显提高.

以抑制大肠杆菌能力为指标,采用紫外-微波诱变的方法对Tu-569菌株进行选育,并以遗传稳定性试验评价正突变菌株的稳定性,以获得抑菌能力更强、遗传更稳定的高产菌株;通过观察高产菌株的菌落和菌体形态,以生理生化试验和API 50 CH细菌鉴定条综合评测高产菌株生理生化特性,结合16S rDNA序列分析来鉴定高产菌株的种属;通过考察硫酸铵盐析、透析处理、蛋白酶处理、加热处理、缓冲液pH值等对突变菌株胞外产抑菌物质活性的影响,探索抑菌物质的性质.结果表明,于30 cm处紫外照射240 s时,筛选出1株抑菌圈面积增大0.79倍且传代十次遗传稳定的正突变菌株T-4M-5.选取T-4M-5菌株进行微波诱变,当微波炉参数为P50,辐射共60 s和70 s时,筛选出4株抑菌圈显著增大且遗传稳定的正突变菌株,其中T-70-1菌株的活性最高(抑菌圈面积达到363.8 mm2)且遗传稳定性最好,是Tu-569菌株抑茵圈面积的2.74倍.T-70-1菌株具有与Tu-569菌株相同的菌落茵体形态;除不产接触酶、可耐受10％和15％的NaCl、可利用D-半乳糖和D-塔格糖外,其余生理生化特性与Tu-569菌株相同;结合16S rDNA序列分析鉴定T-70-1菌株为Bacillus velezensis.T-70-1菌株胞外抑菌物质可被70％饱和度的硫酸铵盐析;该抑菌物质相对分子质量在3.5～8.0 kDa之间;抑菌物质分子结构中含有可被胰蛋白酶或胃蛋白酶酶解的肽键;在pH值3.0～9.0范围内均有较高活性;抑菌物质对40～100℃加热处理具有较强耐受性,但121℃处理后完全失活.经紫外-微波诱变获得了一株高产抗菌肽、遗传稳定的T-70-1菌株,其胞外产抗菌肽抑菌活性较强,耐受胃肠道环境,较为耐热,在畜牧养殖业极具应用潜力.

为了提高益生菌T-70-1胞外产抗菌蛋白的产量,试验采用单因素分析法,以抑制大肠杆菌能力为指标,分别考察碳源、氮源、无机盐种类对T-70-1菌株发酵产抗菌蛋白的影响,再结合正交试验法对该菌株胞外产抗菌蛋白的培养基组成和发酵条件进行优化,利用SPSS软件进行方差分析,确定最佳发酵产抗菌蛋白的条件.结果表明:优化后的发酵条件为葡萄糖2.5％、蛋白胨2.0％、MgSO40.08％、KCl 0.10％;初始pH值为6.5,种子液按照4％接种量接种于装液量为30 mL/250 mL的锥形瓶中,30℃发酵培养32 h.优化后胞外产抗菌蛋白相应的抑菌圈面积增大至525.5 mm2,较优化前增幅达60.7％.说明通过优化发酵条件获得了菌株T-70-1发酵产抗菌蛋白最佳培养基组成和培养条件,抗菌蛋白产量得到了明显提高.

为探讨Tu-1菌剂与抗生素对獭兔肠道消化酶活力、盲肠菌群及生长性能的影响,选取60只40日龄健康断奶獭兔,随机分为对照组(全价日粮)、抗生素组(全价日粮含20 mg/kg硫酸黏杆菌素)和菌剂组(全价日粮添加1.0‰ Tu-1菌剂).预试期5d,正试期30 d.每天观察和记录獭兔腹泻和健康状况.于正试期开始前和结束后对獭兔空腹称体质量,并结算各组剩余饲料.试验期结束后屠宰獭兔,测定十二指肠、空肠、回肠、盲肠内容物中蛋白酶、淀粉酶、脂肪酶、纤维素酶活力及内容物pH值;检测盲肠中大肠杆菌、乳酸杆菌、双歧杆菌数量及细菌总数.结果表明,菌剂组的十二指肠、空肠、回肠和盲肠蛋白酶活力比对照组分别提高13.05％、17.95％、21.27％和31.58％(P＜0.05),淀粉酶活力比对照组分别提高13.93％、14.23％、45.51％和49.58％ (P ＜0.05),脂肪酶活力比对照组分别提高11.71％、18.17％、19.22％和26.84％ (P ＜0.05),纤维素酶活力比对照组分别提高69.84％、83.43％、111.06％和54.59％ (P ＜0.01);抗生素组的十二指肠、空肠、回肠和盲肠纤维素酶活力比对照组降低了16.67％、28.57％、12.90％和23.41％ (P ＜0.05),其他3种酶活力与对照组基本一致.菌剂组獭兔盲肠中大肠杆菌的数量比对照组极显著降低(P＜0.01),乳酸杆菌和双歧杆菌的数量比对照组均显著提高(P＜0.05),细菌总数基本一致;抗生素组盲肠中大肠杆菌和细菌总数均极显著低于对照组(P＜0.01),乳酸杆菌和双歧杆菌略低.菌剂组盲肠的pH值比对照组降低0.72(P ＜0.05),其他各肠段的pH值稍低于对照组(P＞0.05);抗生素组各肠段pH值与对照组相比无显著变化.菌剂组和抗生素组的日增体质量比对照组分别提高16.61％和13.74％ (P ＜0.05);菌剂组的料重比、腹泻率与对照组相比分别降低了9.51％、68.11％ (P＜0.05);抗生素组的料重比、腹泻率比对照组分别降低了8.29％、64.03％(P＜0.05).因此,Tu-1菌剂在提高獭兔生产性能和肠道消化酶活力,维护肠道微生态平衡和降低腹泻率方面优于硫酸黏杆菌素.

为探索Z-27菌剂的饲喂效果,研究了其对猪舍空气中NH3、H2 S减排及对育肥猪生长性能的影响.选取400头50 kg左右健康杜 × 长 × 白三元杂交育肥猪,随机平均分为对照组和试验组,每组1栋猪舍,每栋20栏,每栏10头猪.对照组饲喂基础日粮,试验组在基础日粮中添加0.1％ 的Z-27菌剂.试验共15 d,期间检测猪舍空气中NH3、H2 S的含量及细菌总数、大肠杆菌数量,测定猪粪、尿的pH值,检测猪粪尿混合物中NH3、H2 S的48 h排放量;观察每组腹泻情况,计算腹泻率;每组分出3栏(30头)分别于试验开始和结束时空腹12 h称体质量,并结算剩余料,计算均增质量和料重比.结果显示,与对照组相比,试验组猪舍空气中NH3、H2 S含量分别下降了63.27％(P<0.01)、54.61％(P<0.01),细菌总数、大肠杆菌总数分别下降了46.68％(P<0.01)、59.89％(P<0.01);猪粪的pH值降低0.54(P<0.05),猪尿的pH值降低0.86(P<0.05);猪粪尿混合物中NH3、H2 S的48 h释放量分别下降32.76％(P<0.05)、35.69％(P<0.05);试验组均增质量提高了10.38％(P<0.05),料重比降低9.05％(P<0.05),腹泻率降低了60.06％(P<0.01).可见,Z-27菌剂具有净化猪舍内空气环境、提高育肥猪的生长性能、防治腹泻的作用.

为了研究枯草芽孢杆菌(Bacillus subtilis)J-4菌株胞外产抑菌物质的性质,试验采用琼脂打孔扩散法,以大肠杆菌(Escherichia coli)为指示菌,考察硫酸铵盐析、透析处理、水浴处理、缓冲液pH值、蛋白酶、变性剂、离子种类等对该抑菌物质活性的影响.结果表明:J-4菌株胞外产生的抑菌物质可被80％饱和度的硫酸铵盐析;该抑菌物质的分子质量在8.0 ku以上;100℃水浴60 min,该抑菌物质仍有较高抑菌活性;在pH值为2.0～8.0范围内均有较高活性;抑菌物质分子结构中含有可被胃蛋白酶或胰蛋白酶酶解的肽键;抑菌物质的活性可被十六烷基三甲基溴化铵(CTAB)和高浓度的CaCl,增强.说明枯草芽孢杆菌J-4菌株胞外产生的抑菌物质为抗菌蛋白类物质,具有较高的抗菌活性,热稳定性好,耐受鸡消化道pH值为4.0～7.0环境和消化酶,在养鸡业极具应用潜力.

Using the transparent ring method,primary screening was done with an acid skimmed milk medium as defined medium.Secondary screening was done with acid protease activity as the index.The test strain was identified by the combination of observations with colony morphology and microbial morphology,determination of physiological and biochemical characteristics,and 16S rDNA phylogenetic analysis.Using the solid fermentation test with soybean meal at 18 ℃,the feasibility of degradation of macromolecule antinutritional factors and increase of relative content of acid soluble protein by the test strain was discussed.With relative content of acid soluble protein as the index,the solid fermentation with soybean meal was optimized by an orthogonal experimental design,in which factors,such as ratio of feed to water,corn flour content,ammonium sulfate content and inoculation amount,were investigated.133 strains were obtained in primary screening.Strains which could produce a transparent ring larger than 2.00 cm,such as SD47,SD48,SD56 and SD62,were tested in secondary screening.With the acid protease activity 75.40 U/ml,the strain SD48 was screened out as the test strain.The strain SD48 was identified as Bacillus methylotropbicus.Fermented soybean meal was golden color,with a strong acid flavor and no agglomeration phenomenon,after the solid fermentation test by strain SD48 for 30 d.Meanwhile,the pH value of fermented soybean meal decreased and both of the relative content of acid soluble protein and the antioxidant activity increased.And 3-conglycinin and glycinin were degraded nearly completely.The optimal condition was composed of ratio of feed to water 1.1,corn flour content 10.0％,ammonium sulfate content 6.0％,inoculation amount 8.0％ and fermentation time 30 d.Compared with that of the basic fermentation condition,the relative content of acid soluble protein increased 127.6％,and the antioxidant activity increased 185.8％ under the optima] condition.With the characteristic of tolerance to acid environment,strain SD48,which could produce acid protease and increase the nutritional value of fermented soybean meal,showed excellent performance as the strain used for making fermented soybean meal.

In order to reduce the realease of ammonia,purify the enviroment of henhouse,and improve the production performance of broilers,Bacillus subtilis JA-14 preparation was added into broiler diets.Fecal ammonia release rate was measured by Nessler's colorimetry.Protease activity,total nitrogen content and ammonia nitrogen content,pH value and moisture content of the feces were determined.The results showed that after addition of JA-14 agent,the fecal ammonia volatilization of test group was 24.88％ lower than the control group.The activity of protease was 23.25％ higher than the control group.Total nitrogen content,ammonia nitrogen content,pH value and water content decreased by 35.72％,63.80％,6.31％ and 25.66％,respectively.Preparation of bacillus can improve protease activity of broiler intestines and reduce ammonia emission.

In order to improve the content of antibacterial substance in the fermentation broth of Bacillus subtilis strain J-4,the combined method of single factor test and orthogonal test was used to optimize the factors,such as carbon source,nitrogen source,inorganic salts,fermentation time,media amount,fermenta-tion temperature and inoculation amount. The medium composition and fermentation conditions after opti-mization were as follows:glucose 1%, soybean cake powder 1%, MgSO40. 15%, Na2 HPO40. 10%, NaH2PO40. 10%,fermentation time 36 h,media amount 100 mL(250 mL),fermentation temperature 37 ℃,inoculation amount 5%. The inhibition area after optimization increased by 50. 25% compared with the inhibition area when using the basal fermentation medium.

In order to evaluate the feeding effect of agent Z-27 which was a substitution of antibiotics on weaned piglets,96 weaned piglets(Doric×Landrace) were randomly and averagely divided into 4 groups.Basal diet was fed to weaned piglets in the groupⅠ.Basal diet with additions of 0.02% colistin sulfate and 0.05‰ gentamicin sulfate was fed to weaned piglets in the groupⅡ.Basal diet with additions of 0.02% colistin sulfate,0.05‰ gentamicin sulfate and 0.10% agent Z-27 was fed to weaned piglets in the group Ⅲ.Basal diet with additions of 0.10% agent Z-27 was fed to weaned piglets in the group Ⅳ.Regular observation of weaned piglet feces was recorded every day during the feeding period and diarrhea index was calculated.Weights of weaned piglets and the surplus deed were obtained by fasting for 12 hours at both the beginning and the end of experimental stage and average daily gains and feed-weight ratios were calculated.After 30 days,slaughter of weaned piglets was executed.And digestive enzymes,such as acid protease,alpha-amylase,lipase and cellulose,in contents of duodenum,jejunum and ileum were determined.Then contents of nutrients,such as crude protein,starch,crude fat and crude fiber,in contents of ileum and cecum and in feces were determined.Compared with the group Ⅱ,activities of acid protease in contents of duodenum,jejunum and ileum in the group Ⅳ were increased by 74.55%(P<0.05),133.40%(P<0.01),177.61%(P<0.01),respectively.And activities of alpha-amylase in contents of duodenum,jejunum and ileum in the group Ⅳ were increased by 36.82%(P<0.05),69.72%(P<0.05),117.73%(P<0.05),respectively.Activities of lipase in contents of duodenum,jejunum and ileum in the group Ⅳ were increased by 30.71%(P<0.05),71.03%(P<0.05),120.38%(P<0.05),respectively.Activities of cellulose in contents of duodenum,jejunum and ileum in the group Ⅳ were increased by 225.07%(P<0.01),244.77%(P<0.01),248.50%(P<0.01),respectively.Contents of nutrients,such as crude protein,starch,crude fat and crude fiber in feces in the group Ⅳ were decreased by 29.49%(P<0.05),53.41%(P<0.05),22.71%(P<0.05) and 31.60%(P<0.05),respectively.The average daily gain in the group Ⅳ was increased by 5.35%(P>0.05).The feed-weight ratio and diarrhea index in the group Ⅳ were decreased by 3.95%(P>0.05) and 22.41%(P>0.05),respectively.The results showed that agent Z-27 had multifunction of improving intestinal digestive enzymes and growth performance of weaned piglets and feed utilization ratio,decreasing contents of nutrients,such as crude protein,starch,crude fat and crude fiber in intestinal tract and in feces of piglets and decreasing weaned piglet diarrhea.The effect of agent Z-27 was superior to antibiotics addition agent.

为了评价芽孢益生菌剂Z-27替代抗生素的效果,试验将96头杜长大杂交断奶仔猪随机分为对照组、抗生素组、抗生素+益生菌组和益生菌组.每天定时观察并记录仔猪粪便情况,最后计算腹泻指数.分别于正试期开始和结束时对仔猪空腹称重,并结算剩余料,计算平均日增重和料重比.饲喂30 d后屠宰,测定回肠、盲肠内容物和粪便中的大肠杆菌、芽孢杆菌、乳酸菌、双歧杆菌等细菌数.结果表明:与对照组相比,抗生素组、抗生素+益生菌组、益生菌组仔猪回肠、盲肠、粪便中大肠杆菌数均极显著降低(P＜0.01),且3组间差异不显著(P＞0.05);抗生素组、抗生素+益生菌组仔猪回肠、盲肠、粪便中芽孢杆菌、乳酸菌、双歧杆菌数极显著下降(P＜0.01);而益生菌组对应的仔猪回肠、盲肠、粪便中芽孢杆菌、乳酸菌、双歧杆菌数极显著增多(P＜0.01).与对照组相比,抗生素组仔猪日增重显著提高(P＜0.05),料重比显著降低(P＜0.05),腹泻指数显著降低(P＜0.05);抗生素+益生菌组日增重提高不显著(P＞0.05),料重比降低不显著(P＞0.05),腹泻指数显著降低(P＜0.05);益生菌组日增重显著提高(P＜0.05),料重比显著降低(P＜0.05),腹泻指数显著降低(P＜0.05).说明益生菌剂Z-27能替代本试验所用抗生素,使用后可提高仔猪生长性能,维护肠道微生态,减少仔猪腹泻.

以灰葡萄孢菌(Botrytis cinerea Pers.)为指示菌,采用单因素试验与正交实验相结合的方式,对TB-12菌株发酵培养基组成及培养条件进行优化,以提高番茄灰霉病拮抗菌Bacillus velezensis TB-12菌株的抑菌效果,并通过盆栽试验考察了TB-12菌株对番茄灰霉病的防治效果,为今后该菌剂生产工艺条件的进一步确定及其防治应用的开展奠定相应的基础.结果表明:TB-12菌株的最佳发酵培养基组合为乳糖2％,酪蛋白胨4％,MgSO4·7H2O 0.1％,KC1 0.05％;最佳培养条件为接种量10％,装瓶量50 mL,初始pH 8,发酵时间60 h,培养温度30℃,摇床转速180 r·min-1.与采用基础发酵培养基相比,优化后TB-12菌株对灰葡萄孢菌的抑制效果增加了69.4％.盆栽试验表明,优化后TB-12菌株发酵上清液对番茄灰霉病的预防效果达到69.2％,治疗效果达到58.2％,分别提高了32.6％和19.5％.TB-12菌株对番茄灰霉病有良好的防治效果.

Poultry used with large-scale and intensive farming generated a lot of waste,which has become a major source of ammonia in the henhouse.The main form of ammonia volatilization in feces is NH4+-N.This study using ammonium sulfate as the sole nitrogen source,was to screen the strains of high efficient ammonia nitrogen degradation from chicken feces.It is studied the properties of ammonia nitrogen degradation and test of inhibition of ammonia gas in vitro.The results showed that strain C-2 could degrade ammonia nitrogen.After 72 h,ammonia nitrogen degradation rate of the strain C-2 is 45.3％,and it can effectively inhibit the release of chicken manure ammonia.Through the colony morphology,morphological characteristics and 16S rDNA sequence analysis and physiological and biochemical experiments,the strain C-2 finally was identified as Bacillus subtilis.It provided the basis for application in poultry manure emissions in the future.