北虫草培养基添加量对酱油制曲及酶活性的影响

在酱油发酵基料(由40 g豆粕和60 g麸皮配制而成)中分别添加5、10、15、20 g北虫草培养基(分别称其为处理1、处理2、处理3、处理4),以不添加北虫草培养基的处理为对照,研究其对酱油制曲及对蛋白酶、淀粉酶、亮氨酸氨肽酶、纤维素酶活性的影响;采用血球计数板法检测种曲孢子数,观察种曲的感官变化。结果表明:1)各处理中,处理2种曲的孢子数最多,孢子生长能力旺盛,制曲48 h时曲料蓬松,菌丝丰满,米曲霉孢子为淡黄色,制曲54 h时蓬松的曲料中长出黄绿色丰满的成熟米曲霉孢子;2)制曲过程中,蛋白酶、淀粉酶、亮氨酸氨肽酶、纤维素酶活性均呈先上升后下降的趋势,酸性蛋白酶活性在制曲42 h出现峰值,其余各酶的活性均在制曲48 h出现峰值;3)除亮氨酸氨肽酶酶活性各处理间与对照间的差异无统计学意义外,处理组中中性蛋白酶、碱性蛋白酶、酸性蛋白酶、淀粉酶及纤维素酶的酶活性均高于对照,在酶活高峰时,处理2的酶活性均显著高于对照组及其他处理组(P0.05)。综上可见,在制曲过程中添加北虫草培养基,可显著提高米曲霉沪酿3.042制曲的质量,提高其酶活性,且以处理2的制曲效果较好,酶活性最高。     

热激修饰瑞士乳杆菌对Cheddar干酪成熟的影响

研究了瑞士乳杆菌Lactobacillus helveticus 6024经热激修饰后,与干酪成熟相关的生化性质变化及其对Cheddar干酪成熟的影响。结果表明:瑞士乳杆菌经70℃、10 s的热激处理后,在10%脱脂乳中经32℃、6 h培养后,其产酸能力仅为6.4%,而与干酪成熟密切相关的平均氨肽酶活力,仍有约25%的保留。热激处理后的菌株加入到干酪中对其组分没有显著影响,但对干酪可溶氮水平有不同程度的影响。与未添加热激菌株的干酪对照组相比,总可溶氮含量增加不显著,而在成熟3个月时5%磷钨酸可溶氮占总氮比例增加2倍,组间差异显著。干酪质构、微观结构分析的结果也证明,热激修饰菌株对促进干酪成熟具有促进作用。     

抗鸡传染性法氏囊病病毒冻干卵黄抗体与同类产品的比较试验

本研究鸡传染性法氏囊病冻干卵黄抗体和市售精制液体卵黄抗体分别以10羽份和3 mL超剂量肌肉注射各10只18日龄SPF雏鸡,观察14 d均安全。两种抗体以1羽份剂量分别肌肉注射各20只18日龄SPF雏鸡24 h后,用IBDV强毒TL株攻击,连续观察144 h,2个试验组分别有20/20、17/20的雏鸡健活,剖检没有发现法氏囊病变;二者分别以1羽份剂量连续2 d肌肉注射各20只18日龄已经被IBDV强毒TL株攻击12 h的SPF雏鸡,连续观察96 h,2个试验组有19/20、17/20的雏鸡健活,而预防和治疗试验中的阳性对照组中20只鸡均有法氏囊特征性病变发生（20/20）,且死亡率在85%（17/20）以上,阴性对照组雏鸡均正常。     

湿拌饲料对仔猪开食及生产性能的影响

本试验选经产大白×DVI系二元仔猪20窝,每窝在9头以上,分为两组,每组10窝,分别以干颗粒料与拌湿的颗粒料作为仔猪的开食料,通过饲养试验,研究湿拌饲料对仔猪开食及生产性能的影响。试验结果表明,饲喂湿拌饲料的仔猪,在14日龄全部开食;仔猪腹泻率,在7～21日龄,试验组比对照组高8.7%,而在21～35日龄与35～42日龄,试验组比对照组低9.4%与5.3%;仔猪个体重,21日龄时,试验组比对照组高1.1%(P>0.05);到35日龄与42日龄时,试验组比对照组分别高10.6%与7.9%(p<0.05);仔猪日增重,7～21日龄时,试验组比对照组高1.0%(P>0.05),而21～35日龄时,试验组比对照组低6.5%(P>0.05),在35～42日龄,试验组比对照组高1.8%(P>0.05)。     

Corn Hybrid Response to Starter Fertilizer Combinations

ABSTRACT

Research has shown that some corn (Zea mays L.) hybrids grown under reduced tillage conditions respond to starter fertilizer containing nitrogen (N) and phosphorus (P), while others do not. This research studied variability of responsiveness among corn hybrids to starter fertilizer containing a more complete complement of nutrients. The experiment was conducted from 1996 to 1998 on a producer's field near Scandia, KS, on a Carr sandy-loam soil (coarse-loamy, mixed, superactive calcareous, mesic Typic Udifluvents). The response of four corn hybrids (Pioneer 3563, Pioneer 3346, DeKalb 591, and DeKalb 646) to starter fertilizer combinations containing N, P, potassium (K), sulfur (S), and zinc (Zn) was evaluated. In all three years of the experiment, starter fertilizer containing N and P consistently increased grain yield, reduced the number of thermal units needed from emergence to maturity, decreased grain-moisture content at harvest, and increased total P uptake (grain plus stover at maturity) of Pioneer 3346 and DeKalb 591, but had no effect on Pioneer 3563 and DeKalb 646. Addition of S to the starter mix produced additional yield increases for Pioneer 3346 and DeKalb 591, whereas addition of K and Zn to the starter did not show any additional yield benefit for these two hybrids. Grain yield of Pioneer 3563 and DeKalb 646 was not improved by starter fertilizer, regardless of the elemental composition. When no starter fertilizer was applied, early-season root development was greater in Pioneer 3563 and DeKalb 646 than in the other two hybrids. However, the addition of starter fertilizer increased numbers of roots and depth of rooting in Pioneer 3346 and DeKalb 591 but had no effect on Pioneer 3563 and DeKalb 636. Results showed starter fertilizer benefited grain yield for two hybrids. Grain yield of the other two hybrids, however, was not influenced by starter, regardless of which nutrients were supplied. This response may be attributed to differences in root-growth characteristics of the hybrids. The two responsive hybrids did, however, yield an average of 0.75 mg ha^?1 greater than the two non-responsive hybrids. This result indicates it is unlikely that all of the yield loss from not using a starter can be avoided by hybrid selection.     

Virgibacillus halodenitrificans MSK-10P,a Potential Protease-producing Starter Culture for Fermented Shrimp Paste (kapi) Production

Fermented shrimp paste (Kapi) is traditionally produced using a high content of salt and mainly consumed as a food condiment by the Thai people. In order to select potential functional autochthonous starter culture, the protease-producing bacteria from Kapi were isolated, screened, and evaluated for technological and safety aspects. Among 195 isolates, five bacterial strains (MSK-3P, MSK-4P, MSK-5P, MSK-7P, and MSK-10P) exhibited the highest activity of protease using Anson method. All of them were identified as Virgibacillus halodenitrificans using 16S rRNA sequence analysis. All selected strains exhibited growth in the presence of NaCl up to 25%. Neither strain showed hemolytic activity nor biogenic amine formation. Among all selected strains, only strain MSK-10P had no ability to form a biofilm, while four other strains showed a weak ability. Strain MSK-7P exhibited multiple resistances to tetracycline and vancomycin, while strains MSK-3P, MSK-4P, and MSK-10P showed susceptibility to all antibiotics tested. According to the obtained results, this protease-producing V. halodenitrificans MSK-10P is a good candidate for further investigation for use in Kapi fermentation to assess its technological performance as a autochthonous starter culture.     

开食料补饲日龄对羔羊瘤胃和小肠组织形态的影响

为研究开食料补饲日龄对羔羊瘤胃和小肠组织形态的影响,选用72只体重接近的湖羊初生公羔(双羔,初生重3.51±0.52 kg),随机分为2组,7或42 d补饲开食料,每组36只羔羊。分别在14,28,42,56,70和84 d每组各屠宰6只羔羊,采集瘤胃和小肠组织样品。结果表明:42 d时7 d补饲组瘤胃背囊和腹囊乳头高显著高于42 d补饲组(P<0.05),42 d时7 d补饲组瘤胃腹囊乳头宽有大于42 d补饲组的趋势(P=0.053),42 d时7 d补饲组背囊肌层厚显著高于于42 d补饲组(P<0.05);28和42 d时7 d补饲组十二指肠和回肠绒毛长均显著高于42 d补饲组(P<0.05),42 d时7 d补饲组回肠隐窝深显著低于42 d补饲组(P<0.05),42 d时7 d补饲组十二指肠和回肠绒毛长和隐窝深比显著高于42 d补饲组(P<0.05)。结论 7 d补饲有利于瘤胃组织形态发育和42 d前小肠粘膜发育。     

东北玉米化肥减施增效技术途径探讨

减肥增效是提高我国玉米竞争力、保护生态环境的重大需求。论文重点以东北玉米为研究对象,从玉米养分需求规律、养分高效品种的节肥潜力、化肥高效施用的4R技术、化肥的有机替代技术等方面论述减肥增效的技术途径。研究表明,东北地区每生产100 kg玉米籽粒产量的平均N、P_2O_5、K_2O的需求量范围分别为1.56—1.89、0.60—0.88和1.27—2.30 kg;吐丝后对氮磷的需求量分别占全生育期需求量的20%—30%和20%—40%,对籽粒氮磷的贡献率分别为20%—30%和30%—38%。在目前东北土壤生产力状况下,实现玉米12 000 kg·hm~(-2)的产量水平平均氮肥投入量约为180 kg·hm~(~(-2))。应用不同类型新型肥料的节约氮肥潜力为9—25 kg·hm~(-2),应用磷酸二铵和硫酸铵+过磷酸钙做启动肥可以促进苗期生长。应用高地隙追肥机可以有效延长追肥的适宜期,有利于使"养分供应匹配养分需求"。滴灌施肥技术适宜在风砂质地土壤及干旱频繁发生地区推广,实现增产19%—128%,产量可达12 000—13 000 kg·hm~(-2)。地下滴灌施肥技术增产效果相同,应该大力推广。利用主动冠层传感器Greenseeker,可以在春玉米V5-V8期很好地估测叶面积指数、地上部生物量以及植株吸氮量,并应用于变量、精准的氮肥推荐。因地制宜地应用秸秆还田技术,可以节省肥料投入,提升土壤质量。其中秸秆覆盖条耕技术(Strip-till)可以协调传统耕作与免耕的优点,有很好的应用前景。未来应该从农民实际应用的角度出发,将技术研究与技术推广相结合,针对不同的栽培耕作技术模式,建立农民可应用、或在不久的将来可应用的技术规程,实现大面积应用,达到区域性减肥增效的目标。     

断奶羔羊4种必需氨基酸限制性顺序和需要量模型探索

本试验旨在采用氨基酸部分扣除法研究断奶羔羊的4种必需氨基酸的限制性顺序和需要模型。选取50日龄断奶湖羊公羊100只随机分为5组,每组4个重复,每个重复5只羊。对照组为氨基酸平衡(PC)组,饲喂氨基酸平衡的开食料,4个试验组开食料在PC组的基础上分别扣除赖氨酸(PD-Lys组)、蛋氨酸(PD-Met组)、苏氨酸(PD-Thr组)和色氨酸(PD-Trp组),其余氨基酸含量保持一致。预试期为10 d,正试期为60 d。于羔羊60、90和120日龄称量体重,在120日龄每组随机选取6只羔羊进行屠宰。结果表明:1)60~120日龄和90~120日龄,PD-M et组羔羊平均日增重(ADG)显著低于其他各组(P0.05),饲料转化率(F/G)显著高于其他各组(P0.05);120日龄时,PD-Met组宰前活重、空体重、胴体重、眼肌面积、头重、蹄重及皮毛重均显著低于PC、PD-Thr和PD-Trp组(P0.05),但是5组间屠宰率(DP)、GR值和血液重差异不显著(P0.05)。2)以最佳ADG和F/G为评价指标时,60~90日龄和90~120日龄氨基酸限制性顺序为Met、Lys、Thr和Trp;而以最佳DP为评价指标时,120日龄氨基酸的限制性顺序为Trp、Thr、Lys、Met。3)以最佳ADG作为评价指标时,60~90日龄和90~120日龄Lys、M et、Thr和Trp的适宜比例分别为100∶44∶44∶8和100∶42∶38∶12;以最佳F/G作为评价指标时,60~90日龄和90~120日龄Lys、M et、Thr和Trp的适宜比例分别为100∶54∶45∶7和100∶47∶39∶12;以最佳DP为评价指标时,60~120日龄Lys、M et、Thr和Trp的适宜比例为100∶34∶38∶8。总之,饲粮必需氨基酸(Lys、Met、Thr和Trp)缺乏严重影响湖羊断奶羔羊的生长性能、屠宰性能和器官指数,特别是Met影响最为明显,其次是Lys,Thr和Trp影响较弱;不同评价指标(ADG、F/G和DP)和不同生长阶段得出的Lys、M et、Thr和Trp的限制性顺序和需要模型是不同的。     

Modification of the rheological behavior of amaranth (Amaranthus hypochondriacus) dough

For people with celiac disease, a lifelong abdication of gluten including-products is necessary to live a life without celiac affected reactions. The production of high-quality bread from gluten free flour is not simple in comparison to gluten including flours such as those derived from wheat (Triticum spp.). The gas binding and crumb structure forming capacity are very low in gluten free batters. They can efficiently be analyzed through the rheological properties of the dough used. The use of acidification in amaranth (Amaranthus hypochondriacus) dough preparation is a possible means of changing the rheological behavior of amaranth in the desired direction. Methods include the use of lactic acid directly, or the fermentation via lactic acid bacteria. Adding up to 20 mL lactic acid/kg flour in amaranth dough preparation led, during oscillation tests, to an increase of the complex shear modulus up to 30% in the range of 0.1 up to 10 Hz. The use of sourdough fermentation decreased the complex shear modulus in the same test up to nearly 60%. In creep recovery tests, the elastic part of amaranth dough decreased from 65.4% without any treatment down to 63.9% by the addition of up to 20 mL lactic acid/kg flour. Sourdough fermentation by Lactobacillus plantarum was able to decrease it to 54%. The acidification showed a significant positive influence on the rheological parameters of amaranth dough only at the higher stress level. In contrast, sourdough fermentation was able to produce doughs with viscosity and elasticity similar to that found in pure wheat flours.