3,5-二硝基水杨酸法与酶法测定甜玉米还原糖和蔗糖含量的比较

针对目前测定甜玉米还原糖和蔗糖含量的3,5-二硝基水杨酸法和酶法进行比较研究,分析两者在育种中的应用。结果显示:酶法的测量准确度比3,5-二硝基水杨酸法高,且其稳定性和重现性都优于3,5-二硝基水杨酸法。通过两种方法对10个甜玉米杂交种种子的还原糖和蔗糖含量的测定,证实了两种方法在甜玉米还原糖和蔗糖含量的检测上是一致的。从育种实践考虑,酶法适于样品数较小的检测,3,5-二硝基水杨酸法更适合于大批量样品的检测。     

UV-C处理对甘薯贮藏品质的影响

以海南桥头产区的“高系14”甘薯为材料,分别进行10、20、30 min的UV-C照射处理,统计甘薯贮藏60 d内的腐烂率、失重率和发芽率,并同时记录5种生理指标的变化,以探讨UV-C处理对甘薯贮藏品质的影响。结果表明：UV-C处理显著降低了甘薯贮藏期间的腐烂率,但同时促进了发芽,而对失重率无显著影响。生理指标方面,30 min的UV-C照射提高了可溶性蛋白的积累,减少可溶性固形物的损耗,并促进了POD、SOD和CAT的总体酶活性。综合来说,UV-C处理若要应用于甘薯贮藏保鲜,还需辅助使用其他的抑芽手段。     

酸化红薯粉渣对肉兔生长性能、免疫器官指数和胃肠pH的影响

为探讨酸化红薯粉渣对肉兔生长性能、免疫器官指数和胃肠pH的影响,试验采用单因子完全随机分组设计,选取128只(公母各半)50日龄体重相近的新西兰兔随机分为4个处理组(对照组、试验1组、2组和3组),每组4个重复,分别饲喂含0%、5%、10%、15%酸化红薯粉渣的饲粮。结果表明,与对照组相比,试验2组和3组肉兔日均采食量、平均日增重、胸腺指数和脾脏指数均显著提高(P<0.05),胃pH显著降低(P<0.05);试验1、2和3组腹泻率、十二指肠pH、盲肠pH均有所降低(P>0.05)。由此可见,在饲料中添加适量的酸化红薯粉渣能提高肉兔的生长性能和免疫器官指数,降低胃肠pH,其中添加量为10%~15%效果较理想。     

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.     

益生菌发酵红薯渣对肉牛生长性能、养分表观消化率的影响

为研究益生菌发酵红薯渣对肉牛生长性能、养分表观消化率的影响,采用单因素随机设计试验,选择体重相近、健康的育肥肉牛40头随机分成4组,每组10个重复,每个重复1头,试验1组饲喂基础日粮,试验2、3、4组分别用10%、15%、20%益生菌发酵红薯渣替代饲粮中的玉米,预试验10 d,试验期60 d。结果表明:(1)试验3、4组的平均日增重较1组比分别提高16.9、14.1%(P<0.05),试验2、3、4组的平均采食量均高于1组(P>0.05);试验3、4组的料重比较1组比分别降低14.9%、12.4%(P<0.05);(2)试验2、3、4组干物质、蛋白质、钙、磷的表观消化率均高于1组(P 0.05);试验3、4组的中性洗涤纤维、酸性洗涤纤维表观消化率较1组比分别提高12.7%、11.0%、18.9%、16.4%(P<0.05)。综上,益生菌发酵红薯渣替代饲料中15%玉米,可以提高肉牛的生长性能和养分表观消化率。     

Characterization and application of lactic acid bacteria for tropical silage preparation

Strains TH 14, TH 21 and TH 64 were isolated from tropical silages, namely corn stover, sugar cane top and rice straw, respectively, prepared in Thailand. These strains were selected by low pH growth range and high lactic acid‐producing ability, similar to some commercial inoculants. Based on the analysis of 16S ribosomal RNA gene sequence and DNA‐DNA relatedness, strain TH 14 was identified as Lactobacillus casei, and strains TH 21 and TH 64 were identified as L. plantarum. Strains TH 14, TH 21, TH 64 and two commercial inoculants, CH (L. plantarum) and SN (L. rhamnosus), were used as additives to fresh and wilted purple Guinea and sorghum silages prepared using a small‐scale fermentation method. The number of epiphytic lactic acid bacteria (LAB) in the forages before ensilage was relatively low but the numbers of coliform and aerobic bacteria were higher. Sorghum silages at 30 days of fermentation were all well preserved with low pH (3.56) and high lactic acid production (72.86 g/kg dry matter). Purple Guinea silage inoculated with LAB exhibited reduced count levels of aerobic and coliform bacteria, lower pH, butyric acid and ammonia nitrogen and increased lactic acid concentration, compared with the control. Strain TH 14 more effectively improved lactic acid production compared with inoculants and other strains. © 2016 Japanese Society of Animal Science     

甘薯黑斑病及其防治研究

本文对甘薯黑斑病病原菌的生物学特性进行了探索,描述了病原菌的生长状况和形态,弄清了生长发育与温度关系,数据经最小二乘法求出发育最低起点温度为9.12℃,最高终止温度为36.28℃,通过矩阵求解推测发育最适温为23.97℃,对储藏防治策略也提出了一些看法。     

甘薯联合收获机高度自适应集薯装置设计与优化

甘薯收获是甘薯生产中用工量最多、劳动强度最大的环节。为了解决甘薯联合收获机集薯环节存在伤薯率高、自动化程度低等问题,该研究开展了高度自适应集薯装置的机械结构设计与控制系统搭建。系统及结构设计充分考虑物料物理性状及作业过程中的运动学与力学特性,通过新的集薯方式以满足落薯高度自适应、集薯装筐和自动卸料换筐等作业要求。通过落薯高度自适应功能减小并控制薯块下落的高度达到有效减少甘薯伤薯率与破皮率的目的。在单因素试验分析结论的基础上,以清选平台转速、落薯机构转速和落薯设定高度为试验因素,开展三因素三水平Box-Benhnken试验,以伤薯率、破皮率、微破率和损伤率为试验指标建立多元回归方程并进行响应面分析。回归模型进行多目标优化后获得装置最优工作参数组合为：清选平台转速108.07 r/min、落薯机构转速74.75 r/min、落薯设定高度18.15 cm。对优化结果进行验证试验,试验结果为：伤薯率0.39%、破皮率0.54%、微破率22.93%和漏薯率0.54%,各评价指标与模型预测值相近。研究结果可为甘薯联合收获机高度自适应集薯装置进一步设计与优化提供参考。     

SUSTAINABLE NUTRIENT MANAGEMENT PACKAGE FOR COST-EFFECTIVE BIOENERGY BIOMASS PRODUCTION

Commercial fertilizer (particularly nitrogen) costs account for a substantial portion of the total production costs of cellulosic biomass and can be a major obstacle to biofuel production. In a series of greenhouse studies, we evaluated the feasibility of co-applying Gibberellins (GA) and reduced nitrogen (N) rates to produce a bioenergy crop less expensively. In a preliminary study, we determined the minimum combined application rates of GA and N required for efficient biomass (sweet sorghum, Sorghum bicolor) production. Co-application of 75 kg ha^?1 (one-half of the recommended N rate for sorghum) and a modest GA rate of 3 g ha^?1 optimized dry matter yield (DMY) and N and phosphorus (P) uptake efficiencies, resulting in a reduction of N and P leaching. Organic nutrient sources such as manures and biosolids can be substituted for commercial N fertilizers (and incidentally supply P) to further reduce the cost of nutrient supply for biomass production. Based on the results of the preliminary study, we conducted a second greenhouse study using sweet sorghum as a test bioenergy crop. We co-applied organic sources of N (manure and biosolids) at 75 and 150 kg PAN ha^?1 (representing 50 and 100% N rate respectively) with 3 g GA ha^?1. In each batch of experiment, the crop was grown for 8 wk on Immokalee fine sand of minimal native fertility. After harvest, sufficient water was applied to soil in each pot to yield ～1.5 L (～0.75 pore volume) of leachate, and analyzed for total N and soluble reactive P (SRP). The reduced (50%) N application rate, together with GA, optimized biomass production. Application of GA at 3 g ha^?1, and the organic sources of N at 50% of the recommended N rate, decreased nutrient cost of producing the bioenergy biomass by ～$375 ha^?1 (>90% of total nutrient cost), and could reduce offsite N and P losses from vulnerable soils.     

双热源半自动控温甜樱桃促成栽培系统设计与试验

为解决甜樱桃促成栽培产量和质量不稳定的问题,该研究根据甜樱桃促成栽培特点,研制了一种双热源半自动控温甜樱桃促成栽培系统。该系统以煤、柴为燃料的地炕式加热炉为补充加热方式,结合太阳能调控温度。通过与传统大棚比较,分析了该系统对甜樱桃栽培产量及经济效益的影响。结果表明:连续2 a应用甜樱桃促成栽培系统的大棚产量稳定在11 550 kg/hm2以上,优质果率超过80%,年经济效益比普通大棚高37%(2012年)和36%(2013年)。该系统采用半自动测控促成栽培环境,使环境因子的检测和报警实现自动化,明显降低了劳动强度,在甜樱桃促成栽培中推广应用,可取得显著经济效益。