仿生法评定抗草甘膦玉米和转Bt基因玉米的酶水解物能值的研究

本试验旨在分析抗草甘膦玉米和转Bt基因玉米原料及饲粮与同源非转基因玉米原料及饲粮体外总能消化率以及酶水解物能值,为转基因玉米的营养实质等同性仿生评定方法的研究提供参考。试验采用单因素完全随机设计,使用单胃动物仿生消化系统模拟饲料原料和饲粮在鸡胃肠道的消化过程,分析同源非转基因玉米、抗草甘膦玉米和转Bt基因玉米以及对应的3种玉米-豆粕饲粮在不同体外模拟消化阶段的干物质消化率、总能消化率和酶水解物能值的差异。结果表明:同源非转基因玉米、抗草甘膦玉米和转Bt基因玉米以及对应饲粮在常规概率成分含量上是相似的。抗草甘膦玉米及饲粮与同源非转基因玉米及饲粮相比,在干物质和能量胃消化率、全消化道消化率及酶水解物能值上均没有显著差异(P0.05)。转Bt基因玉米全消化道总能消化率低于同源非转基因玉米(P=0.03,变异系数=0.50%),对应玉米饲粮的酶水解物能值则高于同源非转基因玉米饲粮(P=0.02,变异系数=1.12%),但均处于仿生消化系统测试的误差范围内(变异系数≤1.64%)。由此可见,抗草甘膦玉米的酶水解物能值与同源对照玉米没有差异,而转Bt基因玉米存在统计学意义上的差异,但所有的测值均处于仿生消化系统的测试误差之内。仿生法发现的差异是否具有生物学意义有待体内试验验证。仿生法可为转基因饲料营养等同性研究提供一种新方法。     

油茶高接换冠枯桩现象调查与研究

为了探寻影响油茶高接换冠后枯桩的相关因素,为今后油茶高接换冠技术改良提供理论依据,调查研究了嫁接方法、接穗品种、砧木粗度、留截高度和嫁接方位等因素对油茶高接换冠后枯桩现象的影响。结果表明:5种因素对油茶枯桩程度影响极显著。其中,采用插皮腹接、砧木直径2~6 cm枯桩程度最低;采用‘华硕’和‘湘林XLJ14’其枯桩程度显著低于其它品种;留截高度越低枯桩程度越低;嫁接方位在外侧枯桩程度最低。偏相关分析结果表明,留截高度对油茶枯桩程度的影响最大;其次是嫁接方法、砧木直径和嫁接品种;而嫁接方位对油茶枯桩程度的影响最小。     

Design of Automatic Quasi-synchronizing Device in Rural Small Hydropower Station

Generator synchronization is an important and frequent operation in rural small hydropower station. In order to ensure that generator can be paralleled in the grid automatically, efficiently, and stably in the rural small hydropower station whose parallel in operation still needs to be accomplished manually. This paper described an automatic quasi-synchronizing device, based on 89C52 Single-chip Microcomputer （SCM）. Its hardware includes three modules and its software is structuralized. The device structure is simple, and its reliability is high and the maintenance is easy. Besides, convenient Human Machine Interface （HMI） makes the parameter setting simple and flexible     

中国荷斯坦牛干奶期长度的群体特征及其与生产性能的关系

本研究旨在探究北京地区中国荷斯坦牛干奶期长度（DPL）的变化规律及其变异对奶牛各项生产性能的影响，包括产奶性能、繁殖性能、初乳品质和乳房健康。收集了北京地区34个牧场出生于2009—2018年136 231头中国荷斯坦牛的干奶日期、生产性能记录、繁殖性能记录等。通过整理试验牛群的干奶记录，揭示了北京地区中国荷斯坦牛1胎和2胎DPL的群体规律，利用固定模型分析了胎次、产犊季节、场-产犊年和初产月龄对DPL的影响；此外，利用固定模型分析了DPL的变异对日产奶量、乳脂率、乳蛋白率、首末次配种间隔（interval from first to last insemination，IFL）、产犊至首次配种间隔（interval from calving to first insemination，ICF）和初乳品质的影响，利用Logistic回归过程分析了DPL的变异对首次配种受胎率（conception rate of first insemination，CR）、首次配种56 d不返情率（56-days non-return rate of first insemination，NRR56）、难产率和乳房健康的影响。研究结果显示，北京地区中国荷斯坦牛DPL平均为58.81 d，胎次、产犊季节、场-产犊年和初产月龄均对DPL有显著影响（P<0.05）。DPL的变异对日产奶量、乳蛋白率、ICF、CR、NRR56、难产率和乳房健康有显著影响（P<0.05）。干奶期短的奶牛测定日平均乳蛋白率、CR和NRR56更高；DPL适中的奶牛测定日平均产奶量更高、乳房健康水平更好、ICF更短、难产率更低。本研究在国内利用大规模牛群数据揭示了中国荷斯坦牛DPL的群体规律，可为中国规模化奶牛场提升管理水平提供参考。     

不同方法制备的雷竹竹沥化学成分分析

分别采用烧制法、干馏法和渗漉法3种不同方法提取雷竹(Phyllostachys praecox)竹沥,运用气相色谱-质谱联用技术(GC-MS)分析所含化学成分的差异。结果表明,烧制法提取竹沥检出峰104个,可定性成分为20个,含量占总检出成分的62.89%;干馏法提取竹沥检出峰100个,可定性成分21个,含量占总检出成分的57.14%;渗漉法提取竹沥检出峰99个,可定性成分33个,含量占总检出成分的64.81%。雷竹竹沥所含的有机化合物含量与不同的提取方法有关,有机酸类化合物提取应采用烧制法;醛类化合物、醇类化合物提取宜采用渗漉法;酚类化合物提取采用干馏法最优。     

超干种子老化方法比较研究

本试验种用谷子、绿豆，经４０℃及４５℃，湿度ＲＨ＝９５％－１００％老化６天及５天。然后测各含水量的５项活力指标。经生物统计表明：谷子４０℃，４５℃二处理间差异显著，且４０℃高温老化６天时间，在不同含水量的组合上，除含水量０．８５％外，其余二因子组合均优于４５℃老化６天的不同含水量处理，且有０．０１显著差异。绿豆老化温度亦以４０℃较好，种子含水量老化结合谷子和绿豆均以５．８％处理效果最好，二种作物经     

Hepatic lipidosis: Liver characteristics and acute phase proteins in affected turkeys

The hepatic lipidosis (HL) in fattening turkeys is a disease has been known for a long time, but the cause and pathogenesis is still not clarified. A recent study reported unexplained high levels of iron in liver tissue of fattening turkeys suffering from HL. In this study, the iron status, possible infectious or inflammatory influences in form of an acute phase reaction and the analysis of fatty acid pattern in liver tissue of turkeys affected by HL were examined. Three cases of HL on three different fattening turkey farms were investigated during the outbreak of the disease. Clinically affected and non-affected animals were subjected to a pathological examination, where the diagnosis HL or non-affected was made. In total, 70 birds were examined (40 with HL, 30 without HL) and blood and liver samples were taken. Additionally, samples from 15 slaughtered birds were taken as a further control group. In liver tissue, the iron content and the content of long-chain fatty acids were determined; in blood samples, ferritin and transferrin were measured. The iron content in liver tissue was more than three times higher for animals with HL than among non-affected animals and the control group. The transferrin levels were lowest for animals with HL, highest in the control group and in between for non-affected animals. The fatty acid pattern in liver tissue of affected animals indicated a shift from polyunsaturated fatty acids to saturated fatty acids and monounsaturated fatty acids compared to the control group and the non-affected animals. Overall, the non-affected animals of a flock affected by HL were similar to the healthy animals of the abattoir. The low acute phase protein levels for animals with HL together with high iron contents could indicate a previous malnutrition/starvation period and/or severe liver damage for those animals suffering from HL.     

Selenium supplementation improves nutrient intake and digestibility,and mitigates CH4 emissions from sheep grazed on the mixed pasture of alfalfa and tall fescue

Low selenium (Se) in soil and forage can adversely affect on the quality of animal-derived foods, and hence on human health. Lambs grazed on mixed pastures of alfalfa (Medicago sativa) and tall fescue (Festuca arundinacea) were supplemented with five levels of Se [0, 3, 6, 9 and 12 µg/kg body weight (BW)]. The intake of dry matter (DM) and organic matter (OM) varied with the level of Se supplementation, with a peak at 6 µg Se per kg BW (p ≤ 0.05). Gross energy (GE) intake, digestive energy (DE) intake and metabolic energy (ME) intake were higher at 6 µg Se per kg BW than at other Se levels (p < 0.01); in addition, methane energy (CH₄-E) output was lower at 6 µg Se per kg BW. Supplementation with Se significantly increased nitrogen (N) intake, faecal N and urine N, for which the peak values were 20.2 g N/, 5.62 g N/day and 7.92 g N/day, respectively, at 6 µg Se per kg BW. Se intake, blood Se, faecal Se, urine Se and retained Se were negatively correlated with forage crude protein (CP) content (p < 0.001) but were positively correlated with the content of neutral detergent fibre (NDF) (p < 0.001) and acid detergent fibre (ADF) (p < 0.001). Thus, we recommend the addition of 6 µg Se per kg BW to sheep grazed on pastures in regions with low soil Se.     

分散固相萃取结合UPLC-Orbitrap MS联用测定鸡蛋中五氯苯酚残留量

建立了超高效液相色谱-静电轨道阱质谱联用测定禽蛋中五氯苯酚残留量的分析方法。取均质后的禽蛋样品经乙腈溶液提取,加入无水硫酸镁和氯化钠进行脱水和盐析,高速离心分层后,取适量乙腈层溶液经0.1%(V∶V)甲酸稀释后,用酸性氧化铝粉末进行样品净化并以10000 r/min离心取上清液,过0.22μm滤膜后上机测定。使用反相色谱柱进行分离,流动相为乙腈:0.1%甲酸=75∶25,采用等度程序进行洗脱,静电轨道阱质谱进行定性定量分析。结果表明,五氯苯酚在0.5~100μg/kg范围内线性关系良好(r>0.995),方法的最低检出限为0.2μg/kg,最低定量限为0.5μg/kg,添加回收率在74.43%~96.85%之间,批内批间变异系数CV%<10%。该方法具有较好的准确度与精密度,适用于禽蛋中五氯苯酚残留量的测定。     

兴安盟地区旱作条件下11个苜蓿品种生产性能和饲用价值比较

为筛选兴安盟地区旱作条件下适宜引进栽培的优良苜蓿品种,在兴安盟乌兰浩特市呼和马场种植11个苜蓿(Medicago sativa)品种,通过连续2年观测参试品种的越冬率、株高、产量、茎叶比及营养成分等指标,对旱作条件下11个苜蓿品种的生产性能和饲用价值进行灰色关联分析。结果表明:图牧2号、敖汉苜蓿和呼伦贝尔杂花苜蓿两年的平均越冬率较高;SK3010、呼伦贝尔杂花苜蓿和敖汉苜蓿在株高、生长速度和干草产量方面表现较好;图牧2号的茎叶比均最大,其次是呼伦贝尔杂花苜蓿、SK3010和敖汉苜蓿;WL168HQ、斯普雷德和呼伦贝尔杂花苜蓿两年的粗蛋白质含量均高于18%;巨能2和斯贝德的粗纤维含量较高;WL168HQ、呼伦贝尔杂花苜蓿、WL343HQ、SK3010和WL319HQ的粗灰分含量均高于10%。对11个苜蓿品种的越冬率、产量特性和饲用品质进行灰色关联分析表明,呼伦贝尔杂花苜蓿的综合表现最优,适合在该地区种植推广。