叶蛋白提取与应用的研究进展

叶蛋白是从绿色植物的茎叶中提取得到的一种功能性蛋白质,其粗蛋白质含量一般可达30%～60%。随着经济与科技的发展,人类营养和动物营养逐渐得到调整完善。叶蛋白作为蛋白质的良好来源,在人类蛋白质营养补充和蛋白源饲料开发中具很大的发展前景。本文根据国内外相关研究资料,概述了叶蛋白的营养价值,对目前叶蛋白常用的提取技术进行了综述和讨论,并展望了叶蛋白的应用前景,以期为未来新型叶蛋白产品开发奠定理论基础。     

滴灌小麦根系生理特性及其空间分布

通过管栽滴灌根区水分控制试验,研究不同滴灌条件下,春小麦根系生理特性、垂直分布变化及其产量构成等。结果表明:①孕穗～灌浆初期是滴灌春小麦根系生长的关键时期,此期根系的总根质量和总根长、根系总吸收面积、活跃吸收面积和根系活力达最大值。②土壤水分过少,根系过氧化物酶活性降低,脯氨酸含量虽有所增加,但后期下降过快,根系过早衰亡;水分过多,影响根系吸收面积增加,根系活力下降,植株贪青晚熟,经济生产效率低;适宜水分(田间饱和质量含水量的70%～75%)处理能有效促进根系生长及生理功能提高,产量最高。通过滴灌控制小麦根区水分状况,可以实现以水调根,促进小麦高产形成并获得较高的水分利用效率。     

Plant poisonings and mycotoxicoses of importance in horses in southern Africa

Well-known plant poisonings such as 'dunsiekte' (seneciosis) and 'jaagsiekte' (crotalariosis) of horses in southern Africa are briefly reviewed. Relatively unfamiliar mycotoxicoses such as stachybotryotoxicosis and perennial rye grass staggers and potentially occurring exotic intoxications such as equine nigropallidal encephalomalacia and ergot alkaloid poisoning are also discussed. This article is aimed at informing the southern African equine practitioner about probable poisonings that might occur locally in horses.     

Milk yield of primiparous beef cows from three calving systems and varied weaning ages

Primiparous beef cows produced in 3 calving systems were used in a 2-yr study with a completely random design to measure milk yield throughout a 190-d lactation (2002, n = 20; 2003, n = 24 per calving system). Calving occurred in late winter (average calving date = February 4 +/- 2 d), early spring (average calving date = March 30 +/- 2 d), and late spring (average calving date = May 26 +/- 1 d). Additionally, cows used in this study had been weaned at varied ages as calves, creating 6 dam treatments. Dam age at weaning was 140 (late spring), 190 (late winter, early spring, late spring), or 240 (late winter, early spring) d of age. Milk production was measured by using the weigh-suckle-weigh technique at an average of 20, 38, 55, 88, 125, 163, and 190 d in milk. Milk yield for the 190-d lactation period was calculated as area under the curve by trapezoidal summation. Data were analyzed with a model containing treatment, year, and their interaction. Orthogonal contrasts were used to separate effects when treatment was significant (P < 0.10). Total milk yield did not differ (P = 0.42) between cows in the late winter and early spring systems, but cows in the late spring system tended to differ (P = 0.09) from the average of the other 2 systems. Cows in the late spring calving system had increased milk yield in 2002 and lesser milk yield in 2003 compared with the other calving systems (treatment x year interaction, P < 0.001). Cows born in late spring that had been weaned at 140 d of age produced more (P = 0.05) total milk than those weaned at 190 d of age. Peak milk yield was affected (P < 0.001) by treatment and showed a treatment x year interaction (P = 0.006). Day of peak lactation differed among treatments (P = 0.002), with cows in the late winter system peaking later (P = 0.007) than early spring cows, and late spring cows peaking earlier (P = 0.004) than the average of late winter and early spring cows. The average date of peak lactation was May 4 for the late winter system, May 31 for the early spring system, and July 19 for the late spring system. Calf ADG differed (P < 0.001) for the late spring system compared with the average of the late winter and early spring systems, but the relationship interacted with year (P < 0.001). Cow BW and BW change differed among treatments (P < 0.004), with much of the difference associated with the amount of milk produced or the timing of peak lactation. Season of calving affects milk yield of primiparous cows grazing Northern Great Plains rangelands and ADG of their calves.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

不同固化剂组配对固化成型肥料浸水稳定性的影响

为研究固化剂不同组配对固化成型肥料浸水稳定性的影响,本试验设置不施加固化剂(CK1)、施加优选固化剂组配(C K2)及施加不同固化剂组配的4个处理(分别为T 1、T2、T3和T4),测定其抗压强度并对其浸水稳定性进行分析.结果表明:各处理肥料颗粒的抗压强度大小顺序为CK1>CK2>T4>T3>T1>T2,加入固化剂降低...     

新时期农产品质量安全监管问题探讨

2009年《食品安全法》的颁布与实施,将我国的食品安全管理推入了一个新阶段。食用农产品作为食品的一个重要组成部分．其质量安全的监管范畴相对独立地划归《农产品质量安全法》调整。农业行政管理部门作为《农产品质量安全法》监管的主体部门．相对独立地承担食用农产品质量安全的监管工作。目前,《农产品质量安全法》颁布已近4年．在新形势下,     

不同水肥处理对核桃光合特性和产量的影响

[目的]以新疆薄皮核桃新新2号为试材,研究施肥量及灌水量对生育期核桃光合特性和产量的影响,为提高核桃产量和品质提供理论依据.[方法]采用Li-6400便携式光合测定仪对不同灌水量及施肥量处理下的核桃叶片净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)和水分利用效率(WUE)进行了测量和分析,对不同灌水量和施肥水平下核桃产量进行比较.[结果]3个施肥水平和3个灌溉水平下,从核桃果实膨大期至成熟期新新2号核桃净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)均呈"升高-降低"的趋势,水分利用效率(WUE)逐渐降低.胞间CO2浓度(Ci)在Ⅰ和Ⅲ施肥水平下呈"下降-升高-急剧下降"的变化趋势,Ⅱ施肥水平下呈下降趋势.不同施肥水平核桃Pn、Tr、WUE、Gs和Ci顺序均为Ⅲ＞Ⅱ＞Ⅰ施肥水平.Ⅲ75o和Ⅱ600灌溉水平下核桃Ci呈现"降低-升高-降低"的变化趋势,Ⅰ450灌溉水平呈逐渐降低的趋势,不同灌溉水平下核桃Pn和Ci顺序为Ⅲ750＞ Ⅱ600＞ Ⅰ450灌溉水平.HⅢ75o灌溉水平和Ⅲ施肥水平下,核桃平均单株产量最高.[结论]核桃在一定范围内增加灌水量和施肥量可以提高核桃平均单株产量.