Effect of dietary supplementation with an ethanolic extract of propolis on broiler intestinal morphology and digestive enzyme activity

The present study aimed to evaluate the effect of different levels of an ethanolic extract of propolis (EEP) on broiler performance, carcass characteristics, weight of gastrointestinal organs, intestinal morphometry and digestive enzyme activity. 1020 male broiler chicks were assigned in a completely randomised experimental design to six treatments (EEP supplement levels of 0, 1000, 2000, 3000, 4000 and 5000 ppm) and five replications, and 34 birds per experimental unit. The experimental diets were administered from 1 to 21 days of age, and the birds were subsequently provided a ration based on corn and soybean meal. EEP supplementation from 1 to 7 days negatively affected (p < 0.05) the weight gain and feed intake. The proventriculus weight at 7 days exhibited a quadratic response (p < 0.05), which predicted a lower weight at a dose of 2865 ppm of the EEP. For the duodenum at 21 days of age, the response pattern (p < 0.05) predicted that birds that were fed 2943 and 3047 ppm of the EEP would exhibit an improved crypt depth and villus‐to‐crypt ratio respectively. The villus height, crypt depth and villus‐to‐crypt ratio in the jejunum and the ileum were not affected (p > 0.05). With increased EEP doses, the duodenal sucrase activity linearly decreased at 7 days of age and linearly increased in the jejunum at 21 days of age (p < 0.05), while pancreatic enzyme activity was unaffected (p > 0.05). Although the carcass and cut yields did not improve, the percentage of abdominal fat decreased (p < 0.05). The supplementation of the broiler pre‐starter diet with 1000–5000 ppm of the EEP impaired performance at this stage, most likely due to the decreased sucrase activity. However, the EEP supplementation from 3000 ppm improved intestinal morphophysiology at 21 days of age and did not affect the performance or carcass yield at 42 days of age.     

绵羊冷冻精液研究进展

随着肉羊产业化、工厂化的发展,冷冻精液人工授精技术亟待应用于生产中.绵羊精液冷冻保存技术虽然得到了快速发展,但目前仍处在试验研究或小范围的应用阶段.因此,绵羊精液冷冻技术还需要深入、系统的研究.文章从绵羊精液冷冻保存稀释液中的添加剂、冷冻速率、冷冻-解冻对绵羊冷冻精液品质的影响,精液输精对受胎率的影响等方面进行了综述,为精液冷冻保存研究提供一定参考.     

水分和添加剂对苜蓿青贮效果的影响

为研究苜蓿的水分、添加剂对苜蓿青贮发酵品质的影响,通过对头茬苜蓿设置3个水分梯度,并添加4个水平的甲酸、丙酸、双乙酸钠,装入聚乙烯袋抽真空,发酵45 d 后进行营养分析和品质鉴定。结果表明：适宜苜蓿青贮的水分条件为55%,这一水分条件下苜蓿青贮料的 pH、氨态氮、粗纤维最低,可溶性糖、乳酸最高;而3种添加剂对青贮料的影响具体表现为：与对照组相比,能够显著降低苜蓿青贮料的 pH 和氨态氮含量（P 〈0.05）,并且能够很好地保存青贮料中的可溶性糖,通过对灰色关联度分析,甲酸对苜蓿青贮的影响效果最佳,丙酸次之;且55%的水分条件下添加15 mL/kg 的甲酸,青贮效果为最好。     

Distribution and richness of diadromous fish assemblages in Western Europe: large-scale explanatory factors

Abstract –  The aim of this study was to analyse the distribution of 14 diadromous fish at the beginning of the 20th century in western Europe. This study was conducted on a set of 41 water basins. Five environmental variables were selected and we used generalised additive models for explaining the presence–absence of species. The richest basins were located in the centre of the study area. Six main assemblage types were identified along a latitudinal gradient; they were constituted of a common species basis but differed by the absence or presence of other species. The 10 single species models produced have moderate to very good discrimination level and they can correctly predict both absence and presence. Temperature is included in all but one model, response curves vary according to the species; surface area is included in six models.     

秸秆腐熟剂对水稻秸秆还田应用效果的影响研究

秸秆腐熟剂对水稻秸秆还田应用效果试验结果表明,水稻秸秆还田施用秸秆腐熟剂能提高水稻产量,最高增产850.5 kg/hm2,增产率8.4%。同时有效促进了水稻秸秆快速腐解,土壤容重略有下降、CEC值有所增加,对提高土壤保水保肥能力、培肥地力有一定的效果。     

中草药饲料添加剂在鸡养殖中的应用

随着人们生活水平的提高,消费者对肉和蛋等禽类食品质量的要求越来越高,中草药添加剂因天然、安全和无抗药性等特性成为家禽养殖业的焦点。为了对中草药饲料添加剂有个全面、深入的了解,通过查阅大量文献,对中草药饲料添加剂的特性、作用机理及其在鸡养殖中的应用状况进行研究,并分析了家禽养殖业中中草药饲料添加剂所具有的广阔应用前景。     

姜黄素作为饲料添加剂的研究进展

姜黄素是从姜科植物中提取的一种天然活性物质,具有保护肠黏膜、抗氧化、调节代谢、抑菌抗炎等功能。姜黄素作为一种多效的天然活性物质,已逐渐取代抗生素在饲料中得到广泛应用。文章主要从姜黄素的理化性质、生理功能及其在饲料中的应用等方面作以综述。     

中草药添加剂对关岭黄牛生长及免疫功能的影响

为探明中草药添加剂对牛增重及免疫功能的影响,选取贵州关岭黄牛15头,随机分为对照组、试验Ⅰ组、试验Ⅱ组、试验Ⅲ组和试验Ⅳ组,每组3头,对照组饲喂基础日粮,试验Ⅰ～Ⅳ组分别在基础日粮中添加首乌、黄芪等12味中草药添加剂3％、4％、5％和6％,试验期29 d;试验前和试验后分别空腹称重,计算日增重、料肉比,并采集血样检测血常规指标、免疫球蛋白（IgG、IgA 和 IgM）含量变化。结果表明：在基础日粮中添加不同比例的中草药添加剂对关岭黄牛的增重均有促进作用,能提高大未染色细胞数和单核细胞百分率以及 IgG、IgM 和 IgA 的水平,降低中性粒细胞百分率和血小板平均体积。中药添加剂具有促进关岭黄牛增重、增强免疫功能的作用,其中以添加5％的比例最佳。     

变分不等式的加性广义Schwarz算法

将加性广义Ｓｃｈｗａｒｚ算法推广到求解变不等式，并在适当条件下证明了其收敛性。     

草原蝗虫开发利用的研究

青海草原环湖及柴达木蝗区大部分地面平缓，宜于机械作业。蝗虫种群密度８０～１２０头／ｍ２者居多，面积为４０～５０万ｈｍ２，贮量小年为４８４０Ｔ，大年为６５６０Ｔ，开发前景广阔。蝗虫粉含粗蛋白７４．８８％，居我国目前优良饲料之首。经试验，作为饲料添加剂与５０％的进口鱼粉比较，京黄１号７日龄肉仔鸡饲喂４９天后成活率为８８．７１％，体重平均增长１０２０．２ｇ，二者差异不显著；星杂二八八６～８月龄蛋鸡饲喂后产蛋量提高１８．０８％，产蛋率提高７．９９％，完全可以代替鱼粉。新研制的捕蝗机捕蝗率为６５．０～７４．２％，生产率２．７４ｈｍ２／ｈ，单机捕幅４ｍ。以１９９３年的市场价格为准，机捕的经济效益为２８．６０元／ｈｍ２，且有突出的社会和生态效益。