青木香提取物对兔离体肠段运动的影响

为了探讨青木香对腹痛腹泻的治疗作用机制,采用离体肠肌试验,应用BL-420E生物机能实验系统,比较青木香提取物对正常肠段及工具药酚妥拉明、氯化钡作用下离体肠平滑肌活动的影响,记录肠段的收缩频率和振幅。结果显示,青木香提取物可浓度依赖性地抑制兔小肠段自发性收缩的频率和振幅;2．5mg／mL青木香提取物对由氯化钡引起的离体肠段的兴奋性收缩有明显的拮抗作用,而对酚妥拉明阻断肾上腺素能受体后,仍能显著降低离体肠段收缩的振幅。提示青木香提取物对小肠蠕动有一定的抑制作用。     

味精菌体蛋白对鸡蛋白质和氨基酸利用率的影响

选用24只2 kg左右的蛋公鸡,随机分组进行4个处理,每个处理6只鸡。前3个处理分别给每只鸡强饲占体重4%的待测原料(豆粕、玉米蛋白粉和味精菌体蛋白),第4个处理作为内源对照组,测定内源排泄量,以评定味精菌体蛋白对鸡蛋白质和氨基酸利用率的影响。结果表明,味精菌体蛋白粗蛋白含量达到71.45%,分别比豆粕和玉米蛋白粉高64.03%和22.32%;味精菌体蛋白粗蛋白表观消化率和真消化率、总氨基酸表观消化率和真消化率均极显著低于豆粕和玉米蛋白粉(P<0.01);而干物质表观消化率和真消化率三者间无显著差异(P>0.05);在已测定的17种氨基酸中,除甘氨酸外,味精菌体蛋白粉其他氨基酸表观消化率和真消化率均极显著低于豆粕和玉米蛋白粉(P<0.01)。这表明味精菌体蛋白的蛋白质和氨基酸利用率低于豆粕和玉米蛋白粉。     

肉用仔鹅饲粮适宜粗纤维和粗蛋白水平的研究

采用3×3因子的析因设计,将189只1日龄健康肉用仔鹅随机分成9组,每组3个重复,每个重复7只;将日粮的粗纤维和粗蛋白分前、后期各设低、中、高3个水平,构成9个处理,18种日粮,研究不同粗纤维和粗蛋白水平对1~35日龄(前期)、36~63日龄(后期)肉仔鹅生长性能和营养物质利用率的影响。结果:1~35日龄肉仔鹅对日粮中粗纤维水平非常敏感,但对蛋白质水平要求不高;低纤维水平日粮组日增重与料重比明显好于中、高纤维组(P<0.01),日粮粗纤维和粗蛋白水平极显著影响鹅对能量和蛋白质的利用率(P<0.01);1~35日龄肉仔鹅饲粮粗纤维水平以3.5%、粗蛋白水平以17%~19%为宜。36~63日龄,较低的粗蛋白水平即可满足鹅的需要;高纤维水平日粮组鹅的日增重与料重比明显好于低纤维水平组(P<0.01);日粮粗纤维和粗蛋白水平极显著影响鹅对能量和蛋白质的利用率(P<0.01)。试验表明36~63日龄肉仔鹅饲粮适宜粗纤维水平为10%,粗蛋白水平为14%。     

Screening and isolation of a nematicidal sesquiterpene from Magnolia grandiflora L

The ethanolic extracts from 30 plant species were tested for their nematicidal activity against nematodes Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle and Panagrellus redivivus (L.) Goodey. The leaf extract of Magnolia grandiflora L. exhibited the strongest nematicidal activity against both nematodes, causing 73 and 100% mortality respectively within 48 h at 5 mg mL(-1). A new nematicidal sesquiterpene was obtained from the leaves of M. grandiflora. The compound was determined to be 4,5-epoxy-1(10)E,11(13)-germacradien-12,6-olide, based on spectroscopic methods including 2D NMR techniques. The median lethal concentrations (LC50) of the compound against B. xylophilus and P. redivivus were 71 and 46 mg L(-1) respectively at 48 h. This is the first report of Magnoliaceae species with nematicidal activity.     

Low crude protein diets supplemented with casein hydrolysate enhance the intestinal barrier function and decrease the pro-inflammatory cytokine expression in the small intestine of pigs

To reduce nitrogen excretion and lower feeding costs, low crude protein (CP) diets are sometimes proposed, however, a great reduction of dietary CP concentration (>4% reduction vs. recommended concentration), even supplemented with essential and nonessential amino acids (AA) can detrimentally affect small intestinal barrier function and immunity, possibly due to the excessive lack of peptides. Here we hypothesize that with an extremely low CP concentration diet, protein-derived peptides, rather than AA supplementation, can improve intestinal barrier development and health. To test this hypothesis, 21 growing pigs (19.90 ± 1.00 kg body weight) were randomly assigned to 3 treatments with control diet (16% CP), or low CP diets (13% CP) supplemented with AA (LCPA) or casein hydrolysate (LCPC) for 28 days. In comparison with the control diet, the LCPA diet decreased the protein expression level of jejunal barrier factor zonula occludens-1 (ZO-1) and stem cell proliferation factor leucine-rich repeat-containing G-protein-coupled receptor-5, whereas the LCPC diet enhanced intestinal barrier function by increasing the protein expression level of jejunal occludin and ZO-1 and ileal mucin-2. The LCPA diet reduced Lactobacillus counts, whereas the LCPC diet increased Lactobacillus counts and reduced Escherichia coli counts in the ileum. The LCPA diet also increased protein expression levels of pro-inflammatory cytokine interleukin-6 (IL-6) and IL-22, whereas the LCPC diet decreased protein expression levels of pro-inflammatory IL-1β, IL-17A and tumor necrosis factor-α in the ileum. Collectively, the casein hydrolysate supplementation of low CP diets showed beneficial effects on the small intestinal barrier, bacterial community, and immunity in pigs, pointing to the important role of protein-derived peptides in small intestinal health in cases of low crude protein diets.     

6种植物粗提物对海棠花灰霉菌的抑制效果

采用生长速率法测定了6种常见植物的无水乙醇粗提物和水粗提物对海棠花灰霉菌的抑制效果。结果表明,6种植物的水和无水乙醇粗提物对灰霉菌的抑制效果差别较大,其中马褂木和紫茎泽兰的抑菌效果最明显,而其他材料也有一定的抑菌效果。6种植物材料中除紫茎泽兰外无水乙醇粗提物的提取率均低于水粗提物,在不同浓度时6种植物的无水乙醇、水粗提物对灰霉菌的抑制作用均不同,但基本上表现为无水乙醇粗提物大于水粗提物。     

枇杷籽提取物的生理活性与药理效应研究进展

综述了枇杷籽提取物(ESE)的生理活性与药理效应的研究进展,为枇杷籽资源的综合开发利用提供理论依据。     

山楂粗黄酮抗氧化能力及抑菌活性研究

采用超声提取山楂粗黄酮,并测定了山楂粗黄酮对DPPH清除能力、总还原能力和β-胡萝卜素的漂白能力,结果表明,山楂粗黄酮具有良好的抗氧化活性,并且其抗氧化能力呈现出明显的剂量依赖关系,可作为一种新型的天然抗氧化剂。选取大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、黑曲霉、米曲霉等5种菌种对山楂粗黄酮进行体外抑菌试验,结果表明,山楂粗黄酮对细菌有较强的抑制作用,而对于霉菌则效果不明显。山楂粗黄酮对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌的最低抑菌质量浓度分别为3.125,1.562 5,3.125 mg/mL,最低致死质量浓度分别为6.25,3.125,6.25 mg/mL。因此,山楂粗黄酮可以作为一种理想的抑菌添加剂使用。     

大叶胡颓子茎正丁醇萃取物的抗菌作用研究

[目的]研究大叶胡颓子茎正丁醇萃取物的抑菌作用。[方法]大叶胡颓子茎经乙醇提取后,用石油醚、氯仿、乙酸乙酯和正丁醇依次萃取,然后采用滤纸片法和平板稀释法对正丁醇萃取物进行体外抑菌作用研究。[结果]大叶胡颓子茎正丁醇萃取物对5种常见的呼吸道感染菌(金黄色葡萄球菌、大肠杆菌、铜绿假单胞菌、肺炎克氏杆菌和鲍曼不动杆菌)均有体外抑制作用,最小抑菌浓度分别为1.500、0.750、0.375、0.750和0.375 mg/ml。[结论]大叶胡颓子茎正丁醇萃取物具有抗菌活性,可以进一步开发其药用价值。     

几种植物提取物对枸杞瘿螨的杀虫活性测定

将4种植物提取物对枸杞瘿螨的毒力活性进行了测定,结果表明:艾叶、蛇床子提取物具有较强的毒力活性,两种提取物在稀释1000倍和2000倍时对枸杞瘿螨的毒杀效果均达90%以上,通过毒力回归分析得LC50分别为0.1671 mg/ml和0.1529mg/ml。