Improvement of Poplar Bark Extract on Physiological Characters of Lactococcus lactis in Intestine of White Feather Broilers

[Objective]The paper was to study the improvement of poplar bark extract on intestinal Lactococcus lactis of white feather broilers.[Method]Totally 450 Ross 308 white-feather broilers were randomly divided into five groups:control group,low dose group,medium dose group,high dose group,and antibiotic group(oxytetracycline hydrochloride).The feeding duration was 45 d.The probiotics were screened and isolated through homology,and the physiological and biochemical characteristics of chicken intestinal bacteria in different groups were compared to determine the properties of bacterial strain.The drug resistance,antibacterial ability,proliferation ability,acid resistance and bile salt resistance of isolated strain were tested,and a strain of L.lactis was obtained.[Result]The isolated L.lactis was sensitive to other drugs except natural tetracyclines,and there was no significant difference among the four groups except oxytetracycline group;as the concentration of extract increased,the inhibition of L.lactis against Salmonella sp.increased;the medium dose extract had the largest increase in the ability to tolerate the proliferation of L.lactis.[Conclusion]Feeding poplar bark extract will produce positive effects on the physiological characters of intestinal L.lactis in broiler chicken,which will provide potential probiotic strain for chicken production.

从杨树皮提取分离不饱和脂肪酸的研究

精制的杨树皮不饱和脂肪酸乙酯产品是高纯度的亚油酸制品。产品中主要成分是亚油酸，其含量达９４．０４％。精制不饱和脂肪酸乙酯得率为３０％～３６％。急性毒性试验证明，产品无毒，安全可靠。药效试验证明，精制的不饱和脂肪酸乙酯对试验性高脂血症大鼠有较明显的降血脂作用（Ｐ＜０．００１）。

松针提取物和杨树皮提取物饲料添加剂贮藏研究

松针提取物和杨树皮提取物饲料添加剂，在室温避光条件下贮藏，生物活性物质（维生素Ｅ、胡萝卜素和叶绿素等）降低的含量百分率与贮藏时间关系，符合Ｙ＝－ａｘ￣ｂ（０＜ｂ＜１）的变化规律。其降低幅度依赖水分大小和维生素种类不同而各异。在贮藏期间，杨树皮提取物饲料添加剂中生物活性物质损失比松针提取物饲料添加剂多，因此，不同类型的产品，贮藏期应有不同要求。试验结果表明，松针提取物饲料添加剂，贮藏期定为一年期限较合适；而杨树皮提取物饲料添加剂，最长的贮藏期应不超过半年。

酶-超声辅助提取杨树皮总黄酮及其表征

为优化杨树皮总黄酮的提取方法,并对提取出的黄酮单体进行结构鉴定。笔者通过单因素试验对影响杨树皮总黄酮得率的各因素进行优化,在此基础上采用Design-Expert 8.0.6软件Box-Behnken模块进行响应面试验条件优化,分析酶量、浸提液p H、酶解时间、酶解温度4个因素及各因素间交互作用对总黄酮得率的影响,优化酶-超声辅助提取其总黄酮的工艺条件,提取液经萃取分离纯化得到质量分数为95%以上的单体,同时鉴定其结构。结果表明,经过优化后的最佳工艺条件为:原料杨树皮1 g,每克杨树皮在加酶量37 mg、p H 4.6、酶解时间1.75 h、酶解温度56℃下浸提后再于40℃、功率160 W下超声处理30 min,此条件下黄酮类化合物得率可达4.56%。提取液萃取后经AB-8大孔树脂初步纯化,由乙醇/水梯度洗脱,取乙醇和水体积比为1∶1时分离得到的组分进行葡聚糖凝胶LH-20分离纯化。在葡聚糖凝胶LH-20中用质量分数95%乙醇等度洗脱,合并浓缩相同组分,并结合制备液相色谱仪进一步纯化。采用C_(18)色谱柱,流动相为甲醇-水(含体积分数0.01%甲酸),梯度洗脱,紫外检测波长为280 nm,流速1 m L/min,进样量5μL,建立杨树皮总黄酮的高效液相色谱(HPLC)分析方法。通过液质联用(HPLC-MS)分析、核磁共振(~1H NMR、^(13)C NMR)鉴定该组分为5,7,4',5'-四羟基-3'-甲氧基黄烷醇。本研究结果既可为杨树皮的基础研究提供帮助,也可为杨树皮中功能物质的开发提供借鉴。