生物法提取杜仲胶菌株筛选及发酵条件优化

采集杜仲老林区的土壤和腐殖质,以杜仲皮作为基质多次富集培养,分离其优势菌,通过测定其发酵性能指标并建立菌株综合选择指数,筛选生物法提取杜仲胶的优良菌株,并研究优良菌株的发酵适宜条件。筛选出了优良菌株P-24,该菌株具有降解能力强,发酵周期短,杜仲胶的发酵损失率小等优点,其适宜的发酵温度为30℃、基质含水率65%、初始pH7.0,在此条件下发酵12d,杜仲皮的发酵物去除率可达93.02%,发酵剩余物中杜仲胶的含量为74.71%,杜仲胶的得率为5.25%。筛选优良菌株是生物法提取杜仲胶的关键;菌株P-24在实际生产中具有一定的应用价值。     

Effects of the ruminal comminution rate and microbial contamination of particles on accuracy of in situ estimates of ruminal degradability and intestinal digestibility of feedstuffs

Effects of considering the comminution rate (k_c) and the correction of microbial contamination (using ¹⁵N techniques) of particles in the rumen on estimates of ruminally undegraded fractions and their intestinal digestibility were examined generating composite samples (from rumen‐incubated residues) representative of the undegraded feed rumen outflow. The study used sunflower meal (SFM) and Italian ryegrass hay (RGH) and three rumen and duodenum cannulated wethers fed with a 40:60 RGH to concentrate diet (75 g DM/kgBW^0.75). Transit studies up to the duodenum with Yb‐SFM and Eu‐RGH marked samples showed higher k_c values (/h) in SFM than in RGH (0.577 vs. 0.0892, p = 0.034), whereas similar values occurred for the rumen passage rate (k_p). Estimates of ruminally undegraded and intestinal digestibility of all tested fractions decreased when k_c was considered and also applying microbial correction. Thus, microbial uncorrected k_p‐based proportions of intestinal digested undegraded crude protein overestimated those corrected and k_c?k_p‐based by 39% in SFM (0.146 vs. 0.105) and 761% in RGH (0.373 vs. 0.0433). Results show that both k_c and microbial contamination correction should be considered to obtain accurate in situ estimates in grasses, whereas in protein concentrates not considering k_c is an important source of error.     

节杆菌属甲基对硫磷的降解菌株L-W的分离及降解特性

从生产甲基对硫磷的华阳农药厂污水曝气池中,分离到1株能以甲基对硫磷及其降解中间产物对硝基苯酚为唯一碳源生长,且能够将其彻底降解为CO2和H2O的细菌L-W,经鉴定,为节杆菌属(Arthrobacter sp)。用气相色谱法和分光光度计法深入研究了L-W的降解能力,其7h内对50mg/L甲基对硫磷的降解率为85%,对50mg/L对硝基苯酚的降解率为99%。     

Effects of variety, cropping year, location and fertilizer application on nutritive value of durum wheat straw

This study was carried out to assess the effects of variety, year, location and level of fertilizer application on chemical composition and in sacco dry matter (DM) degradability of durum wheat straw as well as to understand the relationship between straw quality and agronomic traits of the crop and to assess the possibilities of selecting wheat varieties that combine high grain yield with desirable straw quality. Two local (Arendeto and Tikur sinde) and two improved (Boohai and Gerardo) varieties of durum wheat (Triticum turgidum Desf.) were used in the experiment. The four varieties were grown at two locations (Akaki and Ejere) in the years 2001/2002 and 2002/2003 in 5 x 5 m plots in three replications. Diammonium phosphate and urea fertilizers were applied at four levels (0/0, 32/23, 41/23 and 64/46 kg/ha of nitrogen/phosphorus). Straw quality was assessed based on chemical composition and in sacco DM degradability. Correlation of straw quality with grain and straw yield and with other agronomic characteristics of the crop was determined. The potential utility index (a measure that integrates grain and digestible straw yield) was used for ranking of the varieties. The local varieties had higher crude protein (CP) and lower neutral detergent fibre contents and higher digestibility than the improved varieties. The cropping year and location had significant effect on CP content and degradability of the straw, which could be due to climatic variation. However, the fertilizer level did not have any significant effect on straw quality except that the CP content of the straw tended to increase with increasing level of fertilizer application. Based on the potential utility index the varieties ranked, in a decreasing order, as Tikur sinde > Arendeto > Gerardo > Boohai and the ranking was consistent across years and locations. Except the CP content, straw quality was not negatively correlated with grain and straw yield. This indicates that there is a possibility of selecting varieties of wheat that combine high grain and straw yield with desirable straw quality.     

尼龙袋法评价香蕉叶单宁对瘤胃降解特性的影响

旨在探究香蕉叶单宁对奶牛瘤胃降解特性的影响和评价香蕉叶的饲喂价值。样品分别为苜蓿干草组(100%的苜蓿干草)、苜蓿干草和香蕉叶混合组(50%苜蓿干草+50%香蕉叶)、香蕉叶组(100%香蕉叶)、苜蓿干草组(100%的苜蓿干草)+6%聚乙二醇(6% PEG)、苜蓿干草和香蕉叶混合组(50%苜蓿干草+50%香蕉叶)+6%聚乙二醇(6% PEG)、香蕉叶组(100%香蕉叶)+6%聚乙二醇(6% PEG)。测定样品中的营养成分含量,使用3头安装了瘤胃瘘管的荷斯坦奶牛进行半体内试验,用尼龙袋法测定上述样品在瘤胃内0、2、4、8、12、24、48、72 h的干物质(DM)、粗蛋白质(CP)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)的降解率,得到各营养物质的动态降解参数。结果表明,相较于苜蓿干草,香蕉叶干物质和粗蛋白的快速降解部分、慢速降解部分、慢速降解部分的降解速率、有效降解率是显著低于苜蓿干草的(P<0.001),香蕉叶和苜蓿的NDF的有效降解率没有显著差异。添加了PEG后,香蕉叶和香蕉叶苜蓿混合组的快速降解部分和有效降解率显著高于未添加PEG的两组(P<0.001)。结果表明香蕉叶中的单宁会抑制香蕉叶的瘤胃降解率,因此在使用香蕉叶调制反刍动物的饲料时需要控制单宁的含量。     

Degradability of amino acids in selected legume forages using the in situ nylon-bag technique

This study was conducted to determine the amino acid profiles and rumen degradability of amino acids of three cultivated forage legumes – velvet bean (Mucuna pruriens), cowpea (Vigna unguiculata) and silverleaf desmodium (Desmodium uncinatum) – using the in situ nylon-bag technique. Two Friesian cows fitted with 10-cm-diameter rumen cannulae on a complete dairy feed ration (19% crude-protein dairy meal and maize silage) were used. Silverleaf desmodium had significantly (p < 0.05) higher concentration of amino acids compared with cowpea and velvet bean. Aspartic acid showed the highest (p < 0.05) concentration in all legumes and cysteine showed the lowest concentration. Legume forage of cowpea showed the highest (p < 0.05) level of degradability of amino acid followed by silverleaf desmodium and then velvet bean. Readily and slowly degradable components in all amino acids were highest (p < 0.05) in cowpea followed by silverleaf desmodium and then velvet bean. Moreover, silverleaf and cowpea showed higher (p < 0.05) levels of effective degradability of amino acids (at outflow rates p = 0.02, 0.04 and 0.06 h^?1) than velvet bean. Total amino acid disappearance was the least in velvet bean, which suggests that it can be used to supply bypass protein to the duodenum of the ruminant animal.     

甲醛处理对豆饼干物质和蛋白质瘤胃降解率及胃蛋白酶消化率的影响

豆饼用２ｇ／ｋｇＤＭ甲醛处理后,１０ｈ瘤胃干物质（ＤＭ）降解率从８７．１９％下降到豆饼含水量为１４％和６０．９３％和含水量１８％时的５６．２９％,粗蛋白降解率从８７．６９％分别下降到４８．３６％和４３．４３％,随着甲醛用量的增加,干物质的粗蛋白的降解率进一步下降,但下降幅度减少。在甲醛用量低于２ｇ／ｋｇＤＭ的情况下,甲醛用量对ＰＨ为４．５时的胃蛋白酶４ｈ和８ｈ干物质和粗蛋白消化率没有明显影响,但     

山西不同居群白羊草的营养成分及瘤胃降解规律

为研究山西不同居群白羊草抽穗期的营养成分含量及干物质(DM)和粗蛋白质(CP)在绵羊瘤胃中的降解规律,以安装永久性瘘管的杜泊与本地羊杂交一代肉用绵公羊15只为试验动物,采用尼龙袋法对不同居群白羊草抽穗期的DM和CP的降解率及降解参数进行测定。结果表明,居群对白羊草的常规营养成分含量有较大的影响。其中,太谷居群具有最高的粗蛋白质(CP)含量和最低的中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量,其次是原平和沁源居群。不同居群白羊草的DM和CP的降解特性不同,其中,太谷和原平居群72 h的DM降解率最高,显著高于襄汾居群(P<0.05),太谷居群的DM有效降解率最高,达到46.39%,其次是原平和沁源居群;太谷和原平居群72 h同样有最高的CP降解率,显著高于降解率最低的芮城居群(P<0.05)。太谷居群的CP有效降解率最高,其次是方山和阳高居群,三者差异不显著(P>0.05)。由此可见,太谷居群DM和CP降解率最高,优于其他居群。     

瘤胃尼龙袋法测定常用饲料过瘤胃淀粉量及淀粉瘤胃降解率

以9头装有永久性瘤胃瘘管的内蒙古半细毛羯羊为试验动物,采用尼龙袋法对玉米淀粉、玉米、麸皮、豆粕、麻粕、棉籽粕、苜蓿干草、羊草、肋麦野豌豆、玉米秸等10种常用饲料的过瘤胃淀粉量及淀粉瘤胃降解率进行了比较研究。结果表明,各种饲料的过瘤胃淀粉量(g/kg)依次为417.85、404.84、226.31、62.04、110.56、108.61、73.50、50.87、47.55、24.43;其淀粉瘤胃降解率%依次为60.95、50.47、61.70、80.19、65.57、61.01、53.15、64.23、70.40、73.65。