二糖酶及其在动物消化吸收中的作用

本文综述了粘膜二糖酶的性质、种类和在畜禽体内的分布、分泌、发育规律、在消化和吸收中的重要作用 ,以及影响二糖酶水平的因素 ,如激素、日粮组成等     

不同GI与CBI组合饲粮对牦牛瘤胃和直肠细菌区系的影响

【目的】本研究通过探讨不同粗饲料分级指数(GI)与碳水化合物平衡指数(CBI)组合饲粮对牦牛瘤胃和直肠细菌区系的影响,旨在为舍饲牦牛营养物质消化吸收的调控以及饲粮合理配制提供参考。【方法】选取3.5岁健康、体重相近的公牦牛12头分为3组,即玉米青贮-苜蓿干草-精料组(CAC组)、玉米青贮-小麦秸秆-精料组(CWC组)、玉米青贮-燕麦干草-精料组(COC组)。3组试验牛均采用全混合饲粮方式进行饲喂,试验期为28 d。试验结束时采集瘤胃液和直肠粪样,应用16S rRNA测序技术分析瘤胃和直肠细菌区系变化情况。【结果】对于瘤胃,(1)3组牦牛瘤胃细菌区系的Chao1指数、Ace指数、Simpson指数和Shannon指数差异均不显著(P>0.05);(2)PCoA分析结果显示,CAC与COC组的瘤胃细菌区系有明显的PC1差异(P<0.05);(3)在门水平上,CWC组牦牛瘤胃放线菌门与CAC、COC组存在显著差异(P<0.05);在属水平上,3组牦牛瘤胃细菌区系差异不显著(P>0.05);(4)瘤胃细菌基因功能预测结果显示,复制与修复、原核细胞群体、细胞信号传递、环境...     

疏果对黄皮果实发育着色及树体器官碳水化合物含量的影响

以‘大鸡心’黄皮[Clausena lansium(Lour.)Skeels‘Dajixin']为材料,研究了不同程度疏果对果实发育、着色、产量及树体不同器官碳水化合物含量的影响。结果表明：疏果减少了树体产量,但促进了果实的发育,花后95 d（采收）时,疏果50%和25%处理的果实鲜样质量分别比对照果增加了33.7%和13.9%,疏果有利于果实的着色,同时提高了叶片、1cm粗枝条、结果母枝及果实的总碳水化合物含量。此外,疏果有利于采果后新梢生长,显著增加新梢的长度和粗度。     

GA3、IBA以及变温处理对东方百合鳞片扦插繁殖及淀粉降解的影响

以东方百合‘Sorbonne’为试材,研究了GA3、IBA以及温度处理对鳞片扦插繁殖以及碳水化合物代谢的影响。结果表明：GA3处理可在较短时间内促进小鳞茎膨大,IBA处理使小鳞茎形成的时间延后,但可提高繁殖系数和整齐度。GA3、IBA分别结合5 ℃预处理可使小鳞茎质量显著增加,在较短时间内促进小鳞茎膨大;其中IBA 100 mg · L-1,1 h结合5 ℃预处理的鳞片繁殖系数和小鳞茎整齐度依次高于25 ℃与15 ℃变温培养及25 ℃恒温培养;GA3 100 mg · L-1,2 h结合5 ℃预处理获得的小鳞茎品质最佳。鳞片繁殖过程中,GA3、IBA结合各温度处理鳞片淀粉及总可溶性糖含量均呈下降趋势,尤其鳞片下部在25 ℃培养初期（20 d）下降幅度最大;IBA促进淀粉降解,结合低温处理的母鳞片较无低温处理的总可溶性糖含量低,为小鳞茎的诱导和形成提供了营养;5 ℃低温预处理促进GA3处理母鳞片淀粉的降解。     

银杏雌花芽分化期间内源激素、碳水化合物和矿质营养的变化

为了探明银杏Ginkgo biloba雌花芽分化的生理机制,用酶联免疫等方法对银杏雌花芽分化期间内源激素、碳水化合物和矿质营养含量的变化进行了研究。结果表明,银杏雌花芽在生理分化期(花芽诱导期),花芽中赤霉素(GA1 3)和脱落酸(ABA)质量摩尔浓度下降,玉米素(ZRs)、异戊烯基腺嘌呤类(iPAs)质量摩尔浓度出现峰值,ZRs/GA1 3,ABA/GA1 3及iAPs/GA1 3的值也出现峰值。随着形态分化的开始,ZRs和iPAs的质量摩尔浓度、ZRs/GA1 3和iPAs/GA1 3的值下降,并维持较低水平。雌花芽中的ABA质量摩尔浓度、ABA/GA1 3的值在高于雌叶芽的水平上波动。银杏雌花芽分化过程中,雌花芽叶中钾和淀粉质量分数均高于同期雌叶芽叶的质量分数;而雌花芽叶全氮的质量分数基本低于同期雌叶芽叶全氮水平;在生理分化期中雌花芽叶内磷质量分数均高于叶芽叶质量分数。说明银杏雌花芽分化过程中,ABA,ZRs,iPAs及钾和银杏雌花芽的诱导及分化密切相关。图11参16     

Comparative effects of ultrasonic transducers on medium chemical content in a nutrient mist plant bioreactor

The objectives of this study were to evaluate the efficiency of ultrasonic transducers in a nutrient mist bioreactor by analyzing the chemical constituents (carbohydrates and inorganic elements) of the mists produced by ultrasonic transducers from a liquid sucrose-supplemented Murashige and Skoog (MS) medium. The ultrasonic transducer oscillation frequency with an input power of 2.8 MHz and at 17.5 W was the optimum condition since the contents of glucose, sucrose, total soluble carbohydrate, macro-elements (NH₄⁺-N, NO₃⁻-N, P, K, Mg, Ca and S), micro-elements (Na, Fe, Mn, Zn, B, I, Mo and Co), and pH value were similar to those in the MS medium after autoclaving. Further, when MS medium was replaced by Gamborg et al. medium (B-5) or woody plant medium (WPM) in this bioreactor at the same transducer settings, the NH₄⁺-N and NO₃⁻-N contents in nutrient mist generated were also similar to those in B5 or WPM after autoclaving, respectively. The results of this research represent a significant contribution towards development of a functional nutrient mist bioreactor.     

Higher water temperature enhances dietary carbohydrate utilization and growth performance in Labeo rohita (Hamilton) fingerlings

A 60-day experiment was conducted to delineate the effect of three dietary levels of gelatinized carbohydrate (GC) on growth, nutrient-utilization and body composition of Labeo rohita fingerlings (avg. wt 6.5 ± 0.3 g) reared at two water temperatures (ambient-AT (26 ± 0.8 °C) and 32 °C). Two hundred and sixteen fingerlings were randomly distributed into six treatments in triplicates. Three semi-purified isonitrogenous diets were prepared with graded levels of GC viz. D(1) : 40%, D(2) : 50% and D(3) : 58%. Growth rate, feed efficiency and protein efficiency ratio were significantly (p < 0.05) higher in 50% GC and 32 °C reared groups than their AT counterparts. Hepato Somatic Index was higher in AT reared groups compared to 32 °C reared counterparts. Apparent digestibility co-efficient of carbohydrate was significantly (p < 0.05) higher at 32 °C reared groups but decreased with increasing carbohydrate (GC) levels. Fish reared at 32 °C showed significantly (p < 0.05) higher amylase, protease and hexokinase activities while glucose-6-phosphate dehydrogenase and glucose-6-phosphatse were significantly (p < 0.05) higher at ambient temperatures. The results obtained in present study indicated that L. rohita could utilize higher level (50%) of dietary carbohydrate at 32 °C.     

利用CNCPS V5．0预测我国杂种肉牛干物质采食量的效果评价

通过两个动物试验(子试验1和子试验2)比较了CNCPS模型预测的我国杂种肉牛干物质采食量(DMI)与实际观察值间的吻合程度,目的在于评估该模型是否适合于预测我国杂种肉牛生产性能。结果表明:①子试验1中3个处理组分别有93%、80%和73%的点落在-0.4至0.4kg/d的范围内,子试验2的4个处理组分别有87%、73%、73%和80%的点落在-0.4至0.4kg/d的范围内,说明CNCPS较好地预测了我国杂种肉牛的DMI。②经线性回归分析,两个子试验中观察和预测的DMI间相关系数分别为0.83和0.79,具有较高的可信度;所有处理组的DMI误差均方根(RMSE)都很小。以上结果说明,CNCPS对中国杂种肉牛DMI具有较好的预测能力。     

Isolation of lignin–carbohydrate bonds in wood. Model experiments and preliminary application to pine wood

A novel method for analysis of benzylic ether type lignin–carbohydrate bonds has been developed by using model compounds. Four diastereomers of model compound 3-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-3-(methyl -d-glucopyranoside-6-O-yl)-1-propanol (GGMGP), were ozonized in acetic acid/water/methanol 16:3:1 for 1h at 0°C. The product from ozonation of each diastereomer was saponified and the corresponding -etherified tetronic acid (TAMGP) was isolated using ion exchange chromatography. Minor amounts of methyl -d-glucopyranoside (MGP) and small amounts of a gluconic acid etherified with tetronic acid (TAGLCA), tetronic acid, gluconic acid, and glyceric acid were detected in the product mixture of ozonated benzylic ether type model compounds. The results suggest that a benzyl ether bond between lignin and carbohydrate is rather stable during the ozone treatment. Acid treatments with sulfuric acid or trifluoroacetic acid of the derived TAMGP led to cleavage of the glucosidic bond but only a small amount of products (tetronic acid and glucose) resulting from cleavage of the -ether bond were formed. The successful chemical treatments were used for studies of benzylic ether bonds in Japanese red pine. The results suggest the presence of benzylic ether bonds to polysaccharides in the wood.Part of this paper was presented at the 10th International Symposium of Wood and Pulping Chemistry (ISWPC), Yokohama, 1999; the 11th ISWPC, Nice, 2001; and as a rapid comunication in J Wood Sci (2000) 46:263–265