脂肪酸组合对体外瘤胃微生物发酵挥发性脂肪酸的影响

为研究长链脂肪酸组合对体外培养瘤胃微生物发酵挥发性脂肪酸（VFA）的影响，并得出最优脂肪酸组合及添加水平，试验选取硬脂酸、油酸、亚油酸及α-亚麻酸4种脂肪酸因子，设置0.5%、1.0%、1.5%等3个水平进行L₉（3⁴）正交试验，其中Ⅰ~Ⅸ组为试验组、Ⅹ组为对照组，各处理均设3个重复。以3头瘤胃瘘管山羊为瘤胃液供体进行体外发酵试验，测定各组培养液VFA 24 h内的动态变化。结果显示，各组的总挥发性脂肪酸（TVFA）浓度总体上呈先上升后下降再上升的波动变化趋势。其中在6 h时Ⅶ组TVFA浓度最高。乙酸/丙酸比值总体呈下降趋势，6 h前下降较快，6 h后趋于平缓。丁酸摩尔百分比在7.97%~15.41%间变动。主成分与最优组合分析表明，TVFA浓度影响的主次顺序为亚油酸、油酸、硬脂酸、α-亚麻酸；以添加1.5%硬脂酸、0.5%油酸、1.5%亚油酸、0.5%α-亚麻酸时组合效应最好。     

In vitro susceptibility of Brachyspira hyodysenteriae to organic acids and essential oil components

The antibacterial potential of organic acids and essential oil components against Brachyspira hyodysenteriae, the causative pathogen of swine dysentery, was evaluated. Minimum inhibitory concentrations (MIC) of 15 compounds were determined at pH 7.2 and pH 6.0, using a broth microdilution assay. In addition, possible synergism was determined. MIC values for the three tested strains were similar. For organic acids, MIC values at pH 6.0 were lower than at pH 7.2. B. hyodysenteriae was most sensitive to cinnamaldehyde and lauric acid, with MIC values <1.5 mM. Most antibacterial effects of binary combinations were additive, however, for thymol and carvacrol, synergism could be observed. In vitro results demonstrate the antibacterial action of certain essential oil components and organic acids against B. hyodysenteriae.     

防御信号途径在B型烟粉虱取食烟草诱导抗蚜防御中的作用

B型烟粉虱取食能够诱导烟草产生对烟蚜的抗性反应,为了明确水杨酸和茉莉酸防御信号途径与烟粉虱诱导抗蚜防御之间的关系,采用生化分析、实时定量PCR、蚜虫生物活性测定等方法比较了烟粉虱若虫取食对烟草水杨酸、茉莉酸含量、通路下游防御基因表达水平的影响及外源水杨酸、茉莉酸对烟蚜生长发育的影响。结果显示：烟粉虱侵染能够显著激活水杨酸防御途径,在取食15天后,水杨酸水平较对照升高1.40倍,水杨酸下游防御基因PR-1a及PR-2a分别较对照升高3.22和0.74倍;然而烟粉虱侵染后烟草叶片茉莉酸含量与对照相比无显著变化,JA下游防御基因PI-II和TPI的转录水平分别较对照降低73.91%和56.73%。生测结果显示,外源施用水杨酸对烟蚜的存活率和相对平均生长率具有显著不利影响。烟草叶片施用1 mmol/L水杨酸后,蚜虫的存活率及相对生长率分别较对照降低43.2%和11.54%;然而喷施茉莉酸甲酯对蚜虫的生长发育无不利影响。上述结果表明,水杨酸介导的防御应答在B型烟粉虱取食诱导烟草的抗蚜防御中起重要作用。     

Effects of the severity and timing of basal leaf removal on the amino acids profiles of Sauvignon Blanc grapes and wines

The effects of the severity and timing of leaf removal(LR) on the amino acids of Sauvignon Blanc grapes and wines were studied during the 2017 growing season. High-performance liquid chromatography(HPLC) was used to analyze the amino acids profiles of grape berries and wines. The basal leaves were removed at three time points(40, 56 and 72 days after flowering, named LR40, LR56 and LR72, respectively) at two severity levels(one at which the first, third, and fifth basal leaves of each shoot were removed(50% level); and another at which the first six basal leaves were removed(100% level)). The results showed that leaf removal had little impact on total soluble solids(°Brix), titratable acidity, pH or berry weight. The LR72-50% treated grapes had higher berry weight, titratable acidity and °Brix than those of the other treatments. The highest concentrations of total amino acids and of total amino acids except proline were detected in LR72-50% treated grapes(2 952.58 and 2 764.36 mg L~(-1), respectively); the lowest were detected in LR72-100% treated grapes(2 172.82 and 2 038.71 mg L~(-1), respectively). LR72-50% treatment significantly promoted the synthesis of aspartic acid, serine, arginine, alanine, aminobutyric acid and proline at both severity levels for grapes, the concentrations of all of these amino acids were increased relative to the control concentrations. The LR72-50%, LR40-100% and LR72-100% treated wines had higher total amino acids concentrations and higher concentrations of some individual amino acids, such as arginine, alanine and serine, than did the control wines. Of all the amino acids studied, glycine, tyrosine, cysteine, methionine and lysine were not significantly influenced by the timing or severity basal defoliation in grapes and wines. The present study reveals the effects of the timing and severity of leaf removal on the amino acids profiles of grapes and wines.     

Impact of High Night‐Time and High Daytime Temperature Stress on Winter Wheat

High temperature is a major environmental factor that limits wheat (Triticum aestivum L.) productivity. Climate models predict greater increases in night‐time temperature than in daytime temperature. The objective of this research was to compare the effects of high daytime and high night‐time temperatures during anthesis on physiological (chlorophyll fluorescence, chlorophyll concentration, leaf level photosynthesis, and membrane damage), biochemical (reactive oxygen species (ROS) concentration and antioxidant capacity in leaves), growth and yield traits of wheat genotypes. Winter wheat genotypes (Ventnor and Karl 92) were grown at optimum temperatures (25/15 °C, maximum/minimum) until the onset of anthesis. Thereafter, plants were exposed to high night‐time (HN, 25/24 °C), high daytime (HD, 35/15 °C), high daytime and night‐time (HDN, 35/24 °C) or optimum temperatures for 7 days. Compared with optimum temperature, HN, HD and HDN increased ROS concentration and membrane damage and decreased antioxidant capacity, photochemical efficiency, leaf level photosynthesis, seed set, grain number and grain yield per spike. Impact of HN and HD was similar on all traits. Greater impact on seed set, grain number and grain yield per spike was observed at HDN compared with HN and HD. These results suggest that HN and HD during anthesis cause damage of a similar magnitude to winter wheat.     

油菜种子低亚油酸和亚麻酸含量异交稳定技术的建立

为降低油菜种子中的亚油酸和亚麻酸含量并使之在异交条件下保持基本稳定,以高油品种CY2作为受体亲本,采用RNA干涉技术沉默油菜内源Bn FAD2基因的表达,抑制油酸脱饱和反应。育成的3个独立转基因株系的亚油酸和亚麻酸含量下降到6%以下,其中亚油酸含量较受体亲本降低78.2%~86.5%,亚麻酸含量降低53.4%~65.8%。将3个转基因株系与2个亚油酸和亚麻酸含量较高的常规品种正反交,F1种子中这2种脂肪酸的含量依然保持在与转基因亲本相仿的低水平。由此可知,通过RNA干涉技术沉默Bn FAD2基因的表达可赋予油菜低亚油酸和亚麻酸含量的异交稳定特性。这一特性的获得对于今后培育异交稳定的高油酸油菜新品种具有重要意义。     

持续冷热环境对肉鸡生产性能、糖代谢和解偶联蛋白mRNA表达的影响

本试验研究了不同环境温度(10~30℃)持续14 d对肉鸡生产性能、糖代谢和禽类解偶联蛋白(av UCP)mRNA表达的影响。试验选取21日龄爱拔益加(AA)肉鸡288只,随机分到6个人工环境控制舱中,每个舱饲养6笼,每笼8只鸡作为1个重复。预试期7 d,温度22℃,相对湿度60%。28日龄时将各环境控制舱温度分别逐渐(1 h内)调到10、14、18、22、26和30℃,相对湿度60%,温湿度均保持恒定直至试验结束。正试期14 d。结果表明:1)试验期内,30℃组的体重(BW)显著低于14~26℃组(P<0.05);22~30℃组平均日采食量(ADFI)随温度升高而显著下降(P<0.05);10~30℃组平均日增重(ADG)随温度升高出现先升高后下降的趋势,在22℃时最高;料重比(F/G)随温度升高呈现先下降后升高的趋势,22℃时最低;平均日饮水量(ADWC)在10℃组最低。2)试验第14天,26℃组血糖水平显著低于18℃组(P<0.05);肝糖原水平在各组之间差异不显著(P>0.05);22℃组肌糖原水平显著低于10、26和30℃组(P<0.05)。3)试验第14天,18、22℃组av UCP mRNA相对表达量显著高于其他组(P<0.05)。结果提示:在本试验条件下,从生产性能和能量利用效率考虑,28~42日龄AA肉鸡的适宜养殖温度为22~26℃。     

Comparison of Salt and Drought‐Stress Effects on Maize Growth and Yield Formation with Regard to Acid Invertase Activity in the Kernels

The long‐term effects of salt stress (11 dS m^?1) and drought stress (35 % WHC) were investigated for two maize genotypes, focusing on the relation between metabolic changes around the time of pollination and the impact on yield determinants at maturity. The relatively salt‐resistant hybrid Pioneer 3906 and the relatively drought‐resistant hybrid Fabregas were compared. The experiments were conducted in large plastic containers in a vegetation hall in two consecutive years (2011 and 2012). Plant height and leaf area were significantly reduced under both stress conditions. The transpiration rate was only slightly reduced under drought stress; but under salt stress, a significant reduction occurred 40–53 days after sowing. As a significant increase in sucrose concentrations was observed in the salt‐treated maize kernels 2 days after pollination, the availability of assimilates was not limiting and the plants could afford to save water by reduced stomatal opening. Although under both stress conditions the soluble acid invertase activity was reduced 2 days after pollination, concomitantly, an increase in hexose concentrations was observed. Thus, in these experiments, the delivery of hexoses by acid invertase activity did not limit kernel development. Differences in grain yield at maturity between salt and drought stress were most likely caused by salt‐specific effects (Na⁺ toxicity), Fabregas being more affected than Pioneer 3906.     

An improved method for extraction of sorghum polymeric protein complexes

A method for fractionating sorghum proteins using extraction solvents and techniques designed to obtain polymeric protein structures (especially disulfide linked) was developed. Extraction and separation conditions were optimized in terms of completeness of protein extraction, sample stability, and analytical resolution. After pre-extraction of albumins and globulins, a 3-step sequential procedure involving no reducing agents was applied to ground whole sorghum flour. The three fractions obtained represented proportionally different protein polymer contents and molecular weight distribution as evidenced by comparative size exclusion chromatography. Protein composition also varied among the extracts with differences in kafirin composition and non-kafirin proteins detected in the fractions by RP-HPLC and SDS-PAGE analysis. The ability to quantify and further characterize sorghum polymeric protein complexes will be useful for additional studies linking protein structures with functionality and digestibility and variations for these properties within diverse sorghum germplasm.     

Effects of Lactic Acid Bacteria and Fructooligosaccharides on Growth Performance,Nutrient Digestibility and Serum Biochemical Indices of Arctic Foxes (Alopex lagopus) during Early Growth Period北大核心CSCD

This experiment was conducted to study the effects of dietary lactic acid bacteria (LAB) and fructooligosaccharides (FOS) on growth performance, nutrient digestibility and serum biochemical indices of Arctic foxes (Alopex lagopus) during early growth period. Sixty male post-litter Arctic foxes with the average body weight of (1.16±0.15) kg and at the age of (45±3) days were randomly assigned to 4 groups with 3 replicates per group and 5 foxes per replicate. The foxes were fed the following diets, respectively: basal diet (control group), basal diet+3×109 CFU / kg LAB (LAB group), basal diet+5 g / kg FOS (FOS group) and basal diet+3×109 CFU / kg LAB+5 g / kg FOS (LAB+FOS group). The experiment lasted for 30 days. The results showed as follows: 1) on the days 1 to 15, the diarrhea rate of foxes in the LAB group and LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05). On the days 16 to 30, the average daily gain of foxes in the LAB+FOS group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); the diarrhea rate of foxes in the LAB+FOS group was significantly lower than that in the control group and FOS group (P<0.05), but had no significant difference with LAB group (P>0.05); compared with the FOS group, the feed to gain ratio of foxes in the LAB+FOS group was significantly decreased (P<0.05). 2) The dry matter digestibility of foxes in the LAB + FOS group was significantly higher than that in the control group and FOS group (P < 0.05), but had no significant difference with LAB group (P>0.05). There were no significant differences in nitrogen intake, fecal nitrogen, urine nitrogen, nitrogen deposition, net protein utilization and protein biological value among all groups (P>0.05). 3) Serum total protein (TP) content of foxes in the LAB+FOS group was significantly higher than that in the FOS group (P<0.05), but had no significant difference with control group and LAB group (P>0.05). Serum albumin (ALB) content of foxes in the LAB group was significantly higher than that in the control group and FOS group (P<0.05), but had no significant difference with LAB+ FOS group (P>0.05). Serum urea nitrogen (UN) content of foxes in the LAB+FOS group was significantly decreased compared with the control group (P < 0. 05). In conclusion, the combined supplementation of 3 × 109 CFU / kg LAB and 5 g / kg FOS in the diet is beneficial to reduce diarrhea rate, improve dry matter digestibility, improve body immune level, and promote the growth of Arctic foxes during early growth period. © 2023 Chinese Journal of Urology. All rights reserved.