日粮添加亮氨酸和苯丙氨酸对荷斯坦公犊生长性能及血清代谢物的影响

【目的】研究日粮添加亮氨酸和苯丙氨酸对犊牛生长性能和血清代谢物的影响,为亮氨酸和苯丙氨酸在奶牛高效生产中的应用提供理论参考。【方法】试验选取20头1日龄体重为(38±3)kg的荷斯坦公犊,随机分为4组,分别为对照组、亮氨酸组(1.435 g·L~(-1))、苯丙氨酸组(0.725 g·L~(-1))、混合氨基酸组(1.435 g·L~(-1)亮氨酸和0.725 g·L~(-1)苯丙氨酸),每组5头牛,各组以丙氨酸调节为等氮日粮。犊牛单独饲喂,试验共8周,预试期1周,正试期7周。试验犊牛单圈饲养,试验日粮由原奶和开食料组成。犊牛出生后,1 h内饲喂4.0 L初乳。此后1周为过渡期,日喂原奶2次,每次3.0 L。过渡期内以氨基酸添加量的20%为梯度逐天增加,至出生第6天达到添加量的100%。2—8周为正试期,日饲喂添加氨基酸的原奶2次。第2—3周每次3.5 L,4—8周每次4.0 L。第3周开始定量供给开食料,自由饮水。在犊牛1、3、5、7、8周龄测定体重、体高、体斜长和胸围,计算体躯指数和体长指数;采集10 mL血液用于获得血清,并检测其氨基酸组成、葡萄糖、尿素氮、胰岛素和胆囊收缩素。采用IBM SPSS Statistics V22.0统计软件GLM过程进行统计分析,采用LSD法进行多重比较。【结果】混合氨基酸组平均日增重显著低于其余3组(P0.05)。相对于对照组,各处理组显著提高最终体斜长(P0.05)。亮氨酸和苯丙氨酸具有降低最终体高的趋势(P0.10),而苯丙氨酸显著降低最终胸围(P0.05)。与对照组相比,亮氨酸组和混合氨基酸组显著提高犊牛8周龄体躯指数(P0.05)。但各组犊牛初始体重、体斜长、体高、胸围、体躯指数、体长指数和最终体重及体躯指数无显著差异(P0.05)。添加亮氨酸显著提高血清组氨酸、亮氨酸、苏氨酸、甘氨酸和总必需氨基酸的浓度(P0.05),趋于增加天冬氨酸和总氨酸浓度(P0.10),但显著降低丙氨酸和甘氨酸浓度(P0.05)。苯丙氨酸显著提高血清苯丙氨酸、谷氨酸和甘氨酸浓度(P0.05),对照组因添加丙氨酸调节为等氮日粮,其血清丙氨酸浓度显著高于亮氨酸组与混合氨基酸组(P0.05)。苯丙氨酸和亮氨酸对血清各种氨基酸浓度无交互效应(P0.05)。亮氨酸显著提高血清葡萄糖浓度(P0.05),苯丙氨酸降低血清葡萄糖浓度(P0.05),且与亮氨酸存在负交互效应(P0.05)。此外,苯丙氨酸显著提高血清尿素氮含量(P0.05),但亮氨酸和苯丙氨酸添加对血清中胰岛素及胆囊收缩素浓度无显著影响(P0.05)。【结论】日粮中添加亮氨酸可提高犊牛血清部分必需氨基酸、葡萄糖浓度、8周龄体躯指数和平均日增重。从以上指标可见,亮氨酸添加效果优于苯丙氨酸,但二者在影响血清葡萄糖浓度方面存在负交互效应。     

杜仲叶影响绵羊血清代谢组学的研究

为探索杜仲叶（Eucommia ulmoides leaves,EUL）对绵羊营养代谢和生理功能的影响,本研究选取25~30 kg、70~80日龄的湖羊30只,随机分为3组,每组10只,分别为对照组（无杜仲叶日粮组,CTL）、低剂量添加组（10%杜仲叶日粮组,EUL1）、高剂量添加组（20%杜仲叶日粮组,EUL2）。预试期15 d,正试期90 d。试验结束时,通过静脉采血,离心后分别取血浆和血清,血浆用于生化分析,血清用于代谢组学分析。结果显示,饲喂杜仲叶后,EUL1和EUL2组绵羊血浆中葡萄糖、非酯化脂肪酸、高密度脂蛋白和极低密度脂蛋白均升高,EUL2组与CTL组差异显著或极显著（P<0.05;P<0.01）,EUL1组与CTL组差异不显著（P>0.05）;EUL1和EUL2组尿素较CTL组极显著降低（P<0.01）,总胆固醇水平显著降低（P<0.05）,EUL1和EUL2组间差异不显著（P>0.05）。血清样品采用液相色谱-质谱联用仪（LC-MS）进行检测,在正模式下得到593个代谢物,在负模式下得到1 570个代谢物。通过主成分分析（PCA）、偏最小二乘判别分析（PLS-DA）及正交偏最小二乘判别分析（OPLS-DA）发现,各试验组间的差异代谢物较多,能将其得分图明显区分。进一步对变量重要性因子大于1.0（VIP>1.0）的代谢物进行t检验后发现,各组之间有24种特征代谢物差异显著（P<0.05）。这些差异代谢物涉及体内葡萄糖、脂肪酸和氨基酸等的代谢,有的代谢物还与动物的免疫机能相关。杜仲叶饲料对绵羊的营养代谢、生理状态和免疫状况可产生明显的影响,代谢组学可有针对性地分析代谢物发生的步骤及生理作用,为阐明杜仲叶影响营养代谢的机制提供参考。     

CO_2浓度升高对万寿菊生长发育与光合生理的影响

为探究经济花卉万寿菊响应CO_2浓度升高的生理机制,以万寿菊金币品种为试材,利用OTC(open top chamber)系统进行CO_2浓度控制试验,测定了万寿菊形态特征、叶片组织结构、光合色素含量、光合作用及糖类代谢物的变化。结果表明,本试验种植的万寿菊维管束中无"花环状"结构,是菊科中的C_3植物。CO_2浓度升高后,万寿菊叶片栅栏组织增多,栅栏组织内的叶绿体数量增加,光合色素含量增加,净光合速率增强,气孔导度和蒸腾速率在现蕾期和初花期下降,而在盛花期增加,水分利用率在各生育时期均增加。此外,CO_2浓度升高后,万寿菊叶片中还原糖含量、可溶性总糖含量、淀粉含量、纤维素含量均增加。植株的株高、茎粗、单株茎秆重、单株总生物量均有增加,花朵总产量增加27.46%。综上可知,CO_2浓度升高促进了万寿菊叶片光合作用和碳代谢,有利于万寿菊的生长发育。本研究结果有助于揭示万寿菊响应CO_2浓度升高的生理机制,为未来的万寿菊生产开发提供了依据。     

Root zone selenium reduces cadmium toxicity by modulating tissue-specific growth and metabolism in maize (Zea mays L.)

The effects of selenium (Se) cadmium (Cd) interactions on plant growth and metabolism are not fully clear. In the present study, we assessed whether Se could alleviate the toxic effects of Cd on growth and metabolism of maize. Seeds of maize variety FH-985 were sown in pots filled with sand treated with CdCl₂ (0, 50 and 100 µM) and Se (0, 2 and 4 mg L^?1) through Hoagland’s nutrient solution. Low Se (2 mg L^?1) increased germination percentage and rate, while high Se (4 mg L^?1) increased fresh and dry biomass under Cd stress. Interestingly, all Se concentrations were effective in alleviating the toxic effects of Cd on photosynthetic pigments, whereas higher Se mitigated the Cd-induced oxidative stress and increased flavonoids both in the shoots and roots while phenolics in the roots. The results demonstrated that root zone Se altered tissue-specific primary metabolism in maize. Furthermore, low Se mitigated the Cd-induced decrease in total proteins in the root. Overall, Se-mediated decrease in the oxidative stress in the shoots while increase of secondary metabolites in the roots helped the plants to grow faster at early growth stage and caused increase in the biomass under different Cd regimes.     

Antioxidant activity and soluble sugars of African ginger (Siphonochilus aethiopicus) in response to irrigation regimen and nitrogen levels

African ginger (Siphonochilus aethiopicus), as a medicinal plant, is known for its medicinal properties, containing various antioxidant compounds and carbohydrates. Rhizome yield is improved by water regimens and fertilizers applied at plant phenological stages. However, the rhizomatous herb, which is traditionally used for the treatment of asthma, inflammation and malaria has limited information on water and nitrogen requirements for its production. This study assessed the effect of irrigation regimens (30%, 50% and 70% allowable depletion level (ADL) and nitrogen (N) levels (0, 50, 100, 150 and 200?kg?ha^?1) on antioxidant activity and carbohydrates on plant leaf, root and rhizome. The interaction treatment effect of severely stressed (70% ADL) with the N application of 100?kg?ha^?1 had significant effect on leaf phenolic concentration (87.02?±?2.51?mg?g^?1 gallic acid equivalent). Interaction effect of moderately stressed (50% ADL) and severely stressed (70% ADL) treatment with N application rate of 0?kg?ha^?1 had significant effect on plant flavonoids and phenolics in all plant parts. In plant carbohydrates, root had high sucrose content (47.68?±?9.0?mg?g^?1 dry weight) with the application of low N (0?kg?ha^?1) grown under severely stressed treatment. In conclusion, this implies that different S. aethiopicus parts can produce substantial amount of antioxidants and carbohydrates, as exhibited under low N and reduced water supply applied during the phenological cycle.     

Subsequent bone and metabolic responses of broilers to high-non-phytate phosphorus diets in the starter period

1. An experiment was performed to elucidate the subsequent effects of high-non-phytate phosphorus (NPP) diets on growth performance, blood metabolites, bone characteristics and P retention of broilers fed on low-NPP grower diets. The 42-d study was designed as a 2 × 2 × 2 + 1 factorial, which included two starter NPP concentrations (4.5 and 5.5 g/kg; d 0–21), two grower NPP concentrations (1.5 and 2.3 g/kg; d 22–42), with or without phytase (1000 FTU/kg), with a reference diet containing an adequate NPP concentration over the course of the trial.

2. In the starter period, growth performance and P retention were not affected by experimental diets. The high-NPP diet increased plasma P concentration, increased tibia ash and tibia P contents and decreased plasma alkaline phosphatase (ALP) activity at d 21.

3. No significant interaction was observed between NPP concentrations in the starter and grower periods and phytase. The main effect data indicated that the increase in NPP concentration in the starter diets had no effects on growth performance in the grower period and overall. The high-NPP diet in the early stage of growth reduced plasma P concentration, plasma ALP activity and tibia ash content at d 42. The main effect data also showed that exogenous phytase increased body weight gain in the grower period and overall.

4. It can be concluded that feeding increased NPP diets have no effects on growth performance in the starter period. This feeding strategy results in negative effects on plasma P concentration and bone ash content at d 42. Also, exogenous phytase is effective in improving growth performance, bone characteristics and apparent P retention of growing broilers fed diets that are inadequate in phosphorus.     

一株蓝麻黄拮抗内生真菌的分离鉴定及代谢物的初步分析

[目的]分离获得对农作物致病菌有高效拮抗作用的植物内生菌,并对其进行系统鉴定和代谢成分分析.[方法]用研磨法从蓝麻黄中分离内生真菌,并用琼脂扩散法筛选具有抗农作物致病菌活性的内生真菌;利用菌株形态特征和ITS-5.8S rDNA序列分析进行拮抗菌鉴定,经酚硫酸法测定多糖含量.[结果]从蓝麻黄中分离得到5株内生真菌,其中XJEG-GF-79对葡萄白腐病菌的抑菌圈直径为23 mm.经形态学观察和分子分类学分析鉴定,内生拮抗真菌XJEG-GF-79与Pleosporaceae sp. SN-2008同源性达到100;,该菌株代谢产物中含有生物碱和多糖,其经测定,发酵液中多糖含量为1.914 mg/mL.[结论]蓝麻黄内生真菌XJEG-GF-79对葡萄白腐病菌有明显的拮抗作用,最终鉴定为链格孢霉 Pleosporaceae sp..     

HPLC检测猪血浆和尿液中的喹烯酮及其主要代谢物

本试验旨在建立猪血浆和猪尿液中喹烯酮及其主要代谢物3-甲基-喹噁啉-2-羧酸(MQCA)、脱一氧喹烯酮、脱二氧喹烯酮同时检测的高效液相色谱法。血浆样品用乙腈沉淀蛋白,经高速离心后直接检测。尿液样品用乙酸乙酯提取喹烯酮、脱一氧喹烯酮、脱二氧喹烯酮,用盐酸提取MQCA,再用乙酸乙酯萃取,50 ℃氮气吹干后过HLB固相萃取小柱。以0.1%甲酸水-乙腈为流动相梯度洗脱,314 nm波长下检测。喹烯酮及3种代谢物在血浆中的回收率在72.54%~104.2%之间,尿液中的回收率在63.20%~86.24%之间。4种目标化合物在血浆和尿液中定量限均为0.05 μg/mL。     

高效液相色谱-串联质谱法检测猪肝中苯并咪唑类药物及其代谢物残留

建立了猪肝中阿苯哒唑及其代谢物阿苯哒唑砜、阿苯哒唑亚砜、2-氨基阿苯哒唑砜,噻苯哒唑及其代谢物5-羟基噻苯哒唑,甲苯哒唑及其代谢物氨基甲苯哒唑、5-羟基甲苯哒唑,芬苯哒唑及其代谢物芬苯哒唑砜、等效物奥芬哒唑,氟苯哒唑及其代谢物2-氨基-氟苯哒唑共14种苯并咪唑类药物及其代谢物残留检测的高效液相色谱-串联质谱方法。样品用乙酸乙酯提取,MCX固相萃取柱净化。WatersXterraC18色谱柱（2．1mm×150mm,5μm）分离,流动相A相为0．1％甲酸乙腈溶液;B相为0．1％甲酸水溶液,梯度洗脱,外标法定量。结果表明,14种苯并咪唑类药物及其代谢物标准溶液在10～1000ng／mL的浓度范围内呈现良好的线性关系,尺。均大于0．99,方法检测限为5斗g／kg,定量限为10μg／kg,14种苯并咪唑类药物及其代谢物在10—200μg／kg添加浓度范围内回收率均70％～120％之间。批内、批间相对标准偏差均小于20％。本方法灵敏、准确,满足食品安全检测法规的要求。     

桃蚜危害胁迫对菜心植株主要次生物质含量的影响

研究了菜心在桃蚜危害后主要次生物质的活性变化动态。结果表明,随着桃蚜胁迫强度的增大,菜心植株内的超氧化物歧化酶(SOD)、过氧化物酶(POD)、丙二醛(MDA)活性均增加。在相同的危害时间和胁迫强度下,3个菜心品种的SOD、POD、MDA增加的幅度不同,表明菜心品种之间对桃蚜的抗性有较大差异。