蒸汽压片玉米在奶牛生产中的应用研究进展

玉米是奶牛舍饲的主要能量饲料来源之一,而蒸汽压片技术是一项目前较为成熟的日粮加工技术,主要通过机械的湿热加工方法改变原料物理形态和营养物质的化学结构,广泛应用于反刍动物日粮中。蒸汽压片处理工艺中的蒸汽压力、温度和处理时间会影响压片产品的容重和淀粉糊化度,进而影响其饲喂效果。研究发现,经蒸汽压片处理的玉米可有效提高其淀粉消化率,加快瘤胃内的发酵速度,改变瘤胃发酵模式,促进瘤胃微生物蛋白合成,有利于维持瘤胃pH及瘤胃内环境的稳定。也有研究表明,蒸汽压片玉米饲喂奶牛后,对其采食量没有明显影响,但可以提高产奶量,改善乳成分,从而提高奶牛的产奶性能。作者对蒸汽压片玉米技术及其在奶牛生产中的应用研究进展进行综述,以期为蒸汽压片玉米在中国奶牛生产中的合理使用提供参考。     

不同加工方式玉米粉对12月龄伊犁马消化代谢、血浆生化指标及体增重的影响

本试验旨在研究蒸汽压片玉米粉、膨化玉米粉对12月龄伊犁马消化代谢、血浆生化指标及体增重的影响,为蒸汽压片玉米粉、膨化玉米粉在马的饲养实践中的应用提供参考。选取体重相近[(261.95±14.73)kg]、年龄相近(12月龄左右)的伊犁马公马24匹,随机分为3组,每组8匹,分别为对照组、试验Ⅰ组、试验Ⅱ组。各组马匹每天每匹饲喂1.5 kg浓缩料和8 kg苜蓿干草,在此基础上对照组、试验Ⅰ组、试验Ⅱ组马匹每天每匹再分别饲喂1.5 kg的粉粹玉米粉、蒸汽压片玉米粉、膨化玉米粉,进行26 d的消化代谢试验,其中预试期19 d,正试期7 d。结果表明:试验Ⅱ组的干物质、有机物、粗蛋白质、中性洗涤纤维及酸性洗涤纤维的表观消化率分别比对照组高出4.93%(P0.05)、5.84%(P0.05)、7.10%(P0.05)、14.78%(P0.05)、17.45%(P0.05),而试验Ⅰ组的干物质、有机物、粗蛋白质及中性洗涤纤维的表观消化率与对照组相比均差异不显著(P0.05)。试验Ⅱ组的氮沉积量、氮沉积率显著高于对照组及试验Ⅰ组(P0.05),分别高出81.19%、79.86%及104.78%、97.50%,而对照组、试验Ⅰ组间差异不显著(P0.05);试验Ⅱ组的钙、磷沉积量及沉积率均高于对照组、试验Ⅰ组(P0.05)。试验Ⅱ组血浆中葡萄糖含量分别比对照组及试验Ⅰ组高出10.04%、20.79%(P0.05)。饲喂蒸汽压片玉米粉和膨化玉米粉对12月龄伊犁马的体增重和平均日增重无显著影响(P0.05),但试验Ⅱ组试验期内的体增重、平均日增重分别较对照组高出18.88%、20.37%,分别较试验Ⅰ组高出20.43%、20.37%。因此,饲喂膨化玉米粉可提高12月龄伊犁马对饲粮中营养物质的表观消化率及能量代谢,并促进马的生长;而饲喂蒸汽压片玉米粉对12月龄伊犁马的营养物质代谢、血浆生化指标及体增重均无显著影响。     

Interactions between body mass and water temperature cause energetic bottlenecks in juvenile steelhead

Across taxa, it is generally accepted that there are fitness advantages to rapid growth early in life. For stream‐dwelling salmonids, however, high temperatures and associated energetic costs during the summer growing season might offset or even prevent the competitive advantage of large body size. Our overall objective was to understand the relative importance of factors that can cause variation in growth rates in an age‐0 cohort of wild steelhead (Oncorhynchus mykiss) in Idaho, USA, where temperatures approach, and temporarily exceed, their tolerance level. For individually tagged fish inhabiting the same stream reach, we found that growth rates were negatively related to fish mass (slopes of the two best approximating models were both ?0.024). Comparing growth rates from 16 different stream reaches throughout the watershed, we found that temperature‐induced metabolic cost was the single best approximating model (AIC w_i = 1.0) of the variation in individual growth rates. The bioenergetic model showed that mass‐specific metabolic costs decreased with mass, but the absolute energetic demands increased over the same size range. Because temperature had a multiplicative effect on metabolic cost, our results suggest that the effect of food limitation increased with fish size. We conclude that high water temperatures pose energetic bottlenecks and can be a potentially strong mechanism limiting growth in juvenile salmonids in summer, particularly as streams in the region experience warming trends.     

甘氨酰谷氨酰胺二肽对黄羽肉鸡肝脏脂肪代谢的影响及其机制的研究

选择360只1日龄优质黄羽肉鸡，随机分为4组，分别饮用凉开水配制的浓度为0、0．01、0．05和0．10mg／L的甘氨酰谷氨酰胺（Gly—Gin）二肽溶液，连续饮用41d。用甘油三酯试剂盒测定肝脏总甘油三酯的含量。采用相对定量RT—PCR的方法来检测ACC（acetyl—CoAcarboxylase）和PPAR0a（peroxisomeproliferator—activatedreceptorsa）mRNA的表达水平。试验结果表明：①Glv—Gln二肽能够呈现剂量依赖性的降低肝脏4CCmRNA的表达水平，0．10mg／LGly—Gin二肽处理组较对照组差异显著（P〈0．05）。②Glv—Gln二肽能够显著上调只附R仅基因mRNA的表达水平，其中0．05mg／LGly—Gln二肽处理组较对照组差异显著（P〈0．05）。③Gly—Gln二肽具有提高肝脏甘油三酯含量的趋势，但差异不显著（P〉0．05）。以上结果提示，Glv—Gln二肽能够通过降低肝脏甘油三酯的合成，促进代谢，从而减少脂肪沉积水平。     

利用VIGS技术研究草莓FaMYB5的功能

以‘丰香’草莓(Fragaria×ananassa‘Toyonaka’)为材料,采用病毒诱导的基因沉默技术(Virus-induced Gene Silencing,VIGS)对果实中类黄酮化合物代谢相关转录因子基因FaMYB5进行沉默,并对沉默后果实类黄酮化合物代谢途径相关的结构基因和其他转录因子基因表达量进行半定量RT-PCR及RT-qPCR分析。并分别采用HPLC和香草醛—硫酸比色法对沉默后果实中花青素苷和原花青素含量进行测定。成功构建了pTRV2-FaMYB5的VIGS沉默载体,并建立了草莓果实VIGS沉默体系,FaMYB5基因沉默效率达60%;FaMYB5基因沉默处理与阴性对照相比,草莓类黄酮化合物代谢途径相关结构基因和转录因子表达量均发生改变,其中FaMYB9、FaLAR、FaDFR、FaANR表达量显著增加,从而导致果实中原花青素含量增加;而花青素合成相关基因FaANS的表达量减少1/2,FaMYB10表达量变化并不显著。此外,bHLH家族的转录因子基因FabHLH3和FabHLH3Δ随着FaMYB5的沉默表达量显著下降,而FaGL3显著升高。结果进一步证明FaMYB5转录因子对草莓类黄酮化合物代谢途径中的原花青素合成途径起负调控作用。     

Effect of Sugarcane Tops Silage and Corn Straw Silage on the Growth Performance,Digestion and Metabolism,and Blood Biochemical Indexes of Growing Buffalo

The objective of this work was to investigate the effects of sugarcane tops silage and corn straw silage on the growth performance, digestibility and metabolisability of nutrient and blood biochemical indexes of growing buffalo.Trial 1:21 buffalos were randomly divided into 3 groups according to the principle of body weight and birth similarity for 30 days feeding trial.The buffalos in 3 groups were fed with SS+concentrate, CS+concentrate and SS+CS +concentrate, respectively.Trial 2:Six buffalos were randomly divided into 2 groups according to the principle of body weight and birth similarity, and fed with SS and CS, respectively.There were 4 days for digestion-metabolism trial using total feces collection methods.The results showed that:①There were no significant difference on average dry matter intake(ADMI)of buffalos fed with CS and SS(P>0.05), but comparing with SS, the average daily gain(ADG)was higher of buffalos fed with CS(P>0.05).Both ADMI and ADG were higher when buffalos fed with CS+SS.②Compare to SS, the nutrient digestibility, nitrogen metabolization and energy metabolic rate of CS were higher.And the effects of SS and CS on the digestibility of NDF, ADF were no significant difference(P>0.05).③The effect of feeding with CS, SS on blood biochemical indexes were no significant difference, and did not have any bad effect on animal body.Thus the digestibility of nutrient was higher when fed with CS, and SS and CS separately had no bad effect on blood biochemical indexes.Feeding SS+CS could improve the growth performance of growing buffalo.     

紫外线辐射对葡萄生长发育的影响

概述了紫外线辐射特别是UV-B辐射对葡萄节间长度、叶面积以及植株高度等形态特征,叶片光合特性、叶片抗氧化作用、叶片代谢及果实代谢、果实品质等生理生化变化和葡萄酒质量的影响;并从前人的研究结果中得出经验并探寻新的突破点,为葡萄抗辐射胁迫的研究提供条件并为提高酿酒葡萄品质提供依据。     

Effects of uniconazole or gibberellic acid application on the lignin metabolism in relation to lodging resistance of culm in common buckwheat (Fagopyrum esculentum M.)

Lignin plays an important role in increasing the mechanical intensity of culm and improving lodging resistance of culm. In this study, three common buckwheat, Youqiao2 (lodging‐tolerant cultivar; YQ2), Ningqiao1 (middle lodging‐tolerant cultivar; NQ1) and Ukraine daliqiao (lodging‐susceptible cultivar; UD), were used to investigate the effects of spraying exogenous hormones uniconazole (S‐3307) or gibberellic acid (GA3) on lignin metabolism and its relation to lodging resistance in the three common buckwheat cultivars. Results showed that application of S‐3307 significantly increased lignin content and its related enzymes activities of phenylalanine ammonia‐lyase (PAL), 4‐hydroxy cinnamoyl CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POD). The major genes involved in lignin synthesis, PAL, CCR (cinnamyl CoA reductase), C4H (cinnamate4‐hydroxylase), 4CL and CCoAOMT (caffeoyl CoA O‐methyltransferase), were all upregulated expression, and COMT (catechol‐O‐methyltransferase) was downregulated. What is more, application of S‐3307 significantly improved the resistance of common buckwheat stem to lodging and increased yield. Whereas, spraying with GA3 caused opposite effect on those characteristics. These results suggested that application of exogenous S‐3307 or GA3 significantly changed the risk of lodging occurred by regulating the lignin metabolism in culms of common buckwheat.     

非常规蛋白饲料原料对泌乳山羊氮代谢和微生物蛋白合成的影响

文章旨在研究不同蛋白质来源精饲料对泌乳山羊氮代谢及微生物蛋白合成的影响。试验选择平均初始体重为(43.62±2.35)kg的泌乳期山羊72头,随机分为3组,每组4个重复,每个重复6头。各组分别饲喂以豆粕、大豆浓缩蛋白和豆科植物(银合欢)为基础的精料,试验为期8周。结果:大豆浓缩蛋白组尿液和尿素氮排泄量较豆科植物组显著提高21.41%和23.31%(P<0.05),但大豆浓缩蛋白和乳尿素氮排泄量最低(P<0.05)。大豆浓缩蛋白组尿液和尿素氮排泄量占体重的比例也显著高于豆科植物组(P<0.05)。大豆浓缩蛋白组氮摄入量最低(P<0.05)。大豆浓缩蛋白组尿氮含量显著高于豆粕和豆科植物组(P<0.05)。豆科植物组微生物氮、微生物蛋白量及合成效率也显著高于豆粕组(P<0.05)。结论:在本研究条件下,以大豆浓缩蛋白为蛋白源的精饲料饲喂哺乳期山羊,尿液氮排泄量更大,导致负氮平衡,而以豆科植物(银合欢)为蛋白源时,可以提高乳山羊瘤胃微生物蛋白合成能力。