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81.
0~3周龄北京鸭氨基酸理想模式的研究   总被引:5,自引:1,他引:5  
依据扣除法原理,根据现有氨基酸需要量标准和目前的研究结果规划出一种氨基酸模式,依次将模式中赖氨酸、蛋氨酸、色氨酸、苏氨酸、异亮氨酸扣除20%,而非扣除的氨基酸量保持不变,来确定扣除某一种氨基酸后对育雏期北京鸭生产性能和血液生化指标的影响,确定出理想的氨基酸比例。试验共设6个处理组,为6种氨基酸模式,每个处理设4个重复。结果表明:北京鸭育雏期氨基酸理想模式为赖氨酸:蛋氨酸:色氨酸:苏氨酸:异亮氨酸=100:42:22:38:48。  相似文献   
82.
营养学中氨基酸平衡的度量   总被引:8,自引:0,他引:8  
本文基于聚类分析理论,提出了失衡度(IBD)这一新的化学指数,借以定量地研究蛋白质营养中的氨基酸平衡问题。当样品中氨基酸完全平衡时,IBD取值为零;而当其氨基酸平衡最差时。IBD取值为1。IBD的氨基酸增量模型为非对称最大值式;且IBD与变异系数(CV)之间有着密切的关系。通过IBD这一指数,可以对各种单一饲料的蛋白质营养价值加以分类列等;通过计算两种以上饲料蛋白质混合物的IBD,可以从理论上预测它们之间是否互补,以及何时发生最佳互补关系。若引申IBD的概念框架,还可以用来研究其它养分之间的平衡关系,并有助于实现计算机配方过程的自动鉴别和筛选。  相似文献   
83.
桑树内源激素及其生理效应的研究进展   总被引:3,自引:2,他引:3  
楼程富  谈建中 《蚕业科学》1996,22(4):241-247
综述了近20年来桑树生长素、赤霉素、细胞分裂素、乙烯和脱落酸的研究进展。探讨了这五类激素在桑树生长发育和组织培养等方面的应用前景。  相似文献   
84.
本研究分析了共轭亚油酸(CLA)对C2C12肌细胞生脂转分化和生肌分化的影响。分别培养并诱导C2C12鼠源肌细胞生脂转分化和正常的生肌分化,同时分别使用终浓度为50μmol/L的c9,t11-CLA和t10,c12-CLA处理细胞,并设对照组,取生脂转分化第10天和生肌分化第8天的细胞用于实时定量PCR检测,观察c9,t11-CLA和t10,c12-CLA对C2C12肌细胞不同分化的影响。结果表明:1)与对照组相比,c9,t11-CLA促进了C2C12肌细胞的生脂转分化,显著增加了细胞内甘油三酯(TG)含量(P0.05),显著上调了细胞内脂肪酸合成酶(FAS)、CCAAT增强子结合蛋白α(C/EBPα)、过氧化物酶体增殖剂激活受体γ(PPARγ)和脂肪酸结合蛋白4(FABP4)基因的表达水平(P0.05);与对照组相比,t10,c12-CLA则抑制了C2C12肌细胞的生脂转分化,显著减少了细胞内TG含量(P0.05),显著下调了细胞内C/EBPα、PPARγ和FA BP4基因的表达水平(P0.05)。免疫印迹杂交结果显示FAS和FABP4的蛋白质表达水平也发生了与基因表达相一致的变化。2)与对照组相比,t10,c12-CLA抑制了C2C12肌细胞的生肌分化,显著减少了细胞内肌管数/细胞数(P0.05),显著下调了细胞内肌细胞生成素(MYOG)和成肌分化抗原(MYOD)基因的表达水平(P0.05);与对照组相比,c9,t11-CLA则显著上调了细胞内MYOG基因的表达水平(P0.05),对C2C12肌细胞的生肌分化有一定程度的促进作用。免疫印迹杂交结果显示MYOG和MYOD的蛋白质表达水平也发生了与基因表达相一致的变化。以上结果表明,CLA对动物骨骼肌细胞的正常生肌分化和生脂转分化都具有重要的调节作用。  相似文献   
85.
硬脂酰辅酶A去饱和酶是体内饱和脂肪酸向单一不饱和脂肪酸转化的关键酶类,也是瘦素(Ob)基因通过信号传导发挥代谢生理调控作用的重要组分。其活性的高低关系到动物体脂肪酸的组成和瘦肉率的高低,进而影响产肉率和腌肉制品的产量,本文仅就日粮脂肪酸组成对该酶基因表达和酶活的调控进行综述。  相似文献   
86.
In order to assess the survival of lactic acid bacteria (LAB) in whole crop maize silage in the gut of dairy cows, one representative silage sample and three different feces samples were collected from dairy cows on three dairy farms in Hua Bei, China and three dairy farms in Kyushu, Japan. The composition of the bacterial community was examined by denaturing gradient gel electrophoresis and quantitative polymerase chain reaction. Lactobacillus acetotolerans was detected in all bunker‐made maize silage samples, regardless of the dairy farm or sampling region from which they were sourced. A total of eight LAB species were detected in the maize silage samples, of which three (L. acetotolerans, L. pontis and L. casei) appeared to survive digestion. The populations of L. acetotolerans in silage and feces were 106–7 and 103–4 copies/g, respectively, indicating that, even for the LAB species showing potential survival in the gut, competition in this niche may be harsh and the population may substantially decrease during the digestion process. It may be difficult for silage LAB to survive in the gut of silage‐fed dairy cows, because marked decrease in population can take place during the digestion process, even for surviving species.  相似文献   
87.
To increase public understanding on cloned cattle derived from somatic cell nuclear transfer (SCNT), the present review describes the effect of calf death loss on an SCNT cattle herd. The incidence of death loss in SCNT cattle surviving more than 200 days reached the same level as that in conventionally bred cattle. This process could be considered as removal of SCNT cattle with congenital defects caused by calf death loss. As a result of comparative studies of SCNT cattle and conventionally bred cattle, the substantial equivalences in animal health status, milk and meat productive performance have been confirmed. Both sexes of SCNT cattle surviving to adulthood were fertile and their reproductive performance, including efficiency of progeny production, was the same as that in conventionally bred cattle. The presence of substantial equivalence between their progeny and conventionally bred cattle also existed. Despite these scientific findings, the commercial use of food products derived from SCNT cattle and their progeny has not been allowed by governments for reasons including the lack of public acceptance of these products and the low efficiency of animal SCNT. To overcome this situation, communication of the low risk of SCNT technology and research to improve SCNT efficiency are required.  相似文献   
88.
鹌鹑肌肉肌苷酸含量和鹑肉保鲜时间的研究   总被引:2,自引:1,他引:2  
用纸层析法测定鹌鹑肌肉提取液中的肌苷酸含量,实验结果表明:1.鹌鹑性别不同的肌苷酸含量(平均值):雌鹑为5.557μM/g(肉);雄鹑为5.274μM/g(肉),差异不显著(p>0.05)。2.两组不同日龄鹌鹑胸肌肌苷酸含量(平均值):35日龄为5.739μM/g,70日龄为4.941μM/g,差异极显著(p<0.01)。3.鹌鹑不同部位肌苷酸含量,胸肌明显高于腿肌,腿肌的肌苷酸含量平均值仅为胸肌的60.51%,差异极显著(p<0.01)。4.不同条件保存鹑肉时,随着时间的延长,肌肉中的肌苷酸均降解,降解速度,低温(0℃)较室温缓慢。5.测定肌肉中肌苷酸的含量可作为衡量鹌鹑肌肉鲜度的一项有用的指标。  相似文献   
89.
陶雅  李峰  高凤芹  孙启忠 《草业学报》2015,24(12):66-73
以短芒大麦草为研究对象,利用传统培养法从叶围和青贮发酵体系中分离出乳酸菌、大肠杆菌、好氧细菌、酵母菌和霉菌,并计数;结合细菌形态学、生理生化特征及16S rDNA序列分析鉴定分离出的乳酸菌菌株;通过研究乳酸菌的生长曲线、产酸特性及耐酸性,筛选优质乳酸菌。以期探明短芒大麦草叶围及青贮发酵体系中微生物菌群特性及青贮料中乳酸菌多样性,筛选出具有促发酵效果的乳酸菌菌株,为有益微生物饲料研发奠定基础。试验结果表明,短芒大麦草经青贮发酵后各微生物菌群数量发生不同程度变化,乳酸菌数量由0 cfu/g FM增加到4.00×108 cfu/g FM,酵母菌数量由8.50×105 cfu/g FM增加到1.02×108 cfu/g FM,而好氧细菌、大肠杆菌和霉菌数量变化不明显;从短芒大麦草青贮发酵体系分离得到4株乳酸菌,经鉴定Lx36为Lactobacillus pentosus,Lx37为Lactobacillus brevis,Lx53为Pediococcus pentosaceus,Lx54为Lactobacillus parabuchneri;筛选得到1株益于青贮的乳酸菌株Lx36,约在20 h后进入稳定生长期,OD值达到4.21,且发酵12 h的pH仅为4.08,并可以在pH=3.0环境条件下生长。综上所述,青贮发酵是体系中各种微生物相互作用的过程,微生物菌群的数量及变化直接影响青贮饲料发酵品质。短芒大麦草青贮饲料中乳酸菌种类较丰富,筛选得到的戊糖乳杆菌繁殖速度快、产酸能力强同时表现出了较强的耐酸性,具有潜在的生产应用价值,适宜用作促发酵的青贮添加剂菌种。  相似文献   
90.

Background

The branched chain amino acid leucine is a potent stimulator of insulin secretion. Used in combination with glucose it can increase the insulin response and the post exercise re-synthesis of glycogen in man. Decreased plasma amino acid concentrations have been reported after intravenous or per oral administration of leucine in man as well as after a single per oral dose in horses. In man, a negative correlation between the insulin response and the concentrations of isoleucine, valine and methionine have been shown but results from horses are lacking. This study aims to determine the effect of repeated per oral administration with a mixture of glucose and leucine on the free amino acid profile and the insulin response in horses after glycogen-depleting exercise.

Methods

In a crossover design, after a glycogen depleting exercise, twelve Standardbred trotters received either repeated oral boluses of glucose, 1 g/kg body weight (BW) at 0, 2 and 4 h with addition of leucine 0.1 g/kg BW at 0 and 4 h (GLU+LEU), or repeated boluses of water at 0, 2 and 4 h (CON). Blood samples for analysis of glucose, insulin and amino acid concentrations were collected prior to exercise and over a 6 h post-exercise period. A mixed model approach was used for the statistical analyses.

Results

Plasma leucine, isoleucine, valine, tyrosine and phenylalanine concentrations increased after exercise. Post-exercise serum glucose and plasma insulin response were significantly higher in the GLU+LEU treatment compared to the CON treatment. Plasma leucine concentrations increased after supplementation. During the post-exercise period isoleucine, valine and methionine concentrations decreased in both treatments but were significantly lower in the GLU+LEU treatment. There was no correlation between the insulin response and the response in plasma leucine, isoleucine, valine and methionine.

Conclusions

Repeated post-exercise administration with a mixture of leucine and glucose caused a marked insulin response and altered the plasma amino acid profile in horses in a similar manner as described in man. However, the decreases seen in plasma amino acids in horses seem to be related more to an effect of leucine and not to the insulin response as seen in man.  相似文献   
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