The relationship between carcass characteristics,plasma hormones and metabolites in young fattening bulls

Six Belgian Blue bulls (double-muscled type) and six Friesian bulls were offered a fattening diet for 34 weeks. Plasma samples were obtained once a week and also every 20 min over a 24 h period, 7 weeks before slaughter.No differences were observed between the breeds in plasma glucose, urea and free amino nitrogen concentrations, while creatinine was significantly higher in the Belgian Blue bulls. Tri-iodothyronin, tetra-iodothyronin, insulin-like growth factor 1, insulin and testosterone concentrations were higher in the Holstein group. In contrast, the Belgian Blue bulls appeared to produce more growth hormone. The slaughter weight, carcass weight, dressing percentage and proportion of lean meat were significantly higher in the Belgian Blue group. The characteristics of muscle mass (carcass weight, dressing percentage and proportion of lean meat) were positively correlated with creatinine and with the total peak area or peak amplitude of growth hormone. The insulin concentration was positively correlated with the proportion of adipose tissue in the carcass and negatively correlated with the proportion of muscle. There were no correlations between the carcass characteristics and insulin-like growth factor 1 or testosterone. No further information was provided when the ratios of the hormones were correlated with carcass characteristics.     

Immunopathology of Chlamydophila abortus infection in sheep and mice

Chlamydophila abortus targets the placenta, causing tissue damage, inflammation and abortion (enzootic abortion of ewes). It is one of the main infectious causes of abortion in ewes, resulting in major economic losses to agricultural industries worldwide. Although ruminants and pigs are the principal hosts, humans are also susceptible to infection. Control of disease requires a host inflammatory response, which is likely to contribute to pathology and abortion. Mouse models have been widely used to provide insight into the role of specific immune cells in controlling infection and disease. The use of such model systems for investigating the mechanisms of abortion, latency, persistence, and immunity to reinfection will result in the identification of novel vaccine control strategies for sheep.     

猕猴桃果实发育中内源激素水平变化的研究

应用酶联免疫法（ＥＬＩＳＡ）测定了美味猕猴桃＇Ｈａｙｗａｒｄ＇受精和果实发育中内源生长素（ＩＡＡ）、玉米素（ＺＲｓ）和脱落酸（ＡＢＡ）水平的变化，以及未受精果实对这些激素变化的影响。结果表明，在花前子房中三类激素已有一定的水平。花后２天完成受精作用，初生胚乳核开始分裂。花后５－７天，合子分裂，果实中ＡＩＩ、ＡＢＡ含量达到高峰。花后１０－４０天和８０－１００天，果实各有一次快速膨大期，前期与果肉中Ｚ     

猪内源氨基酸测定技术评述

氨基酸的真消化率是评价饲料蛋白质生物学效价的重要指标,而要测定氨基酸的真消化率,就必须对内源氨基酸排泄量进行估测。本文就目前内源氨基酸的测定方法进行了综述,并对各种方法的优缺点进行了评述。在内源氨基酸的测定方法中,以传统方法(无氮日粮法、回归外延法和完全可消化蛋白源或静脉灌注平衡氨基酸法)最为常用,但存在种种缺陷。为克服传统方法的缺陷,学者们提出了新的估测内源氨基酸的方法,如同位素标记法、高精氨酸法、肽营养超滤技术、氨基糖测定法以及体内体外结合测定法,但这些方法也存在或多或少的缺陷,还有待于改进。     

Lactogenic hormones stimulate expression of lipogenic genes but not glucose transporters in bovine mammary gland

During the onset of lactation, there is a dramatic increase in the expression of glucose transporters (GLUT) and a group of enzymes involved in milk fat synthesis in the bovine mammary gland. The objective of this study was to investigate whether the lactogenic hormones mediate both of these increases. Bovine mammary explants were cultured for 48, 72, or 96 h with the following hormone treatments: no hormone (control), IGF-I, insulin (Ins), Ins + hydrocortisone + ovine prolactin (InsHPrl), or Ins + hydrocortisone + prolactin + 17β-estradiol (InsHPrlE). The relative expression of β-casein, α-lactalbumin, sterol regulatory element binding factor 1 (SREBF1), fatty acid synthase (FASN), acetyl-CoA carboxylase α (ACACA), stearyol-CoA desaturase (SCD), GLUT1, GLUT8, and GLUT12 were measured by real-time PCR. Exposure to the lactogenic hormone combinations InsHPrl and InsHPrlE for 96 h stimulated expression of β-casein and α-lactalbumin mRNA by several hundred-fold and also increased the expression of SREBF1, FASN, ACACA, and SCD genes in mammary explants (P < 0.01). However, those hormone combinations had no effect on GLUT1 or GLUT8 expression and inhibited GLUT12 expression by 50% after 72 h of treatment (P < 0.05). In separate experiments, the expression of GLUTs in the mouse mammary epithelial cell line HC11 or in bovine primary mammary epithelial cells was not increased by lactogenic hormone treatments. Moreover, treatment of dairy cows with bovine prolactin had no effect on GLUT expression in the mammary gland. In conclusion, lactogenic hormones clearly stimulate expression of milk protein and lipogenic genes, but they do not appear to mediate the marked up-regulation of GLUT expression in the mammary gland during the onset of lactation.     

水分胁迫对芒果成花效应及内源激素变化的影响

以３ａ生盆栽红芒６号为试材,研究水分胁迫对芒果成花的效应。发现水分胁迫能改变芒果植株梢尖内源激素的水平及激素间的平衡,使 ＧＡ减少,ＡＢＡ和 ＣＴＫ增加,ＣＴＫ／ＧＡ及ＡＢＡ／ＧＡ的比率提高,抑制营养生长,促进开花,成花率高达 ７５％;而对照（灌水）植株营养生长旺盛,萌发新梢,抽梢率３７．５％,成花率仅６．２５％。      

干旱胁迫下木薯叶片和离层内源乙烯含量变化

利用木薯光系统II(PSII)最大光化学效率(Fv/Fm)量化木薯受到干旱胁迫的程度,并测量木薯叶片与离层的内源乙烯在不同程度干旱胁迫下的量,以探讨内源乙烯的产生、Fv/Fm的下降速度与木薯抗旱性之间的关系。结果表明,抗旱性越强的品种,Fv/Fm下降速度越慢,内源乙烯上升的时间也越靠后。     

粗酶制剂对鹅生长及某些激素的影响

选用２４只７日龄雏鹅,随机分成对照和试验２组。饲以大麦（占４５％）基础日粮,试验组添加０．１％的Ｂｉｏｋｙｏｗａ商品粗酶制剂。试验期为７～６０日龄,每周称量体重和记录采食量。６０日龄时由翅静脉采取血样,分离血浆用激素测定。结果如下：试验组体重自３周龄起显著高于对照组,而周增重于２～５周龄显著提高,且该期间的采食量增加,料重比略为下降;血液中ＧＨ、ＩＧＦ－Ｉ含量较对照组高３６．６３％（Ｐ〈０．０５）和６６．５５＾（Ｐ〈０．０１）,β－ＥＮＤ却下降了５１．６６％（Ｐ〈０．０１）;试验组的ＴＳＨ、Ｔ３水平较对照组分别高２４．３９％（Ｐ〈０．０５）和１６．８１％（Ｐ〈０．０５）,而Ｔ４水平却低１８．３３（Ｐ〉０．０５）,Ｔ３／Ｔ４比值升高。以上结果表明：添加粗酶制剂不仅能改善生长鹅对大麦日粮的消化,而且影响机体的代谢激     

酶制剂对雏鹅代谢激素和生化指标的影响

18只7日龄雏鹅，随机分成为对照组和试验组，饲以大麦（占45％）基础日粮，试验组添加0．1％的Biokyowa粗酶制剂。试验期为7－21日龄，21日龄采取血样，测定其中激素含量和生化指标。结果显示：与对照组比较，酶制剂使21日龄雏鹅血糖水平高13．95％（P＜0．01），胰岛素有升高的趋势，胰岛血糖素低28．05％（P＜0．01）；血浆谷丙转氨酶活性较对照组升高14．53％（P＜0．05），而尿酸浓度却下降35．37％（P＜0．01）；添加粗酶制剂后，血浆的TSH和T3分别较对照升高11．76％和11．43％（P＜0．05）。以上结果表明：酶制剂通过解除饲料中β-葡聚糖的抗营养作用，影响机体代谢激素水平，改变糖和蛋白质的代谢，从而促进雏鹅的生长。     

新型植物激素——系统素

系统素最初是指在番茄叶片中发现的与植物防卫反应相关的1种含18个氨基酸的多肽信号,现已成为植物伤害生理研究领域的热点。概述了植物系统素的结构特点、前体及其在伤信号转导中的作用等方面的研究进展,并展望了系统素今后的研究方向。