Central and peripheral serotonergic control of forestomach motility in sheep

Participation of tryptaminergic receptors in the control of forestomach motility was investigated in conscious sheep using strain-gauges and chronically implanted electrodes. Two hours after feeding the sheep, serotonin (5-HT) was infused into the jugular vein (i.v.), or the carotid artery (i.c.), or into the lateral cerebral ventricles (i.c.v.), over a 10-min period. An i.v. dose of 16 micrograms/kg/min abolished the cyclic propagated contractions throughout the forestomach, increased ruminoreticular tone, and induced simultaneous contractions of all the parts of the rumen. A dose of 1.6 micrograms/kg/min i.c. or i.v. 5-HT inhibited phasic contractions. The effects of 5-HT were blocked completely by i.c.v. administration of methysergide (20 micrograms/kg) and imipramine (200 micrograms/kg), and blocked partially by naloxone (25 micrograms/kg), but unaffected by atropine (50 micrograms/kg). The inhibitory effects of i.v. 5-HT were antagonized by methysergide (200 micrograms/kg, i.v.) but unaffected by imipramine (2 mg/kg, i.v.) and atropine (250 micrograms/kg, i.v.). Only the i.v. administration of methysergide blocked the inhibition induced by i.c. infusion (1.6 micrograms/kg/min) of 5-HT. It is suggested that 5-HT exhibits an inhibitory control on forestomach phasic contractions through hypothalamic and bulbar 5-HT receptors, and exerts peripheral excitatory effects on the tone of the rumen wall.     

《木材水运建筑安装工程预算定额》修订和《概、预算编制办法及费用定额》编制

1994年9月～1995年9月,由主编单位四周林业勘察设计研究院承担《木材水运建筑安装工程预算定额》的修订和《木材水运建筑安装工程概、预算编制办法及费用定额》的编制。定额的修定一方面要与相关定额水平协调,同时将工程实体消耗量和施工措施性消耗分开;贯彻政府有关文件精神并反映当前平均先进水平;保留(64)定额的框架只对章,节目和消耗量,基价作调整。 新编《木材水运建筑安装工程概、预算编制办法及费用定额》,以办法与费用定额合一,简化文字实用为原则,项目设置、费用定额符合政府部门最新规定。结合实际控制水平,按工程性质划分为7项生产性主体工程;5项附属性工程;2项非生产性工程和其它工程及费用两大部分。     

Prediction of Sensorial Properties (Color and Taste) of Amala,a Paste From Yam Chips Flour of West Africa,Through Flour Biochemical Properties

Color and taste are permanent features of amala, a traditional thick paste obtained from yam chips flour. To assess these attributes, 23 yam chips presenting various quality attributes were processed. The sensory attributes of their derived amala were determined and some biochemical characteristics of yam flours measured. A panel defined five main taste attributes for amala: sweetness, bitterness, acidity, fermented, and roasted tastes. Amala color was measured instrumentally and sensory scores were highly correlated with flour biochemical analyses; amala sweetness was positively correlated with glucose and fructose content of the flour, whereas amala acidity and fermented taste were linked to organic acids and lactic acid contents of flour, respectively. In addition, darkness, bitterness, and roasted tastes of amala could be tightly predicted by multiple regression analysis from phenolic compound and glucose–fructose contents. Phenolic content of yam flour plays thus a key role on sensorial quality of amala. However, polyphenol oxidase and peroxidase activities were almost null in yam flours and their specific role on yam flour phenolic content needs to be clarified.     

四川森林航测和林业遥感回顾与展望（上）

1953～1959年林业部航测队在四川省袭江下游、金沙江下游、青衣江上游以及川、陕、鄂交界的大巴山林区进行航测航调工作,1956～1958年林业部三、八森林经理调查大队使用航片在四川小金、会东等县及甘、青交界的祁连山林区完成323hm~2的森林经理调查;1959～1983年间森勘一大队使用航片调查总面积达1432万hm~2、森勘二大队调查1211万hm~2;营林调查队1959～1962年使用航片调查设计达128万hm~2。使用航片节省劳力提高工效,便于野外调查作业和小班区划调绘,不受地形限制以及有利于室内检核调绘质量等优点。放大航片象幅,蒙片调绘,内业航片加密,辐射隔网和透视格网转绘技术可提高航片实用性和精度     

遮荫对紫肉甘薯块根鲜质量、花色苷含量及产量的影响

以渝苏紫43等3个品种为材料,采用4种遮荫处理,并于栽后不同时间挖根测定块根鲜质量及花色苷含量,研究遮荫对紫肉甘薯块根鲜质量、花色苷含量及产量的影响.结果表明,不同品种栽后153 d,单层遮荫处理使块根鲜质量降低23.33%~76%,块根花色苷含量提高32.72%~49.07%,块根花色苷产量降低32.74%~66.28%;双层遮荫整体上增强了单层遮荫的效果.因此,紫肉甘薯最适宜净作.单层或双层遮荫时,渝苏紫43或渝紫263鲜薯或花色苷产量最高.在麦-玉-苕耕作制度下,以收获鲜薯为目的,渝紫263较适与玉米等作物套作,渝苏紫43次之;以获得花色苷为目的,渝苏紫43较适,渝紫263次之.遮荫处理对块根鲜质量和花色苷含量的影响主要表现在生长前期(栽后1~25 d).     

Factors affecting nutrient digestibility in rainbow trout (Oncorhynchus mykiss) fed a plant protein–based diet supplemented with microbial phytase

Factors influencing apparent digestibility coefficient (ADC) of nutrients from a plant protein–based diet supplemented with microbial phytase were investigated in a series of experiments with rainbow trout (Oncorhynchus mykiss). The influence of phytase level, water temperature, feed particle size and addition of a protease/non‐starch polysaccharidase (PNSP) enzyme cocktail were tested in a phytase‐supplemented (2000 FTU kg^?1) diet. Finally, the influence of Ca/P ratio, addition of 1,25‐hydroxycholeocalciferol, or inclusion of lactic acid (LA) in diets with and without phytase was evaluated. Addition of microbial phytase improved ADC of dry matter (DM), protein, ash and minerals (P, Ca, Mg, Fe and Zn) (P < 0.05). Reducing feed particle size potentiated the effect of phytase on P and ash ADC, as did the addition of a PNSP enzyme cocktail; the latter also significantly improved DM ADC in both control and phytase‐supplemented diets. Increasing the Ca/P ratio reduced the effect of phytase on P and ash ADC. Addition of 1,25‐dihydroxycholecalciferol and LA had no effect on DM, P and ash ADC in control diets and tended to reduce the phytase‐induced increase in P ADC.     

Proteolytic properties of Funastrum clausum latex

As part of a screening of latex endopeptidases from plants growing in Argentina, the presence of proteolytic activity in the latex of Funastrum clausum stems is reported. The proteases present in the crude extract showed the main characteristics of the cysteine proteolytic class, i.e. optimum pH at alkaline range, isoelectric point (pI) higher than 9.0, and inhibition of proteolytic activity by thiol blocking reagents. A remarkable thermal stability was also evident in the crude extract. Endosterolytic preference tried on p-nitrophenyl esters of N-alpha-carbobenzoxy-L-amino acids was higher for the alanine, asparagine and tyrosine derivatives. Preliminary peptidase purification by two-step ionic exchange showed the presence of two proteolytic fractions with molecular masses of approximately 24.0 kDa according to SDS-PAGE.     

大比例尺地面数字化测图初试

大比例尺地面数字化测图是一种高效率的作业方式,它可在传统测量方式基础上提高效率几倍甚至几十倍。其基本硬件配置包括全站仪、电子记录手簿、计算机及数字绘图仪等。软件包括野外电子记录手簿和计算机自动仪成图系统。     

Central and peripheral β-adrenergic influences on reticulo-rumen and upper-gut myoelectrical activity in sheep

The effects of intravenous (i.v.) and intracerebroventricular (i.c.v.) administration of beta-adrenoceptor agonists were evaluated on the reticulo-rumen and upper-gut myoelectrical activity in six ewes chronically fitted with intraparietal electrodes and a cannula in a lateral ventricle of the brain. Intravenous infusion of the beta 1 agonist dobutamine (30 micrograms/kg/min for 15 min) reduced the frequency of reticulo-ruminal and abomasal contractions and stimulated duodeno-jejunal motility, inducing a Phase III on the jejunum. These effects were reproduced by i.c.v. dobutamine at a dose of 10 micrograms/kg. Intravenous infusion of the beta 2 agonist ritodrine (15 micrograms/kg/min for 15 min) selectively inhibited antral and duodenal motility. Ritodrine i.c.v. (15 micrograms/kg) did not affect forestomach or gastrointestinal motility. The mixed beta 1, beta 2 agonist isoprenaline infused i.v. (0.6 micrograms/kg/min for 15 min) reproduced the effects of i.v. dobutamine, except at the antro-duodenal level which was strongly inhibited. The effects of i.v. dobutamine were antagonized by i.v. or i.c.v. acebutolol, a specific beta 1 antagonist. The effects of i.v. ritodrine were blocked by i.v. but not i.c.v. administration of propranolol, a mixed beta 1, beta 2 antagonist. These data indicate that the stimulation of central beta 1 adrenoceptors inhibits forestomach and antral motility and stimulates duodeno-jejunal motility. Stimulation of peripheral beta 2 adrenoceptors selectively inhibits duodeno-jejunal motility.     

Gastro-intestinal motor disturbances induced by lysine-acetylsalicylate treatment in sheep

The effects of intravenous (i.v.), intramuscular (i.m.) and oral administration of lysine-acetylsalicylate (Lys-ASA) on gastro-intestinal motility were investigated in sheep using electromyography. A dose of 20 mg/kg Lys-ASA intravenously reduced the frequency of reticular contractions for 86 ± 18 min, produced abomasal hypomotility and caused a disruption of the cyclical pattern of intestinal motility for at least 120 min. The frequency of reticular contractions measured from 20 to 30 min after Lys-ASA administration was negatively correlated (ß= 0.97; PΔ0.01) to the log of the dose used for doses varying from 10 to 40 mg/kg. Similar effects were observed with intramuscular and oral dose rates of 40 and 80 mg/kg, respectively. Previous i.v. administration of phentolamine (0.1 mg/kg) or tolazoline (2 mg/kg) abolished the effects of Lys-ASA (20 mg/kg) administered intravenously on both reticular contractions and abomaso-intestinal motility.
It was concluded that Lys-ASA administered at therapeutic doses in sheep produced gastro-intestinal motor disturbances and that α-and α₂-adrenergic antagonists are able to block them.