The effects of feeding medium-chain triglycerides on the growth, insulin responsiveness, and body composition of Holstein calves from birth to 85 kg of body weight

The objective of this study was to determine the effects of feeding calves isocaloric, isonitrogenous diets that varied in the amount and type of fatty acids on growth, response to an insulin challenge, and body composition. Thirty-six calves were assigned to a randomized block design with 3 dietary treatments, 10 calves per treatment, and a baseline group of 6 calves. Three different milk-replacer-based diets were designed to deliver less than 2% of the lipid as medium-chain triglycerides (control; diet contained no added medium-chain triglycerides), 32% medium-chain triglycerides primarily as caprylate (CAP oil), and 32% of fatty acids primarily as laurate from coconut oil (CCO). Calves were offered 0.28 Mcal of intake energy/kg of body weight (BW)^0.75 from d 1 to 7 and 0.32 Mcal of intake energy/kg of BW^0.75 adjusted weekly for BW from d 8 to harvest. Dry matter, intake energy, crude protein, and fat intakes were 53.7 kg, 281.8 Mcal, 14.6 kg, and 13.0 kg; 56.6 kg, 297.2 Mcal, 15.8 kg, and 14.2 kg; and 53.8 kg, 280.4 Mcal, 15.4 kg, and 13.3 kg for the control, CAP oil, and CCO treatments, respectively. Dry matter, energy, protein, and fat intakes did not differ among treatments. At approximately 65 kg of BW, 5 calves per treatment were given an insulin challenge. After the challenge the decrease in plasma glucose concentration was greater for the calves fed the CAP oil diet compared with those fed the control and CCO diets. Calves were harvested at approximately 88 kg of BW. Empty body gains were 0.92, 0.79, and 0.87 kg/d for control-, CAP oil-, and CCO-fed calves, respectively, and the gains of the CAP oil-fed calves were less than those of the control-fed calves. Empty body crude protein, ash, and water were not different among treatments. Empty body retained energy and fat tended to be 5.6 and 8.7% greater for calves consuming the CCO diet than for those fed the control diet. The livers of calves consuming the CCO diet were 330 g heavier and contained 15% more fat than the livers of the control and CAP oil calves. The results of this study demonstrate that the energy demand of the calf to maintain body temperature resulted in increased oxidation of intake energy; thus, overall body composition differences could not be detected. However, the intake of CCO increased the accumulation of lipid in the liver and carcass despite the apparent cold stress conditions.     

Relationships between milk protein composition, milk protein variants, and cow fertility traits in Dutch Holstein-Friesian cattle

Selective breeding can change milk protein composition to improve the manufacturing properties of milk. However, the effects of such breeding strategies on other economically important traits should be investigated before implementation. The objectives of this study were to examine the association between cow fertility traits and (1) milk protein composition and (2) milk protein variants (β-lactoglobulin, β-casein, κ-casein, and β-κ-casein) in commercial Dutch Holstein-Friesian cattle. Data on 1,644 first-lactation cows were analyzed by fitting linear mixed models. Greater relative concentration of α_S1-casein within total milk protein had a positive phenotypic relationship with nonreturn rates and calving rate after first insemination. Furthermore, results showed virtually no significant relationship between cow fertility and concentration of other milk proteins or milk protein variants. Results of this study can be used to assess the correlated effects of breeding for improved milk protein composition on reproduction, thereby allowing for better evaluation of breeding programs before implementation. Our findings suggest that selecting cows based on milk protein composition or milk protein variants for improved manufacturing properties would have no negative influence on reproductive performance.     

废蜜的化学组成与生物制氢

利用甜菜制糖废蜜、废水作为底物进行连续流生物制氢，既可回收废物又能生产能源。着重阐述了甜菜废蜜中的主要成分及其在生物制氢反应中对微生物的作用。     

烹调油烟的组成与危害及防治措施

烹调油烟是厨房内的主要污染物。主要阐述了烹调油烟的形成、形态组成、主要成分以及对人体可能造成的危害,并对近年来防治烹调油烟对人体危害方面所做的研究进行了报道,其目的是提醒人们应重视烹调油烟对人体的危害,采取必要预防措施减少烹调油烟给人体造成的伤害。     

甘薯叶片可溶性蛋白提取方法探索及其成分分析

探索了甘著叶片可溶性蛋白质的浸提方法,确定了蛋白质的沉淀方法,并分析了叶片可溶性蛋白粉中粗蛋白含量、粗纤维、粗脂肪和蛋白质中的氨基酸组成。结果表明,甘薯叶片主要含有一种分子量为53000Da的可溶性蛋白质,用pH为6．5～7．5的1％亚硫酸氢钠溶液浸提甘薯叶片粉末可较好地提取甘薯叶片中的可溶性蛋白质。经浸提、沉淀、透析、冻干处理获得的台农叶片蛋白粉中含有62．6％粗蛋白、0．18％粗纤维和0．51％粗脂肪。台农叶片可溶性蛋白质含有各种人体所需要的氨基酸,主要氨基酸是赖氨酸(99．88mg/g蛋白质)、亮氨酸(12026mg/g蛋白质)和天门冬氨酸(140 74mg/g蛋白质),并且必需氨基酸含量高于非必需氨基酸的含量,其比值为1．04,第一限制性氨基酸为色氨酸,氨基酸分数为75．9。     

大豆胚芽油的提取及组成分析

以大豆胚芽出油率为指标,石油醚为脱脂溶剂,通过单因素和正交试验对大豆胚芽索氏提取工艺进行了研究,并用气相色谱对胚芽油的脂肪酸组成进行了分析。结果表明,大豆胚芽制油的最佳提取工艺为:粒度30目、料液比1:12、回流时间5h,在此条件下,大豆胚芽出油率为10.50%,其主要组成为亚麻酸20.73%、亚油酸52.21%、油酸10.51%、棕榈酸为13.47%。     

南瓜粉的营养价值评价

了解本地区南瓜粉的营养价值。按国标等方法进行检测。结果表明,南瓜粉营养丰富,每100g南瓜粉中含脂肪2.50g、膳食纤维19.03g、VE3.14mg、胡萝卜素0.63mg、钠9.9mg、钾1763mg、钙311mg,为低脂、低钠、高膳食纤维、高VE、高胡萝卜素、高钾、高钙食品。可见南瓜粉含人体所需多种元素和氨基酸,是心脑血管病、糖尿病患者和老年人理想的健康食品,值得开发利用。     

单元水溶性助留剂用于生产新闻纸的试验

本文对比广纸PM8纸机使用三元助留系统和单元助留系统的生产情况，并详细分析成纸质量变化。     

具有特殊结构的微泡沫钻井液技术综述

近来开发出一种新的钻井液工艺--具有独特结构的微泡沫基钻井液,用它在世界范围内几百口井中顺利完成了枯竭储层的钻进.该钻井液的主要特点是,密度低,微泡沫具有架桥作用,基液粘度特别高,所以在钻低压地层时能很好地控制滤失量.微泡沫钻井液主要由增粘生物聚合物、表面活性剂和滤失控制剂组成,基液具有很高的低剪切速率粘度,通过在混合漏斗中采取合适的操作,表面活性剂将体系中的空气包裹起来即产生了微泡沫,钻井液从钻头喷射出时由于压力的降低也可能产生微泡沫,所以使用微泡沫钻井液不需要井场添加注入气体用到的设备.微泡沫具有特殊的结构,不会聚结,可循环使用;在井眼条件下能聚集在一起,在孔隙中及微裂缝处形成架桥,减少钻井液的侵入.在现场应用中微泡沫钻井液表现出许多优良性能:微泡沫能起到架桥粒子的作用,在枯竭储层及低压地层的钻进顺利;对粘土和页岩有好的抑制性能;流变性能易于维护,具有优良的井眼清洁能力、岩屑悬浮能力和滤失控制能力;可以连续完成上部地层和储层钻进,减少技术套管的使用;对井下工具无不良影响,可以用于定向井和水平井,不影响电测;井眼规则;完井顺利而且固井质量好;对环境的污染极小.介绍了微泡沫钻井液的室内研究及其现场应用情况.     

地层条件下天然气扩散过程中地球化学组分变化的模拟实验研究

采用固体样品,实验模拟了地层条件下(8MPa,70℃)气藏天然气在扩散过程中的地球化学变化特征。模拟实验结果研究表明:a)随着天然气扩散作用的进行,气藏气中甲烷的相对百分含量逐渐减少,而乙烷和丙烷的相对含量相应地增大;扩散气与气藏气存在类似的组分变化趋势,但扩散气中甲烷的相对百分含量高于同一时间气藏气中甲烷的相对百分含量,而乙烷及丙烷的相对百分含量低于气藏气中乙烷和丙烷的相应值,这些都是地层色层效应的具体体现;b)同一时间气藏气中正丁烷的相对百分含量高于扩散气中正丁烷的相对百分含量,而异丁烷的相对百分含量低于扩散气中异丁烷的相应值,这也是地层色层效应的结果;c)C₁/(C₂+C₃)和iC₄/nC₄可作为天然气运移的地球化学指标;d)气藏气和扩散气组分百分含量与气体扩散比例之间分别存在对数线性相关关系和二次函数相关关系,这种函数关系可为应用模拟实验结果计算气藏扩散量,评价气藏天然气资源前景,探讨天然气在扩散过程中的组分变化以及预测同源不同层天然气藏资源量提供启示。