国内外肉牛分子标记辅助育种的研究进展

分子标记辅助育种(Marker assisted selection,MAS),直接从DNA分子水平上反映种间差异,不受环境、发育阶段、组织等的影响,稳定可靠,多态性好,因而在家畜育种中被广泛利用,本文详尽概述了分子标记辅助选择对于遗传力低的性状如肉质性状和屠宰性状等改良效率相关的研究进展。     

我家的三条腿小狗"乐乐"

我的小狗,名叫乐乐,少了一条后腿的乐乐有一双亮亮的眼睛,每每看着它我就忍不住要抱着它,贴着它毛茸茸的耳朵,轻轻地和它聊天。它似乎总能感受到我的疼爱,每天睡觉前,它会利用它完整的一支后腿站在我的床边,等着我扶它上来。清早醒来,它会一直悄悄地等在床边,不知道怎么,它就是能听出来我醒了。咧着小嘴,乐呵呵地用小前爪使劲勾着我,嘴里不时发出它特有的哼哼唧唧的声音跟我撒娇,叫你不忍心对它置之不理。不管什么时候,只要我能看到它,只要它没有睡着,我都可以看见它用那双明亮的眼睛看着我,或者是兴奋的,或者是依恋的,或者是渴望着。每一次我都被感动得将它小心翼翼地抱起,感受着它那双小脚丫紧紧搂着我的脖子时带给我的快乐。     

核桃酸奶加工工艺研究

以牛奶为主要原料,添加适量的核桃碎等辅料,利用保加利亚乳杆菌和嗜热链球菌作为发酵剂,确定对核桃发酵乳的制作工艺条件。通过单因素试验和L9（34）正交试验确定最佳核桃酸奶生产工艺流程及工艺参数为：100mL牛奶和10g/100mL白砂糖→灭菌（63℃,30min）→接入5g/100mL发酵剂→35℃恒温发酵12h→加入5g核桃碎→后发酵24h（5～7℃）。利用此工艺制备的核桃酸奶风味独特、营养价值较高,在0～6℃时的货架期可达10d左右。     

巴比妥类镇静剂的检测研究进展

本文对巴比妥类安眠镇静剂检测方法的研究进展进行了综述。重点讨论了样品前处理方法及各种衍生化方法,GC、GC-MS、HPLC、HPLC-MS等检测方法。     

三江白猪组织基因组提取及RAPD反应条件的优化

本试验从三江白猪组织中提取总DNA,获得较高质量的模板样品。并对RAPD反应的条件进行了优化,提高RAPD分析的可靠性和重复性。确保三江白猪遗传分析的真实性和准确性,为进一步的研究提供参考条件。     

添加甲酸对白花草木樨青贮品质的影响

在收获后经过0、8和30h晾晒的初花期草木樨(干物质含量分别为27.36%、38.69%和44.98%)原料中,加入甲酸(添加量为2.5、4.0和5.5ml/kg)进行青贮。结果表明,添加甲酸能使草木樨青贮料氨态氮含量降低,并保存较多的可溶性糖;添加甲酸4.0ml/kg对三个干物质水平草木樨青贮均有良好效果,但以干物质含量27.36%组效果最好。     

后生元及其在乳制品中的应用研究进展

后生元是近年来出现的一种干预肠道生态系统的新手段.后生元是指由活细菌分泌或细菌裂解后释放的可溶性因子(产物或代谢副产物),如酶、肽、磷壁酸、肽聚糖衍生的多肽、多糖、细胞表面蛋白和有机酸等可调控宿主健康的小分子.尽管目前国际益生菌和益生元科学协会尚未发表关于后生元的共识,但作为与益生菌密切相关的概念依旧引起了人们的关注....     

Energy utilisation in germ-free and conventional chicks fed diets containing sorbose

1. In experiment 1, growing conventional (CV) chicks were fed on diets containing graded amounts (0, 100, 200 and 300 g/kg diet) of sorbose from 4 to 14 d. Protein, fat and energy deposition were determined after carcase analysis. The values for growth, food efficiency, metabolisable energy (ME) and fat and energy depositions declined as the dietary sorbose content increased. 2. In experiment 2, the performances of germ-free (GF) and CV chicks fed on diets with (100 g sorbose/kg diet) or without sorbose were investigated. On both diets, body weight gain, food consumption and protein accumulation in GF chicks were significantly higher than those in CV birds. No significant differences were observed between the dietary treatment except for ME values, which were significantly lower for the sorbose diet. 3. It is suggested that dietary sorbose decreased energy utilisation, and that the microbial contribution to the utilisation of dietary sorbose was negligible in the chicken.     

Effect of short chain fatty acids on the performance and intestinal weight in germ-free and conventional chicks

1. In experiment 1, the performance and tissue weights of germ-free (GF) and conventional (CV) chicks fed on diets containing 25.4 g acetic acid/kg diet (AD) or 25.4 g kaolin/kg diet (KD) were investigated. Body weight gain in GF chicks was significantly higher on the AD, but significantly lower on the KD compared with their CV counterparts. The values for food efficiency, protein retention and energy retention followed a similar pattern to that of the body weight gain. 2. The weights of all sections of the intestine except the colon were significantly greater in CV chicks. In CV but not in GF birds the jejunum and ileum were heavier from birds fed on the AD than from those on the KD diet. 3. In experiment 2, the influence of butyric acid administration on the weight of some organs in chicks was investigated. The weight of duodenum, jejunum and ileum was significantly increased by intraperitoneal administration of butyric acid (2 ml of 100 mM solution/d) for 4 d, but no significant effect was observed by oral administration. 4. It might be suggested that short chain fatty acids such as acetic and butyric acids formed by bacterial action in the crop and subsequently absorbed are at least partly responsible for the heavier gut weight in CV birds.