饲料代谢能水平对农大3号小型蛋鸡生产性能的影响

180只140日龄的农大3号小型蛋鸡随机平均分为A、B、C、D、E五组，每组6个重复，每个重复6只鸡，体重大小基本一致，各组间生产性能差异不显著。分别饲喂代谢能水平11．5MJ／kg、11．3MJ／kg、11．1MJ／kg、10．9MJ／kg和10．7MJ／kg的饲料，其他营养成分含量设计上保持一致。通过30周的观察，发现在产蛋高峰前饲喂稍低能值的饲料(10．9MJ／kg)有利于采食量的增加和产蛋率的迅速上升。在一定饲料代谢能值范围内，饲料能值的高低对小型蛋鸡采食量影响不显著，所以从产蛋高峰期开始，必须使用代谢能水平较高的日粮，才能满足小型蛋鸡维持高产蛋率对能量的需求。综合来看，饲料代谢能为11．3MJ／kg时，小型蛋鸡有较高的产蛋量和饲料报酬。     

林地平菇栽培技术

林地平菇栽培投资少,见效快,技术简单,方便易行。一般可利用林地总面积的25%左右,每亩林地每年可增加纯收入1200元以上,同时对改良土壤、提高土壤肥力、加速林木生长具有明显的促进作用。自1985年以来,我们进行了平菇林地栽培研究,经小区试验和大面积推广,均取得了很好的效果,生物效率达80%以上,现将栽培技术简介如下:     

MRCKα is a novel regulator of prolactin-induced lactogenesis in bovine mammary epithelial cells

Myotonic dystrophy-related Cdc42-binding kinase alpha(MRCKα) is an integral component of signaling pathways controlling vital cellular processes, including cytoskeletal reorganization, cell proliferation and cell survival. In this study, we investigated the physiological role of MRCKα in milk protein and fat production in dairy cows, which requires a dynamic and strict organization of the cytoskeletal network in bovine mammary epithelial cells(BMEC). Within a selection of 9 Holstein cows, we fou...     

Integrating remotely sensed water stress factor with a crop growth model for winter wheat yield estimation in the North China Plain during 2008–2018

Accurate estimation of regional-scale crop yield under drought conditions allows farmers and agricultural agencies to make well-informed decisions and guide agronomic management. However, few studies have focused on using the crop model data assimilation(CMDA) method for regional-scale winter wheat yield estimation under drought stress and partial-irrigation conditions. In this study, we developed a CMDA framework to integrate remotely sensed water stress factor(MOD16 ET PET^-1) with t...     

苹果园除(控)草节本增效技术示范

<正>为进一步加快陕西岐山县果业转型升级,加强农业科技园区示范引领作用,更好地开创现代农业种植模式,带动周边农户引进新技术,利用现代化设备促进农业增效、农民增收,我们进行了苹果园节本增效除(控)草技术研究与示范推广。1示范内容通过在苹果园树盘内铺设黑色防草地布、树行间生草,结合乘座式割草机除草的方式,研     

An 8bp indel in exon 1 of Ghrelin gene associated with chicken growth

Ghrelin, acts as the endogenous ligand for growth hormone secretagogues receptor (GHS-R), is a novel growth hormone (GH) releasing peptide with reported effects on food intake in chickens. In this study, an 8 bp indel polymorphism in exon 1 of the chicken Ghrelin (cGHRL) gene was genotyped in a F(2) designed full-sib population to analyze its associations with chicken growth and carcass traits. Later, mRNA level in the proventriculus was determined by real-time PCR to reveal the expression feature of cGHRL gene. Result showed that this 8 bp indel was significantly associated with body weight at the age of 28 days (BW28) and 56 days (BW56), eviscerated weight (EW) and leg muscle weight (LMW) (P<0.05), highly significantly associated with hatch weight (HW), BW14, 21, 35, 42, 49, 90 and body length (BL), dressed weight (DW), eviscerated weight with giblet (EWG), wing weight (WW), breast muscle weight (BMW) and head and neck weight (HNW) (P<0.01). Meanwhile, A allele (with 'CTAACCTG') was positive for chicken growth as individuals with AA genotype had the highest value of all traits. Analysis on cGhrelin mRNA level revealed that it differed significantly among individuals with three genotypes (P<0.05). Individuals with AB genotype had the highest mRNA level, whereas that of AA had the lowest one. It was concluded that this 8 bp indel of cGHRL gene was significantly associated with most body weight and body composition traits, and negative effect of endogenous Ghrelin on chicken growth were indicated by this study.     

畦灌的分析模型

<正> 一、模型的建立 为了推导这个模型作了如下假定:①入流是恒定的;②畦面是均匀的(即畦面坡度、宽度,综合糙率均不随位置变化;③畦足够宽以致于可以忽略边界效应;④畦面坡度小到Sinα=tgα=Sa且Cosα=1,这里α为畦面与水平面的夹角。