猪基因组结构变异研究进展

结构变异（structural variation,SV）广泛分布在基因组中,并主要以缺失、插入、重复、倒位和易位的形式出现。SV可以通过不同的机制直接或间接影响基因剂量,从而导致畜禽的表型变异,甚至引起疾病。随着分子生物学的发展和新基因组技术的进步,SV在猪基因组的研究越来越多,主要包括繁殖性状、肉质性状、生长性状、毛色、疾病等。本文参考了国内外相关报道,对SV的定义、分类、形成机制、检测方法以及在猪基因组的研究进展进行综述,并对目前SV研究存在的问题提出了建议以及未来的研究趋势进行了展望。     

施氮量对不同水稻品种氮肥利用率与农艺性状的影响

为探明施氮量对不同水稻品种产量、氮肥利用率和农艺性状的影响,以适合江苏省种植的12个中粳稻（含籼/粳杂交稻）品种为材料,大田种植,设置0N（全生育期不施氮）、200N（全生育期施纯氮200kg/hm ²）和360N（全生育期施纯氮360kg/hm²）3个施氮量处理,研究各品种产量、氮肥利用率和一些农艺性状的差异。结果表明：甬优2640在3个施氮水平产量均最高,库容量大是其高产的主要原因。其他品种产量对氮肥响应的表现不一。在较低氮（0N、200N）条件下,淮稻13号和武运粳30的产量较高,宁粳1号和扬粳4038的产量较低。在高氮（360N）条件下,宁粳1号和扬粳4038产量较高。在较低施氮量条件下,产量和氮肥利用率较高的品种具有较高的干物质积累量、茎蘖成穗率、叶面积指数、粒叶比及群体生长速率,这些指标可作为筛选氮高效品种的农艺性状指标。     

牛组织蛋白D基因多态性与肉质、胴体性状的关联分析

以51头西门塔尔和鲁西黄牛的杂交后代作为试验动物,扩增组织蛋白酶D(cathepsin D,CTSD)基因部分外显子,通过DNA测序方法检测到该基因第5、6、8外显子共4个SNPs(T581C、T599C、A861T、A1128G)的遗传变异。SAS软件采用最小二乘法拟合线性模型,将几个位点的不同基因型与牛肉质、胴体性状进行关联分析。结果表明,位于CTSD基因外显子5的T581C突变与大理石纹性状呈显著相关(P<0.05),BB基因型显著优于AA和AB基因型,这为T581C作为肉牛大理石纹的分子标记提供了一定的理论依据。     

奶牛乳质性状相关基因及其单核苷酸多态性的研究进展

乳质性状为奶牛重要的经济性状,主要包括乳蛋白量、乳蛋白率、乳脂量和乳脂率等。乳质性状改良是当今遗传育种界的研究热点之一,利用候选基因策略寻找影响乳质性状的功能基因或功能性单核苷酸多态,并将其应用于奶牛乳质性状的分子育种实践已经成为后基因组时代的发展趋势。目前针对乳质性状的功能基因或功能性单核苷酸多态已经开展了大量的研究工作,作者就参与泌乳调控的乳质相关基因、脂肪合成与次生物质代谢通路,以及其他一些与乳质性状相关基因及功能性单核苷酸的研究现状进行简要综述。     

桑白毛虫生物学特性研究

桑白毛虫在重庆市一年发生2代,越冬后的蛹在5月中旬进入羽化期.第1代桑白毛虫各虫态历期:卵期3.9天,幼虫期21.2天(25.99℃),蛹期61.5天,成虫寿命5~7天;幼虫发生盛期在5月中旬~6月中旬,每头幼虫全龄食桑量9234.73mg,经6个龄期而化蛹;成虫羽化盛期在8月下旬~9月上旬,每雌平均产卵量447粒,雌:雄=1:1.48.第2代桑白毛虫幼虫发生期从8月下旬开始至11月底结束,盛期在10月中旬~11月中旬,幼虫全龄经过46.22天(17.48℃),幼虫食桑量与第1代相近似,化蛹期集中在气温较低(15℃~16℃)的11月份.     

不同种植密度对早熟玉米‘晋单84号’产量及品质的影响

为了研究不同种植密度条件对早熟玉米‘晋单84号’生长性状及品质的影响,以玉米品种‘晋单84号’为试验材料,在4.5万株/hm²、5.25万株/hm²、6万株/hm²、6.75万株/hm²、7.5万株/hm² 5个不同种植密度条件下,研究‘晋单84号’的农艺性状表现、产量及籽粒品质的变化规律。结果表明：‘晋单84号’的产量随着种植密度的增加呈先增加后减少的趋势,在密度6.75万株/hm²时最高,为12825.8 kg/hm²;籽粒品质蛋白质含量随密度增大表现为逐渐下降的趋势;粗脂肪含量表现为与密度负相关的变化趋势;粗淀粉含量在6.75万株/hm²密度下达到最高73.4%。以上试验研究为确定‘晋单84号’在山西中部地区最适宜密度及高产栽培提供科学依据。     

发酵油茶饼粕饲喂荷斯坦牛的试验研究

试验采用发酵油茶饼粕代替部分豆粕饲喂泌乳期荷斯坦牛,旨在研究其对奶牛产奶量、乳品质和血液生化指标的影响。试验选取16头泌乳天数相近的荷斯坦牛,采用配对分组设计4个处理组：对照组饲喂基础日粮,试验组分别在基础日粮的精料中,用发酵油茶饼粕分别代替15％、30％和45％的豆粕。试验结果表明,发酵油茶饼粕代替部分豆粕饲喂泌乳期荷斯坦牛,对其产奶量、乳蛋白和乳脂率有一定的提升作用．且发酵油茶饼粕价格相对于豆粕有很大的优势;采用发酵油茶饼粕饲喂荷斯坦牛,能够有效降低饲养成本,值得推广应用。     

Beneficial impacts of bee pollen in animal production,reproduction and health

Bee pollen (BP) is one of the most useful therapeutic products favoured by natural medicine scientists because of its possible nutritional and medical applications. It exhibits many impacts such as antimicrobial, immunostimulating, antioxidants and hepatoprotective. Furthermore, BP has some useful therapeutic features in numerous pathological situations such as its impact to normalize wound healing. Based on previous literatures, the level of BP supplement in livestock and poultry ranged from 0.1 to 20 g/kg diet. This variation depends on the species, physiological status, age and purpose of addition; so far generally, it accepted to use the level with no side effects. It has been observed that BP enhanced growth performance, immunity responses and blood variables and had hypoglycaemic activity by reducing the lipid in the blood and carcass. Also, BP contains more nutrients, which stimulate faster differentiation and proliferation of the cells of immune system of birds. Therefore, the present review recommends that BP supplementation (up to 20 g/kg diet) had possible beneficial impacts, antioxidants and protective activities on most of the production, productive and health patterns of livestock.     

Whole genome sequence analysis to detect signatures of positive selection for high fecundity in sheep

Ovulation rate and prolificacy are the most important reproductive traits that have major impact on the efficiency of lamb meat production. Here, we compared the whole genomes of the Romanov sheep, known as one of the high prolific breeds, and four other sheep breeds namely Assaf, Awassi, Cambridge and British du cher, to identify genetic mechanisms underlying prolificacy in sheep. Selection signature analysis revealed 637 and 477 protein‐coding genes under positive selection from F_ST and nucleotide diversity (Pi) statistics, respectively. Further analysis showed that several candidate genes including LEPR, PDGFRL and KLF5 genes are involved in sheep prolificacy. The identified candidate genes in the selected regions are novel and provide new insights into the genetic mechanisms underlying prolificacy in sheep and can be useful in sheep breeding programmes to develop improved breeds for high reproductive efficiency.     

Genetic parameters for semen production traits in Swiss dairy bulls

Variance components (VC) were estimated for the semen production trait ejaculate volume, sperm concentration and sperm motility in the Swiss cattle breeds Brown Swiss (BS), Original Braunvieh (OB), Holstein (HO), Red‐Factor‐Carrier (RF), Red Holstein (RH), Swiss Fleckvieh (SF) and Simmental (SI). For this purpose, semen production traits from 2,617 bulls with 124,492 records were used. The data were collected in the years 2000–2012. The model for genetic parameter estimation across all breeds included the fixed effects age of bull at collection, year of collection, month of collection, number of collection per bull and day, interval between consecutive collections, semen collector, bull breed as well as a random additive genetic component and a permanent environmental effect. The same model without a fixed breed effect was used to estimate VC and repeatabilities separately for each of the breeds BS, HO, RH, SF and SI. Estimated heritabilities across all breeds were 0.42, 0.25 and 0.09 for ejaculate volume, sperm concentration and sperm motility, respectively. Different heritabilities were estimated for ejaculate volume (0.42; 0.45; 0.49; 0.40; 0.10), sperm concentration (0.34; 0.30; 0.20; 0.07; 0.23) and number of semen portions (0.18; 0.30; 0.04; 0.14; 0.04) in BS, HO, RH, SF and SI breed, respectively. The phenotypic and genetic correlations across all breeds between ejaculate volume and sperm concentration were negative (?0.28; ?0.56). The other correlations across all breeds were positive. The phenotypic and genetic correlations were 0.01 and 0.19 between sperm motility and ejaculate volume, respectively. Between sperm motility and sperm concentration, the phenotypic and genetic correlations were 0.20 and 0.36, respectively. The results are consistent with other analyses and show that genetic improvement through selection is possible in bull semen production traits.