Multimarker and rare variants genomewide association studies for bone weight in Simmental cattle

Bone weight, defined as the total weight of the bones in all the forequarter and hindquarter joints, can reflect somebody conformation traits and skeletal diseases. To gain a better understanding of the genetic determinants of bone weight, we used a composite strategy including multimarker and rare‐marker association to perform genomewide association studies (GWAS) for that character in Simmental cattle. Our strategy consisted of three models: (i) A traditional linear mixed model (LMM) was applied (Q+K‐LMM); (ii) single nucleotide polymorphisms (SNPs) with p‐values less than .05 from the LMM were selected to undergo the least absolute shrinkage and selector operator (Lasso) in the second stage (LMM‐Lasso); (iii) genes containing two or more rare SNPs were examined by performing the sequence kernel association test (gene‐based SKAT). A total of 1,225 cattle were genotyped with an Illumina BovineHD BeadChip containing 770,000 SNPs. After the quality‐control procedures, 1,217 individuals with 608,696 common SNPs and 105,787 rare SNPs (with 0.001 < minor allele frequency [MAF] <0.05) remained in the sample for analysis. A traditional LMM successfully mapped three genes associated with bone weight, while LMM‐Lasso identified nine genes, which included all genes found by traditional LMM. Only a single gene, EPHB3, surpassed the significance threshold after Bonferroni correction in gene‐based SKAT. In conclusion, based on functional annotation and results from previous endeavours, we believe that LCORL, RIMS2, LAP3, PRKAR2B, CHSY1, MAP2K6 and EPHB3 are candidate genes for bone weight. In general, such a comprehensive strategy for GWAS may be useful for researchers seeking to probe the full genetic architecture underlying economic traits in livestock.     

补饲水平对甘肃高山细毛羊生产性能的影响

为了探讨补饲水平对高寒牧区甘肃高山细毛羊生产性能的影响,本研究选择12月龄甘肃高山细毛后备母羊48只,随机分为补饲Ⅰ组(颗粒饲料)、Ⅱ组[玉米(Zea mays)和苜蓿(Medicago sativa)干草]、Ⅲ组[玉米、苜蓿干草和燕麦(Avena sativa)干草]和对照组(不补饲),进行冬春季"放牧"+"补饲"试验,比较了后备母羊体重,剪毛量,毛纤维长度、细度、白度、强度和伸度等物理指标。结果表明,试验Ⅰ组、Ⅱ组和Ⅲ组试验羊平均日增重分别比对照组高148.29%、133.09%、96.76%;剪毛量各组之间差异不显著(P0.05);自然长度和伸直长度对照组均极显著低于Ⅰ、Ⅱ、Ⅲ组(P0.01),且自然长度Ⅰ组极显著高于Ⅱ组和Ⅲ组(P0.01),伸直长度Ⅲ组极显著低于Ⅰ组和Ⅱ组(P0.01),Ⅱ组显著高于Ⅰ组(P0.05);细度(直径)Ⅰ组最大,Ⅰ组极显著高于对照组(P0.01),且显著高于Ⅱ组(P0.05);白度Ⅰ组最高,Ⅰ组显著高于对照组(P0.05),其他各组之间均差异不显著(P0.05);强度和伸度补饲组均极显著高于对照组(P0.01),且强度Ⅰ组极显著高于Ⅱ组(P0.01),伸度Ⅰ组显著高于Ⅱ组(P0.05)。由此可见,补饲对体重、羊毛品质都有显著正向影响,高寒牧区冬春季节牧草营养缺乏,为了满足羊只营养需要,使甘肃高山细毛羊后备母羊能在1.5岁进行配种繁殖,在冷季放牧的基础上补饲1号料为最佳选择。     

紫花苜蓿细胞质雄性不育恢复基因的初步定位

以紫花苜蓿(Medicago sativa)不育系MS-GN-1A为母本,恢复系MS178为父本组合构建BSA分离群体,获得的F1代均表现为雄性可育,在大田种植了221株F2代群体单株,盛花期将花粉颗粒染色后,显微镜下观察统计出,不育的F2代株数为57,可育F2代株数164,并没有观察到半不育植株。将所有植株划分为可育和不育两组,并构建可育和不育DNA混池,混池DNA从可育和不育植株组DNA中各随机抽取20个样品,以此对恢复基因定位。随机挑选160对已知的四倍体苜蓿SSR引物扩增基因池DNA,获得2个具有多态性的分子标记,分别是Mt2c12、AW166,初步定位Rf基因在类群Composite5上。将类群Composite5上的所有引物进行合成,进一步进行引物筛选,最终获得4个具有多态性的标记BI68、Mt2c12、BG267和AW776153,遗传距离分别为19.0、20.9、44.6和72.1cM。     

藜麦不同生育期营养物质积累与分配规律

为探究藜麦(Chenopodium quinoa)生育期营养物质积累与分配动态规律,促进藜麦营养资源高效开发利用,本研究以"陇藜1号"为研究材料,通过田间试验,研究苗期、开花期、灌浆期和成熟期茎秆、籽粒、叶片、果穗以及全株粗蛋白含量(CP)、粗脂肪(EE)、磷(P)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量变化及转运差异,并对不同时期饲用品质进行比较,为藜麦生长期间营养价值研究提供参考。结果表明,单株干物质积累量呈先慢后快再慢的积累规律;果穗及籽粒中干物质含量(DM)最大值分别出现在灌浆期和成熟期,不同生育期各器官生物产量及营养价值差异显著(P0.05),叶片干物质的移动率最高,干物质输出率最大,转运率最高,根系干物质移动率和转运率最低;DM、NDF、ADF和P在生育期内均表现出先降低后上升的变化过程。整个生育时期内各器官营养物质转运率大小表现为叶片果穗茎秆根系,各生育时期不同器官间营养成分转运差异较大,总体表现为成熟期开花期灌浆期苗期,相对饲用价值苗期灌浆期开花期成熟期。     

Impact of cold-season grazing and supplementary feeding on rumen metabolic parameters and micro-organisms in the ewes of Gansu Alpine Fine Wool Sheep北大核心CSCD

An experiment was conducted to scientifically identify the appropriate feed for Gansu Alpine Fine Wool ewes in order to change the animals' breeding mode, which currently can only be mated at the age of 2.5 years due to insufficient nutritional supply. The experiment selected 48 12-month-old ewes and randomly divided them into group a (Diet 1), group b (Diet 2), group c (Diet 3), and a control group with no supplementary feeding. The feed test was run for 90 days. The rumen pH of groups a and b were very significantly higher (P<0.01) or group c significantly lower (P<0.05) than control group. The rumen ammonia nitrogen, protein nitrogen and total nitrogen of groups a, b and c were all higher than control group (P<0.01). The total volatile fatty acids of group a and b were all higher than the control group (P<0.01), group b significantly higher than group c (P<0.05). The molar ratio of acetic acid and propionic acid in group a was very significantly higher than control group (P<0.01), group b and c were significantly higher than control group (P<0.05). The molar ratio of butyric acid in group a was very significantly higher than group c (P<0.01). The ratio of acetic acid and propionic acid in group b was significantly lower than control group (P<0.05). The number of several rumen fiber-degrading bacteria and protozoa in groups a, b and c were very significantly (P<0.01) or significantly (P<0.05) higher than the control. In conclusion, this study shows that supplementary feeding can positively affect the rumen metabolic parameters and the number of several rumen microorganisms in Gansu Alpine Fine Wool ewes. In general, the effects of Diet 1 were the strongest, while Diet 2 also produced notable improvements. © 2018, Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

湖南省某生猪批发市场疫病传播风险评估

为评估湖南省某生猪批发市场猪群疫病的发生风险,找出可能的风险因素,便于提出针对性预防措施,采用自行设计的调查问卷,结合访谈和现场调查,对27户经营户进行了调查,并将调查结果和调运数据相结合进行了疫病传播风险定性评估。结果显示:该市场疫病传入的可能性"高",内部传播的可能性"中等",疫病传出的可能性"高"。生猪调运频次多、数量大,经纪人行为复杂,运输车辆清洗消毒不彻底是可能的风险因素。评估结果提示,应尽量减少经纪人行为影响,重点加强对运输车辆的清洗消毒。     

基于生态足迹模型的西北干旱绿洲农业区可持续发展评价——以张掖市为例

利用生态足迹和生态承载力的理论和方法,以西北干旱绿洲农业区城市张掖为例,对其可持续发展状况及程度进行了评价和度量。结果表明：张掖市2009年人均生态足迹为3.798hm2,人均承载力为1.453hm2,人均生态赤字为2.345hm2。在此基础上,对张掖市的生态可持续发展进行了评价,并提出解决对策。     

安化黑毛茶加工现状与机械化发展趋势

本文结合安化黑毛茶初制加工现状及发展黑茶机械化生产的必要性,指出黑茶渥堆机的设计重点及难点,以期达到渥堆过程的量化控制,实现机械化生产,使黑茶生产的环境条件及加工流程符合现代化茶叶加工的要求。     

Copper‐Induced Oxidative Stress and Responses of the Antioxidant System in Roots of Medicago sativa

The effects of various copper (Cu) concentrations on the antioxidative system in the roots of Medicago sativa were explored. The results indicated that the Cu content of the roots reached a value of 854 μg g^?1 DW at 10 μm Cu and a value of 4415 μg g^?1 DW at 100 μm Cu, suggesting that M. sativa has better ability to tolerate and accumulate Cu than other Cu‐bioaccumulators, and is a potential plant for phytoremediation. Treatment with Cu resulted in a significant increment in the levels of H₂O₂, O₂˙^? and OH˙. The reduced form of ascorbate and glutathione reached a peak at 30 μm Cu, and was followed by a sharp depletion to a lower level than that of the control. In contrast, the levels of the oxidised forms of ascorbate and glutathione showed a progressive increment with increasing Cu concentrations, suggesting that the antioxidant system was unable to cope with Cu stress at higher Cu levels. Under the Cu concentrations tested, the activity of catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) increased at lower Cu concentrations, and then decreased, reaching a maximum at 30 μm of Cu for APX and GR, at 10 μm for CAT, whereas the activities of guaiacol peroxidase (POD, EC 1.11.1.7) were gradually increased with increasing Cu concentrations. PAGE analysis of superoxide dismutase (SOD, EC 1.1.5.1.1) revealed that one band is a Mn‐SOD and five bands are identified as Cu, Zn‐SOD, whereas Fe‐SOD isoforms were not found in the roots of alfalfa. Cu at 10–100 μm increased the intensity of constitutive isozymes of CAT, APX and POD, whereas it decreased the intensity of isozymes of glucose‐6‐phosphate dehydrogenase (G6PDH, EC 1.1.1.49) significantly. The activities of lipoxygenases (LOX, EC 1.13.11.12) were gradually augmented with increasing Cu concentrations, demonstrating that LOXs are probably involved in production of lipid hydroperoxides and superoxide anion. There was a continuous and pronounced enhancement in the activity of esterase (EST, EC 3.1.1.1) in roots treated with 10–30 Cu μm , whereas EST activity in roots exposed to above 30 μm Cu declined, suggesting that EST plays a protective role under lower Cu concentrations stress.     

NaCl胁迫对沙葱苗期根系特征及无机离子含量的影响

【目的】研究NaCl胁迫对沙葱苗期根系形态特征及无机离子含量的影响,分析沙葱的耐盐强度,以提高沙葱在盐碱地上的生产能力,为盐碱地的开发利用提供参考。【方法】以沙葱幼苗为材料,采用盆栽法,经不同浓度(0(对照,CK),25,50,75,100,150 mmol/L) NaCl胁迫15 d后,研究沙葱根系干质量、鲜质量、长度、表面积、体积、活力和无机离子(K~+、Na~+、Ca~(2+)、Mg~(2+))含量的变化。【结果】随着NaCl浓度的增加,沙葱根系干、鲜质量和根系活力均呈降低趋势;而根系长度、表面积、体积均呈先增加后下降的趋势,当NaCl浓度为50 mmol/L时均达最大值。在不同浓度NaCl胁迫处理下,沙葱幼苗根系中Na~+、K~+含量均较对照增加,且当NaCl浓度为150 mmol/L时Na~+、K~+含量较高;但幼苗根系中Ca~(2+)、Mg~(2+)含量均较对照下降。【结论】适宜沙葱幼苗根系生长的NaCl浓度为25～50 mmol/L,此时根系生长良好,Ca~(2+)、Mg~(2+)含量无明显降低。