皮南牛新品种培育现状、存在问题与对策

南阳牛是我国五大良种黄牛品种之一,近些年国家越来越重视通过杂交改良的方法产生新品种培育工作,1986年引进了皮埃蒙特牛,与南阳牛进行杂交改良,通过30多年来的持续选育,横交固定形成了皮南牛新类群,它保持了南阳牛适应性好、耐粗饲的优点,同时继承了皮埃蒙特牛生长发育快、瘦肉率高的特点,但在皮南牛新品种培育过程中,仍存在核心...     

Embryo-mediated genome editing for accelerated genetic improvement of livestock

Selecting beneficial DNA variants is the main goal of animal breeding. However, this process is inherently inefficient because each animal only carries a fraction of all desirable variants. Genome editing technology with its ability to directly introduce beneficial sequence variants offers new opportunities to modernize animal breeding by overcoming this biological limitation and accelerating genetic gains. To realize rapid genetic gain, precise edits need to be introduced into genomically-selected embryos, which minimizes the genetic lag. However, embryo-mediated precision editing by homology-directed repair (HDR) mechanisms is currently an inefficient process that often produces mosaic embryos and greatly limits the numbers of available edited embryos. This review provides a summary of genome editing in bovine embryos and proposes an embryo-mediated accelerated breeding scheme that overcomes the present efficiency limitations of HDR editing in bovine embryos. It integrates embryo-based genomic selection with precise multi-editing and uses embryonic cloning with elite edited blastomeres or embryonic pluripotent stem cells to resolve mosaicism, enable multiplex editing and multiply rare elite genotypes. Such a breeding strategy would enable a more targeted, accelerated approach for livestock improvement that allows stacking of beneficial variants, even including novel traits from outside the breeding population, in the most recent elite genetic background, essentially within a single generation.     

稻草与牛粪混合腐解的最佳配比筛选

【目的】以腐殖质组成特征为评价依据,筛选稻草与牛粪混合腐解的最佳配比,为两类农业固体废弃物的资源化应用提供参考。【方法】以稻草和牛粪为材料,采用室内培养法,研究稻草与牛粪质量比为10∶0(Rs),9∶1(Rd1),7∶3(Rd2),5∶5(Rd3),3∶7(Rd4),1∶9(Rd5)和0∶10(Dm)混合腐解90 d,各处理水溶性物质(WSS)、可提取腐殖酸(HE)、胡敏酸(HA)、胡敏素(Hu)组分的有机碳含量(依次表述为C_(WSS)、C_(HE)、C_(HA)、C_(Hu)),以及胡敏酸碱溶液E_4/E_6、腐殖化系数(C_(HA)/C_(FA))的动态变化,筛选稻草与牛粪腐解的最佳配比。【结果】与0 d相比,在腐解完成(90 d)后,各处理C_(WSS)含量均有不同程度降低,相比于稻草,牛粪腐解后更易促进微生物对C_(WSS)的利用,使其下降86.2%;Rd2和Rd5处理使物料C_(HE)含量分别增加10.2%和28.6%,其余处理C_(HE)均有不同程度消耗;与0 d相比,腐解完成后,Rd1、Rd3和Dm处理均有助于C_(HA)的积累,其中牛粪腐解更易促进C_(HA)的形成,使其增加30.5%。在各处理下,物料HA分子均先发生降解、脂族化,而后逐渐缩合、芳香化,但HA分子结构仍趋于简单;在促进HA分子脂族化方面,Rd4处理的优势最大,而Dm处理更有利于HA结构的稳定。Rd3处理在促进腐殖质品质方面的贡献最大,其次为Rd1处理,Dm和Rs处理次之,但Rd2和Rd5处理不利于腐殖质品质的改善;Rs、Rd1、Rd2、Rd3和Rd4处理在腐解过程中更有利于C_(Hu)的分解,且Rd3处理的优势最大,使C_(Hu)含量下降91.0%,而牛粪比例≥90%更有助于C_(Hu)的累积。【结论】稻草与牛粪按照质量比5∶5混合腐解,易促进C_(Hu)的分解和C_(HA)的积累,利于腐殖质品质提升。     

安格斯牛和南阳牛肌内脂肪组织中差异表达circRNAs分析

【目的】筛选牛肌肉脂肪组织中差异表达的circRNAs,为进一步探索circRNAs在牛肌内脂肪沉积和代谢过程中的潜在作用及肉牛改良提供理论基础。【方法】采集安格斯牛和南阳牛右侧背部最长肌第12/13肋骨间肌肉,分离其脂肪组织并提取RNA,采用RNA-seq和生物信息学方法分析2种牛肌内脂肪组织中circRNAs的表达情况,筛选差异表达的circRNAs,并对其进行GO和KEGG富集分析。选取4个差异表达的circRNA(circRNA.9560、circRNA.7431、circRNA.2083、circRNA.6528),对其表达水平进行qRT-PCR验证。【结果】在所有牛样本肌内脂肪组织中共检测到14 649个circRNAs,从中筛选并初步鉴定出111个安格斯牛与南阳牛差异表达的circRNAs,其中有75个在安格斯牛肌内脂肪组织中表达上调,36个表达下调。差异表达的circRNAs主要富集于细胞进程、单有机体进程、代谢过程、细胞、细胞部分、细胞器、分子结合、催化活性、核酸结合转录因子活性的GO条目中。KEGG富集分析结果发现,差异表达的circRNAs共富集到66条信号通路中,其中具有显著差异(P0.05)的信号通路有10个。qRT-PCR验证结果显示,circRNA.9560和circRNA.7431表达量显著下调,circRNA.2083和circRNA.6528表达量显著上调,与测序结果一致。【结论】筛选出111个安格斯牛与南阳牛差异表达的circRNAs,这些circRNAs可能在牛脂肪沉积和脂质代谢过程中发挥着一定的调控作用。     

Proteomic profiling of plasma-derived small extracellular vesicles: a novel tool for understanding the systemic effects of tick burden in cattle

Cattle ticks pose a significant threat to the health and profitability of cattle herds globally. The investigation of factors leading to natural tick resistance in cattle is directed toward targeted breeding strategies that may combat cattle tick infestation on the genetic level. Exosomes (EXs), small extracellular vesicles (EVs) of 50 to 150 nm diameter, are released from all cell types into biofluids such as blood plasma and milk, have been successfully used in diagnostic and prognostic studies in humans, and can provide essential information regarding the overall health state of animals. Mass spectrometry (MS) is a highly sensitive proteomics application that can be used to identify proteins in a complex mixture and is particularly useful for biomarker development. In this proof of principle study, EXs were isolated from the blood plasma of cattle (Bos taurus) with high (HTR) and low tick resistance (LTR) (n = 3/group). Cattle were classified as HTR or LTR using a tick scoring system, and EXs isolated from the cattle blood plasma using an established protocol. EXs were subjected to MS analysis in data-dependent acquisition mode and protein search performed using Protein Pilot against the B. taurus proteome. A total of 490 unique proteins were identified across all samples. Of these, proteins present in all replicates from each group were selected for further analysis (HTR = 121; LTR = 130). Gene ontology analysis was performed using PANTHER GO online software tool. Proteins unique to HTR and LTR cattle were divided by protein class, of which 50% were associated with immunity/defense in the HTR group, whereas this protein class was not detected in EXs from LTR cattle. Similarly, unique proteins in HTR cattle were associated with B-cell activation, immunoglobins, immune response, and cellular iron ion homeostasis. In LTR cattle, unique exosomal proteins were associated with actin filament binding, purine nucleotide binding, plasma membrane protein complex, and carbohydrate derivative binding. This is the first study to demonstrate that MS analysis of EXs derived from the blood plasma of HTR and LTR cattle can be successfully applied to profile the systemic effects of tick burden.     

Signatures of positive selection for local adaptation of African native cattle populations: A review

Cattle are central to the lives and diverse cultures of African people. It has played a crucial role in providing valuable protein for billions of households and sources of income and employment for producers and other actors in the livestock value chains. The long-term natural selection of African cattle typically signals signatures in the genome, contributes to high genetic differentiations across breeds. This has enabled them to develop unique adaptive traits to cope with inadequate feed supp...     

低温下牛粪接种发酵剂对堆肥温度与微生物的影响

试验针对北方寒区特殊地理环境条件,采用牛粪好氧堆肥发酵,研究室外温度低于0℃时,接种复合发酵剂对堆肥温度、微生物数量及区系变化特征的影响。结果表明,牛粪接种复合发酵剂24h和48h堆温分别升至40.1℃和55.6℃;高温期持续6d;发酵周期缩短至12d。细菌对堆肥升温起主要作用;细菌和放线菌是高温阶段主要作用菌群;腐熟阶段细菌、放线菌和真菌共同作用,且细菌作用强于放线菌和真菌。     

去势和热应激对筠连黄牛生产性能、瘤胃发酵和血液生化指标的影响

为研究去势和热应激对筠连黄牛生产性能、瘤胃发酵和血液生化指标的影响,本研究选用18头16月龄、体重相近((292.35±28.71) kg)的不同去势程度筠连黄牛(全去势FCG、半去势HCG、假手术SOG),分为3组,每组6个重复,每个重复1头牛,根据试验期间牛舍温湿度指数(THI),分为热应激期(7、8月)和非热应激期(9月),分析去势和热应激对黄牛各指标的影响。结果表明：1)与非热应激期相比,热应激期牛舍THI、肉牛呼吸频率和直肠温度均显著提高(P<0.05)。2)去势和热应激均显著提高血清热休克蛋白70、高密度脂蛋白(HDL-C)、低密度脂蛋白(LDL-C)和雌二醇浓度(P<0.05),而睾酮、甲状腺素(T4)、胰岛素和游离脂肪酸浓度显著降低(P<0.05),且除血清葡萄糖、T4和LDL-C外,去势和热应激对其他血清指标存在显著互作效应(P<0.05)。3)全去势和热应激均显著降低肉牛平均日增重(ADG),且存在显著互作效应(P<0.05)。4)热应激期,去势显著降低粗蛋白、酸性洗涤纤维和钙表观消化率以及血清总抗氧化能力(T-AOC)(P<0....     

牛日本血吸虫病5种血清学诊断技术比较

为找寻特异性强、敏感性高,且操作简便、费用低廉,并能大规模应用于临床的日本血吸虫病血清学诊断方法,以疫区黄牛为研究对象,应用环卵沉淀试验(COPT)、血清法间接血凝试验(sIHA)和血纸法间接血凝试验(bpIHA)、胶乳凝集试验(PAPS)、三联斑点酶联免疫吸附试验(三联Dot-ELISA)5种血清学诊断方法与粪检方法检测牛日本血吸虫病,并对5种血清学检测结果进行评价.检测分析结果表明,用血清学方法COPT,sIHA,三联Dot-ELISA对疫区黄牛进行血吸虫病检测,与三粪九检结果符合率高,具有灵敏度高、特异性好、简捷方便、费用低等特点,特别适用于疫区家畜血吸虫病的诊断、普查,是比较理想的现场检测方法,值得推广.血清学方法bpIHA和PAPS检测血吸虫病,尽管方法简便、费用低廉,但其灵敏度、特异性与三粪九检结果符合率低于血清学方法COPT,sIHA,三联Dot-ELISA,易造成漏检,假阳性,故在普查时,不建议采用.     

鲁西黄牛耳缘组织成纤维细胞的体外培养

实验以鲁西黄牛耳缘组织为研究材料,采用组织块贴壁培养法对其进行了成纤维细胞的体外培养。通过细胞的传代培养、形态学和动力学观察与分析,结果表明,所建立的鲁西黄牛耳缘组织成纤维细胞系具有典型的成纤维细胞形态,胞体均为梭形和不规则三角形,且细胞丰满;细胞核形态为卵圆形,并位于胞质中央,核仁清晰。在细胞生长于繁殖过程中亦经历了潜伏期、指数增生、停滞期和衰退死亡期等4个时期。细胞群体倍增时期为72h。实验结果表明,已成功地培养了鲁西黄牛耳缘组织成纤维细胞。