SNP芯片评估柯尔克孜羊群体遗传多样性和遗传结构

旨在了解柯尔克孜羊群体的遗传多样性和遗传结构,有效地保护和利用其遗传资源。本研究利用绵羊SNP 50K v3芯片检测61只柯尔克孜种羊(31只公羊、30只母羊)个体的单核苷酸多态性(single nucleotide polymorphism, SNP);Plink(V1.90)软件对数据进行质控,计算群体有效含量、多态标记的比例、观测杂合度、期望杂合度、多态信息含量、有效等位基因数、最小等位基因频率,分析群体的遗传多样性;Plink计算连续性纯合片段(runs of homozygosity, ROH)和近交系数F_ROH;构建状态同源距离矩阵(identical by state, IBS),并采用Gmatrix软件构建G矩阵,解析柯尔克孜羊群的遗传距离和亲缘关系;使用Mega X软件构建种公羊进化树,分析群体家系结构。结果显示,61只柯尔克孜羊共得到64 734个SNPs标记,通过质检的SNPs为56 763个;平均多态信息含量为0.273±0.112,平均观察杂合度和平均期望杂合度分别为0.368±0.140和0.368±0.130,平均最小等位基因频率为0...     

Liveweight changes of sheep grazing a range of herbage allowances underPinus radiata agroforestry regimes

A range of improved pasture herbage feed allowances (1 to 5 kg dry matter/head/day) were offered to young sheep, grazing underPinus radiata grown at 0, 50, 100 and 200 stems per hectare. Six trials were conducted, each for 30 days duration between spring 1986 and autumn 1988, at tree age 13–15 years. Mean liveweight gain over all trials for 0 (open pasture), 50, 100 and 200 stems per hectare were 170, 155, 136 and 94 g/sheep/day, respectively. Liveweight gain increased curvilinearly with increasing pasture allowance at all tree stockings and tended to level off above 3 kg green dry matter/head/day. Green matter pasture in vitro digestibility of the green pasture fraction changed little with increasing tree stocking despite changes in pasture composition. Pine needle accumulation under the higher tree stockings depressed the quality of the total feed on offer. Livestock performance under low tree stocking agroforestry regimes can be satisfactory, providing pasture management encourages fresh nutritious feed.     

Clearcutting Brazilian caatinga: assessment of a traditional forest grazing management practice

Clearcutting is a common practice for removing woody vegetation in the semiarid tropics of northeast Brazil. The prevalent belief is that clearing increases carrying capacity for livestock by increasing herbaceous vegetation, yet little empirical evidence exists to support or refute the contention. We investigated the implications to small ruminant nutrition of clearcutting in the semiarid tropics of northeast Brazil. We found that biomass of herbaceous species increased sixfold following cutting of trees, but much of this increase was in the form of poorly palatable stem. The large supply of leaf litter from woody species that was typical of uncleared areas during the dry season was replaced by persistent green foliage on coppicing trees the year following clearing. This green foliage may enhance the nutritional quality of the diets of sheep and goats foraging on cleared areas during the dry season.     

绵羊经济性状相关基因研究进展及其应用

绵羊是重要的农业经济动物之一,不同绵羊品种具有各自独特的性状。利用性状存在变异的绵羊个体,对其进行基因组水平的分析,可以定位获得影响某种性状的基因区段或主效突变位点,鉴定得到的这些重要基因可为绵羊遗传育种提供分子标记,加快遗传选育进程。文章综述了在绵羊中鉴定得到的影响繁殖、生长、抗病及抗逆性状的主效基因发现过程及相应的调控机理,同时还综述了这些基因在绵羊分子育种方面的研究进展,有助于后续探索这些重要基因的具体分子机制,并为绵羊分子育种提供新思路。     

黄体期注射PGF2α对母羊血清生殖激素及相关细胞因子的影响

旨在研究黄体期不同阶段注射前列腺激素(PGF2α)对育成母羊生殖激素和生殖相关细胞因子的影响。本研究选择健康、体况良好、体重相近、发情周期正常的湖羊育成母羊60只,用“孕酮栓(MAP)+PMSG”法进行发情周期同步化处理后,选择发情正常的48只母羊随机均分为6组。发情当天记为第0天,黄体前期试验组、中期试验组和末期试验组母羊分别在第6(黄体前期)、11(黄体中期)、16天(黄体末期)注射1 mL PGF2α(0.1 mg),黄体前期对照组、中期对照组和末期对照组母羊分别在第6、11、16天注射1 mL生理盐水,每次注射后0.5、1、2、3 h采血,用于血液指标检测。结果表明,所有试验组和对照组母羊于注射后的0.5~3 h间血清中FSH、LH、PRL、P₄、E₂水平以及TNF-α、IL-1β、IL-6、IFN-β无显著变化(P＞0.05);母羊在黄体期不同阶段注射PGF2α对0.5、1、2、3 h血清中FSH、LH、PRL及IL-1β、IFN-β无显著影响(P＞0.05),前期试验组注射后3 h P₄水平显著低于前期对照组,E₂和IL-6水平显著高于前期对照组(P＜0.05),前期试验组注射后2和3 h TNF-α水平显著高于前期对照组(P＜0.05);中期试验组注射后1 h P₄水平显著低于中期对照组(P＜0.05)。黄体前期注射PGF2α后,前期试验组0.5~ 3 h内FSH、E₂、TNF-α、IL-6整体水平显著高于前期对照组(P＜0.05),P₄整体水平显著低于前期对照组(P＜0.05),对LH、PRL、IL-1β和IFN-β无显著影响(P＞0.05);黄体中期注射PGF2α后,中期试验组0.5~3 h内E₂整体水平显著高于中期对照组(P＜0.05),P₄整体水平显著低于中期对照组(P＜0.05),对FSH、LH、PRL、TNF-α、IL-1β、IL-6和IFN-β无显著影响(P＞0.05);黄体末期注射PGF2α对生殖激素与相关细胞因子没有显著性影响(P＞0.05)。本研究结果表明,PGF2α对黄体的溶解作用存在阶段性差异,母羊在黄体前期对PGF2α的短期应答反应强于黄体中、末期,且黄体前期时,卵巢可以响应PGF2α为卵泡发育营造更佳的发育环境。     

绵羊精子细胞核质转运蛋白KPNA4的研究

旨在对绵羊附睾头、体和尾部的精子进行蛋白质组学分析,获得差异表达蛋白,对数据进行功能富集分析,挖掘精子发生/成熟关键蛋白质。本研究选择12月龄左右健康的3只雄性湖羊为试验动物,分离附睾并按区域收集精子,3组样本(附睾头部组、附睾体部组和附睾尾部组),每组3个生物学重复,共计9例绵羊精子细胞样本。基于TMT标定定量蛋白质组学分析和R语言等工具,在获取的差异表达蛋白中进行GO和KEGG富集分析,并利用蛋白质免疫印迹(Western bolt)、免疫荧光(immunofluorescence)和流式细胞术(flow cytometry)试验验证结果的可靠性。从22 841个唯一性肽中鉴定到差异蛋白质616种,其中,尾vs头组鉴定出309个差异表达蛋白(上调213个,下调96个);尾vs.体组鉴定出167个差异表达蛋白(上调107个,下调60个);体vs头组鉴定出140个差异表达蛋白(上调88个,下调52个)。根据差异倍数与蛋白质功能,筛选出可能与精子成熟、核质物质转运相关的关键蛋白-KPNA4。本研究揭示了绵羊附睾不同部位精子的特点与差异,这些数据为研究雄性绵羊的生殖机制和精子成熟提供了丰富的资源。     

Rumen degradation in sheep,goats and cattle and voluntary intake by sheep of four browse species

Two experiments were conducted using dried leaves ofAlchornea cordifolia, Ficus capensis, Manniophytum fulvum andAlbizza niopoides. In Experiment 1, dry matter (DM) degradation characteristics were investigated using thein sacco nylon bag technique in West African Dwarf (WAD) sheep, WAD goats and Bunaji steers. In Experiment 2, voluntary intake of the browse forage when fed as supplements to sheep at 0, 10 and 30% levels was measured. In Experiment 1,A. cordifolia andM. fulvum had significantly higher rapidly degradable DM fraction thanA. niopoides andF. capensis. Averaged across browse species, the extent of DM degradation for sheep (58.3%) was significantly higher than for goat (47.7%) or cattle (44.1%). Ranking order of browse species for the extent of DM degradation was:F. capensis>A. cordifolia=M. fulvum=A. niopoides. In Experiment 2, as the level of supplementation increased from 10 to 30%, voluntary intake ofA. niopoides andM. fulvum increased while voluntary intake ofA. cordifolia andF. capensis declined. The results suggest that dried leaves ofA. niopoides andM. fulvum are more acceptable to WAD sheep than those ofA. cordifolia andF. capensis.     

Forage production and small ruminant grazing responses in Mediterranean shrublands as influenced by the reduction of shrub cover

Reduction of shrub cover in Mediterranean shrublands is considered as a method of optimising forage and animal production. In this study, forage production in grazed and protected plots and grazing responses of small ruminants in cleared (25% shrub cover), slashed (34% shrub cover) and not treated (control, 55% shrub cover) kermes oak (Quercus coccifera L.) shrublands were compared during the spring seasons of 1992, 1993 and 1994. The alterations in shrub density were done in October 1991 and pastures remained ungrazed until spring of 1992. Clearing and slashing of shrub vegetation resulted in higher amounts of available herbaceous forage and useable browse. At the end of the growing season, averaged across years, herbaceous biomass was generally two to three times higher in the treated shrublands than in the control; also, browse biomass was slightly less (1,078 vs 1,533 kg/ha) but easily accessible because of the open structure and the lower height of the sprouting shrubs. There were generally no grazing response differences between the cleared and slashed pastures. However, grazing animals (sheep and goats) had a higher bite rate (bites/min; P 0.05) in the treated pastures than in the control. Levels of crude protein in the forage selected by animals were higher (P 0.05) in the treated pastures than in the control. Animals in the improved pastures maintained diets that were significantly more digestible (53.5%) than those in the control pasture (48.5%). Neutral detergent fibre and lignin contents of animal diets were similar in the improved pastures but lower (P 0.05) than those of the control. It is concluded that removing of woody vegetation in Mediterranean shrublands results in increased forage production (available herbage and useable browse) and improved forage quality and availability for small ruminants.     

多肽的酶法制备

以羊脾脏为原料,用菠萝蛋白酶和胰蛋白酶双酶水解,选择最佳水解条件。结果表明,温度60℃,pH值7.0,加酶量5.0%,时间5.0h为最佳水解条件。     

Examination of non-genetic factors affecting the growth performance of djallonke sheep in soudanian zone at the Okpara breeding farm of Benin

A study was carried out at the Okpara breeding farm in Benin. Records on 558 lambs of the Djallonke sheep breed, born from 1997 to 2000, were used to determine the weekly growth curve from birth up to 119 days of age. Non-genetic factors affecting lamb weights at birth and at 30, 60, 90 and 120 days and average daily gains from 0 to 30 days, from 0 to 60 days, from 0 to 90 days and from 0 to 120 days were investigated. A linear model comprising the fixed effects of birth season, birth year, parity number of ewe and sex of lambs was used for analysis of variance by least squares. All fixed effects were significant for weight at 30 and 60 days and average daily gains at 30 days, with the exception of the parity of the ewe for birth weight, weight and average daily gain at 90 days. All fixed effects tended to cancel out for weight and average daily gains by 120 days. Lambs born in the dry season were the heaviest. Single lambs and male lambs were heavier than twins and females. Lambs from ewes of 3rd and 4th parity were heavier, with higher, average daily gains.