夜间灯光数据DMSP/OLS在贫困地区亮化度模型构建中的应用

贫困县亮化度一定程度上反映着贫困县居民的生活水平发展状况,但与贫困区经济收入等相关指标的定量关系不太明确。针对该情况,提出了一种应用灯光数据的亮度统计数据,结合与贫困县经济收入等密切相关的经济规模指标、人口数量、财政收入等来定量研究贫困县亮化度模型,并选取样本贫困县对该模型进行验证。经数据验证,该模型具有较高的可信度。     

2种方法在荒漠草原植物种群分布格局中的适用性比较

研究首次比较了2种方法在测定荒漠草原6种植物种群分布格局中的适用性.结果表明,方差均值比率法及聚集强度指数法中的多个指数都适合于这6种植物分布格局的计算.但其中的聚块性指数法的运算难度较大,宜慎用.比较结果这6种植物种群皆为聚集分布,但聚集程度有所差别.     

畜禽饲粮豆粕减量营养调控技术研究进展

XUE Junjing;LI Siyuan;FANG Rejun(College of Animal Science and Technology,Hunan Agricultural University,Changsha 410128,China;Hunan Co-Innovation Center of Animal Production Safety,Changsha 410128,China)     

基于近红外光谱的北京市全株玉米原料康奈尔净碳水化合物-蛋白质体系组分分析与预测

本试验旨在基于康奈尔净碳水化合物-蛋白质体系(CNCPS)建立北京市全株玉米原料营养成分数据库,并利用近红外光谱(NIRS)方法建立其营养价值预测模型。试验采集北京市18个牧场89份全株玉米原料样品,测定其营养成分,利用CNCPS 6.5计算各样品碳水化合物(CHO)和蛋白质组成。定标集和验证集根据4∶1的配比关系,分别选用71份和18份全株玉米原料样品作为定标集和验证集评价NIRS模型。结果显示:1) NIRS分析技术对全株玉米原料常规营养成分、CNCPS中蛋白质组成和CHO组成均具有较好的预测能力,且精确度较高。2)干物质(DM)、粗灰分(Ash)、粗蛋白质(CP)、粗脂肪(EE)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、酸性洗涤木质素(ADL)、淀粉(Starch)、中性洗涤不溶蛋白质(NDIP)、酸性洗涤不溶蛋白质(ADIP)、可溶性蛋白质(SP)、CHO、非纤维性碳水化合物(NFC)、可溶性纤维(CB2)、可消化纤维(CB3)、不消化纤维(CC)、可溶性真蛋白质(PA2)、难溶性真蛋白质(PB1)、纤维结合蛋白质(PB2)和非降解蛋白质(PC)的定标决定系数(1-VR)均>0.80,验证决定系数(RSQv)均≥0.84,这些模型均可用于日常快速检测分析。DM、Ash、EE、NDF、ADF、ADL、Starch、NDIP、CHO、NFC、CB2、CB3、PC和PB1的NIRS模型参数均采用二阶导数处理,CP、SP、ADIP、CC、PA2和PB2的NIRS模型参数均采用标准正态变量+二阶导数处理。综上所述,本研究提供了全株玉米原料的基础化学分析数据,并通过NIRS分析技术建立了主要营养成分的快速预测模型,有利于养殖场青贮前对全株玉米原料质量的快速评估。     

不同收获期对全株玉米青贮营养价值、发酵品质和瘤胃降解率的影响

本试验旨在研究不同收获期对全株玉米青贮营养价值、发酵品质和瘤胃降解率的影响。试验抽样采集山东省44个区县130个养殖场130份全株玉米青贮饲料样品,按照收获时玉米籽粒的乳线位置,共分为1/2乳线、2/3乳线和3/4乳线3个时期,样品数量分别为40、60和30份,测定其营养价值、发酵品质和瘤胃降解率。结果表明:1)随着收获期的延迟,全株玉米青贮的干物质(DM)含量显著增加(P<0.05),粗灰分(Ash)含量显著降低(P<0.05)。1/2乳线期全株玉米青贮的中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)和酸性洗涤木质素(ADL)含量显著高于2/3乳线期和3/4乳线期(P<0.05)。2)随着收获期的延迟,全株玉米青贮的淀粉(CB1)含量显著增加(P<0.05)。1/2乳线期全株玉米青贮的总碳水化合物(CHO)、可溶性糖(CA)含量显著低于3/4乳线期(P<0.05),1/2乳线期全株玉米青贮的不可利用纤维(CC)和可利用中性洗涤纤维(CB3)含量显著高于2/3乳线期和3/4乳线期(P<0.05)。3)随着收获期的延迟,全株玉米青贮的发酵系数和费氏评分显著增加(P<0.05)。1/2乳线期和2/3乳线期全株玉米青贮的乳酸含量显著高于3/4乳线期(P<0.05),1/2乳线期全株玉米青贮的的丙酸含量显著高于2/3乳线期和3/4乳线期(P<0.05)。4)随着收获期的延迟,全株玉米青贮的总可消化养分含量及消化能、代谢能均显著增加(P<0.05)。1/2乳线期全株玉米青贮的维持净能、增重净能和泌乳净能显著低于2/3乳线期和3/4乳线期(P<0.05)。5)1/2乳线期和2/3乳线期全株玉米青贮的24和48h的干物质降解率显著低于3/4乳线期(P<0.05)。综上所述,收获期为3/4乳线期时,全株玉米青贮的营养价值和发酵品质最优。     

Evaluating the rumen‐protected lysine stability in forage‐based total mixed rations in vitro and determining the lysine Brix value

Three rumen‐protected lysine (RPL) products (AjiPro^®‐L, LysiPEARL^TM, and Feedtech Bypass Lysine^TM: A, B, and C, respectively) were tested for stability in two forage‐based total mixed rations (TMR1, 41.3% dry matter (DM), and TMR2, 49.5% DM) (experiment 1) and for Brix value (experiment 2). In experiment 1, each RPL product (2 g each) and TMR diet (200 g) were mixed and stored in plastic bags at 20°C for 0, 1, 3, 6, 12, 24, and 48 hr. In experiment 2, each RPL product (2 g) was dispensed into ion‐exchanged water (20 ml) and kept at 20°C for 0, 0.5, 1, 3, 6, 12, 24, and 48 hr. At each time point, free lysine (Lys) content and Brix values of extracts were measured, and Lys release (LR, %) was calculated. All RPL products LR% varied with varying diets DM and increased with increasing of time exposed to diets; it was highest in C, followed by B, and then A. Water LR% positively correlated with that from diets and with Brix values of Lys dissociated in water. Our results indicated that Lys dissociation from RPL products is affected by diet DM content. Brix value may be used as a potential marker for RPL protection efficacy.     

Communal farmers’ ecological knowledge and perceptions of grasses in the central Eastern Cape province,South Africa: similarities with field studies and scientific knowledge and their implications

The local ecological knowledge (LEK) and perceptions of grasses were investigated in six semi-arid communal areas in the central Eastern Cape province, South Africa, and compared with field studies and scientific knowledge. Of the total of 21 grasses identified in the field survey, communal farmers had vernacular names only for 11 species. Respondents rated Digitaria eriantha and Pennisetum clandestinum to have the highest (p < 0.05) grazing value. Respondents’ ratings of Eragrostis obtusa and Sporobolus africanus as having similar (moderate) grazing values to Themeda triandra is against the established knowledge. Respondents’ ratings of T. triandra and S. africanus as having higher (p = 0.01) ecological value than the other grasses concur with the scientific knowledge, whereas their nomination of E. obtusa and D. eriantha as providing less ecological benefits than Aristida conjesta disagrees with some ecologists. The study hinted at the complementarity and discrepancies between LEK and scientific knowledge that need ratification. The respondents’ lack of detailed knowledge is suggestive of a gradual eroding of LEK among the local communities that will adversely impact the local people’s ability to implement sustainable rangeland utilisation practice. The current study also recognised farmers’ familiarity as well as training needs that would expound their knowledge and management of grasses.     

Effect of microbial inoculants on the fermentation characteristics,nutritive value,and in vitro digestibility of various forages

This study was aimed to examine the characteristics of three isolated lactic acid bacteria (LAB) strains (HG24, M1, and TG1), and to evaluate their effects on fermentation characteristics, nutritive value, and in vitro digestibility in a variety of substrates. The experiments were conducted with Italian ryegrass (Lolium multiflorum Lam.), tall fescue (Festuca arundinacea Schred.), and oat (Avena sativa L.) in laboratory silo (1 L) for ensiling 30 days. All the treated silages had significantly (p < 0.05) higher in vitro dry matter digestibility (IVDMD), and lower undesirable microorganism populations compared with controls. In Italian ryegrass and oat silages, all the inoculants improved the fermentation quality, evidenced by distinctly (p < 0.05) higher LA contents and ratios of LA to acetic acid, and lower pH, butyric acid and ammonia nitrogen contents. Strains HG24 and commercial inoculant G (Lactobacillus plantarum MTD‐1) performed better than strains M1 and TG1, indicated by obviously (p < 0.05) higher LA contents, LAB numbers, and IVDMD. In tall fescue silage, all the isolated LAB strains (HG24, M1 and TG1) markedly (p < 0.05) increased IVDMD compared with strain G. Strain HG24 is recommended as a good LAB inoculant for ensiling in various forages.     

家畜毛色形成分子基础及应用研究进展

动物毛色是一种容易被识别的表型,也可作为筛查某些疾病的有效手段。毛色主要由黑色素细胞产生的真黑色素和棕黑色素的分布、比例和产生速率所决定。许多基因对黑色素的产生和分布起着重要调控作用,各基因间的不同基因型形成多种基本毛色、淡化毛色和花斑。此外,miRNA靶向结合毛色主效基因mRNA,诱导抑制/增强其转录翻译过程,从而调控毛色基因的表达,影响黑色素合成。文章简述了家畜调控毛色的主效基因黑色素皮质素受体1（MC1R）、野灰位点信号蛋白（ASIP）、原癌基因（KIT）、酪氨酸酶关联蛋白（TYRP）、小眼畸形相关转录因子（MITF）和内皮素受体B（EDNRB）的DNA序列多态性（不同基因型）与毛色性状、疾病之间的关系;介绍了毛色形成相关miRNA挖掘鉴定、miRNA调控毛色相关基因研究进展与毛色基因研究应用价值,旨在为今后研究家畜毛色机理提供理论依据。     

旱地栽培小麦及秸秆青贮饲料的发酵特性、营养成分及体外瘤胃降解特性

本研究总结了全珠小麦青贮饲料和小麦秸秆青贮饲料的保存和营养特性。选择25包来自4个不同田间的全珠小麦青贮饲料和10包小麦秸秆青贮饲料,分别进行了全株小麦青贮和秸秆青贮试验。全珠小麦青贮饲料保存良好,平均pH值为4.46,乳酸、乙酸和丁酸盐的浓度分别为19.2、10.4和4.7g/kg。小麦秸秆青贮饲料的平均pH值为5.46,由于干物质含量较高,发酵受到抑制,乳酸、乙酸和丁酸盐的浓度分别1.9、2.2和1.0g/kg。全株小麦青贮饲料粗蛋白含量为78g/kg,中性洗涤纤维含量为546g/kg,非纤维碳水化合物含量为306g/kg。全珠小麦青贮饲料中粗蛋白和非纤维碳水化合物含量变化较大,中性洗涤纤维含量变化相对较小,这与籽粒成熟度的差异有关。全株小麦青贮饲料和秸秆青贮饲料的体外有机质降解率分别为56.1%和29.3%。全株小麦青贮饲料的体外有机质降解与pH、乳酸和乙酸盐含量无显著相关性(P>0.05),与丁酸盐含量和氨氮比值有显著相关性的趋势(P=0.07)。瘤胃对全珠小麦青贮饲料的发酵早期体外气体生成的变异系数越高,相对于一些纤维组分,如中性洗涤纤维和酸性洗涤纤维,测定的非纤维碳水化合物变异系数也相应升高。综上所述,冬季旱地栽培的小麦可以作为全株青贮饲料在瘤胃中发酵提供能量,小麦秸秆也可以作为纤维原料进行青贮。