Screening and Identification of Laccase Fungi in Alpine Meadow北大核心CSCD

Nine strains of fungi that isolated from alpine meadow were used as research objects. The laccase-producing strains were identified by rDNA-ITS method. According to the strains, guaiacol, anthrone, catechol and neighbors were identified. Growth on selective medium of toluidine, o-toluidine, crnaphthol, benzidine, gallic acid as substrate, colony size, size of the color circle produced by laccase-catalyzed redox reaction, and the degree of color depth, the laccase-producing fungus is firstly screened, and the laccase activity is determined by the liquid-producing enzyme fermentation method using ABTS as a substrate for re-screening. The results showed that strain 1. 9 was Uncultured fungus clone. 2. la was Scytalidium, 310b was Marasmius tricolor, 2.1c was Saccharicola, 2. 3a was fungal sp, 2. 4d was Saccharicola. 10a was Marasmiusrotalis, 3. 7c was Alternaria. WB was Verticilliumlongisporum. The screening results showed that except for strain 3. 7c, the other 8 strains basically produced oxidative bands on the culture medium with guaiacol, anthrone, ortho-toluidine and benzidine as substrates, and cultured in gallic acid substrate. No oxidative bands were produced on the culture medium; strains 1. 9, 2. la, 310b, 2. 4d, 10a, 2. lc, and 2. 3a all had laccase activity, and strain 310b had stronger laccase activity than the other strains. © 2019 China Agricultural University. All rights reserved.     

Growth performance,carcass quality characteristics and colonic microbiota profiles in finishing pigs fed diets with different inclusion levels of rice distillers’ by‐product

The aim of this study was to evaluate the effects of diets containing rice distillers’ by‐product (RDP) on growth performance, carcass characteristics, meat quality, and gut microbiota of fattening pigs. Twenty‐four crossbred finishing pigs (Duroc × Landrace × Yorkshire), 56.9 ± 3.1 kg initial body weight, were randomly allocated to three groups. For 56 days, pigs were fed one of three diets including RDP0 (control), RDP15 (15% RDP in DM), and RDP30 (30% RDP in DM). With RDP level in diet, average daily gain and backfat thickness linearly increased (p < 0.05), and drip loss tended to increase (p ≤ 0.08). In addition, 16S ribosomal RNA gene amplicon profiling showed that RDP was associated with modulation of colonic microbiota composition, especially at family and genus levels. Relative abundance of Porphyromonadaceae and Erysipelotrichaceae families in colonic digesta increased with inclusion of RDP, while that of Enterobacteriaceae decreased. The proportion of genera unclassified Erysipelotrichaceae, and Butyrivibrio increased as inclusion of RDP. These results indicate that up to 30% inclusion in diet of finishing pigs, RDP can modulate colonic microbiota composition, and induces an improvement of animal growth and fat deposition.     

农村市场的契约式营销

新希望的饲料从厂里到养猪户家里,养猪户的生猪从农村到新希望火腿肠的生产车间,这个简单的产业链条,要打造得顺畅和完善,在营销和管理过程中,无不暗含着一种契约精神。     

Sucrose assists selection of high‐quality oocytes in pigs

We investigated whether high‐quality in vitro matured (IVM) oocytes can be distinguished from poor ones based on the morphological changes after treatment with hyperosmotic medium containing 0.2 mol/L sucrose in pigs. We hypothesize that IVM oocytes maintaining round shape have higher quality than mis‐shapened oocytes following dehydration. Oocyte quality was verified by determining embryonic developmental competence using in vitro fertilization, nuclear transfer and parthenogenetic activation. In all cases, the round oocytes had greater (p < .05) developmental competence than that of mis‐shapened oocytes in terms of blastocyst rate and total cell number in blastocysts obtained after 6 days of in vitro culture. We also confirm that round aged oocytes are higher in quality than mis‐shapened aged oocytes. In an attempt to find out why high‐quality oocytes maintain a round shape whereas poorer oocytes become mis‐shapened following sucrose treatment, we examined the arrangement of actin microfilaments and microtubules. Abnormal organization of these cytoskeletal components was higher (p < .05) in mis‐shapened oocytes compared to round oocytes after 52 hr of IVM. In conclusion, sucrose treatment helps selection of high‐quality oocytes, including aged oocytes, in pigs. Abnormal cytoskeleton arrangements partly explain for low developmental competence of mis‐shapened oocytes.     

优良牧草引种试验初报

为寻求适合毛乌素沙区大力发展舍饲养殖业的优质高产主效牧草品种,探索农牧交错牧业 可持续发展的有效途径,特在红石峡沙地引进７种牧草进行试验。结果表明,所引牧草新品种完全适生于引种区的气候条件和土壤条件,其抗逆性强,并能获得较高的经济、生态和社会效益。建议在毛乌素沙区大力推广。     

沟壑密度调查应采取水文网络法

沟壑密度是评价小流域沟蚀程度的指标,具体地反映了小流域沟蚀轮廓。目前,对于沟壑密度调查,尚无统一规定,有方格网法,小斑号法等。这些方法虽能描述小流域沟蚀现状但不能为沟壑治理的工程设计提供前期资料。水文网络法,从沟道发育入手,将大流域依沟道分布划分为若干小流域,结合工程布局进行调查,计算结果与其它方法相同,结论相同,而基础资料均为以后的工程设计提供了必要的准备,可随时调用。     

火地塘林区主要林分土壤营养状况评价

本文通过建立隶属函数,按最大隶属度原则,对火地塘林区７种主要不同林分的土壤营养状况进行了评价。结果表明这７种不同林分的土壤营养状况均属富级以上,并进行了相对分析排序     

山东省部分地区水貂养殖场户貂源冠状病毒和新型冠状病毒认知调查及病原检测

国外水貂感染新型冠状病毒(SARS-CoV-2)遭扑杀事件引起了国内水貂养殖业关注。为了解SARS?CoV-2对山东省水貂养殖场户的影响,通过问卷调查方法了解水貂养殖场户对貂源冠状病毒和SARS-CoV-2的认知情况,同时采集样本应用双重荧光定量PCR方法进行核酸检测,确定水貂中两种病毒的感染状况。结果显示:47.83%的养殖场户对国外水貂感染SARS-CoV-2被扑杀事件有所了解,36.23%的养殖场户认为该事件会对水貂养殖业带来影响,其中10.14%的养殖场户对水貂进行过SARS-CoV-2核酸检测;84.06%的养殖场户认为貂源冠状病毒不会感染人,57.49%认为国外水貂感染SARS-CoV-2的主要途径是通过养殖场其他动物(如犬猫等)感染,仅0.97%认为貂源冠状病毒与SARS-CoV-2存在一定关系,更多的(52.17%)是不清楚;310份样品的双重荧光定量PCR检测结果均为阴性。结果表明,山东省水貂养殖场户普遍意识到貂源冠状病毒与SARS?CoV-2相关性很小,其对水貂养殖业影响不大。但部分养殖场户对这两种病毒及其对水貂养殖业的潜在威胁尚缺乏足够认知,因此需要加强对养殖场户的认知宣传和病毒监测。     

西藏土壤放线性菌初步研究

采用常规方法研究了西藏８个主要土类１１个土样的土壤放线菌数量、主要属与类群、生理生化特性及拮抗特征。结果表明：①西藏不同土类及同一土类不同剖面表层土壤放线菌数量差异很大,随海拔升高,冻结期增长,土壤放线菌数量显著减少;②西藏土壤放线菌种类简单,供试菌株分为５属,链霉菌属占优势;③供试菌株大部分无明胶液化能力,约１／３无淀粉水解能力,淀粉水解能力较强者仅占１／３左右;④供试菌株约有１９％对革兰氏阳性菌有极强抗性,约９％对棉枯萎菌有较强抗性,仅有２％菌株对革兰氏阴性菌有抗性。