耐受自身代谢产物及耐二甲基亚砜红霉素高产菌株的选育

为提高红霉素发酵单位,考察了二甲基亚砜(DMSO)添加时间和体积分数对红霉素合成的影响,采用筛选自身代谢产物突变株的方法,将突变株进行常压室温等离子体(ARTP)诱变和耐受高浓度DMSO处理。结果显示,在36 h向发酵瓶中添加30000μg/m L红霉素,筛选得到化学效价比对照提高22.4%的菌株。DMSO最适添加时间为发酵48 h,最适添加剂量为0.2%,其可提高发酵单位10.1%。     

Effect of mixed rearing of barrows and gilts on backfat thickness and serum metabolite profiles of the Kagoshima-Kurobuta (Berkshire) pig

We investigated the effect of mixed rearing of barrows and gilts on the backfat thickness and the serum metabolite profiles of Kagoshima-Kurobuta (Berkshire) pigs. A total of 149 pigs with an average body weight of 35 kg were divided into the following groups: 100%, 90%, 70%, 50%, 30%, 10%, and 0% groups consisting of 10 barrows (1 pen), 9 barrows + 1 gilt (3 pens), 7 barrows + 3 gilts (2 pens), 5 barrows + 5 gilts (3 pens), 3 barrows + 7 gilts (2 pens), 1 barrow + 9 gilts (3 pens), and 9 gilts (1 pen), respectively. All pigs were raised to a shipping weight of 120 kg. Mixed rearing significantly reduced (p < 0.001) backfat thickness, and the optimum mixing ratio of barrows and gilts was 7:3 (the 70% group). Four types of circulating sex steroids were found in both the barrows and gilts in the 50% group but were not detected in barrows from the 100% group. These results indicated that mixed rearing of barrows and gilts was effective for reducing the backfat thickness of barrows, and induced sex steroid hormones may influence the backfat thickness of barrows in mixed-reared groups.     

UPLC/Q-TOF MS鉴定沃尼妙林在大鼠体内的代谢产物

利用超高效液相色谱/四级杆-飞行时间质谱（UPLC/Q-TOF MS）分析鉴定了VLM在大鼠体内的代谢产物,并讨论了VLM在大鼠体内的代谢途径。按20 mg/kg体重的剂量,给Sprague-Dawley大鼠口服灌食沃尼妙林（VLM）,分别采集给药前及给药后的尿液样品。采用UPLC/Q-TOF MS对样品进行分析,代谢物数据经MetaboLynx XS软件处理后,根据常见代谢途径的准确质量数变化对代谢产物进行筛选,利用代谢物的MS/MS信息鉴定了五种代谢产物,并确定VLM代谢途径包括母核羟基化和侧链硫醚键氧化等。研究结果表明,VLM在大鼠体内代谢迅速,母核的羟基化是主要的代谢途径。     

单宁酸对红、绿色型豌豆蚜生长发育及繁殖的影响

为明确单宁酸对两种色型豌豆蚜生长发育及繁殖的影响,本研究采用豌豆蚜全纯人工饲料薄膜饲养技术,设置5组不同浓度的单宁酸,在适宜条件下分别饲养绿色型、红色型豌豆蚜,测定了豌豆蚜的存活率、产蚜量、相对日均体重增长率等指标。结果表明:单宁酸对两种生物型豌豆蚜的生长发育及繁殖有明显抑制作用,且对绿豌豆蚜的抑制作用明显大于红豌豆蚜。随着单宁酸浓度升高,两种色型豌豆蚜存活率、相对日均体重增长率均下降,5mg·L-1处理12天时绿色型豌豆蚜存活率、相对日均体重增长率分别为13.3±3.3%和0.20±0.01%,红色型分别为20.0±5.8%和0.19±0.00%,与CK间差异显著(P0.05);5mg·L-1时绿豌豆蚜产蚜量和产蚜率最低,分别为2.0±0.0头/单雌和6.7±3.3%,与CK间差异显著(P0.05)。研究结果可为次生代谢物质抗豌豆蚜的生化机理研究提供理论依据和技术支持。     

Effect of short‐term supplementation with rumen‐protected fat during the late luteal phase on reproduction and metabolism of ewes

This study was designed to study the effect of short‐term supplementation with rumen‐protected fat during the late luteal phase on reproduction and metabolism of sheep during breeding season. Seventy‐six ewes (Rahmani, Barki and Awassi × Barki) were allocated to two groups considering genotype: the control ewes (C‐group) received a maintenance diet, and the fat‐supplemented ewes (F‐group) received the maintenance diet plus 50 g/head/day of rumen‐ protected fat (Megalac) for 9 days during which oestrus was synchronized. The latter had been accomplished using double intramuscular injection of prostaglandin F_2α (PGF_2α) 11 days apart. Ovarian activity, serum concentration of cholesterol, glucose, insulin and reproductive performance variables were recorded. Data were analysed considering treatment (group) and genotype. Supplementation had positive effects on the overall mean serum concentrations of cholesterol (p < 0.05), glucose (p < 0.05) on day 6 of nutritional treatment and insulin (p = 0.07) on day 8. Fat supplementation did not affect the total number of follicles, follicle populations and ovulation rate. However, fat‐supplemented Rahmani ewes tended to have higher ovulation rate compared with other breeds (treatment × breed interaction, p = 0.06). Treatment also did not affect the mean concentration of serum estradiol or progesterone. Supplemented ewes had higher conception (p = 0.06) and lambing rates (p < 0.05) compared with control. In conclusion, short‐term supplementation with rumen‐protected fat as a source of energy around breeding time improved metabolism, conception and lambing rates of ewes without effects on steroidogenic capacity and ovarian activity being apparent.     

Age‐dependent baseline values of faecal cortisol metabolites in the American mink (Neovison vison) under semi‐natural housing conditions

The welfare of an animal is ensured if it is able to fully satisfy its essential species‐typical needs in all functional aspects of behaviour. In mink, stereotypies and apathy, internal and/or external injuries as well as increased susceptibility to disease have been known to occur as a result of chronic stress. The non‐invasive method of analysing faecal cortisol metabolites (FCM) allows conclusions to be drawn about the stress level in the respective housing system. The objective of this study is to find out how the cortisol metabolites content in the faecal changes with increasing age of the mink under semi‐natural housing conditions. Thus, 40 American mink (Neovison vison) were housed in two outdoor enclosures imitating natural conditions. Throughout the entire study (13th to 32nd week of life), faecal samples were collected to measure cortisol metabolites. No differences in FCM concentrations between the two outdoor enclosures were found. In the young mink lower, less fluctuating FCM levels were found than in older animals. After the first faecal collection in the 13th/14th week of life, the level of metabolites decreased slightly (p = 0.032; 17th/18th week). From the 22nd/23rd week onwards until the 30th/31st week, shortly before the animals were pelted, continuously increasing concentrations were then measured. Increasing FCM levels with advancing age of the animals are probably attributable to the onset of sexual maturity and/or the respective season. This has to be taken into account in future studies using this method for assessing welfare and when comparing different mink housing systems.     

不同剂量25羟基维生素D3对断奶前犊牛生长性能、营养物质表观消化率、血浆代谢物及粪便菌群的影响

本试验旨在研究饲粮添加不同剂量25羟基维生素D₃[25(OH)VD₃]对断奶前犊牛生长性能、营养物质表观消化率、血浆代谢物及粪便菌群的影响。选取18头健康、体重[(40.68±1.20)kg]相近的新生荷斯坦犊牛,随机分为3个组,每组6头牛。对照组饲喂基础饲粮,不添加25(OH)VD₃;试验组每头犊牛每天分别在基础饲粮中添加6000(低剂量组)和12000 IU(高剂量组)的25(OH)VD₃。试验期56 d。结果表明:1)与对照组相比,低剂量组和高剂量组体重和平均日增重显著提高(P<0.05),高剂量组体高显著提高(P<0.05),低剂量组和高剂量组粪便评分显著降低(P<0.05)。2)与对照组相比,低剂量组和高剂量组干物质表观消化率显著提高(P<0.05),高剂量组中性洗涤纤维(P=0.05)和钙表观消化率(P<0.05)显著提高。3)与对照组相比,低剂量组和高剂量组血浆25(OH)VD₃和钙含量显著提高(P<0.05),高剂量组血浆磷含量显著提高(P<0.05)。4)与对照组相比,低剂量组和高剂量组血浆白细胞介素-2含量显著降低(P<0.05)。5)与对照组相比,低剂量组和高剂量组粪便中毛螺菌科(Lachnospiraceae)和普雷沃式菌科(Prevotellaceae)相对丰度显著提高(P<0.05),粪便中鼠杆菌科(Muribaculaceae)、克里斯滕森菌科(Christensenellaceae)、螺旋体科(Spirochaetaceae)和未培养_细菌_o_柔膜菌纲_RF39(uncultured_bacterium_o_Mollicutes_RF39)相对丰度显著降低(P<0.05)。由此可见,饲粮添加25(OH)VD₃可以提高断奶前犊牛生长性能,促进营养物质消化吸收,降低炎症反应,改善粪便菌群,降低腹泻发生。     

Effects of Mowing and Tebuthiuron on the Nutritional Quality of Wyoming Big Sagebrush

Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young) is the most abundant and widely distributed subspecies of big sagebrush and has been treated through chemical application, mechanical treatments, and prescribed burning in efforts thought to improve habitat conditions for species such as greater sage-grouse (Centrocercus urophasianus) and mule deer (Odocoileus hemionus). Although the response of structural attributes of sagebrush communities to treatments is well understood, there is a need to identify how treatments influence the quality of sagebrush as winter food for wildlife. Our purpose was to identify how mowing and tebuthiuron treatments influenced dietary quality of Wyoming big sagebrush in central Wyoming. Two study areas were mowed in January and February 2014, and tebuthiuron was applied in two study areas in May 2014. We constructed 6 exclosures in each of these four study areas (24 total), which encompassed 30 × 30 m areas of treated and untreated sagebrush within each exclosure. Samples of current annual growth were collected from 18 sagebrush plants from treated and 12 plants from control portions of mowing exclosures during November 2013–2015 and tebuthiuron exclosures during November 2014–2015. Samples were analyzed for crude protein and plant secondary metabolites known to influence dietary selection of sagebrush by sage-grouse and other sagebrush-occurring herbivores. Our results suggest mowing and tebuthiuron treatments may slightly increase crude protein concentrations directly after treatments without immediate changes in plant secondary metabolites. Slight increases in dietary quality of sagebrush following treatments coupled with potential trade-offs with loss of biomass associated with treatments corroborates previous research that treating Wyoming big sagebrush may have little benefit for sage-grouse and other sagebrush-dependent wildlife. Future work should evaluate not only how treatments influence sage-grouse habitat use and reproductive success but also how treatments influence other wildlife species in fragile sagebrush ecosystems.     

Physiological but not morphological adjustments along latitudinal gradients in a human commensal species,the Eurasian tree sparrow

Human commensal species take advantage of anthropogenic conditions that are less likely to be challenged by the selective pressures of natural environments. Their morphological and physiological phenotypes can therefore dissociate from habitat characteristics. Understanding how these species adjust their morphological and physiological traits across latitudinal gradients is fundamental to uncovering the eco-physiological strategies underlying coping mechanisms. Here, we studied morphological traits in breeding Eurasian tree sparrows (ETSs; Passer montanus) among low-latitude (Yunnan and Hunan) and middle-latitude (Hebei) localities in China. We then compared body mass; lengths of bill, tarsometatarsus, wing, total body, and tail feather; and baseline and capture stress-induced levels of plasma corticosterone (CORT) and the metabolites including glucose (Glu), total triglyceride (TG), free fatty acid (FFA), total protein, and uric acid (UA). None of the measured morphological parameters varied with latitude except in the Hunan population, which demonstrated longer bills than those in other populations. Stress-induced CORT levels significantly exceeded baseline levels and decreased with increasing latitude, but total integrated CORT levels did not vary with latitude. Capture stress-induced significantly increased Glu levels and decreased TG levels, independent of site. However, the Hunan population had significantly higher baseline CORT, baseline and stress-induced FFA levels, but lower UA levels, which differed from other populations. Our results suggest that rather than morphological adjustments, physiological adjustments are mainly involved in coping mechanisms for middle-latitude adaptation in ETSs. It is worth investigating whether other avian species also exhibit such dissociation from external morphological designs while depending on physiological adjustments.     

雄蜂蛹中硝基呋喃类代谢物含量的测定及超标原因分析

雄蜂蛹中硝基呋喃类抗生素尤其是呋喃西林代谢物-氨基脲(SEM)残留超标是困扰我国雄蜂蛹出口的一个难题。本文对不同日龄雄蜂蛹中硝基呋喃类代谢物含量进行了测定,并对超标原因进行了分析。测定结果表明,在蜂群没有使用任何硝基呋喃类药物情况下,各日龄雄蜂蛹中的SEM含量依然严重超标,随着日龄的增长,雄蜂蛹中的SEM含量大幅增长,特别是16d以后,每过2d,含量增加2μg/kg左右。推测雄蜂蛹中SEM含量超标是非人为因素造成的,可能与雄蜂蛹生长后期体内甲壳素含量的增加相关。