组学技术在奶牛乳房炎上应用的相关研究进展

奶牛乳房炎发病率较高、病因复杂,是影响世界奶牛业发展的主要常见疾病之一。由金黄色葡萄球菌、大肠杆菌、链球菌等病原体引起的临床和隐形乳房炎对动物性食品安全及畜牧业的正常发展构成巨大安全隐患,全球每年因奶牛乳房炎导致的经济损失多达数十亿美元。近年来随着测序技术的不断突破和测序成本的不断降低,生命科学的研究进入了多组学时代,其在畜牧业中的应用也越来越广泛。对奶牛乳房炎来说,传统的组织病理学筛查、体细胞计数、牛乳pH检测、牛乳电导率检测、酶活检验、红外热显影等诊断技术由于其自身的局限性难以充分全面地阐明其发病机理,已不能满足科研人员的需求。组学技术即Omics,主要包括基因组学技术、蛋白质组学技术和代谢组学技术等。通过基因组学研究不仅能从转录层面上揭示奶牛乳房炎复杂性状的表型变异及遗传基础,还能从转录后调控（miRNAs、LncRNAs等）和表观遗传学修饰（DNA甲基化、组蛋白修饰等）层面挖掘出相关的DNA和RNA变化及多分子间的相互作用规律,能够帮助我们更好地了解奶牛乳腺组织对病原体的免疫应答机制,筛选鉴定出乳房炎抗性的信号通路及关键候选基因,从而提高基因组预测或选择的准确性。利用蛋白质组学技术能够对不同环境不同状态的牛乳及乳腺组织的蛋白质种类、表达丰度、蛋白互作、翻译后修饰等进行比较分析,对差异表达的蛋白质经过COG功能注释、数据库比对、GO和Pathway富集分析,可以从蛋白水平揭示乳房炎发生及防御过程中的复杂调控机制,同时还能发现乳房炎诊断的标记分子,进而为乳房炎治疗药物的研发提供潜在的精准靶点。代谢组学是系统生物学的重要组成部分。通过代谢组学研究,能够同时对机体在内、外环境等复杂因素作用下及特定生理时期内所有低分子量代谢产物（如氨基酸、脂类、碳水化合物等）进行精准、高效的定性和定量分析,从而阐明相关的代谢途径;其作为基因表达的最下游,能使基因和蛋白质表达的微小变化在代谢物水平上得到放大,进而可以更充分地反映细胞功能。将代谢组学技术应用到奶牛乳房炎研究中,能够分析出差异代谢物、鉴定出相关的生物标志物,进而揭示奶牛乳腺的生理及病理变化过程。总之,将各组学技术及多组学整合关联分析应用到奶牛乳房炎研究中可以更深入地揭示其病原防御机制,进而为乳房炎的预测、诊断和治疗提供有价值的参考和借鉴。本文就最近几年组学技术在奶牛乳房炎领域的研究进展进行综述,以期为我国奶牛健康及奶业安全发展提供指导。     

干酪乳杆菌CRISPR基因座分析

目的 目前基于酿脓链球菌(Streptococcus pyogenes)spCas9为核心的CRISPR/Cas9基因编辑系统在乳酸菌上的应用受到很多限制,亟待开发适合于乳酸菌的基因编辑系统。对6株干酪乳杆菌(Lactobacillus casei)的CRISPR系统进行深入分析,并预测激活干酪乳杆菌自身Cas9蛋白所识别的PAM序列,为开发适用于乳酸菌的CRISPR/lcCas9基因编辑系统奠定基础。方法 以已完成全基因组测序的6株干酪乳杆菌为研究对象,利用生物信息学方法对其CRISPR系统进行深入分析,重点对不同菌株的CRISPR系统结构进行解析,并且对Cas蛋白以及spacer的同源性进行分析,最后对CRISPR区重复序列的二级结构以及Cas9蛋白识别的PAM序列进行预测。结果 6株干酪乳杆菌CRISPR系统具有相似的结构,均具有特征性的Cas9蛋白,并且Cas基因序列保守。预测到tracrRNA位于Cas9和Cas1之间,重复序列可以形成茎部长达7个碱基的二级结构。根据CRISPR的间隔区序列,6株干酪乳杆菌可被分为3个基因型,将间隔区逐一进行blast比对,结果表明6个间隔区比对上14个来源不同的原间隔序列,这些间隔序列均来源于不同质粒。干酪乳杆菌lcCas9蛋白识别PAM序列的1、3位碱基偏好T/C、A/C,2、4位碱基对G、A的偏好性比较大。结论 6株干酪乳杆菌CRISPR系统均为type-ⅡA型,Cas序列和重复序列高度保守。DR序列可以形成稳定的二级结构,TGMA为干酪乳杆菌Cas9蛋白高效识别的PAM序列。     

我国畜禽饲料资源中微量元素锌含量分布的调查

目的 研究我国不同地区间各种饲料原料中锌含量分布情况,以及我国畜禽基础饲粮中锌水平,为饲粮中合理添补锌提供科学依据。方法 对采自全国31个省、直辖市和自治区的37种共3 919个主要畜禽饲料原料,经微波消解后,用IRIS Intrepid II等离子体发射光谱仪测定其锌含量。主要畜禽饲料原料可分为七大类,包括谷类籽实（玉米、小麦、稻谷及大麦）、谷物籽实加工副产品（碎米、次粉、小麦麸、米糠、玉米DDGS、小麦DDGS、玉米胚芽粕及玉米蛋白粉）、植物性蛋白饲料（膨化大豆、豆粕、菜籽粕、棉粕、花生粕、亚麻粕、葵花粕）、动物性蛋白饲料（鱼粉、肉粉、水解羽毛粉、肠系膜蛋白粉、血浆蛋白粉和血球蛋白粉）、秸秆类饲料（玉米秸、甘薯藤、稻秸和小麦秸）、牧草类饲料（羊草、黑麦草、苜蓿和青贮玉米）和矿物质饲料（石粉、磷酸氢钙、贝壳粉和骨粉）。结果 结果表明：这37种饲料原料的平均锌含量范围为5.5—268.2 mg·kg ^-1之间,而各类饲料原料锌含量分布规律是：矿物质饲料（107.8 mg·kg ^-1）＞动物性蛋白饲料（69.8 mg·kg ^-1）＞植物性蛋白饲料（54.9 mg·kg ^-1）＞谷类籽实加工副产品（43.0 mg·kg ^-1）＞牧草类饲料（26.4 mg·kg ^-1）＞谷类籽实（22.7 mg·kg ^-1）＞秸秆类饲料（18.8 mg·kg ^-1）。同一类饲料中,除牧草类饲料中的锌含量无显著差异（P＞0.05）外,其他类别的不同饲料中的锌含量均存在显著差异（P＜0.05）,其中矿物质饲料锌含量以磷酸氢钙最高（268.2 mg·kg ^-1）,石粉最低（7.3 mg·kg ^-1）;动物性蛋白饲料锌含量以水解羽毛粉最高（120.8 mg·kg ^-1）, 血球蛋白粉最低（19.6 mg·kg ^-1）;植物性蛋白饲料锌含量以亚麻粕最高（85.2 mg·kg ^-1）, 膨化大豆最低（38.9 mg·kg ^-1）;谷物籽实加工副产品锌含量以小麦麸最高（86.2 mg·kg ^-1）,碎米最低（12.5 mg·kg ^-1）;谷类籽实锌含量以小麦最高（30.4 mg·kg ^-1）,玉米最低（16.9 mg·kg ^-1）;秸秆类饲料锌含量以稻秸最高（27.6 mg·kg ^-1）, 小麦秸最低（5.5 m·kg ^-1）。通过比较不同省（区）玉米、小麦和豆粕的锌含量发现,不同省（区）同一种饲料原料的锌含量均存在显著差异（P＜0.05）,其中广东省玉米锌含量最高（20.6 mg·kg ^-1）,而吉林省最低（13.7 mg·kg ^-1）;四川省小麦锌含量最高（41.4 mg·kg ^-1）,甘肃省最低（22.4 mg·kg ^-1）;山西省豆粕锌含量最高（51.5 mg·kg ^-1）,江苏省最低（46.6 mg·kg ^-1）。根据全国各地猪、鸡常用的142个饲粮配方所计算出的基础饲粮中锌含量范围为21.3—31.0 mg·kg ^-1,如按我国猪、鸡饲养标准或美国NRC畜禽锌营养需要量的要求,基础饲粮中锌含量可提供猪、鸡前期约1/4的锌营养需要,可提供猪、鸡后期约1/2的锌营养需要结论 不同种类和不同地区饲料原料中锌含量差异较大,全国各地猪、鸡常用的基础饲粮配方中锌含量可提供猪、鸡部分锌营养需要量。因此,在实际生产中,应充分考虑不同地区基础饲粮中的锌含量,精准配制饲粮,以满足畜禽高效生产的需要,同时减少锌的添加和排放对环境的污染。     

我国畜禽饲料资源中矿物元素含量分布的调查

<正>饲料是畜牧业赖以发展的物质基础,饲料成本约占整个畜禽养殖成本的60%—70%。三十多年来,我国饲料工业取得了巨大成就,走过了许多发达国家五十年甚至上百年才走完的历程,实现了世界第一大饲料生产国的飞跃,2018年我国饲料总产量已达2.28亿吨[1]。我国饲料工业的快速发展,有力地推动了我国畜牧经济的发展,改善了人们的物质生活水平。近年来,我国畜禽养殖业规模化、集约化发展迅速,饲料企业的规模和产品结构也发生了较大变化。一些小型饲料企业逐渐被淘汰,规模生产企业占绝对主导地位,配合饲料的比例越来越高,     

The Effect of Bat Guano Applied to the Soil in Different Forms and Doses on Some Plant Nutrient Contents

This research was conducted for the purpose of determining the effects of bat guano on plant nutrient contents in the soil and in lettuce (Lactuca sativa L.) during the spring of both 2014 and 2015 with three replications according to randomized blocks experiment design. Bat guano was applied to the soil in two different forms; According to the results organic matter, P, Cu and Mn amounts in the soil were found to be statistically significant and increased compared to the control. Likewise, in the application of bat guano dust, organic matter, P and Mn amounts in the soil were found to be statistically significant and increased compared to the control. In lettuce, N, K, Mg, Fe, Cu, Zn and Mn amounts in the application of bat guano powder and K, Ca, Mg, Fe, Zn and Mn amounts in the application of bat guano dust were found to be statistically significant.     

Quality Changes in Chum Salmon (Oncorhynchus keta) Caviar (ikura) Affected by Thermal Pasteurization,Storage Time,and Packaging Material

Changes in quality parameters including pH, water activity, texture, and lipid oxidation were studied in pasteurized chum salmon (Oncorhynchus keta) ikura samples packaged using two films with different oxygen transmission rates (OTR) (40 and 62 cm³·m^?2·day^?1; F-40 and F-62), during 60 days storage at 4°C. No significant differences in pH and water activity (a_w) were observed between ikura packaged using two different films with different OTR (P > 0.05). However, compared to the first day of study, water activity decreased significantly in ikura (P < 0.05). Ikura thiobarbituric reactive substance (TBARS) in the pouches significantly increased during the storage at 4°C (P < 0.05). Both pouches showed similar trends in TBARS until day 29, while after day 29, ikura packaged in F-62 (OTR = 62 cm³·m^?2·day^?1) showed a significant increase in TBARS compared to F-40 with less OTR (P < 0.05). The texture of ikura became softer compared to the first day; however, no significant difference was observed between the ikura samples in two pouches (P < 0.05). The quality changes of ikura measured during storage indicate that packaging ikura in a lower OTR film would provide greater quality retention than one with higher OTR.     

Growth performance,haematological and serum biochemical profiles in rainbow trout (Oncorhynchus mykiss) fed diets with varying levels of lupin (Lupinus albus) meal

A feeding experiment was conducted to study the response of rainbow trout juveniles fed different levels of lupin meal in diets for rainbow trout juveniles. Very limited information is available on the relationship between dietary lupin meal in rainbow trout health status. Therefore, this study aimed to determine the effects of lupin meal inclusion levels (0%, 15%, 30%, 45%, and 60%) on growth performance and health status of rainbow trout juveniles. The experimental diets (LM₀, LM₁₅, LM₃₀, LM₄₅, and LM₆₀) were formulated iso‐nitrogenous (41% crude protein) and iso‐calorific (18% crude lipid). The fish were fed twice a day. As a result, the best growth performance was observed in fish fed with LM₁₅ and LM₃₀ diets. No significant differences were detected among experimental groups in terms of body compositions. The haematological values showed significantly (p < 0.05) lower heamatocrit and mean cellular volume (MCV) in the group of LM₆₀ compared with the other groups. For the other haematological parameters such as haemoglobin, red blood cell and mean cellular haemoglobin studied in the present study no significant differences were observed (p < 0.05). The lupin meal included groups showed significant reduction in total protein (TPROT), triglyceride (TROG), cholesterol (CHOL), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) compared with the control group (p < 0.05). The inclusion of lupin meal did not cause any changes in glucose (GLU), glutamic oxaloacetic transaminase (GOT), and glutamic pyruvic transaminase (GPT) between the treatment groups (p < 0.05). In conclusion, lupin meal might be used in rainbow trout diets up to 30% without any malnutrition effect on growth performance, haemotological and serum biochemical parameters.     

Ultrasound-guided vessel catheterization in adult Yorkshire cross-bred pigs

Objective

To describe an ultrasound-guided approach for venous and arterial vascular access and catheterization in anesthetized adult Yorkshire cross-bred pigs.

Withdrawal time of four pharmaceutical formulations of enrofloxacin in poultry according to different maximum residues limits

San Martin, B., Cornejo, J., Lapierre, L., Iragüen, D., Pérez, F., Hidalgo, H., Andre, F. Withdrawal time of four pharmaceutical formulations of enrofloxacin in poultry according to different maximum residues limits. J. vet. Pharmacol. Therap. 33 , 246–251. To ensure delivery of safe animal products to consumers, the withdrawal time (WDT) of drugs must be respected. Property differences among pharmaceutical formulations, for the same drugs, can lead to differences in the WDTs estimation. The WDTs of four commercial formulations of enrofloxacin (ENRO) in broiler chickens, considering MRLs established by different countries, were studied. Two hundred‐thirty‐four broiler chicks were allotted among four groups; the formulations were orally administered daily with 10 mg/kg bw. After treatment, six chickens of each group and two controls were slaughtered daily until day 9 post‐treatment. Samples of muscle and liver were collected, and analyzed using HPLC‐MS‐MS. The WDTs among formulations of ENRO showed differences of 24 and 48 h. Based on the European Community and Chile MRLs of 100 μg/kg (muscle) and 200 μg/kg (liver), the WDTs did not exceed 5 days. When Japan MRL was considered (10 μg/kg_,), the WDTs increased up to 8 days. These results indicate that for WDTs determination, the differences among pharmaceutical formulations of a drug must be considered as well as the MRLs.     

Integrating Biochemical,Morpho-physiological,Nutritional, and Productive Responses to Cd Accumulation in Massai Grass Employed in Phytoremediation

Biosurfactants are promising substitutes for chemical surfactants during polycyclic aromatic hydrocarbon (PAH) bioremediation. However, recent studies have revealed contrasting findings and critical knowledge gaps regarding the impacts of biosurfactants on the soil PAH biodegradation efficiency and microbial community. Here, a laboratory study was conducted to evaluate the impact of rhamnolipid on the PAH dissipation efficiency and microbial community structure during the time-course incubation. The data showed that the contribution ratio of biotic loss and abiotic loss depended on the ring number of PAH. In the microcosms supplemented with 20 μg g^?1 rhamnolipid, the biodegradation efficiencies of phenanthrene, fluoranthene, and pyrene increased by 10.1%, 12.3%, and 22.0%, respectively, compared to those in the rhamnolipid-free treatment after incubation for 7 days. In contrast, rhamnolipid either had no impact on or inhibited PAH degradation in the later time points (21–35 days). The abundance of bacterial 16S rRNA and phnAc genes showed significant increase in soil amended of both PAH and rhamnolipid. MiSeq sequencing results revealed that potential PAHs-degrading Massilia, Bacillus, Lysobacter, Archrobacter, and Phenylobacterium became dominant genera in PAH treatment, irrespective of the rhamnolipid added. Nevertheless, PAH addition in the presence of rhamnolipid also significantly stimulated the growth of Delftia, Brevundimonas, Tumebacillus, and Geobacillus. In contrast, the rhamnolipid altered the microbial community composition through the selection of Gaiella, Solirubrobacter, Nocardioides, and Bacillus. The results reveal the intensive selectivity effect of PAH and rhamnolipid on the soil microbes that are involved in bioremediation, and highlight the positive effect on PAHs biodegradation.