Multi‐level mixed models for evaluating factors affecting the mortality and weaning weight of piglets in large‐scale commercial farms in central China

This study investigated the factors affecting piglet mortality (square root of mortality, SQRM) and average weaning weight (AWW) in commercial farms in central China. Information on sow diets, management and climate from 2478 weaning batches completed in 16 pig farms was collected from 2009 to 2013. Multi‐level mixed models, which included batch level (level 1) and farm level (level 2), were used to analyze the factors associated with SQRM and AWW. The mean values of SQRM and AWW were 2.52% (SD = 0.96) and 7.31 (SD = 0.77), respectively. Lactation sow diets supplemented with oregano essential oils (OEOs) decreased the SQRM (P < 0.05) and increased the AWW of piglets (P < 0.01). The SQRM was lower in period 2 (June to September, hot) than in period 1 (February to May, warm) and period 3 (October to January, cold; P < 0.05 and 0.001, respectively). The AWW was lower in periods 2 and 3 than in period 1 (P < 0.01). In conclusion, supplying OEOs to lactation diets can increase the weaning weight and reduce the mortality of piglets. The sources of variations in SQRM and AWW are of greater concern in the warm season than in the hot season.     

Seasonal variations in the diet and food selection of the Algerian hedgehog Atelerix algirus

The Algerian hedgehog Atelerix algirus is an insectivorous species. However, the exact composition of its natural diet remains largely undetermined, especially in relation to seasonal variations in food availability. From March to November, we simultaneously analysed the composition of 180 hedgehog faecal samples and food availability in the Soumman Valley, Algeria to assess food selection in this species. The faeces contained 196 different prey species, of which 92% belonged to the class Insecta. The highest prey species diversity was found in the Coleoptera order (100 species recorded) and the highest species occurrence was found in Hymenoptera (65% of the prey items, mainly represented by the harvester ant Messor barbarus, a crop-ravaging species). This study shows that the Algerian hedgehog is mainly a generalist species with a diet that is strongly linked to food availability. However, seasonal variations were observed in prey selection, and a notable shift in food preference was observed during autumn. The exact nature of these changes in feeding behaviour remains to be investigated, notably in relation to changes in energy requirements of this species before hibernation, in terms of quantity and/or quality.     

Exploiting a readily available but hard to digest resource: A review of exudativorous mammals identified thus far and how they cope in captivity

Gum is a widely available carbohydrate, composed mainly of non‐digestible structural carbohydrates. No mammalian enzymes can digest gum; therefore, a mammal ingesting gum must rely on microbial fermentation to access the energy it possesses. Gums are relatively nutrient poor. Despite this, some mammals have evolved to exploit this food resource. We aim to review the literature for all mammal species which have been recorded to ingest gum, whether quantified or not, and discuss this in the context of their evolutionary adaptations. We also investigated the recommended captive diets for these species to look at whether gum is recommended. We conducted a literature search on ISI Web of Knowledge to tabulate all mammal species observed ingesting gum and classified them as obligate, facultative or opportunistic feeders. We encountered 94 mammal species that eat gum in the wild (27 obligate feeders, 34 facultative feeders and 33 opportunistic feeders). Obligate feeders have entirely evolved to exploit this resource but were found to not be given gum in captivity, which may explain why they are failing to thrive, as opposed to facultative feeders, which have fewer issues. Gum may be necessary for the health of obligate feeders in captivity. Future research should focus on the physiological effects that gum ingestion poses on different digestive systems.     

β-丙氨酸的生理功能及其在动物生产中的应用

β-丙氨酸是一种不参与蛋白质合成的氨基酸,为肌肽、鹅肌肽等肌源活性肽合成的前体物,作为增强肌肉耐力的运动营养补充剂已经广泛应用于临床营养。研究表明,β-丙氨酸可提高动物生产性能,调控肌肉生长和肌源活性肽含量,改善肉品质量。本文旨在对β-丙氨酸的来源和代谢、生理功能及其在动物生产领域的应用进行综述,为β-丙氨酸在动物营养调控和生产实践中的应用提供理论依据。     

不同钾水平下花魔芋差异表达基因分析

为了探索魔芋对不同水平钾素营养的反应机制,提取施用低、中、高水平硫酸钾5d后的富源花魔芋叶片总RNA,合成了c DNA,采用优化的c DNA-SRAP技术体系分析了在低钾、中钾、高钾水平下富源花魔芋叶片的差异表达基因,并对其进行了生物信息学分析。结果显示:29对引物组合共扩增出507条基因片段,其中差异片段126条。相对于中钾处理,低钾、高钾处理的差异片段包括抑制型表达片段19条,诱导型表达片段14条,上调表达型片段29条,下调表达型片段64条。选取表达量高的13条差异片段进行回收测序,并在NCBI上进行BLAST比对,共比对出9条差异片段的同源序列,其中4条与已知功能基因(谷氨酰胺酰-t RNA合成酶、β-ATP合成酶、GTP结合蛋白、核苷酸还原酶)有较高同源性,5条与假定基因或预测基因同源性较高,剩余序列未找到同源序列,可能是一些新的魔芋与钾营养吸收利用相关的基因,具体功能还有待于进一步研究。     

Salt marshes – present functioning and future change

Salt marshes are no longer viewed as intertidal wastelands of little value to anyone. They are now widely recognised as playing a major role in coastal defence, in wildlife conservation on the coast and as a key source of organic material and nutrients vitally important for a wide range of marine communities. This appreciation of the importance of salt marshes has been brought even more sharply into focus because of the threats posed by predicted rise in sea level as a result of global climatic change. Three decades ago the possibilities of exchanges of organic matter between salt marshes and the sea were already being recognised in certain areas but it is only in the past five years or so that this process has been studied in a wide range of different areas. Detailed studies have been made into the way that salt marsh fluxes change with the development of increasingly mature and, therefore, increasingly complex salt marsh communities. As well as being sources and sinks of mineral nutrients and organic matter, salt marshes can also function as a sink for pollutants that would otherwise be damaging to the environment. Salt marshes also act as a sink for sediment within coastal ecosystems. Through their various functions they can be seen to be acting as dynamic living filters for various ecologically important materials. With increasing threats to the survival of salt marshes as a result of man's activities in the coastal zone being augmented by the threats from predicted sea level rise, a new approach to salt marsh conservation has come to the fore and that is the actual creation of new salt marshes. For this process to be fully effective we have to make full use of our increased understanding of salt marsh structure and function. Following a review of the current state of the art in the field of salt marsh research, an assessment is made of specific future research needs. Despite the greatly increased effort which has been directed to salt marsh research over the past few years we still have to recognise that resources are limited and, therefore, critical evaluations of the various options regarding the direction of our future efforts need to be made.     

神府煤田大柳塔镇的土壤资源及其养分评价

本文概述了神府煤田在柳塔镇辖区内的土壤类型及其分布和土壤的基本理化性质。并应用模糊综合指数法对区内土壤养分状况进行评价,表明河谷川道区及部分沟底地土壤养分充足;而盖沙丘陵区的长期耕种和培肥的土壤养分充足,但是不便于培肥的农地土壤以及稀疏草地土壤养分缺乏。根据养分的测定值及养分的模糊综合评价结果,提出了培肥土壤和提高土壤有效养分途径。     

雷达液位计在黄岛地下油库罐位监测中的应用

在黄岛地下油库改造工程中,分别在１号和３号地下储罐安装了雷达液位计监测系统,该系统可通过天线发出到达介质液面的发射液,检测出其与反射波之间的频率变化,与被测液面距离成正比关系,能够准确地计算出罐存介质的液位,并可同时将液位、温度及裂隙水位等重要数据传至地面控制中心进行监测,减轻了工人的劳动强度,提高了安全生产的保障系数。该系统具有精度度高、传输速度快、防爆性能好及维修方便等特点。介绍了系统的结构原     

几种常用中草药对皱纹盘鲍摄食行为的影响

通过实验观察了皱纹盘鲍对党参、黄芪、当归、白术、白芍、麦芽、莱菔子、神曲、山楂、鸡内金１０种中草药的摄食行为反应,发现均未对皱纹盘鲍产生驱避效应,其中山楂还表现出诱食活性。结果表明这１０种中草药均可作为皱纹盘鲍的饲料添加剂。     

高比例添加农产品工业加工下脚料对肉猪生长性能的影响

选用豆腐渣、啤酒渣、淀粉下脚料、酒精糟液、酱渣和药渣６种工业加工下脚料,作为肉猪配合饲料的主要来源进行不同比例的添加,经过１４０天生长育肥饲养试验表明,添加５０％以上多种加工下脚料替代常规饲料,肉猪日增重提高５％,饲料成本降低１３％～２５％,经济效益提高６４％～８４％,每头猪比喂常规饲料组多盈利８０～１０８元。而屠宰猪屠宰率、瘦肉率和胴体品质不受影响。