响应面法优化常温饮用型酸乳配方

采用响应曲面法对常温饮用型酸乳的配方进行优化。用Plackett-Burman设计法研究全脂乳粉与乳清粉的蛋白比例、琼脂、淀粉、果胶、果糖和稀奶油添加量6 个因素对酸乳黏度及持水力的影响,筛选出影响酸乳黏度和持水力的显著因素,用Box-Behnken试验设计优化最佳配方。结果表明：全脂乳粉与乳清粉的蛋白比例、琼脂、淀粉及果胶添加量是影响常温饮用型酸乳黏度和持水力的显著因素（P＜0.05）;经过响应面试验设计建立黏度、持水力和4因素的模型,对此模型进行求解得到最佳配方为全脂乳粉与乳清粉的蛋白比例5∶1、琼脂     

Whole‐genome analysis identifying candidate genes of altitude adaptive ecological thresholds in yak populations

The domestic yak (Bos grunniens) is an iconic symbol of animal husbandry on the Qinghai–Tibet Plateau. Long‐term domestication and natural selection have led to a wide distribution of yak, forming many ecological populations to adapt to the local ecological environment. High altitude is closely related to oxygen density, and it is an important environmental ecological factor for biological survival and livestock production. The aim of the present study was to perform a preliminary analysis to identify the candidate genes of altitude distribution adapted ecological thresholds in yak using next‐generation sequence technology. A total of 15,762,829 SNPs were obtained from 29 yaks with high‐ and low‐altitude distribution by genome‐wide sequencing. According to the results of the selective sweep analysis with FST and ZHp, 21 candidate genes were identified. 14 genes (serine/threonine protein kinase TNNI3K, TEN1, DYM, ITPR1, ZC4H2, KNTC1, ADGRB3, CLYBL, TANGO6, ASCC3, KLHL3, PDE4D, DEPDC1B and AGBL4) were grouped into 32 Gene Ontology terms, and four genes (RPS6KA6, ITPR1, GNAO1 and PDE4D) annotated in 35 pathways, including seven environmental information processing and one environmental adaptation. Therefore, the novel candidate genes found in the current study do not only support new theories about high‐altitude adaptation, but also further explain the molecular mechanisms of altitude adaptation threshold in yaks.     

Audiograms estimated from brainstem tone-evoked potentials in dogs from 10 days to 1.5 months of age

The objective of this study was to build audiograms from thresholds of brainstem tone-evoked potentials in dogs and to evaluate age-related change of the audiogram in puppies. Results were obtained from 9 Beagle puppies 10-47 days of age. Vertex to mastoid brainstem auditory-evoked potentials in response to 5.1-millisecond Hanning-gated sine waves with frequencies octave-spaced from 0.5 to 32 kHz were recorded. Three dogs were examined at 10, 13, 19, 25, and 45 days. Four other dogs were examined at 16 days. Data from 7 dogs between 42 and 47 days of age were pooled to obtain audiogram reference values in 1.5-month-old puppies. The best auditory threshold lowered from above 60 dB sound pressure level (SPL) to values close to 0 dB SPL between 13 and 25 days of age and then stabilized. The audible frequency range widened, including 32 kHz in all tested dogs from the 19th day. In the 7 1.5-month-old puppies, the mean auditory threshold decreased by 11 dB per octave from 0.5 to 2 kHz. The auditory threshold was lowest and held the same value from 2 to 8 kHz. The mean auditory threshold increased by 20 dB per octave from 8 to 32 kHz. Near threshold, click-evoked potentials test only a small part of the audible frequency range in dogs. Use of tone-evoked potentials may become a powerful tool in investigating dogs with possible partial hearing loss, including during the auditory system maturation period.     

Defining the immune response to Ehrlichia species using murine models

Pathogenic bacteria belonging to the family Anaplasmataceae include species of the genera Ehrlichia and Anaplasma. Ehrlichia chaffeensis, first known as the causative agent of human monocytic ehrlichiosis, also infects several vertebrate hosts including white-tailed deer, dogs, coyotes and goats. E. chaffeensis is transmitted from the bite of an infected hard tick, such as Amblyomma americanum. E. chaffeensis and other tick-transmitted pathogens have adapted to both the tick and vertebrate host cell environments. Although E. chaffeensis persists in both vertebrate and tick hosts for long periods of time, little is known about that process. Immunological studies will be valuable in assessing how the pathogen persists in nature in both vertebrate and invertebrate hosts. Understanding the host immune response to the pathogen originating from dual host backgrounds is also important to develop effective methods of diagnosis, control and treatment. In this paper, we provide our perspective of the current understanding of the immune response against E. chaffeensis in relation to other related Anaplasmataceae pathogens.     

超高压提取黄精多糖及提高运动耐力机制

为确定炮制黄精多糖(PPP)的最佳提取工艺,本试验以黄精为原料,进行炮制,利用超高压技术提取PPP,分析了压力强度、保压时间、料液比对PPP提取率的影响,采用Box-Behnken响应面分析法(RSM)优化PPP提取条件,并对所得多糖进行动物体内试验,分析小鼠血清、肝脏和左腿腓肠肌中相关酶的活性变化,探究其提高机体运动耐力机制。结果表明,PPP最佳提取工艺条件为:液料比23 mL·g^-1、保压时间6.73 min,压力强度293 MPa,在此条件下PPP得率为13.46%;能显著提高小鼠力竭游泳时间(P<0.05),相比于游泳对照组,小鼠血清中尿素氮(SUN)、乳酸(Lac)和肝脏丙二醛(MDA)含量显著下降(P<0.05),同时乳酸脱氢酶(LDH)活性下降、Ca²⁺Mg²⁺-ATP酶及肌酸激酶(CK)活性上升,对提高小鼠运动耐力具有较好的效果。本研究结果为超高压提取PPP奠定了基础,并为PPP提高运动耐力的机制研究提供了数据支持。     

血浆极低密度脂蛋白浓度的双向选择对肉鸡腹脂、肝脂和产肉性能的影响

对零世代８周龄血浆极低密度脂蛋白（ＶＬＤＬ）浓度进行降低腹脂的间接选择，一世代取得了明显效果：腹脂和肝脂向两极分化，其中肌胃脂和肝脂选择反应较大。低血浆ＶＬＤＬ的选择使腹脂降低，肝脂增加，对产肉性状未产生不利影响。９周龄腹脂率、板油率和肌胃脂率在高ＶＬＤＬ系分别高于低ＶＬＤＬ系２１％，１６％和５１％；肌胃脂率品系间差异极显著（Ｐ＜０．００１）。品系与性别互作对肌胃脂率有明显影响（Ｐ＜０．０５）。腹脂、肌胃脂存在性别差异，腹脂率雌性略高于雄性，而肌胃脂率雄性高于雌性。９周龄肝脂率，高ＶＬＤＬ系显著低于低ＶＬＤＬ系（Ｐ＜０．０１），雌性高于雄性。一世代８周龄血浆ＶＬＤＬ产生了直接选择反应，血浆ＶＬＤＬ浓度，高ＶＬＤＬ系高于低ＶＬＤＬ系。血浆ＶＬＤＬ存在性别差异，雄性高于雌性。一世代高、低ＶＬＤＬ系血浆ＶＬＤＬ和腹脂的变异系数仍然很大，继续对其选择仍然有效。由于血浆ＶＬＤＬ属中等遗传力，并且家系间差异显著，因此，在世代选育中应采取家系结合个体选择法     

啤酒糟制备低聚木糖功能饲料添加剂酶解条件优化

为提高啤酒糟的饲用价值,开发啤酒糟功能性饲料添加剂,对啤酒糟采用碳酸钠和双氧水进行预处理,采用单因素试验和响应面分析法,对啤酒糟制备低聚木糖饲料添加剂的酶解条件进行了研究。结果表明:当初始pH5.5,木聚糖酶201 U/g,纤维素酶248 U/g,酶解温度48℃,酶解时间3 h时,啤酒糟中低聚木糖含量为23.8673 mg/g。     

Response to lipopolysaccharide in Octodon degus pups produces age‐related sickness behavior but does not have effects in juveniles

During vertebrate development, the immune function is inefficient and is mainly controlled by innate defense. While there have been detailed studies of various aspects of innate immune function, the effects of this function in the growth of vertebrates is still not well known. Similarly, there is little information regarding how early endotoxin exposure would affect juvenile phenotypes, specifically in a non‐model mammal like a precocial rodent. We evaluated the response to an antigen and its cost in offspring of the rodent Octodon degus. We inoculated pups at 4 different ages (8, 15, 22 and 30 days after birth) with an antigen to determine the ontogeny and costs of the response to an endotoxin. We assessed changes in body mass, body temperature, sickness behavior and the levels of a key mediator of the inflammatory response, the cytokine interleukin‐1β. We also determined the effects of early endotoxin exposure on the resting metabolic rate of juvenile animals (i.e. 90 days after birth). The cytokine levels, body mass and body temperature were unaffected by time of inoculation and treatment. However, pups subjected to inoculation at 22 days after birth with the antigen showed reduced locomotion. Juvenile resting metabolic rate was not affected by early endotoxin exposure. These results suggest that the magnitude of O. degus responses would not change with age. We discuss whether the lack of effect of the response on body mass or body condition is caused by environmental variables or by the precocial characteristics of O. degus.     

树莓叶黄酮提取的正交试验和响应曲面法工艺优化对比

旨在为树莓叶黄酮的开发应用提供数据参考,通过正交试验与响应曲面法设计改良乙醇提取工艺,并通过HPLC建立树莓叶黄酮的色谱分离条件为:Agilent ZorBax SB色谱柱,流动相为1mg/mL乙酸-乙腈=72.5∶27.5,等度分离,柱温30℃,检测波长:257nm,完成树莓叶黄酮的初步分离,以及黄酮中芦丁含量的准确测定和验证。最佳提取工艺为:646mL/mL乙醇,料液比1∶12.5,41.9℃加热回流173.3min,最佳工艺所得提取率1.127%,响应曲面法最佳工艺提取率略高于正交试验法,且其工艺条件均较优于正交试验所得工艺,可为后期研发树莓叶芦丁兽用中药制剂提供理论参考。