Effect of yeast with bacteriocin from rumen bacteria on laying performance,blood biochemistry,faecal microbiota and egg quality of laying hens

The purpose of this study was to evaluate the effect of yeast with bacteriocin from Ruminococcus albus 7 (albusin B) on physiological state and production performance of laying hens. One hundred and twenty 26‐week‐old Single Comb White Leghorn (Hyline) laying hens were assigned into five groups including: (i) control group, (ii) yeast control (YC), (iii) 0.125% yeast with bacteriocin (0.125B), (iv) 0.25% yeast with bacteriocin (0.25B) and (v) 0.5% yeast with bacteriocin (0.5B). All supplements were added to the experimental diets of the hens from 26 to 46 weeks of age. Samples were collected every 4 weeks. Blood samples were collected from the wing vein for blood biochemical parameters assay, and faecal samples were collected by swab for the microbiota test. The egg production performance was recorded daily, and fresh eggs were collected for quality test. The blood biochemical assay results indicated that the addition of yeast with bacteriocin decreased the AST (aspartate aminotransferase) activity and it also affects the lactate concentration in laying hen blood. The result of egg quality indicated that yeast with bacteriocin supplementation had no effect on the mass of yolk and the strength of eggshell, but it had positive effect on the laying performance under hot environment. Low concentration bacteriocin (0.125B) supplementation could decrease total yolk cholesterol. The faecal microbiota result indicated that the supplementation of bacteriocin increased the lactobacilli counts. The yeast with bacteriocin supplementation significantly decreased the clostridia counts under hot environment condition, especially in hens receiving 0.25B. Combining the data from clinic chemistry, faecal microbiota, egg production and egg quality, the 0.25B supplementation may result in the best physiological parameter and egg production performance of laying hen.     

黄土丘陵区白羊草与达乌里胡枝子混播草地土壤呼吸日变化特征

土壤呼吸是反映土壤质量和肥力性状的重要指标,阐明禾―豆混播草地土壤呼吸作用的变化规律及其影响因素,可以为准确评估混播草地的环境效应及响应提供依据。在2011和2012年6月份,采用动态密闭气室分析法,比较了白羊草(Bothriochloa ischaemum)与达乌里胡枝子(Lespedeza davurica)不同比例间作混播草地总土壤呼吸速率的日变化特征、混播植物贡献率以及温度敏感性等。结果表明,不同混播比例草地的总土壤呼吸速率日变化为单峰型曲线,峰值出现在12:00~14:00。总土壤呼吸速率日均值高低顺序为单播白羊草白羊草和达乌里胡枝子间作单播达乌里胡枝子。不同间作比例草地的总土壤呼吸速率与白昼气温相关显著(P0.05),而与5、10和15 cm土层白昼土壤温度关系不明显;单播条件下,白羊草草丛的土壤呼吸对温度的敏感性高于达乌里胡枝子;各草地土壤呼吸Q10值的变化范围为1.48~2.61,以单播白羊草最高,单播达乌里胡枝子和两者间作混播草地间无显著差异(P0.05)。     

镉对苗期高羊茅的形态和生理影响

以20份高羊茅(Festuca arundinacea)品种为试验材料,通过测量其形态指标,运用标准差系数赋予权重法,对其进行综合评价。结果筛选出耐镉性较强的高羊茅材料M15和M8,分别采自美国的猎狗5和荷兰的巴弗斯;耐镉性较差的高羊茅材料M5和M11,分别采自荷兰的米斯特拉尔和来自日本的法恩。在此基础上,采用分光光度法,测定了这4份材料的生理指标,过氧化物酶(POD)、过氧化氢酶(CAT)、叶绿素和脯氨酸(Pro)含量的变化,进一步研究了他们的生理反应。结果表明,随着镉浓度的升高,耐镉性较强的高羊茅材料猎狗5与和巴弗斯POD和CAT含量一直呈上升趋势,而耐镉性较差的材料米斯特拉尔和法恩POD和CAT含量则呈现先升后降的趋势。随着镉浓度的升高,不同材料的叶绿素含量呈下降趋势,不同材料的脯氨酸含量则呈不断上升趋势。     

盐胁迫下外源Ca~(2+)对红豆草幼苗抗性生理的影响

以蒙农红豆草为材料,研究了100mmol/L NaCl胁迫下不同浓度外源Ca2+对红豆草幼苗的生长、脯氨酸、可溶性糖和叶绿素含量及根系活力的影响;探讨了Ca2+对盐胁迫伤害的缓解作用。结果表明:随着Ca2+浓度的增加,与CK相比,红豆草脯氨酸、可溶性糖、叶绿素含量及根系活力呈先升高后降低的明显变化趋势,在T3(100mmol/L NaCl+30mmol/L CaCl2)处理下,红豆草脯氨酸、可溶性糖及叶绿素含量与对照相比提高了32.3%,60.0%和9.7%,差异显著(P0.05);T3、T4处理的根系活力显著高于CK(P0.05),其他处理与CK无明显差异;T3处理的株高显著高于对照CK(P0.05),其他处理与CK间无显著差异,达到最佳的效果。     

ASSESSMENT OF RESPIRATION‐INDUCED DISPLACEMENT OF CANINE ABDOMINAL ORGANS IN DORSAL AND VENTRAL RECUMBENCY USING MULTISLICE COMPUTED TOMOGRAPHY

Respiratory‐induced organ displacement during image acquisition can produce motion artifacts and variation in spatial localization of an organ in diagnostic computed tomography (CT) examinations. The purpose of this prospective study was to quantify respiratory‐induced abdominal organ displacement in dorsal and ventral recumbency using five normal dogs. All dogs underwent CT examinations using 64 multidetector row CT (64‐MDCT). A “3‐dimensional (3D) apneic CT exam” of the abdomen was acquired followed by a “4‐dimensional (4D) ventilated CT exam.” The liver, pancreas, both kidneys, both medial iliac lymph nodes, and urinary bladder were delineated on the 3D‐apneic examination and the organ outlines were compared to the maximum alteration in organ position in the 4D‐ventilated examination. Displacement was measured in dorsal‐to‐ventral (DV), right‐to‐left (RL), and cranial‐to‐caudal (CC) directions. Respiratory‐induced displacement of canine abdominal organs was not predictable and showed large variability in the three directions evaluated. For most canine abdominal organs, dorsal recumbency provided overall the least amount of displacement among all directions evaluated except for liver and urinary bladder. For liver, a large variability was found for all directions and a statistically significant difference was found only in the RL direction with ventral recumbency exhibiting less displacement (P = 0.0099). For the urinary bladder, ventral recumbency also provided less displacement but this was statistically significant only in the RL direction (P < 0.0001). Findings from this study indicated that dorsal recumbency may be preferred for minimizing respiratory motion artifacts in whole abdomen studies, but ventral recumbency may be preferred for liver and urinary bladder studies when respiration cannot be controlled.     

Comparison of the effects of propofol or alfaxalone for anaesthesia induction and maintenance on respiration in cats

ObjectiveTo compare the effects of propofol and alfaxalone on respiration in cats.Study designRandomized, ‘blinded’, prospective clinical trial.AnimalsTwenty cats undergoing ovariohysterectomy.MethodsAfter premedication with medetomidine 0.01 mg kg⁻¹ intramuscularly and meloxicam 0.3 mg kg⁻¹ subcutaneously, the cats were assigned randomly into two groups: group A (n = 10) were administered alfaxalone 5 mg kg⁻¹ minute⁻¹ followed by 10 mg kg⁻¹ hour⁻¹ intravenously (IV) and group P (n = 10) were administered propofol 6 mg kg⁻¹ minute⁻¹ followed by 12 mg kg⁻¹hour⁻¹ IV for induction and maintenance of anaesthesia, respectively. After endotracheal intubation, the tube was connected to a non-rebreathing system delivering 100% oxygen. The anaesthetic maintenance drug rate was adjusted (± 0.5 mg kg⁻¹ hour⁻¹) every 5 minutes according to a scoring sheet based on physiologic variables and clinical signs. If apnoea > 30 seconds, end-tidal carbon dioxide (Pe′CO₂) > 7.3 kPa (55 mmHg) or arterial haemoglobin oxygen saturation (SpO₂) < 90% occurred, manual ventilation was provided. Methadone was administered postoperatively. Data were analyzed using independent-samples t-tests, Fisher's exact test, linear mixed-effects models and binomial test.ResultsManual ventilation was required in two and eight of the cats in group A and P, respectively (p = 0.02). Two cats in both groups showed apnoea. Pe′CO₂ > 7.3 kPa was recorded in zero versus four and SpO₂ < 90% in zero versus six cats in groups A and P respectively. Induction and maintenance dose rates (mean ± SD) were 11.6 ± 0.3 mg kg⁻¹ and 10.7 ± 0.8 mg kg⁻¹ hour⁻¹ for alfaxalone and 11.7 ± 2.7 mg kg⁻¹ and 12.4 ± 0.5 mg kg⁻¹ hour⁻¹ for propofol.Conclusion and clinical relevanceAlfaxalone had less adverse influence on respiration than propofol in cats premedicated with medetomidine. Alfaxalone might be better than propofol for induction and maintenance of anaesthesia when artificial ventilation cannot be provided.     

透明质酸生理功能及其应用研究进展

透明质酸是一种在体内广泛分布的黏多糖,已成功用于骨科、眼科、整形美容、保健食品等领域,但仍有许多新的应用领域不断被开发。主要介绍了透明质酸的生理功能,并结合透明质酸的结构特性,综述了透明质酸在保健食品、化妆品、美容、骨科、眼科等几个方面应用的研究进展。     

林地土壤压实对土壤呼吸影响的数学模型研究

介绍土壤呼吸对于林地树木生长的重要性。分析人工干扰等外力作用导致土壤压实,使土壤容重增加,改变土壤孔隙度和二氧化碳浓度等。通过对影响因素和机理的分析,从微观角度利用微分原理,推导出土壤压实对土壤呼吸影响的数学模型,并就各主要影响因素对土壤呼吸的影响进行简要分析。