不同饲养方式对固始鸡生产性能的影响

将固始鸡饲养至4周后,分别笼养和放养至18周,测量其体尺、屠体性能,到42周龄测量蛋品质。结果表明,笼养和放养的活重差异显著(P>0.05),其余屠宰指标差异不显著;蛋品质除了蛋重和蛋壳厚度差异显著(P<0.05)外,其余指标差异均不显著;放养条件下,纤维素酶高于笼养,而对总蛋白水解酶、胰蛋白酶和胃蛋白酶影响不显著。     

植物低聚糖提取和生物活性鉴定

应用酶解法从小麦细胞壁中提取出低聚糖。经过活性鉴定,具有诱导大豆和小麦抗毒素产生,特别是从小麦代谢、细胞、植株等水平上改善该作物体内防御功能等生物作用。水解酶的种类、纯度、酶活值与所降解低聚糖的活性程度密切相关;高纯度、高酶活单位的水解酶提取的低聚糖,具有较强的生物功能。对来源不同的低聚糖进行了活性差异的比较,同时还讨论了其它因素——诸如小麦细胞的生理状态,低聚糖保存条件等对低聚糖活性的影响。     

干酪乳杆菌LC2W细胞壁组分体外对巨噬细胞活性的影响

探讨干酪乳杆菌LC2W细胞壁组分体外对小鼠巨噬细胞功能的影响。以培养液单纯培养小鼠巨噬细胞系RAW264.7细胞作为对照,研究干酪乳杆菌LC2W细胞壁主要组分磷壁酸和肽聚糖对RAW264.7细胞代谢水平、吞噬中性红能力及释放NO的影响。不同浓度磷壁酸和肽聚糖对小鼠巨噬细胞RAW264.7细胞代谢MTT能力、吞噬中性红能力有明显增强作用,并呈一定的剂量效应,在相同质量浓度时,两种细胞壁组分激活巨噬细胞能力无显著差异。同时诱导产生NO量也随着浓度增大而增加,当浓度达到50μg/mL时,磷壁酸诱导能力显现出较高的水平。干酪乳杆菌LC2W细胞壁主要组分磷壁酸和肽聚糖能激活小鼠巨噬细胞RAW264.7细胞,提高其代谢水平及吞噬能力,同时可诱导具有杀瘤作用的活性因子,并具有一定的剂量效应。     

基于毛细管网的日光温室主动式集放热系统研究

为了对比日光温室传统保温蓄热后墙与基于毛细管网的主动式集放热系统（AHSCTM）的集放热性能,对AHSCTM的集放热性能进行了测试,构建了AHSCTM水温模型,利用一维差分法对相同环境条件下的外保温复合墙（370mm黏土砖和100mm聚苯乙烯板复合而成）日间储热量和夜间放热量进行了模拟。结果表明,AHSCTM的日间储热量和夜间放热量分别为相同条件下外保温复合墙的84.4%~111.3%和74.8%~100.7%,AHSCTM的COP（Coefficient of performance）为1.1~2.4。在夜间运行期间,AHSCTM放热量是相同时间段内外保温复合墙的98.2%~172.5%。因此,与外保温复合墙相比,AHSCTM有利于提高室内最低气温。改进AHSCTM的日间储热量和夜间放热量得到大幅提升,分别较外保温复合墙高67.6%~112.1%和69.0%~128.3%,COP可达2.8~7.0。改进AHSCTM的储放热性能优于外保温复合墙,说明利用改进AHSCTM配合保温墙体替代传统保温蓄热后墙是可行的。     

客车车身骨架强度与刚度的有限元分析

讨论了客车车身骨架有限元模型的建立。对车身骨架结构进行了水平弯曲、极限扭转、紧急转弯和紧急制动工况下的强度、刚度以及模态分析,得到骨架结构的应力、应变、扭矩和弯矩分布情况。最后通过静态应力试验验证该模型的正确性。     

Specific dynamic action in two body size groups of the southern catfish (<Emphasis Type="Italic">Silurus meridionalis</Emphasis>) fed diets differing in carbohydrate and lipid contents

Specific dynamic action (SDA), the energy costs associated with meal digestion and assimilation, is generally affected by body size and food composition. We assessed the postprandial metabolic response and calculated SDA in two size groups of the southern catfish (Silurus meridionalis), each fed one of two diets, high lipid or high carbohydrate, at a meal size of 4% the body mass. Using a continuous-flow respirometer, we determined the oxygen consumption rate at 2-h intervals until the postprandial oxygen consumption rate returned to the prefeeding level. None of the parameters (resting metabolic rate, Rpeak, factorial ratio, time-to-peak, duration, energy expended on SDA, or SDA coefficient) were significantly affected by diet nor was there an interaction between diet and body mass. Rpeak and energy expended on SDA for the whole fish body were significantly higher in the larger fish than the smaller one in both dietary treatments, whereas no significant effect of body size was found in mass specific values. Factorial ratio (range 3.41 to 3.60), peak time (range 9.6 to 12.7 h), SDA coefficient (range 9.36 to 10.36%), and SDA duration (range 62.0 to 71.0 h) did not significantly differ between body size groups. These results suggest that in S. meridionalis the percentage of assimilated energy allocated to SDA may be independent of the body mass.     

Intracellular calcium alterations induced by endotoxin and IL-1β in rabbit hypothalamic neurons

AIM: To investigate intracellular free calcium ( [Ca²⁺]i ) alterations in hypothalamus of febrile rabbits induced by endotoxin (ET), and compare with the effect of ET and IL-1β on i in hypothalamic neurocytes from normothermia rabbits. METHOD: The concentration of [Ca²⁺]i was determined by using spectrofluorometer and fluorescent Ca²⁺ probe fura-2 /Am. RESULTS: 1. A minute dose of ET (2 ng/mL) induced a significant rise in [Ca²⁺]i in hypothalamic neurocytes from normothermia rabbits. The rise in [Ca²⁺]i in hypothalamic neurocytes from febrile rabbits induced by intravenous injection of ET was also observed. 2. In hypothalamic neurocytes from normotheria rabbits, IL-1β failed to affect [Ca²⁺]i at concentrations of 100, 500, 1 000ng/mL, respectively. CONCLUSION:The action site of low concentration of calcium that plays a regulatory role during fever seems unlikely to be in cytosolic compartment of hypothalamic neurons. The change of [Ca²⁺]i in hypothalamic neurocytes by ET can not be considered the direct effect of IL-1β.     

西施舌形态性状与体质量性状的相关性分析

为研究西施舌(Coelomactra antiquata)野生群体壳体性状对体质量性状的影响,文章以广西北海铁山港海区采集的178只西施舌为研究对象,测量壳高(SH)、壳长(SL)、壳宽(SW)、前缘长(AL)、后缘长(GL)、壳质量(SM)、软体部质量(VM)、活体质量(BM),以壳体性状(SH、SL、SW、AL、G...     

高二氧化碳结合低氧处理对杏鲍菇细胞壁的影响

旨在研究高二氧化碳结合低氧处理对杏鲍菇细胞壁成分（蛋白质、多糖、几丁质）、咀嚼度及超微结构的影响。在温度（22±1）℃、相对湿度90％～95％的条件下,以空气为对照（CK）,采用气调（CA,2％O2＋30％CO2）对杏鲍菇进行货架期试验。结果表明,货架期间CA的咀嚼度显著高于CK。 CA可以有效延缓杏鲍菇细胞壁水溶性蛋白质和1 mol/L NaOH可溶性蛋白质的降解,维持了细胞壁总蛋白质含量及细胞壁结构完整。 CA有效抑制杏鲍菇多糖含量的下降,其对水溶性多糖、10 mol/L NaOH可溶性多糖分解的抑制作用较为明显。此外,CA显著促进了水溶性几丁质、10 mol/L NaOH可溶性几丁质、HCl/1 mol/L NaOH可溶性几丁质的积累,延缓其分解,有效抑制了杏鲍菇细胞壁几丁质含量的下降,有助于维持其硬度及咀嚼度。杏鲍菇超微结构结果也表明, CA保持杏鲍菇细胞壁结构的完整性与稳定性,较好地维持杏鲍菇咀嚼度。综上所述,CA通过影响菇体细胞壁的代谢来保持杏鲍菇的食用品质。