Effects of an aqueous alfalfa extract on production performance, egg quality and lipid metabolism of laying hens

The present study was conducted to evaluate the effect of an aqueous alfalfa extract (AAE) on production performance, egg quality and lipid metabolism of laying hens between 28 and 36 weeks of age. Four groups of commercial hens (Hy-Line Brown) were fed with diets containing 0, 0.05%, 0.1% and 0.15% AAE. Dietary AAE had no effect on egg production parameters (p > 0.05). Shell strength was increased (linear and quadratic effects; p < 0.05) with gradient addition of AAE. Furthermore, shell strength was notably higher (p < 0.05) in 0.1% and 0.15% AAE groups than the control group. With an exception of serum low and high density lipoprotein cholesterol, serum total triglycerides and liver cholesterol concentration (day 42), lipid indices in yolk, serum and liver were lowered (linear and quadratic effects; p < 0.05) at day 42 and day 56 as AAE in diets increased, as well as the enzyme activities of acetyl-CoA carboxylase (ACC) and β-hydroxy-β-methylglutaryl-CoA (HMG-CoA) reductase. In relation to the control group, cholesterol and triglycerides in yolk, liver and serum and serum very low density lipoprotein cholesterol were lower in 0.15% AAE-treated birds at day 42 and day 56. It also significantly decreased activities of ACC, HMG-CoA reductase and fatty acid synthetase (FAS) at day 56. The 0.1% AAE decreased triglycerides in yolk, liver and serum, as well as the activities of ACC and FAS at day 56. These data suggest that dietary AAE could be applied to improve egg shell quality and modify the lipid status of laying hens and eggs.     

生物质能的热化学转化技术

生物质能源是未来替代化石资源的丰富和可再生清洁能源之一,它具有二氧化碳中性。生物质的热化学转化可以形成固、液、气3种形态的生物质能源,用以提供热能和动力。对生物质热化学转化中的燃烧、气化、液化和热解技术进行阐述,同时提出生物质热值低、运输贮存不易、反应副产物难分离和政策、资金投入力度仍需加大等问题,对生物质能源发展和研究进行展望。     

城镇居民奶制品消费行为分析——基于新疆的问卷调查

本文依据2008年新疆城镇居民奶制品消费状况的问卷调查数据,对城镇居民的奶制品消费习惯和消费行为进行了分析。调查显示,消费者选购奶制品有明显的消费倾向,奶制品消费的区域性和消费需求的多样化特征十分明显;城镇居民以液态奶的消费为主,尚无固态奶的消费习惯,奶类消费水平还不高;不同性别、民族、职业和文化程度消费者的奶制品消费行为存在一定差异;绝大多数消费者对奶制品的消费知识还不够了解,营养知识和保健意识还不强;同时表明,居民收入、消费偏好、乳品价格、乳品质量、品牌宣传、购买的便利性以及消费观念和保健意识等都是影响城镇居民奶制品消费的重要因素;最后从消费者自身、乳制品生产企业和政府部门三个方面提出了增加城镇居民奶制品消费的对策建议。     

维拉帕米对肉鸡腹水综合征患鸡心肌细胞c-fos和c-jun表达的影响

右心肥大衰竭是导致腹水综合征(ascites syndrome,AS)患鸡发病的重要因素.作者通过免疫组化和原位杂交技术初步探讨c-fos和c-jun在AS肉鸡右心肥大和衰竭过程中的变化及维拉帕米对其表达的影响.结果发现:在22、29、36、43和50日龄时,与对照组肉鸡相比,低温组肉鸡右心室心肌细胞c-fos/c-jun蛋白和mRNA的平均光密度值显著或极显著(P<0.05;P<0.01)升高,其mRNA的阳性面积百分比也极显著升高(P<0.01),与低温组肉鸡相比,维拉帕米组肉鸡右心室心肌细胞c-fos/c-jun蛋白和mRNA的平均光密度值显著或极显著(P<0.05;P<0.01)降低,其mRNA的阳性面积百分比也极显著降低(P<0.01).结果表明c-fos和c-jun癌基因在右心肥大和衰竭中起着重要作用.维拉帕米可有效抑制c-os和c-jun癌基因的表达,有利于防止右心肥大和功能性衰竭.     

Betaine suppresses carnitine palmitoyltransferase I in skeletal muscle but not in liver of finishing pigs

An experiment was conducted to investigate the effect of dietary betaine supplementation on the enzyme activity and mRNA abundance for carnitine palmitoyltransferase I (CPT I) in liver and skeletal muscle of finishing pigs. Forty-eight crossbred barrows and gilts [Duroc × (Seghers × Seghers)] weighing about 55 kg were divided into two dietary treatments, each with three replicates of eight pigs (four barrows and four gilts) per replicate. Pigs were fed a corn–soybean meal basal diet supplemented with betaine at 0 or 1250 mg/kg feed for 42 days. At trial termination, two pigs (one barrow and one gilt) weighing about 90 kg were selected from each replicate (six pigs per dietary treatment) and slaughtered for analyses. The results showed that intramuscular fat content in the longissimus muscle of pigs fed betaine was 23.6% higher than that of controls (P < 0.05), whereas hepatic fat content was not affected with dietary betaine treatment. Muscle-type CPT I (M-CPT I) activity, but not liver-type CPT I (L-CPT I) activity was decreased by betaine supplementation. Furthermore, betaine supplementation reduced M-CPT I mRNA abundance by 14.6% (P < 0.05) but did not affect L-CPT I mRNA abundance. There was a positive correlation between enzyme activity and mRNA abundance for both L-CPT I and M-CPT I (r = 0.67 and r = 0.72 for L-CPT I and M-CPT I, respectively; P < 0.05). The study suggests that betaine may be involved in fat partitioning in pigs by reducing the activity and mRNA abundance of M-CPT I, with a resultant increase in intramuscular fat content.     

基于电子鼻的带鱼货架期预测模型

为探索通过气味分析判断海产品贮藏品质的方法,利用电子鼻对带鱼在不同贮藏温度与贮藏时间下的挥发性气味变化进行了分析,对所获数据进行了主成分分析与货架期分析,并与理化品质指标值挥发性盐基氮（total volatile basic nitrogen,TVBN）相联系,建立了带鱼在273～283 K下的货架期预测模型。结果表明：电子鼻18个金属传感器能很好地将贮藏于273与283 K下的带鱼随着贮藏时间变化的气味进行区分。贮藏于不同温度条件下的带鱼的TVBN值与菌落总数值均随着贮藏时间的增加而增长,且均符合一级化学动力学模型（R2＞0.9）。基于电子鼻货架期分析获得的273～283 K下的气味变化结果与该温度下理化品质指标变化具有较好的对应关系,采用Arrhenius动力学模型推导公式求得带鱼在（273～283 K）温度段内TVBN的Q10（温差为10 K的货架寿命之比）值,对照该温度段下电子鼻货架期分析获得的气味变化货架期分析值,得到带鱼在该温度段内的Q10货架期预测模型,经验证,其预测误差小于20%。可根据获得的货架期预测模型对带鱼在273～283 K条件下的货架期进行预测。     

Characterization of Elemental Species in PM2.5 Samples Collected in Four Cities of Northeast China

A monitoring program of particulate matter was conducted at eight sampling sites in four highly industrialized cities (Shenyang, Anshan, Fushun, and Jinzhou) of Liaoning Province in Northeast China to identify the major potential sources of ambient PM_2.5. A total of 814 PM_2.5 and PM_2.5–10 samples were collected between 2004 and 2005. All PM samples were collected simultaneously in four cities and analyzed gravimetrically for mass concentrations. A sum of 16 elemental species concentrations in the PM samples were determined using inductively coupled plasma atomic emission spectroscopy. Annual means of PM_2.5 concentrations ranged from 65.0 to 222.0 μg m^?3 in all the eight sampling sites, and the spatial and seasonal variations were discussed. Enrichment factors were calculated, and Cr, Cu, Zn, As, Cd, and Pb will be pollution-derived elements. Site-to-site comparisons of PM_2.5 species in each city were examined using coefficient of divergence, revealing that the two sites in each city are similar in elemental species. Principle component analysis was used for preliminary source analysis of PM_2.5. Three or four factors in each city were isolated, and similar sources (crustal source, coal combustion, vehicle exhaust, iron making, or some other metallurgical activities) were identified at four cities.     

大豆胞囊线虫相关G2-like转录因子生物信息学分析

G2-like转录因子在植物中广泛存在,是GARP转录因子超家族中重要成员之一,在叶绿体发育、果实生长、生物或非生物胁迫和植物衰老等方面均起重要作用.研究对大豆胞囊线虫3号生理小种胁迫下东农L-10(抗病)根部进行转录组测序,初步筛选得到8个与大豆胞囊线虫抗性相关G2-like转录因子,并通过在线软件对其作生物信息学分...