Hyperketonemia during lipopolysaccharide-induced mastitis affects systemic and local intramammary metabolism in dairy cows

Hyperketonemia interferes with the metabolic regulation in dairy cows. It is assumed that metabolic and endocrine changes during hyperketonemia also affect metabolic adaptations during inflammatory processes. We therefore studied systemic and local intramammary effects of elevated plasma β-hydroxybutyrate (BHBA) before and during the response to an intramammary lipopolysaccharide (LPS) challenge. Thirteen dairy cows received intravenously either a Na-dl-β-OH-butyrate infusion (n = 5) to achieve a constant plasma BHBA concentration (1.7 ± 0.1 mmol/L), with adjustments of the infusion rates made based on immediate measurements of plasma BHBA every 15 min, or an infusion with a 0.9% NaCl solution (control; n = 8) for 56 h. Infusions started at 0900 h on d 1 and continued until 1700 h 2 d later. Two udder quarters were challenged with 200 μg of Escherichia coli LPS and 2 udder quarters were treated with 0.9% saline solution as control quarters at 48 h after the start of infusion. Blood samples were taken at 1 wk and 2 h before the start of infusions as reference samples and hourly during the infusion. Mammary gland biopsies were taken 1 wk before, and 48 and 56 h (8 h after LPS challenge) after the start of infusions. The mRNA abundance of key factors related to BHBA and fatty acid metabolism, and glucose transporters was determined in mammary tissue biopsies. Blood samples were analyzed for plasma glucose, BHBA, nonesterified fatty acid, urea, insulin, glucagon, and cortisol concentrations. Differences were not different for effects of BHBA infusion on the mRNA abundance of any of the measured target genes in the mammary gland before LPS challenge. Intramammary LPS challenge increased plasma glucose, cortisol, glucagon, and insulin concentrations in both groups but increases in plasma glucose and glucagon concentration were less pronounced in the Na-dl-β-OH-butyrate infusion group than in controls. In response to LPS challenge, plasma BHBA concentration decreased in controls and decreased also slightly in the BHBA-infused animals because the BHBA concentration could not be fully maintained despite a rapid increase in BHBA infusion rate. The change in mRNA abundance of citrate synthase in LPS quarters was significant between the 2 treatment groups. The results indicate that elevated circulating BHBA concentration inhibits gluconeogenesis before and during immune response to LPS challenge, likely because BHBA can replace glucose as an energy source.     

山莴苣苦素改善FFA诱导的HepG2细胞脂肪变性及氧化应激的研究

目的:研究山莴苣苦素对游离脂肪酸(FFA)诱导的HepG2细胞脂肪变性的改善作用,并初步探讨其可能作用机制.方法:观察山莴苣苦素对HepG2细胞活力的影响.采用FFA诱导培养HepG2细胞,构建脂肪变性模型(NAFLD体外模型),并用山莴苣苦素干预72h后,检测各组细胞内脂滴数量、甘油三酯(TG)和总胆固醇(TC)含量...     

Heat stress affects some physiological and productive variables and alters metabolism in dairy ewes

Heat stress (HS) has a significant economic impact on the global dairy industry. However, the mechanisms by which HS negatively affects metabolism and milk synthesis in dairy ewes are not well defined. This study evaluated the production and metabolic variables in dairy ewes under controlled HS conditions. Eight Lacaune ewes (75.5 ± 3.2 kg of body weight; 165 ± 4 d of lactation; 2.31 ± 0.04 kg of milk per day) were submitted to thermoneutral (TN) or HS conditions in a crossover design (2 periods, 21 d each, 6-d transition). Conditions (day-night, 12–12 h; relative humidity; temperature-humidity index, THI) were: TN (15–20°C; 50 ± 5%; THI = 59–65) and HS (28–35°C; 45 ± 5%; THI = 75–83). Ewes were fed ad libitum and milked twice daily. Rectal temperature, respiratory rate, feed intake, water consumption, and milk yield were recorded daily. Milk and blood samples were collected weekly. Additionally, TN and HS ewes were exposed to glucose tolerance test, insulin tolerance test, and epinephrine challenge. Heat stress reduced feed intake (?11%), and increased rectal temperature (+0.77°C), respiratory rate (+90 breaths/min), and water consumption (+28%). Despite the reduced feed intake, HS ewes produced similar milk to TN ewes, but their milk contained lower fat (?1.7 points) and protein (?0.86 points). Further, HS milk tended to contain more somatic cells (+0.23 log points). Blood creatinine was greater in HS compared with TN, but no differences in blood glucose, nonesterified fatty acids, or urea were detected. When glucose was infused, TN and HS had similar insulin response, but higher glucose response (+85%) was detected in HS ewes. Epinephrine infusion resulted in lower nonesterified fatty acids response (?215%) in HS than TN ewes. Overall, HS decreased feed intake, but milk production was not affected. Heat stress caused metabolic adaptations that included increased body muscle degradation and reduced adipose tissue mobilization. These adaptations allowed ewes to spare glucose and to avoid reductions in milk yield.     

单独降脂药物及药物联合饮食控制治疗高脂血症疗效观察对比

目的:对比单独降脂药物及药物联合饮食控制治疗高脂血症的临床疗效,以供参考。方法:将牡丹江医院红旗医院院2011年5月—2013年4月收治的高脂血症患者100例纳入本研究,根据随机原则分组。对照组接受单独降脂药物治疗,实验组接受药物联合饮食控制治疗。用药12w后对比两组患者血脂水平的变化和辛伐他汀日使用剂量的差异。结果:与治疗前对比,治疗后患者TC、TG、LDL-C等指标水平均有所下降,HDL-C水平有所上升,其中实验组各指标改善幅度明显大于对照组,组间差异经统计学分析后认为有意义(P0.05)。与对照组对比,实验组患者辛伐他汀日使用剂量明显较低,组间差异经统计学分析后认为有意义(P0.05)。结论:采用药物联合饮食控制治疗高脂血症的降脂效果优于单独药物治疗,同时可减少降脂药物使用剂量,对减少不良反应和降低医疗费用有益。     

生、炒决明子抗氧化作用的研究与比较

通过4个化学模拟体系:羟自由基(·OH)、超氧阴离子(O-2·)以及小鼠肝匀浆脂质过氧化、血细胞溶血,检测并比较生、炒两种决明子的乙醇提取物的抗氧化活性,并以常用抗氧化剂二丁基羟基甲苯(BHT)或Vc作为阳性对照进行比较。研究结果表明:在4个体系中,两种提取物均有较强的抗氧化活性,在清除氧自由基方面生决明子的乙醇提取物作用优于炒决明子,在小鼠体外氧化体系中,两种决明子提取物的抗氧化能力相差不大,且都与常用抗氧化剂Vc作用相当。     

不同温度下高压处理牛肉TBARS值的变化及抗氧化剂和螯合剂的抑制作用研究

对不同温度(20℃、40℃和60℃)下压力(从200～800MPa)处理20min以及在4℃下贮藏7d后牛肉脂肪TBARS值的变化进行了研究。结果显示:常压下肌肉的TBARS值随热处理温度的升高而增加;同样,室温下压力的增加导致脂肪氧化程度的加剧,尤其是在400MPa及其以上压力;40℃和60℃下的压力处理,TBARS值的变化规律与室温下极为相似。添加1%的Na2EDTA可有效地降低肌肉不同温度(20～60℃)下200MPa和600MPa压力处理和贮藏后的TBARS值,阻止压力和热处理导致的脂肪氧化,此结果表明热和压力处理的肌肉中蛋白质结构的破坏和过渡金属离子的释放是造成脂肪氧化的主要原因。VE和BHT也具有良好的抗氧化作用,0.05%的VE和0.02%BHT结合使用,比单独的VE具有更好的抗氧化效果。     

Enzymatic synthesis of medium‐ and long‐chain triacylglycerols–enriched structured lipid from Cinnamomum camphora seed oil and camellia oil by Lipozyme RM IM

Medium‐ and long‐chain triacylglycerols (MLCTs)–enriched structured lipid (SL) was synthesised through enzymatic interesterification from Cinnamomum camphora seed oil (CCSO) and camellia oil (CO) using Lipozyme RM IM from Rhizomucor miehei as a biocatalyst. Effects of different reaction conditions including substrate molar ratio, reaction time and reaction temperature were investigated. Results showed that 55.81% of total MLCT species (CCO/LaCL, LaCO/LCL, COO/OCO and LaOO/OLaO) was obtained in the interesterified product under the optimal conditions of substrate molar ratio of 1:1.5 (CCSO/CO) at 60 °C for 3 h. Thereafter, fatty acid profiles, tocopherol contents and physiochemical characteristics of the interesterified product and physical blend were comparatively investigated. The fatty acid composition of the interesterified product consisted of capric acid (26.33%), lauric acid (21.29%) and oleic acid (42.33%). It should be mentioned that the interesterified product contained predominantly oleic acid (88.69%) at Sn‐2 position, while MCFAs (68.05%) at Sn‐1,3 positions. Compared with physical blend, the reduction in tocopherol contents and changes of physiochemical characteristics occurred in SL. The smoke point of the interesterified product was much higher than that of the physical blend, which meant that such MLCTs‐enriched SL could be better for cooking purpose.     

大豆低聚肽营养吸收特性的研究

研究了补充大豆低聚肽和大豆分离蛋白对大鼠氮代谢的影响,并探讨了大鼠小肠对大豆低聚肽的吸收特点。将雄性SD大鼠30只,随机分为:灌喂水对照组、灌喂大豆低聚肽组和灌喂大豆分离蛋白组。大鼠在适应性喂养及膳食平衡1周后,开始进行代谢试验。结果发现,补充大豆分离蛋白后,大鼠氮平衡值、氮储存率、氮净利用率和表观消化率比补水大鼠分别增高641.03%、591.42%、553.11%和51.80%;而补充大豆低聚肽后,大鼠氮平衡值、氮储存率、氮利用率和表观消化率比补充水大鼠分别增高1061.54%、982.69%、921.20%和71.43%(P<0.05);比补充大豆分离蛋白大鼠分别增高56.75%、56.59%、56.36%和12.94%(P<0.05)。由此可得出结论,补充大豆低聚肽可显著提高机体对氮的表观消化率储存率和净氮利用率,并使机体处于较高水平的正氮平衡状态。     

原花青素降低脂质过氧化作用的研究

以高、中、低三种剂量的原花青素喂食小鼠45d,对照组给予等体积的蒸馏水,测定各项指标.实验结果是高剂量组与老龄对照组比较,MDA含量明显降低,血清SOD活力明显升高(P＜0.05),表明原花青素具有降低脂质过氧化作用.