Krill Oil Supplementation Reduces Exacerbated Hepatic Steatosis Induced by Thermoneutral Housing in Mice with Diet-Induced Obesity

Preclinical evidence suggests that n-3 fatty acids EPA and DHA (Omega-3) supplemented as phospholipids (PLs) may be more effective than triacylglycerols (TAGs) in reducing hepatic steatosis. To further test the ability of Omega-3 PLs to alleviate liver steatosis, we used a model of exacerbated non-alcoholic fatty liver disease based on high-fat feeding at thermoneutral temperature. Male C57BL/6N mice were fed for 24 weeks a lard-based diet given either alone (LHF) or supplemented with Omega-3 (30 mg/g diet) as PLs (krill oil; ω3PL) or TAGs (Epax 3000TG concentrate; ω3TG), which had a similar total content of EPA and DHA and their ratio. Substantial levels of TAG accumulation (~250 mg/g) but relatively low inflammation/fibrosis levels were achieved in the livers of control LHF mice. Liver steatosis was reduced by >40% in the ω3PL but not ω3TG group, and plasma ALT levels were markedly reduced (by 68%) in ω3PL mice as well. Krill oil administration also improved hepatic insulin sensitivity, and its effects were associated with high plasma adiponectin levels (150% of LHF mice) along with superior bioavailability of EPA, increased content of alkaloids stachydrine and trigonelline, suppression of lipogenic gene expression, and decreased diacylglycerol levels in the liver. This study reveals that in addition to Omega-3 PLs, other constituents of krill oil, such as alkaloids, may contribute to its strong antisteatotic effects in the liver.     

南极微生物中特殊酶类的研究进展

近年来，南极微生物低温酶的研究和开发成为热点。目前关于南极微生物低温蛋白酶、脂肪酶和淀粉酶等已经进行了大量的研究，但是对于一些特殊的酶类研究较少。本文对南极微生物中的特殊酶类的研究进展情况进行综述，详细介绍了几丁质酶、脱氢酶、β-半乳糖苷酶、RNA聚合酶、DEAD-box RNA解旋酶和金属蛋白酶等酶的理化性质和特点，并对其应用前景进行了展望。     

南极冰藻 Berkeleya rutilans H-15中清除自由基活性物质的分离纯化及其结构分析

目的 研究和发现极端环境下南极冰藻中清除自由基活性物质.方法 以南极冰藻Berkeleya rutilans H-15为试验材料,在国内外首先建立起了从南极冰藻中获取清除白由基活性物质的一套完整的方法,包括用甲畔提取活性化合物,用DPPH法和Godin法来追踪和检测活性化舍物的分离效果及变化情况,用硅胶柱层析对活性化舍物进行初步的分离和纯化,用Sephadex LH柱层析来进一步纯化,通过高效液相来进行化舍物纯度检测,高纯度化舍物用红外光谱和液质联用方法来确定化合物的类型和有关的功能基团.结果 在Berkeleya rutilans H-15中获得了一个纯的活性化舍物,经红外光谱和液质联用图谱初步进行分子结构分析,推测此化合物属于酚类化舍物,并具有很强的清除自由基的活性.结论 在南极冰藻中寻找并获得高活性的抗氧化剂是完全可行的.     

Microencapsulated krill and tuna oil blend raises plasma long-chain n-3 polyunsaturated fatty acid levels compared to tuna oil with similar increases in ileal contractility in rats

Long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) may be more bioavailable from krill oil compared to fish oil due to their phospholipid structure. We tested whether a microencapsulated krill and tuna oil blend (ME-TOKO) provided greater LC n-3 PUFA bioavailability, improved blood lipid profiles and increased intestinal contractility compared to microencapsulated tuna oil (ME-TO). Rats were divided into three groups to receive isocaloric diets containing ME-TO, ME-TOKO and microencapsulated olive oil (ME-OO) at 0.3 or 2?g/100?g for 4 weeks. Final body and organ weights, feed intake and waste output were similar. ME-TOKO rats had higher plasma total LC n-3 PUFA levels compared to ME-TO, but liver LC n-3 PUFA levels and plasma triglyceride and cholesterol levels were similar in non-fasted rats. Diets containing 2% ME-TO and ME-TOKO also showed similar increases in ileal contractility. In summary, ME-TO bioavailability of LC n-3 PUFA was similar to ME-TOKO.     

南极磷虾肽对去卵巢骨质疏松症小鼠肠钙吸收的改善作用研究

目的 研究南极磷虾肽(peptide from Antarctic krill,AKP)对双侧去卵巢骨质疏松症模型小鼠肠钙吸收的改善作用。方法 对9周龄雌性健康C57BL/6J小鼠进行双侧卵巢摘除手术,建立骨质疏松症模型,术后12周,随机分为假手术组(生理盐水)、模型对照组(生理盐水)、阳性对照组(阿伦磷酸钠,1 mg/kg.BW)、南极磷虾肽组(800 mg/kg.BW)。每天灌胃一次,连续灌胃90 d后,通过测定血清生化指标(PTH、1,25(OH)2D3、血钙及血磷)以及肠钙吸收通道基因Trpv6、CaBP-d9k、PMCA1b的mRNA表达水平,研究了南极磷虾肽对去卵巢骨质疏松症小鼠肠钙吸收的改善及作用机制;并且通过骨密度和骨钙骨磷含量的测定,进一步验证了南极磷虾肽对肠钙吸收的改善作用。结果 血清结果表明,AKP能够显著抑制血清中PTH的水平,增加血清中1,25(OH)2D3的含量,维持血清中钙、磷稳定;qRT-PCR结果表明,AKP能显著上调十二指肠中激素1,25(OH)2D3的受体VDR以及肠钙吸收通道关键基因Trpv6、CaBP-d9k、PMCA1b的mRNA表达水平,增强去卵巢骨质疏松小鼠的肠钙吸收功能;骨密度和骨钙、骨磷结果表明,AKP能够显著增加模型组小鼠的骨密度及骨钙、骨磷含量,进一步验证了AKP能够增强机体对钙离子的吸收,从而增加骨矿化作用,增加小鼠的骨量。结论 南极磷虾肽能够改善去卵巢骨质疏松症小鼠的肠钙吸收作用,增加去卵巢小鼠的骨矿含量。     

Krill Protein Hydrolysate Provides High Absorption Rate for All Essential Amino Acids—A Randomized Control Cross-Over Trial

Background: adequate protein intake is essential to humans and, since the global demand for protein-containing foods is increasing, identifying new high-quality protein sources is needed. In this study, we investigated the acute postprandial bioavailability of amino acids (AAs) from a krill protein hydrolysate compared to a soy and a whey protein isolate. Methods: the study was a randomized, placebo-controlled crossover trial including ten healthy young males. On four non-consecutive days, volunteers consumed water or one of three protein-matched supplements: whey protein isolate, soy protein isolate or krill protein hydrolysate. Blood samples were collected prior to and until 180 min after consumption. Serum postprandial AA concentrations were determined using ¹H NMR spectroscopy. Hunger and satiety were assessed using visual analogue scales (VAS). Results: whey and krill resulted in significantly higher AA concentrations compared to soy between 20–60 min and 20–40 min after consumption, respectively. Area under the curve (AUC) analyses revealed that whey resulted in the highest postprandial serum concentrations of essential AAs (EAAs) and branched chain AAs (BCAAs), followed by krill and soy, respectively. Conclusions: krill protein hydrolysate increases postprandial serum EAA and BCAA concentrations in a superior manner to soy protein isolate and thus might represent a promising future protein source in human nutrition.     

Krill-Oil-Dependent Increases in HS-Omega-3 Index,Plasma Choline and Antioxidant Capacity in Well-Conditioned Power Training Athletes

There is evidence that both omega-3 polyunsaturated fatty acids (n-3 PUFAs) and choline can influence sports performance, but information establishing their combined effects when given in the form of krill oil during power training protocols is missing. The purpose of this study was therefore to characterize n-3 PUFA and choline profiles after a one-hour period of high-intensity physical workout after 12 weeks of supplementation. Thirty-five healthy power training athletes received either 2.5 g/day of Neptune krill oil^TM (550 mg EPA/DHA and 150 mg choline) or olive oil (placebo) in a randomized double-blind design. After 12 weeks, only the krill oil group showed a significant HS-Omega-3 Index increase from 4.82 to 6.77% and a reduction in the ARA/EPA ratio (from 50.72 to 13.61%) (p < 0.001). The krill oil group showed significantly higher recovery of choline concentrations relative to the placebo group from the end of the first to the beginning of the second exercise test (p = 0.04) and an 8% decrease in total antioxidant capacity post-exercise versus 21% in the placebo group (p = 0.35). In conclusion, krill oil can be used as a nutritional strategy for increasing the HS-Omega-3 Index, recover choline concentrations and address oxidative stress after intense power trainings.     

Krill Products: An Overview of Animal Studies

Many animal studies have been performed with krill oil (KO) and this review aims to summarize their findings and give insight into the mechanism of action of KO. Animal models that have been used in studies with KO include obesity, depression, myocardial infarction, chronic low-grade and ulcerative inflammation and are described in detail. Moreover, studies with KO in the form of krill powder (KP) and krill protein concentrate (KPC) as a mix of lipids and proteins are mentioned and compared to the effects of KO. In addition, differences in tissue uptake of the long-chain omega-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), when delivered in either phospholipid or triglyceride form, are addressed and the differential impact the delivery form has on gene expression profiles is explained. In our outlook, we try to highlight the potential of KO and KP supplementation in clinical settings and discuss health segments that have a high potential of showing krill product specific health benefits and warrant further clinical investigations.     

产EPA南极细菌的筛选及其脂肪酸成分分析

目的从南极细菌中筛选高产EPA(二十碳五烯酸)或DHA(二十二碳六烯酸)的细菌,并对其脂肪酸的成分和含量进行分析。方法从南极采集的海冰和土壤中分离得到200株细菌,利用改良的一步反应法,通过气相色谱(GC)初筛,得到8株EPA或DHA产量较高的细菌。对其中一株EPA产量最高菌株(NJ136)的总脂含量采用索氏抽提法测定,各脂肪酸成分和含量采用气相色谱-质谱(GC-MS)分析测定。结果与结论菌株NJ136的EPA相对含量为6.66%,不饱和脂肪酸的相对含量为51.92%,干菌总脂含量是7.94%,EPA含量达到5.3 mg.g-1,不饱和脂肪酸含量达到41.2 mg.g-1。     

国家南极科考单船医疗保障的实践与探讨

目的 南极科考的医疗保障远不同于一般的卫勤保障,本文旨在总结第30次中国南极科考期间单船、单人医疗保障的方法和效果。方法 出发前加强采取保障军医的体能训练、专业技能的培训、制定保障方案、制定队员健康档案等措施,科考过程中根据科考不同阶段的条件特点针对性地进行疾病宣教、定期体检和日常诊疗工作。结果 通过进行针对性的专业训练,提高了保障军医的远洋和极寒气候条件下的医疗保障能力。坚持预防为主、防治结合的工作方针,科考期间累计门诊量532例次,完成各类手术20例,无传染病暴发、无一例队员发生疾病相关并发症,圆满完成南极科考的医疗保障任务。结论 充分的出发前准备、过硬的专业技能和合理的保障策略是完成任务的保证。