饥饿补偿对日本沼虾生长及生化组成的影响

在(25.0±1) ℃范围条件下,对日本沼虾进行了不同时间的饥饿处理后再投饵的恢复生长实验.饥饿过程中,虾体水分、灰分含量略有上升,蛋白质和脂肪含量以及RNA/DNA值有不同程度下降.分别给饥饿处理0(对照),2,4,8 d的日本沼虾投饵,在恢复生长结束后,各饥饿处理组的虾体生化组成均接近并恢复到对照组水平.饥饿处理组在恢复生长中的特殊生长率、摄食率和食物转化率显著高于对照组,实验结果表明,日本沼虾继饥饿后再恢复喂食不仅食欲增加,而且摄食水平和食物转化率均有所提高,出现完全或部分补偿生长效应.     

部分水解瓜尔豆胶对高脂高糖饮食诱导小鼠代谢紊乱的调节作用

部分水解瓜尔豆胶(partially hydrolyzed guar gum,PHGG)是一种有益于代谢平衡的可溶性膳食纤维,但其对糖脂代谢紊乱的调节效果及其潜在机制尚不明确。利用高脂高糖饮食诱导小鼠16周,使其产生明显的脂代谢紊乱和胰岛素抵抗,进一步通过检测小鼠糖耐量、血清生化指标、脂肪形态、肠道短链脂肪酸及相关mRNA的表达,考察PHGG对模型小鼠的糖脂代谢稳态及肠道环境的调节作用。结果表明:长期高脂高糖饮食条件下,PHGG组小鼠比模型组小鼠的体质量增长率减缓,空腹血糖降低,葡萄糖耐量和胰岛素耐量显著提升；血清中的甘油三酯、总胆固醇、低密度脂蛋白胆固醇和游离脂肪酸可分别降低21.56%、32.67%、25.66%和22.91%,明显抑制了脂肪积累。PHGG将肠道胰高血糖素样肽-1的分泌提升并恢复到67.76pmol/L,盲肠中的丁酸含量比模型组提升了7.14倍。定量PCR显示,PHGG干预后小鼠短链脂肪酸受体GPR43的蛋白表达水平比模型组提升了63.30%。本研究表明,PHGG通过调节短链脂肪酸影响脂联素、胰岛素的分泌,进而改善高脂高糖饮食引起的糖脂代谢紊乱,可以应用于辅助糖脂代谢调控的功能性食品开发中。     

肠道菌群调控脂质代谢的分子机制

人类肠道菌群基因组又被称为“人类第二基因组” ,其在人体脂肪的分解合成过程中起到了重要的调控作用。 体内肠道菌群的失调,会引起肥胖、糖尿病等在内的代谢综合症的发生。 本文从肠道菌群通过调控在脂质代谢中 起重要作用的酶类和调控因子从而为机体提供能量、减脂和改善健康状况的研究进展方面进行了综述。     

Ghrelin induces adiposity in rodents

The discovery of the peptide hormone ghrelin, an endogenous ligand for the growth hormone secretagogue (GHS) receptor, yielded the surprising result that the principal site of ghrelin synthesis is the stomach and not the hypothalamus. Although ghrelin is likely to regulate pituitary growth hormone (GH) secretion along with GH-releasing hormone and somatostatin, GHS receptors have also been identified on hypothalamic neurons and in the brainstem. Apart from potential paracrine effects, ghrelin may thus offer an endocrine link between stomach, hypothalamus and pituitary, suggesting an involvement in regulation of energy balance. Here we show that peripheral daily administration of ghrelin caused weight gain by reducing fat utilization in mice and rats. Intracerebroventricular administration of ghrelin generated a dose-dependent increase in food intake and body weight. Rat serum ghrelin concentrations were increased by fasting and were reduced by re-feeding or oral glucose administration, but not by water ingestion. We propose that ghrelin, in addition to its role in regulating GH secretion, signals the hypothalamus when an increase in metabolic efficiency is necessary.     

慢性间歇饥饿对大鼠神经内分泌功能的影响

探讨了慢性间歇饥饿及重饲过程中神经内分泌功能的动态变化并与急性饥饿进行比较.研究发现慢性间歇饥饿每100克体重垂体重量升高，附性器官无显著变化，重饲后恢复较快，与急性饥饿明显不同；慢性间歇饥饿时血液及垂体催乳素(PRL)无显著变化，PRL诱发反应减弱，与急性饥饿时PRL释放障碍较重，PRL诱发分泌增强有明显不同.结果表明尽管体重下降程度完全一致，不同的饥饿方式和时程也可能对神经内分泌功能造成不同的影响.     

Energetics and the evolution of human brain size

The human brain stands out among mammals by being unusually large. The expensive-tissue hypothesis explains its evolution by proposing a trade-off between the size of the brain and that of the digestive tract, which is smaller than expected for a primate of our body size. Although this hypothesis is widely accepted, empirical support so far has been equivocal. Here we test it in a sample of 100 mammalian species, including 23 primates, by analysing brain size and organ mass data. We found that, controlling for fat-free body mass, brain size is not negatively correlated with the mass of the digestive tract or any other expensive organ, thus refuting the expensive-tissue hypothesis. Nonetheless, consistent with the existence of energy trade-offs with brain size, we find that the size of brains and adipose depots are negatively correlated in mammals, indicating that encephalization and fat storage are compensatory strategies to buffer against starvation. However, these two strategies can be combined if fat storage does not unduly hamper locomotor efficiency. We propose that human encephalization was made possible by a combination of stabilization of energy inputs and a redirection of energy from locomotion, growth and reproduction.     

饥饿时间对日本沼虾能源物质利用和能量收支的影响

研究饥饿时间对不同体重的日本沼虾(Macrobrachium nipponense)能源物质利用和能量收支的影响.结果表明:饥饿初期日本沼虾主要依赖脂肪和碳水化合物供能,随着饥饿时间增加,开始部分消耗体内的蛋白质,最后完全依赖蛋白质作为能量来源,虾体营养组成和含量影响供能物质的利用.能量收支方程表明,在饥饿状态下日本沼虾代谢活动减弱,代谢能(R)逐渐降低,而排泄能(U)逐渐增加,体重对日本沼虾能量收支不产生影响.     

不同的饥饿时间对黑鲷补偿生长的影响

研究了不同的饥饿处理时间下再恢复供食后黑鲷的生长情况。实验结果表明:黑鲷在饥饿后再恢复喂食出现部分或完全补偿生长效应,且这种补偿生长效应主要是通过恢复生长阶段提高摄食率和食物转化率来实现的;黑鲷在饥饿过程中主要是消耗脂肪作为身体能量的来源;经过补偿生长后,鱼体的生化组成与对照组的水平相比有所变化,即蛋白质含量增加,脂肪含量下降,水分和灰分含量基本不变。     

茅苍术多糖对Ⅱ型糖尿病大鼠的治疗作用及机制研究

目的探讨茅苍术多糖对Ⅱ型糖尿病大鼠的治疗作用及机制.方法给予Ⅱ型糖尿病模型大鼠不同剂量的茅苍术多糖,通过对模型大鼠体质量改变情况、空腹血糖含量、胰岛素水平及调节血脂代谢紊乱能力的观察,评价其治疗作用;通过对各组大鼠肝脏组织中MDA含量及CAT,SOD酶活性的测定,评价其抗氧化能力.结果茅苍术多糖可以改善糖尿病大鼠体质量下降情况,能够降低空腹血糖含量,提升胰岛素水平;茅苍术多糖也可以降低MDA含量,增加CAT和SOD活性.结论茅苍术多糖具有抗糖尿病作用,其作用机制可能与其抗氧化作用有关.     

Dynamics of fat cell turnover in humans

Obesity is increasing in an epidemic manner in most countries and constitutes a public health problem by enhancing the risk for cardiovascular disease and metabolic disorders such as type 2 diabetes. Owing to the increase in obesity, life expectancy may start to decrease in developed countries for the first time in recent history. The factors determining fat mass in adult humans are not fully understood, but increased lipid storage in already developed fat cells (adipocytes) is thought to be most important. Here we show that adipocyte number is a major determinant for the fat mass in adults. However, the number of fat cells stays constant in adulthood in lean and obese individuals, even after marked weight loss, indicating that the number of adipocytes is set during childhood and adolescence. To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analysing the integration of 14C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index. Neither adipocyte death nor generation rate is altered in early onset obesity, suggesting a tight regulation of fat cell number in this condition during adulthood. The high turnover of adipocytes establishes a new therapeutic target for pharmacological intervention in obesity.     

鸡体腹脂的遗传、选择方法和效果的研究进展

腹脂是鸡体蓄积脂肪的主要部位,肉用仔鸡的腹脂重和体重呈中等以上的表型相关和遗传相关,低向选择腹脂对肉用仔鸡的体重,生长速度及肉质不会产生明显影响。多项研究表明;血浆ＶＬＤＬ浓度对肉用仔鸡体腹脂进行间接选择是目前认为从遗传选择上控制鸡体脂肪沉只的既经济又现实可行的方法 。     

不同年龄阶段小学生体脂状况对比分析

本研究主要通过实验测试法对126名一二三年级小学生体脂状况进行测试和分析。主要结论是不同年龄阶段小学生腹部肥胖、身体质量指数不随年龄的增长而增长,体重的增长主要以肌肉量的增长为主;身高、肌肉量、标准体重、身体年龄、身体质量指数指标在各年龄组间存在差异;体脂肪量、体脂率指标女生高于男生,其余指标男生均高于女生;不同性别小学生在肌肉量、体脂率、身体质量指数方面存在非常显著性差异。     

饥饿与补偿生长对军曹鱼幼鱼能量收支的影响

采用室内生态实验法研究了军曹鱼（Rachycentron canadum）幼鱼（初始体重(17.43±0.85) g分别饥饿0（对照组）,2,4,6,8 d后的补偿生长规律,探讨军曹鱼幼鱼补偿生长的生物能量学机制.结果表明：随着饥饿时间的延长,幼鱼的能量及体重损失率显著升高;恢复生长过程中,饥饿处理组幼鱼的平均日摄食率（能量指标）均高于对照组,其中以饥饿8 d组幼鱼的平均日摄食率最高（17.20%）;幼鱼在恢复生长过程中的能量、湿重及干重特定生长率均随着饥饿时间的延长而呈上升趋势;军曹鱼幼鱼在饥饿后的恢复生长过程中通过提高摄食率来实现其完全补偿生长能力;军曹鱼幼鱼在饱食条件下的能量收支方程为100.00C = 38.33G + 15.06F + 7.22U + 39.39R,同化能分配式为100.00A = 49.32G + 50.68R.     

体脂含量对维吾尔中老年人群血糖和胰岛素的影响

研究体脂含量及分布对新疆维吾尔中老年人群血糖和胰岛素水平的影响。以新疆喀什市420名45—73岁之间的中老年为研究对象。内容包括身高、体重、腰围、臀围测量以及空腹血糖、胰岛素水平测定，并计算BMI和WHR以及ISI，分析不同BNI和WHR水平人的空腹血糖、胰岛素、ISI的变化情况。结果：随着BMR和WHR水平的增加，空腹血糖、胰岛素呈升高趋势，ISI则呈降低趋势，而且在女性中更加明显。体脂含量及分布与血糖代谢之间存在着密切关系。     

金匮肾气丸对四氧嘧啶糖尿病模型大鼠的降糖作用研究

观察金匮肾气丸对四氧嘧啶糖尿病大鼠的降糖作用,探讨金匮肾气丸治疗糖尿病的应用。方法：给予四氧嘧啶糖尿病大鼠金匮肾气丸方煎剂,连续4周后,测定其空腹血糖、胰岛素、胰高血糖素和血脂水平。结果：与模型组比较,金匮肾气丸组空腹血糖、胰高血糖素、TC、TG、LDL-C水平明显降低（P〈0.05或P〈0.01）;HDL-C水平明显升高（P〈0.05）;胰岛素水平有增高趋势,但无统计学意义（P〉0.05）。结论：金匮肾气丸对四氧嘧啶糖尿病大鼠有明显降糖、调脂作用。     

雀麦膳食纤维对2型糖尿病模型大鼠血糖、血脂影响的研究

目的探讨雀麦膳食纤维粉（Oats dietary fiber bran,ODFB）对2型糖尿病（type 2 diabetes mellitus,T2DM）模型大鼠血糖、血脂的影响.方法将Wister大鼠50只（体质量为194.5±5.3g）随机分5组,每组雌雄各半：A组为阴性对照组,10只,喂饲基础饲料;另40只为糖尿病模型组,制成T2DM大鼠模型,再随机分为B,C,D,E 4组.每组10只即.B（糖尿病对照组即阳性对照组）组继续喂饲高糖、高脂饲料,C,D及E组喂饲分别加入含DF30%、40%和60%的ODFB高糖、高脂饲料,8W后观察DF对大鼠糖代谢、脂代谢和食物利用率的影响.结果①与B组相比,C,D和E组动物食物利用率明显增加;②三个剂量组均有明显的降低空腹血糖（Fasting blood glu-cose,FBG）、血清甘油三酯（Triglycerides,TG）、总胆固醇（Total cholesterol,TC）、低密度脂蛋白胆固醇（Low densitylipid-cholesterol,LDL-C）,同时升高高密度脂蛋白胆固醇（High density lipid-cholesterol,HDL-C）水平的作用,而D,E作用更显著;③与B组比较,C,D,E三组糖耐量曲线下面积明显减少;D,E两组血糖水平已接近阴性对照组（A组）水平.结论一定剂量的ODFB有改善T2DM大鼠模型食物利用率、降糖和降脂作用.     

Recent advances in brown adipose tissue biology

In mammals, white adipose tissue （WAT） store energy, whereas brown adipose tissue （BAT） burns energy. As a thermogenic organ, BAT can help maintain body temperature during cold exposure. Owing to its important roles in energy metabolism and regulating triacylglycerol levels, BAT has received great attention in treating obesity and its related diseases. Recent studies have suggested that BAT may secrete factor（s）—batokines—to regulate whole- body energy metabolism. In this review, we summarize the recent advances in the formation and function of BAT, as well as molecules that regulate the activity of BAT and beige fat.