Feeding rumen-inert fats differing in their degree of saturation decreases intake and increases plasma concentrations of gut peptides in lactating dairy cows

Our objective was to determine the effect of feeding rumen-inert fats differing in their degree of saturation on dry matter intake (DMI), milk production, and plasma concentrations of insulin, glucagon-like peptide 1 (7-36) amide (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and cholecystokinin (CCK) in lactating dairy cows. Four midlactation, primiparous Holstein cows were used in a 4 × 4 Latin square experiment with 2-wk periods. Cows were fed a control mixed ration ad libitum, and treatments were the dietary addition (3.5% of ration dry matter) of 3 rumen-inert fats as sources of mostly saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), or polyunsaturated fatty acids (PUFA). Daily DMI, milk yield, and composition were measured on the last 4 d of each period. Jugular vein blood was collected every 30 min over a 7-h period on d 12 and 14 of each period for analysis of plasma concentrations of hormones, glucose, and nonesterified fatty acids. Feeding fat decreased DMI, and the decrease tended to be greater for MUFA and PUFA compared with SFA. Plasma concentration of GLP-1 increased when fat was fed and was greater for MUFA and PUFA. Feeding fat increased plasma glucose-dependent insulinotropic polypeptide and CCK concentrations and decreased plasma insulin concentration. Plasma CCK concentration was greater for MUFA and PUFA than for SFA and was greater for MUFA than PUFA. Decreases in DMI in cows fed fat were associated with increased plasma concentrations of GLP-1 and CCK and a decreased insulin concentration. The role of these peptides in regulating DMI in cattle fed fat requires further investigation.     

海红米米糠对慢性应激诱导小鼠抑郁样行为和异常肠道微生物及神经递质的改善作用

“微生物-肠-脑轴”失常在抑郁症的发病中发挥着重要作用,调节肠道菌群失衡成为最新的治疗方向。海红米皮可发挥益生元作用调控肠道微生物。本实验目的为探究海红米皮改善慢性不可预测温和应激(CUMS)诱导的小鼠抑郁样行为的作用。对照和暴露于CUMS的小鼠接受正常或含5%海红米皮饮食喂养9周,通过糖水偏好实验和悬尾实验分析小鼠的抑郁样行为,实时荧光定量PCR法检测结肠内容物菌群的数量,HPLC测定前额皮层中单胺类神经递质的含量。应激使小鼠糖水偏好度、乳杆菌属和双歧杆菌属的数量、去甲肾上腺素(NE)与其代谢产物、五羟色胺(5-HT)与其代谢产物、多巴胺(DA)与其代谢产物的含量都显著下降,悬尾不动时间和梭菌属的数量都显著升高；海红米皮干预后提高了小鼠的糖水偏好度、乳杆菌属和双歧杆菌属的数量、5-HT与其代谢产物和NE的含量,降低了悬尾不动时间。海红米皮改善CUMS诱导的小鼠抑郁样行为可能与改善肠道菌群失衡及神经递质有关。     

Contrasting Health Effects of Bacteroidetes and Firmicutes Lies in Their Genomes: Analysis of P450s,Ferredoxins, and Secondary Metabolite Clusters

Species belonging to the bacterial phyla Bacteroidetes and Firmicutes represent over 90% of the gastrointestinal microbiota. Changes in the ratio of these two bacterial groups were found to have contrasting health effects, including obesity and inflammatory diseases. Despite the availability of many bacterial genomes, comparative genomic studies on the gene pools of these two bacterial groups concerning cytochrome P450 monooxygenases (P450s), ferredoxins, and secondary metabolite biosynthetic gene clusters (smBGCs) are not reported. This study is aimed to address this research gap. The study revealed the presence of diverse sets of P450s, ferredoxins, and smBGCs in their genomes. Bacteroidetes species have the highest number of P450 families, ferredoxin cluster-types, and smBGCs compared to Firmicutes species. Only four P450 families, three ferredoxin cluster types, and five smBGCs are commonly shared between these two bacterial groups. Considering the above facts, we propose that the contrasting effects of these two bacterial groups on the host are partly due to the distinct nature of secondary metabolites produced by these organisms. Thus, the cause of the contrasting health effects of these two bacterial groups lies in their gene pools.     

The Gut Microbiome in Depression and Potential Benefit of Prebiotics,Probiotics and Synbiotics: A Systematic Review of Clinical Trials and Observational Studies

An emerging body of literature demonstrates differences in the gut microbiome (GMB) of patients with major depressive disorder (MDD) compared to healthy controls (HC), as well as the potential benefits of prebiotic, probiotic, and synbiotic treatment. We conducted a systematic review of 24 observational studies (n = 2817), and 19 interventional trials (n = 1119). We assessed alpha diversity, beta diversity, and taxa abundance changes in patients with MDD relative to HC, as well as the effect of prebiotics, probiotics, and synbiotics on depressive symptoms in individuals with clinical or subclinical depression. We observed no significant differences in alpha diversity but a significant difference in beta diversity between patients with MDD and HC. There were fluctuations in the abundance of specific taxa in patients with MDD relative to HC. Probiotic and synbiotic, but not prebiotic, treatment showed a modest benefit in reducing depressive symptoms in patients with MDD over four to nine weeks. The GMB profiles of patients with MDD differ significantly from HC, but further studies are needed to elucidate the benefits of prebiotic, probiotic and synbiotic treatments relative to antidepressants and over longer follow-up before these therapies are implemented into clinical practice.     

藜麦皂苷灌胃后大鼠尿液代谢及肠道菌变化

以藜麦皂苷为材料,对成年健康Sprague Dawley大鼠进行90 d经口暴露后结合肠道菌群及尿液代谢组学研究,探究其对肾脏的影响。实验分别将雌雄大鼠（n=48）分为高剂量（500 mg/kg）皂苷灌胃组、中剂量（50 mg/kg）皂苷灌胃组、低剂量（5 mg/kg）皂苷灌胃组与空白对照组,经口灌胃处理后,对肠道内容物进行16S rDNA分析,对尿液代谢物采用UPLC-MS分析,探究皂苷对大鼠的肠道菌群及代谢组学的影响。在雌雄大鼠中高剂量组大鼠肾脏切片均发生部分炎性变化。代谢组学结果显示,中低剂量组与空白对照组相比无明显差异,高剂量组大鼠在藜麦皂苷灌胃后,雌性大鼠尿液中发现差异代谢物101种,雄性大鼠尿液中发现差异代谢物29种,影响了维生素B6代谢、氨循环、色氨酸代谢等代谢过程。肠道菌群分析显示,藜麦皂苷灌胃组与对照组大鼠肠道菌群多样性差异明显。综上所述,藜麦皂苷在低剂量下无明显的毒性反应,然而在不可接触的中高剂量下有潜在的肾毒性。     

膳食纤维通过理化性质和肠道微生物途径调控糖脂代谢的研究进展

糖脂代谢紊乱会引起肥胖,血管疾病,糖尿病等慢性疾病的发生.在膳食构成越来越精细的今天,膳食纤维成为学术界和普通百姓关注的物质,并被营养学界补充认定为第七类营养素,在调节糖脂代谢方面具有重要生理作用.就膳食纤维的理化性质和微生物介导的调控机制与糖脂代谢的关系进行简要综述,并对未来膳食纤维的研究方向和应用前景进行了分析,以...     

发酵制品调控糖脂代谢性疾病作用机制的研究进展

发酵作为一种古老的食品加工技术,不仅能延长食品的保存时间,而且具有改变食品特性的功能。随着近代生物技术的发展,发酵制品的潜在健康价值逐渐显现,在防治糖脂代谢性疾病方面的效应也受到更多关注。该文从调节神经内分泌紊乱、胰岛素抵抗、氧化应激、代谢性炎症和肠道菌群失调5个方面阐述发酵制品对糖脂代谢性疾病的作用机制,评估其作为保健品或药剂的潜力,为今后将发酵制品用于防治糖脂代谢性疾病提供参考。     

益生菌对神经系统疾病作用的研究进展

人体肠道内菌群数量巨大且种类丰富,参与机体的多项生理过程,研究显示肠道菌群能够通过肠道菌群-肠-脑轴来调节机体大脑的发育与行为。益生菌是一类对人体有益的活性微生物,可以通过调节人体肠道微生态平衡从而对人体产生有益作用。临床医学研究表明,益生菌对自闭症谱系障碍、阿尔茨海默病、帕金森病、抑郁症和多发性硬化等神经系统疾病具有良好的防治作用。本文总结了近几年来国内外关于益生菌对神经系统疾病作用机制的研究进展,以期为益生菌对此类疾病的干预治疗提供新思路。     

Recovery and metabolism of xanthohumol in germ‐free and human microbiota‐associated rats

The impact of human intestinal bacteria on the bioavailability of the prenylflavonoid xanthohumol (XN) was studied by comparing germ‐free (GF) and human microbiota‐associated (HMA) rats. After XN application, XN, XN conjugates, and isoxanthohumol (IX) conjugates occurred in blood samples of GF and HMA rats, whereas IX was detected only in the blood of HMA rats. Overall excretion of XN and its metabolites within 48 h was only 4.6% of the ingested dose in GF rats and 4.2% in HMA rats, feces being the major route of excretion. While both GF and HMA rats excreted XN, IX, and their conjugates with urine and feces, 8‐prenylnaringenin and its corresponding conjugates were exclusively observed in the feces of HMA rats. The microbial formation of 8‐prenylnaringenin was confirmed by incubation of XN and IX with human fecal slurries. The amount of conjugates excreted in urine and feces was lower in HMA rats compared to GF rats indicating their hydrolysis by human intestinal microbiota. Thus, the impact of bacteria on the XN metabolism in the gut may affect the in vivo effects of ingested XN.     

粮油制品蛋白氧化对肠道健康影响的研究进展

在粮油原料及其制品的储运和加工过程中,脂质在内源脂肪水解酶和脂肪氧化酶的催化下发生水解、氧化。脂质氧化产物可诱导蛋白质氧化,导致蛋白质结构发生共价交联,使得蛋白质难以被机体消化,从而影响肠道微生物组成以及肠道屏障功能。本文首先分析了粮油原料及其制品在储运和加工过程中的氧化应激环境,随后介绍了蛋白质氧化对蛋白质结构特征和消化性质的影响,最后探讨了蛋白质氧化对肠道微生物以及肠道健康的可能影响,以期对摄食氧化蛋白质对肠道健康影响的研究提供一定理论参考,为安全合理有效开发蛋白质资源提供理论依据。