Effects of different energy levels in low-protein diet on liver lipid metabolism in the late-phase laying hens through the gut-liver axis

Background The energy/protein imbalance in a low-protein diet induces lipid metabolism disorders in late-phase laying hens.Reducing energy levels in the low-protein diet to adjust the energy-to-protein ratio may improve fat deposition,but this also decreases the laying performance of hens.This study investigated the mechanism by which different energy levels in the low-protein diet influences liver lipid metabolism in late-phase laying hens through the enterohepatic axis to guide feed optimization and nutrition strategies.A total of 288 laying hens were randomly allocated to the normal-energy and normal-protein diet group(positive control:CK)or 1 of 3 groups:lowenergy and low-protein diet(LL),normal-energy and low-protein diet(NL),and high-energy and low-protein diet(HL)groups.The energy-to-protein ratios of the CK,LL,NL,and HL diets were 0.67,0.74,0.77,and 0.80,respectively.Results Compared with the CK group,egg quality deteriorated with increasing energy intake in late-phase laying hens fed low-protein diet.Hens fed LL,NL,and HL diets had significantly higher triglyceride,total cholesterol,acetylCo A carboxylase,and fatty acid synthase levels,but significantly lower hepatic lipase levels compared with the CK group.Liver transcriptome sequencing revealed that genes involved in fatty acid beta-oxidation(ACOX1,HADHA,EHHADH,and ACAA1)were downregulated,whereas genes related to fatty acid synthesis(SCD,FASN,and ACACA)were upregulated in LL group compared with the CK group.Comparison of the cecal microbiome showed that in hens fed an LL diet,Lactobacillus and Desulfovibrio were enriched,whereas riboflavin metabolism was suppressed.Cecal metabolites that were most significantly affected by the LL diet included several vitamins,such as riboflavin(vitamin B2),pantethine(vitamin B5 derivative),pyridoxine(vitamin B6),and 4-pyridoxic acid.Conclusion A lipid metabolism disorder due to deficiencies of vitamin B2 and pantethine originating from the metabolism of the cecal microbiome may be the underlying reason for fat accumulation in the liver of late-phase laying hens fed an LL diet.Based on the present study,we propose that targeting vitamin B2 and pantethine(vitamin B5 derivative)might be an effective strategy for improving lipid metabolism in late-phase laying hens fed a low-protein diet.

Effects of Abrus cantoniensis Hance Extract on Blood Lipid of Laying Hen Feed with High Energy and Low Protein Diet

[Objectives]To explore the effects of Abrus cantoniensis Hance(ACH)extract on blood lipid indicators of laying hen fed with high energy and low protein diet.[Methods]Sixty 90-day-old laying hens were randomly divided into five groups:the blank control group(basic diet),the model group(high-energy and low-protein diet,HELPD),the low-dose group(HELPD+0.5 g ACH extract per hen,LACH),and the medium-dose group(HELPD+1 g ACH extract per hen,MACH),high dose group(HELPD+2 g ACH extract per hen,HACH).The ACH extract was administrated by drinking water for 48 d.[Results]Different doses of ACH could improve the pathological changes induced by high energy and low protein.ACH extract had no significant effect on blood routine indicators of laying hens(P>0.05).The contents of total cholesterol(TC),triglyceride(TG)and low density lipoprotein cholesterol(LDL-C)in the model group were significant-ly higher than those in the control group(P<0.05),while the content of high density lipoprotein cholesterol(HDL-C)was significantly lower than that in the control group(P<0.05).There was no significant difference in blood lipid between LACH group and model group(P>0.05).In MACH and HACH groups,the contents of TC,TG and LDL-C were significantly lower than those in the model group(P<0.05),and the content of HDL-C was significantly higher than that in the model group(P<0.05).[Conclusions]The ACH extract can regulate theHELPD-induced dyslipidemia in laying hens.

Intermittent energy restriction in type 2 diabetes: A short discussion of medication management

AIM To discuss type 2 diabetes mellitus(T2DM) medication changes required during the popular 5:2 intermittent energy restriction(IER) diet. METHODS A search was conducted in MEDLINE, EMBASE, AMED, CINAHL and Cochrane library for original research articles investigating the use of very low calorie diets(VLCD) in people with T2 DM. The search terms used included "VLCD" or "very low energy diet" or "very low energy restriction" or "IER" or "intermittent fasting" or "calorie restriction" or "diabetes mellitus type 2" and "type 2 diabetes". Reference lists of selected articles were also screened for relevant publications. Only research articles written in English, which also included an explanation of medication changes were included. A recent pilot trial using the 5:2 IER method, conducted by our research group, will also be summarized.RESULTS A total of 8 studies were found that investigated the use of VLCD in T2 DM and discussed medication management. Overall these studies indicate that the use of a VLCD for people with T2 DM usually require the cessation of medication to prevent hypoglycemia. Therefore, the 5:2 IER method will also require medication changes, but as seen in our pilot trial, may not require total cessation of medication, rather a cessation on the 2 IER days only. CONCLUSION Guidelines outlined here can be used in the initial stages of a 2-d IER diet, but extensive blood glucose monitoring is still required to make the necessary individual reductions to medications in response to weight loss.

Low-protein diets supplemented with casein hydrolysate favor the microbiota and enhance the mucosal humoral immunity in the colon of pigs

Background:High-protein diets can increase the colonic health risks.A moderate reduction of dietary crude-protein(CP)level can improve the colonic bacterial community and mucosal immunity of pigs.However,greatly reducing the dietary CP level,even supplemented with all amino acids(AAs),detrimentally affects the colonic health,which may be due to the lack of protein-derived peptides.Therefore,this study evaluated the effects of supplementation of casein hydrolysate(peptide source)in low-protein(LP)diets,in comparison with AAs supplementation,on the colonic microbiota,microbial metabolites and mucosal immunity in pigs,aiming to determine whether a supplementation of casein hydrolysate can improve colonic health under very LP level.Twenty-one pigs(initial BW 19.90±1.00 kg,63±1 days of age)were assigned to three groups and fed with control diet(16%CP),LP diets(13%CP)supplemented with free AAs(LPA)or casein hydrolysate(LPC)for 4 weeks.Results:Compared with control diet,LPA and LPC diet decreased the relative abundance of Streptococcus and Escherichia coli,and LPC diet further decreased the relative abundance of Proteobacteria.LPC diet also increased the relative abundance of Lactobacillus reuteri.Both LP diets decreased concentrations of ammonia and cadaverine,and LPC diet also reduced concentrations of putrescine,phenol and indole.Moreover,LPC diet increased total short-chain fatty acid concentration.In comparison with control diet,both LP diets decreased protein expressions of Toll-like receptor-4,nuclear factor-κB,interleukin-1βand tumor necrosis factor-α,and LPC diet further decreased protein expressions of nucleotide-binding oligomerization domain protein-1 and interferon-γ.LPC diet also increased protein expressions of G-protein coupled receptor-43,interleukin-4,transforming growth factor-β,immunoglobulin A and mucin-4,which are indicators for mucosal defense activity.Conclusions:The results showed that supplementing casein hydrolysate showed beneficial effects on the colonic microbiota and mucosal immunity and barrier function in comparison with supplementing free AAs in LP diets.These findings may provide new framework for future nutritional interventions for colon health in pigs.

Effect of low-protein diet with supplementing different levels of DL-methionine on production performance of minks in growing-furring period

A study was conducted to evaluate production performance of minks in growing-furring period with supplementing DL-Methinnine （Met） in low protein diet. Seventy healthy male minks were randomly divided into five groups of 14 minks each. The minks were fed in five kinds of experiment diets （HP, LP, LP＋M1, LP＋M2 and LP＋M3）. The dietary protein levels, expressed as percentage of dry matter （DM）, were 32% （high protein, HP） and 24% （low protein, LP）. LP was supple- mented with Met 0.4% （M1）, 0.8% （M2） and 1.2% （M3） DM. From mid of September to December 10, apparent digestibility of CP （crude pro- tein）, N intake and urinary N excretion were decreased with declining dietary protein levels （p 〈 0.05） and N retained was the highest in treat- ment LP＋M2. No significant difference was found in total serum protein （TP） and serum urea nitrogen （SUN） among all treatment groups （p 〉 0.05）. Skin length of treatment HP and LP^M2 was higher than that of other groups （p 〈 0.05）. Body length, skin weight, length of guard hair and under hair were not affected by different dietary protein levels （p〉0.05）. The best performance could be observed in treatment LP＋M2. In diet, 24% （DM） protein level with 1.54% Met supplementing was enough for minks during growing-farring period. Dietary protein lowered from 32% to 24% with supplementing Met in diets would result in a37.9% decrease in urinary N excretion. Furthermore, addition of Met in diets for minks would be beneficial in terms of reducing feed expenses and lessening nitrogen emissions to the environment.

Effects of adding sodium dichloroacetate to low-protein diets on nitrogen balance and amino acid metabolism in the portaldrained viscera and liver of pigs

Background:Identifying regulatory measures to promote glucose oxidative metabolism while simultaneously reducing amino acid oxidative metabolism is one of the foremost challenges in formulating low-protein(LP)diets designed to reduce the excretion of nitrogen-containing substances known to be potential pollutants.In this study,we investigated the effects of adding sodium dichloroacetate(DCA)to a LP diet on nitrogen balance and amino acid metabolism in the portal-drained viscera(PDV)and liver of pigs.To measure nitrogen balance,18 barrows(40±1.0 kg)were fed one of three diets(n=6 per group):18%crude protein(CP,control),13.5%CP(LP),and 13.5%CP+100 mg DCA/kg dry matter(LP-DCA).To measure amino acid metabolism in the PDV and liver,15 barrows(40±1.0 kg)were randomly assigned to one of the three diets(n=5 per group).Four essential amino acids(Lys,Met,Thr,and Trp)were added to the LP diets such that these had amino acid levels comparable to those of the control diet.Results:The LP-DCA diet reduced nitrogen excretion in pigs relative to that of pigs fed the control diet(P<0.05),without any negative effects on nitrogen retention(P>0.05).There were no differences between the control and LP-DCA groups with respect to amino acid supply to the liver and extra-hepatic tissues in pigs(P>0.05).The net release of ammonia into the portal vein and production rate of urea in the liver of pigs fed the LP-DCA diet was reduced relative to that of pigs fed the control and LP diets(P<0.05).Conclusion:The results indicated that addition of DCA to a LP diet can efficiently reduce nitrogen excretion in pigs and maximize the supply of amino acids to the liver and extra-hepatic tissues.

Analysis of Overall Popularization of Low-Protein Diet

The shortage of protein feed resources and environmental pollution restrict the healthy and sustainable development of breeding industry,so it is imperative to promote low protein diet. Based on the current industry trends and national policies, this paper analyzes the background con-ditions, significance and specific measures of popularizing low-protein diets, in order to provide policy, theoretical and technical support for the im-plementation of low-protein diets throughout the year.

“三低三不”饮食原则联合高强度间歇有氧运动对老年糖尿病伴高脂血症患者的影响

目的:探讨“三低三不”饮食原则联合高强度间歇有氧运动对老年糖尿病伴高脂血症患者的影响。方法:选取2022年8月—2023年8月厦门大学附属第一医院收治的102例老年糖尿病伴高脂血症患者。随机将其分为对照组与观察组,各51例。对照组给予“三低三不”饮食原则联合中低强度持续有氧运动,观察组给予“三低三不”饮食原则联合高强度间歇有氧运动。比较两组干预前后的血糖指标、血脂指标、体格指标、血管内皮功能指标。结果:干预后,两组空腹血糖(FBG)、餐后2 h血糖(2 h PG)均低于干预前,观察组FBG、2 h PG均低于对照组,差异有统计学意义(P<0.05)。干预后,两组总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(lLDL-C)均低于干预前,HDL-C高于干预前,观察组TC、TG、LDL-C均低于对照组,HDL-C高于对照组,差异有统计学意义(P<0.05)。干预后,两组体重、体重指数及腰围均低于干预前,观察组体重、体重指数及腰围均低于对照组,差异有统计学意义(P<0.05)。干预后,两组内皮素(ET-1)低于干预前,一氧化氮(NO)高于干预前,观察组ET-1低于对照组,NO高于对照组,差异有统计学意义(P<0.05)。结论:“三低三不”饮食原则联合高强度间歇有氧运动能够降低老年糖尿病伴高脂血症患者的血糖血脂水平,降低其体格指标,改善其血管内皮功能。

Leucine Supplementation in a Chronically Protein-Restricted Diet Enhances Muscle Weight and Postprandial Protein Synthesis of Skeletal Muscle by Promoting the mTOR Pathway in Adult Rats

Low protein intake causes a decrease in protein deposition in most animal tissues. The purpose of this study was to investigate whether leucine supplementation would increase the synthesis rate of protein and muscle weight in adult rats, which chronically consume only 58.8% of their protein requirements. Thirty-six male Sprague-Dawley rats were assigned to one of three dietary treatments including a 20% casein diet （CON）, a 10% casein ＋ 0.44% alanine diet （R）, and a 10% casein ＋ 0.87% leucine diet （RL）. After a 10 d dietary treatment, plasma amino acid levels were measured after feeding, the gastrocnemius muscles and soleus muscles were harvested and weighed, and the fractional synthesis rate （FSR） and mammalian target of rapamycin （mTOR） signaling proteins in skeletal muscle were measured. Regarding the plasma amino acid level, the RL group had the highest concentration of leucine （P 〈 0.05） and the lowest concentration of isoleucine （P 〈 0.05） among the three groups, and the CON group had a lower concentration of valine （P 〈 0.05） than the R and RL groups. Compared with the R and RE groups, the CON group diet significantly increased （P 〈 0.05） feed intake, protein synthesis rate, and the phosphorylation of eukaryutic initiation factor 4E binding protein 1 （4E-BP1）, and decreased the weight of abdominal adipose. Compared with the R group, the RL group significantly increased in gastrocnemius muscle weight, protein synthesis rate, and phosphorylation of both ribosomal protein $6 kinase 1 （56K1） and 4E-BP1. In conclusion, when protein is chronically restricted in adult rat diets, leucine supplementation moderately improves body weight gain and increases muscle protein synthesis through mTOR activation,

Different dietary starch patterns in lowprotein diets:effect on nitrogen efficiency,nutrient metabolism,and intestinal flora in growing pigs

Background:Protein releases amino acids faster than starch releases glucose in digestive tract of pigs fed lowprotein(LP)diets.Poor synchronization of dietary glucose and amino acids supply leads to compromised nitrogen efficiency.Dietary starch patterns modulation may improve this situation.Methods:Growing barrows(29.7±2.0 kg)were randomly allotted into 5 dietary treatments with LP diets consisting of different purified starches.Treatments included:waxy corn starch(W LP),corn starch+waxy corn starch(C+W LP),corn starch(C LP),pea starch+waxy corn starch(P+W LP)and pea starch(P LP).In the experiment,growth performance,protein deposition,nutrient metabolism,and fecal microbial community of pigs were investigated.In vitro starch digestion was used for predicting the in vivo glucose response.Results:Dietary starch in vitro glucose release profile was determined by starch source and the ratio of amylopectin and amylose.C+W LP treatment showed decreased total nitrogen excretion and plasma citrulline concentration and improved plasma leptin concentration among treatments(P<0.05).Besides,the highest nitrogen apparent biological value,whole-body protein deposition and growth performance and lowest urinary nitrogen excretion were also observed in C+W LP treatment.Compared with the other groups,C+W LP and C LP showed increased plasma pyruvate,IGF-1,and lipase concentrations(P<0.05).The W LP group presented dramatically increased plasma alanine and urea nitrogen concentration and decreased aldolase and leptin concentrations(P<0.05).Dietary starch patterns did not make an impact on bacterial richness and diversity,but changed the taxonomic and functional structures of the microbial communities.Microbial protein fermentation product(isobutyrate and isovalerate)presented increased in P LP treatments compared with the other treatments(P<0.05).Conclusions:Dietary starch patterns modulation can regulate dietary glucose release profile,nutrient metabolism,protein turnover,and fecal microbial fermentation in pigs.The optimal dietary glucose release profile effectively strengthened whole-body protein deposition and improve nitrogen efficiency and growth performance in growing pigs fed LP diets.

膳食营养干预与脑健康:调整饮食节律中的“肠-脑”轴机制研究进展

随着生活节奏加快和人口结构变化,焦虑、抑郁以及与衰老相关的神经退行性疾病等脑健康问题日渐成为公共卫生和人民健康的重大威胁。“健康中国2030”计划和《国民营养计划2017—2030》指出,对特定人群开展膳食营养干预至关重要。膳食结构和饮食规律对于机体健康影响重大。近年来,团队系列研究证实调整饮食规律、延长空腹时间对于改善脑健康具有改善作用。本文围绕调整饮食节律这一营养干预中,肠道微生物及其代谢产物通过“肠-脑”轴影响中枢神经系统功能的最新研究进展进行综述,总结在精神、神经类疾病以及慢性代谢性疾病中调整饮食规律的干预效果及分子机制,为未来开展针对特殊人群的精准营养干预提供理论参考。

SIRT1介导间歇性禁食改善高脂饮食诱导的肥胖小鼠脂肪组织线粒体功能和炎症状态

目的探讨间歇性禁食对高脂饮食诱导的肥胖小鼠白色脂肪组织线粒体功能和炎症状态的影响以及沉默信息调节因子2相关酶1(SIRT1)在其中的作用。方法将5~6周龄雄性C57BL/6小鼠随机分为普通自由饮食组(CD组)、高脂自由饮食组(HFD组)和高脂间歇性禁食组(HFD-IF组,隔日禁食24 h),每组各5只,喂养12周。用HE染色观察各组小鼠白色脂肪组织情况,并检测白色脂肪SIRT1、磷酸化腺苷酸活化蛋白激酶(p-AMPK)、叉头转录因子1(FOXO1)、线粒体功能和炎症相关基因的表达情况。在小鼠尾静脉注射腺相关病毒(AAV)-shSIRT1敲减SIRT1表达,分别给予小鼠高脂自由饮食和高脂间歇性禁食,检测上述指标。结果HE染色结果显示HFD-IF组脂肪细胞体积减小。蛋白免疫印迹结果显示高脂自由饮食时脂肪组织SIRT1、p-AMPK、FOXO1蛋白表达均下调,间歇性禁食后均上调(P均<0.05)。定量PCR结果显示HFD组线粒体功能基因Tfam、Nrf1、Pgc-1a表达下调(P均<0.001),炎症基因TNF-α、单核细胞趋化蛋白1、生长因子样模体黏液样激素样受体表达均上调(P均<0.01),间歇性禁食后线粒体功能相关基因均上调(P均<0.05),炎症相关基因均下调(P均<0.05)。敲减SIRT1后,HFD-IF组的上述指标上调或下降的趋势均有所减弱甚至消失(P均<0.05)。结论SIRT1通过改善小鼠内脏白色脂肪组织线粒体功能和炎症状态从而介导间歇性禁食改善高脂喂养诱导的肥胖。

间歇性冷刺激对高脂饮食小鼠的血清脂质相关指标、肝脏组织形态及肝脏脂质合成相关基因和蛋白表达的影响

为了探究间歇性冷刺激对高脂饮食小鼠血清脂质相关指标、肝脏组织形态以及肝脏脂质合成的影响,试验选择5周龄的雄性C57BL/6小鼠48只,随机分为常温对照组、常温高脂组、冷刺激组和冷刺激高脂组,每组3个重复,每个重复4只。常温组小鼠饲养温度为(26±2)℃,冷刺激组小鼠饲养温度为4℃,试验期30 d(每天6 h)。处理结束后采集各组小鼠的肝脏组织和血清样本,通过苏木素-伊红(HE)染色、蛋白质免疫印迹(Western blot)、实时荧光定量PCR(qRT-PCR)等方法,对小鼠肝脏形态结构和脂质合成相关指标进行检测。结果显示:1)饲喂高脂饲粮的小鼠在14周时,体重极显著高于常温对照组(P<0.01)。2)HE结果表明,常温对照组小鼠肝脏肝小叶结构清晰,肝索排列规则有序,未见水肿变性和坏死,未见炎细胞;冷刺激组小鼠的肝脏组织出现颗粒变性,炎性细胞浸润,并观察到充血和出血现象;常温高脂组小鼠肝脏可见大小不一的圆形空泡,发生大泡性脂肪变;冷刺激高脂组小鼠肝脏肝小叶排列紊乱,肝细胞水肿可见空泡变性,炎性细胞浸润。3)小鼠高脂造模后,常温高脂组小鼠血清中血脂相关指标甘油三酯(TG)、游离脂肪酸(NEFA)、总胆固醇(T-CHO)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)的含量均极显著升高(P<0.01)。4)冷刺激组小鼠血清中TG、NEFA、T-CHO、HDL-C、LDL-C的含量极显著低于对照组(P<0.01)。5)常温高脂组小鼠在冷刺激后血清中TG、NEFA、T-CHO、HDL-C、LDL-C的含量极显著低于高脂组(P<0.01)。6)小鼠高脂造模后,常温高脂组小鼠肝脏脂质合成相关[脂肪酸合酶(FASN)、乙酰辅酶A羧化酶1(ACC1)、固醇元件结合蛋白1c(SREBP1c)、ATP-柠檬酸裂解酶(ACLY)]基因和蛋白表达水平极显著升高(P<0.01);小鼠间歇性冷刺激后,冷刺激组小鼠肝脏ACC1蛋白表达水平极显著升高(P<0.01),FASN蛋白表达水平极显著降低(P<0.01);与冷刺激组相比,冷刺激高脂组小鼠肝脏SREBP1c、ACC1、FASN和ACLY蛋白表达水平显著降低(P<0.05)。综上所述,间歇性冷刺激可使高脂饮食小鼠肝脏脂肪组织变得致密并对其血脂异常现象具有一定的缓解作用,并抑制肝脏的脂质合成。

线粒体动力学在OSAHS合并肥胖所致腓肠肌损伤中的作用及其机制研究

目的探究慢性间歇性缺氧(chronic intermittent hypoxia,CIH)合并高脂饮食(high-fat diet,HFD)对小鼠腓肠肌的作用及其可能机制。方法通过模拟CIH、HFD建立阻塞性睡眠呼吸暂停低通气综合征(obstructive sleep apnea hypopnea syndrome,OSAHS)合并肥胖小鼠模型。分为正常对照组(NC组)、CIH组、HFD组、CIH+HFD组。采用苏木精-伊红(hematoxylin-eosin,HE)染色观察各组小鼠腓肠肌结构变化,采用三磷酸腺苷(adenosine triphosphate,ATP)酶染色分析腓肠肌中肌纤维类型的改变,采用实时荧光定量聚合酶链反应(real-time quantitative polymerase chain reaction,RT-qPCR)检测小鼠腓肠肌细胞中MHC同工型基因(MHC1、MHC2)和线粒体功能相关基因(Cs、Ant、NQO1、Hmox1、OGG1)的mRNA表达水平,采用蛋白质免疫印迹(Western blot)法检测细胞凋亡相关蛋白(cleaved-caspase-3)、线粒体融合蛋白(Mfn1、Mfn2、OPA1)及线粒体分裂蛋白(Drp1 Ser616、Fis1)的表达。结果与NC组比较,CIH+HFD组小鼠的腓肠肌结构明显损伤,同时腓肠肌中Ⅰ型肌纤维减少,Ⅱ型肌纤维增加,腓肠肌细胞中MHC1mRNA表达水平下降、MHC2mRNA表达水平增加;另外,CIH+HFD组小鼠腓肠肌细胞中cleaved-caspase-3蛋白和线粒体分裂蛋白(Drp1 Ser616、Fis1)的表达明显上调,线粒体融合相关蛋白Mfn1表达下调。结论CIH合并HFD能导致小鼠腓肠肌结构及功能损伤,该作用可能与线粒体动力学紊乱引起的线粒体功能障碍有关。

Current Evidence Concerning Effects of Ketogenic Diet and Intermittent Fasting in Patients with Nonalcoholic Fatty Liver

Nonalcoholic fatty liver disease (NAFLD) is emerging globally, while no therapeutic medication has been approved as an effective treatment to date, lifestyle intervention through dietary modification and physical exercise plays a critical role in NAFLD management. In terms of dietary modification, Mediterranean diet is the most studied dietary pattern and is recommended in many guidelines, however, it may not be feasible and affordable for many patients. Recently, a ketogenic diet and intermittent fasting have gained public attention and have been studied in the role of weight management. This article reviews specifically whether these trendy dietary patterns have an effect on NAFLD outcomes regarding intrahepatic fat content, fibrosis, and liver enzymes, the scientific rationales behind these particular dietary patterns, as well as the safety concerns in some certain patient groups.

Dietary crude protein and protein solubility manipulation enhances intestinal nitrogen absorption and mitigates reactive nitrogen emissions through gut microbiota and metabolome reprogramming in sheep

Dietary nutrient manipulation(e.g.protein fractions)could lower the environmental footprints of ruminants,especially reactive nitrogen(N).This study investigated the impacts of dietary soluble protein(SP)levels with decreased crude protein(CP)on intestinal N absorption,hindgut N metabolism,fecal microbiota and metabolites,and their linkage with N metabolism phenotype.Thirty-two male Hu sheep,with an age of six months and an initial BW of 40.37±1.18 kg,were randomly assigned to four dietary groups.The control diet(CON),aligning with NRC standards,maintained a CP content of 16.7%on a dry matter basis.Conversely,the experimental diets(LPA,LPB,and LPC)featured a 10%reduction in CP compared with CON,accompanied by SP adjustments to 21.2%,25.9%,and 29.4%of CP,respectively.Our results showed that low-protein diets led to significant reductions in the concentrations of plasma creatinine,ammonia,urea N,and fecal total short-chain fatty acids(SCFA)(P<0.05).Notably,LPB and LPC exhibited increased total SCFA and propionate concentrations compared with LPA(P<0.05).The enrichment of the Prevotella genus in fecal microbiota associated with energy metabolism and amino acid(AA)biosynthesis pathways was evident with SP levels in low-protein diets of approximately 25%to 30%.Moreover,LPB and LPC diets demonstrated a decrease in fecal NHþ4 eN and NO2 eN contents as well as urease activity,compared with CON(P<0.05).Concomitantly,reductions in fecal glutamic acid dehydrogenase gene(gdh),nitrite reductase gene(nirS),and nitric oxide reductase gene(norB)abundances were observed(P<0.05),pointing towards a potential reduction in reactive N production at the source.Of significance,the up-regulation of mRNA abundance of AA and peptide transporters in the small intestine(duodenum,jejunum,and ileum)and the elevated concentration of plasma AA(e.g.arginine,methionine,aspartate,glutamate,etc.)underscored the enhancement of N absorption and N efficiency.In summary,a 10%reduction in CP,coupled with an SP level of approximately 25%to 30%,demonstrated the potential to curtail reactive N emissions through fecal Prevotella enrichment and improve intestinal energy and N utilization efficiency.

连续和间断运动对高脂饮食大鼠肥胖和脂肪肝作用效果的比较

目的探讨连续运动与间断运动对高脂饮食大鼠肥胖和脂肪肝的作用效果。方法根据饮食结构不同分为常规饮食(R)和高脂饮食(H)两大组,再根据运动的不同又分为静坐组(S)、连续运动组(CE)和间断运动组(IE),随机将Wistar大鼠分为6组(n=8)。CE组大鼠每天游泳1次,90 min/次;IE组大鼠每天游泳3次,30 min/次,每隔4 h 1次;两组每周运动5 d,持续8周。重量分析法测定:腹膜后(RET)、附睾(EPI)和内脏(VIS)的白色脂肪组织、棕色脂肪组织(BAT)、肝脏(L)和腓肠肌(GAST)。体内脂肪生成率测定:3H20与皂化后脂肪结合计算脂肪生成率。测定血总胆固醇(CHOL)、高密度脂蛋白胆固醇(HDL-C)、甘油三酯(TG)的含量。每天记录体质量和摄食量。结果间断运动能够改善血脂,减轻增加的体质量、中心性和内脏性肥胖和脂肪肝,能对控制肥胖症和相关并发症包括非酒精性脂肪肝疾病有效;间断运动在减少高脂饮食和久坐状态引起的肥胖和脂肪肝等不良反应方面较连续运动更有效;高脂饮食和不同运动方案对大鼠体质量增加、肥胖症、脂肪肝以及血脂的影响与运动方式、间隔时间、年龄、性别和实验周期有关。结论间断运动是一种非药物治疗控制肥胖及其他并发症的重要措施。

间歇低氧暴露对高脂膳食大鼠胰岛素敏感性的影响

目的:探讨间歇低氧暴露对高脂膳食肥胖大鼠胰岛素抵抗的影响。方法:40只雄性SD大鼠随机分为普通膳食常氧组、普通膳食间歇低氧组、高脂膳食常氧组、高脂膳食间歇低氧组。普通膳食采用普通饲料,高脂膳食采用高脂饲料,间歇低氧暴露采用常压低氧方法,氧浓度控制在15.4%,每天10小时。干预6周后取材测试大鼠内脏脂肪总量、空腹血糖和胰岛素,并计算胰岛素敏感指数。结果:与普通膳食常氧组相比,高脂膳食常氧组大鼠Lee指数、内脏脂肪总量和血清胰岛素水平极显著增加而胰岛素敏感指数极显著下降(P<0.01),但普通膳食间歇低氧组大鼠Lee指数、内脏脂肪总量显著减少(P<0.05,P<0.01),胰岛素敏感指数显著升高(P<0.05);与高脂膳食常氧组比较,高脂膳食间歇低氧组大鼠Lee指数、内脏脂肪总量和胰岛素水平极显著下降(P<0.01),胰岛素敏感指数极显著提高(P<0.01)。相关性分析显示,内脏脂肪总量与胰岛素水平存在一定正相关,且胰岛素水平和胰岛素敏感指数存在高度负相关(P<0.01)。结论:体内脂肪总量增加可使血清胰岛素水平升高,胰岛素敏感性下降,而间歇低氧暴露可以减少高脂膳食大鼠体内脂肪含量,提高胰岛素敏感性,改善胰岛素抵抗。

间歇性低氧通过上调脂蛋白相关磷脂酶A_2和氧化型低密度脂蛋白表达促进动脉粥样硬化形成

目的研究间歇性低氧及高脂饮食通过上调脂蛋白相关磷脂酶A2(Lp-PLA2)、氧化型低密度脂蛋白(ox-LDL)的表达促进动脉粥样硬化的形成。方法采用随机对照、前瞻性动物实验和析因设计的方法,建立间歇性低氧和高脂饮食兔动物模型,将24只4月龄新西兰大耳白兔随机分为四组:对照组、间歇性低氧组(IH组)、高脂饮食组(HFD组)和间歇性低氧+高脂饮食组(IH+HFD组),每组6只。IH组和IH+HFD组置于间歇性低氧舱中,每天8 h,每循环5 min,舱内最低氧浓度8%,最高氧浓度21%,HFD组和IH+HFD组给予高脂饲料饲养,间歇性低氧和高脂饮食干预12周,利用酶联免疫吸附法测定间歇性低氧和高脂饮食干预0、4、8和12周血浆中Lp-PLA2和ox-LDL含量的变化,在实验终点12周取主动脉弓和腹主动脉观察动脉粥样硬化的形成情况。结果在第8周和12周时,IH组、HFD组和IH+HFD组Lp-PLA2含量较对照组和第4周时升高(P<0.05);在第4、8和12周时IH+HFD组Lp-PLA2含量分别较对照组、IH组和HFD组升高(P<0.05);间歇性低氧和高脂饮食分别在第4、8和12周对Lp-PLA2的影响存在交互效应(P=0.000,P=0.001,P=0.000)。在第4、8和12周时,IH组、HFD组和IH+HFD组ox-LDL含量较对照组均升高(P<0.05),在第4周时明显高于第8周和12周(P<0.05);在第4、8和12周时IH+HFD组ox-LDL含量分别较对照组、IH组和HFD组升高(P<0.05);间歇性低氧和高脂饮食在第4周时对ox-LDL的影响存在交互效应(P=0.000),在第8周和12周时不存在交互效应(P=0.104和P=0.166)。间歇性低氧和高脂饮食干预下腹主动脉油红"O"染色及主动脉弓和腹主动脉组织HE染色后可观察到动脉粥样硬化的形成。结论间歇性低氧和高脂饮食可能通过上调血浆中Lp-PLA2和ox-LDL表达促进动脉粥样硬化形成。

间歇性低蛋白饮食对慢性肾功能衰竭患者的疗效观察

目的评估间歇性低蛋白饮食干预对慢性肾功能衰竭(CRF)患者的影响。方法以24例CRF患者为研究对象,按每日每千克标准体重蛋白质供给量为0.6g,每隔3天为0.8g设计个体化食谱,严格按食谱进食3个月,观察患者营养状况的改善及病情变化。结果营养干预后患者的上臂围明显高于干预前(P<0.05);干预前后血清白蛋白变化差异有显著性(P<0.05);干预后患者的血尿素氮明显低于干预前(P<0.05)。结论间歇性低蛋白饮食可以预防CRF患者发生营养不良,控制病情发展。