Regulation of serotonin production by specific microbes from piglet gut

Background Serotonin is an important signaling molecule that regulates secretory and sensory functions in the gut.Gut microbiota has been demonstrated to affect serotonin synthesis in rodent models.However,how gut microbes regulate intestinal serotonin production in piglets remains vague.To investigate the relationship between microbiota and serotonin specifically in the colon,microbial composition and serotonin concentration were analyzed in ileum-cannulated piglets subjected to antibiotic infusion from the ileum when comparing with saline infusion.Microbes that correlated positively with serotonin production were isolated from piglet colon and were further used to investi-gate the regulation mechanisms on serotonin production in IPEC-J2 and a putative enterochromaffin cell line RIN-14B cells.Results Antibiotic infusion increased quantities of Lactobacillus amylovorus(LA)that positively correlated with increased serotonin concentrations in the colon,while no effects observed for Limosilactobacillus reuteri(LR).To understand how microbes regulate serotonin,representative strains of LA,LR,and Streptococcus alactolyticus(SA,enriched in feces from prior observation)were selected for cell culture studies.Compared to the control group,LA,LR and SA supernatants significantly up-regulated tryptophan hydroxylase 1(TPH1)expression and promoted serotonin production in IPEC-J2 cells,while in RIN-14B cells only LA exerted similar action.To investigate potential mechanisms mediated by microbe-derived molecules,microbial metabolites including lactate,acetate,glutamine,andγ-aminobutyric acid were selected for cell treatment based on computational and metabolite profiling in bacte-rial supernatant.Among these metabolites,acetate upregulated the expression of free fatty acid receptor 3 and TPH1 while downregulated indoleamine 2,3-dioxygenase 1.Similar effects were also recapitulated when treating the cells with AR420626,an agonist targeting free fatty acid receptor 3.Conclusions Overall,these results suggest that Lactobacillus amylovorus showed a positive correlation with sero-tonin production in the pig gut and exhibited a remarkable ability to regulate serotonin production in cell cultures.These findings provide evidence that microbial metabolites mediate the dialogue between microbes and host,which reveals a potential approach using microbial manipulation to regulate intestinal serotonin biosynthesis.

Development of innovative tools for investigation of nutrient-gut interaction

The gastrointestinal tract is the key interface between the ingesta and the human body.There is wide recognition that the gastrointestinal response to nutrients or bioactive compounds,particularly the secretion of numerous hormones,is critical to the regulation of appetite,body weight and blood glucose.This concept has led to an increasing focus on“gut-based”strategies for the management of metabolic disorders,including type 2 diabetes and obesity.Understanding the underlying mechanisms and downstream effects of nutrient-gut interactions is fundamental to effective translation of this knowledge to clinical practice.To this end,an array of research tools and platforms have been developed to better understand the mechanisms of gut hormone secretion from enteroendocrine cells.This review discusses the evolution of in vitro and in vivo models and the integration of innovative techniques that will ultimately enable the development of novel therapies for metabolic diseases.

Effects of galacto-oligosaccharides on growth and gut function of newborn suckling piglets

Background: Most research on galacto-oligosaccharides(GOS) has mainly focused on their prebiotic effects on the hindgut,but their beneficial effects on the small intestine(SI) have received little attention.Since jejunum is the important place to digest and absorb nutrients efficiently,optimal maturation of the jejunum is necessary for maintaining the high growth rate in the neonate.Therefore,this study investigates the effect of the early intervention with GOS on the intestinal development of the jejunum.Methods: A total of 6 litters of neonatal piglets(10 piglets per litter; Duroc × Landrace × Large White) with an average birth weight of 1.55 ± 0.05 kg received 1 of 2 treatments based on their assignment to either the control(CON) group or the GOS(GOS) group in each litter.Piglets in the GOS group were orally administrated 10 mL of a GOS solution(reaching 1 g GOS/kg body weight) per day from the age of 1 to 7 d; the piglets in the CON group were treated with the same dose of physiological saline.All piglets were weaned on d 21.On d 8 and 21 of the experimental trial,1 pig per group from each of the 6 litters was euthanized.Results: The early intervention with GOS increased the average daily gains in the third week(P < 0.05).Decreased crypt depth was also observed in the jejunum of the piglets on d 21(P < 0.05).The early intervention with GOS increased the jejunal lactase activity on d 8,maltase activity and sucrase activity on d 21(P < 0.05).In addition,the early intervention with GOS also facilitated the mRNA expression of Sodium glucose co-transporter 1(SGLT1) on d 8 and the m RNA expression of Glucose transporter type 2(GLUT2) on d 21(P < 0.05).It was further determined that GOS up-regulated the m RNA expression of preproglucagon(GCG),insulin-like growth factor 1(IGF-1),insulin-like growth factor 1 receptor(IGF-1 R) and epidermal growth factor(EGF).GOS also up-regulated the protein expression of glucagon-like peptide-2(GLP-2) and EGF in the jejunum of the piglets.Furthermore,it was also found that GOS enhanced the protein expression of ZO-1 and occludin on d 8(P < 0.05),as well as increased the mRNA expression of TGF-β and decrease the mRNA expression of IL-12(P < 0.05).Conclusions: These results indicate that GOS have a positive effect on piglet growth performance in addition to decreasing the crypt depth and enhancing functional development in jejunum of suckling piglets.

Diversity and community pattern of sulfate-reducing bacteria in piglet gut

Background: Among the gut microbiota,sulfate-reducing bacteria(SRB) is a kind of hydrogen-utilizing functional bacteria that plays an important role in intestinal hydrogen and sulfur metabolism.However,information is lacking regarding diversity and community structure of SRB in the gut of piglets.Middle cecum contents were collected from 6 Yorkshire and 6 Meishan piglets at postnatal days(PND) 14,28 and 49.Piglets were weaned at PND28.Real-time quantitative PCR was performed to detect the number of SRB in the cecum based on dissimilatory sulfite reductase subunit A(dsrA) gene.Prior to real-time PCR,plasmid containing the dsrA gene was constructed and used as external standard to create a standard curve,from which the gene copies of dsrA were calculated.H2S concentration in the cecal contents was measured.Illumina PE250 sequencing of dsrA gene was used to investigate SRB diversity in cecum contents.Results: The qPCR results showed that the number of SRB at PND49 was significantly higher than that at PND28 in Meishan piglets.The concentration of H2S has no significant difference between piglet breeds and between different ages.The Illumina sequencing analysis revealed that the Chao1 richness index was significantly higher at PND49 than that at PND14 and PND28 in Yorkshire piglets.Based on dsrA gene similarities,Proteobacteria,Actinobacteria,and Firmicutes were identified at the phylum level,and most sequences were classified as Proteobacteria.At the genus level,most of sequences were classified as Desulfovibrio.At the species level,Desulfovibrio intestinalis was the predominant SRB in the piglet cecum.The relative abundance and the inferred absolute abundance of Faecalibacterium prausnitzii at PND49 were significantly higher than that at PND14 in Yorkshire piglets.Pig breeds did not affect the dsrA gene copies of SRB,diversity index and community pattern of SRB.Conclusions: Sulfate-reducing bacteria are widely colonized in the cecum of piglets and D.intestinalis is the dominant SRB.The age of piglets,but not the pig breeds affects the diversity and community pattern of SRB.

Impact of the gut microbiome on atherosclerosis

Atherosclerosis is a chronic inflammatory metabolic disease with a complex pathogenesis.However,the exact details of its pathogenesis are still unclear,which limits effective clinical treatment of atherosclerosis.Recently,multiple studies have demonstrated that the gut microbiota plays a pivotal role in the onset and progression of atherosclerosis.This review discusses possible treatments for atherosclerosis using the gut microbiome as an intervention target and summarizes the role of the gut microbiome and its metabolites in the development of atherosclerosis.New strategies for the treatment of atherosclerosis are needed.This review provides clues for further research on the mechanisms of the relationship between the gut microbiota and atherosclerosis.

The direct and gut microbiota-mediated effects of dietary bile acids on the improvement of gut barriers in largemouth bass(Micropterus salmoides)

Fish gut barrier damage under intensive culture model is a significant concern for aquaculture industry.This study aimed to investigate the effects of bile acids(BAs)on gut barriers in Micropterus salmoides.A germ-free(GF)zebrafish model was employed to elucidate the effects of the direct stimulation of BAs and the indirect regulations mediated by the gut microbiota on gut barrier functions.Four diets were formulated with BAs supplemented at 0,150,300 and 450 mg/kg,and these 4 diets were defined as control,BA150,BA300 and BA450,respectively.After 5 weeks of feeding experiment,the survival rate of fish fed with BA300 diet was increased(P<0.05).Histological analysis revealed an improvement of gut structural integrity in the BA150 and BA300 groups.Compared with the control group,the expression of genes related to chemical barrier(mucin,lysozyme and complement 1)and physical barrier(occludin and claudin-4)was increased in the BA150 and BA300 groups(P<0.05),and the expression of genes related to immunological barrier(interleukin[IL]-6,tumor growth factorβ,IL-10,macrophage galactosetype lectin and immunoglobulin M[Ig M])was significantly increased in the BA300 group(P<0.05),but the expression of genes related to chemical barrier(hepcidin)and immunological barrier(IL-1β,tumor necrosis factor-a,IL-6 and arginase)was significantly decreased in the BA450 group(P<0.05).Gut microbiota composition analysis revealed that the abundance of Firmicutes was augmented prominently in the BA150 and BA300 groups(P<0.05),while that of Actinobacteriota and Proteobacteria showed a downward trend in the BA150 and BA300 groups(P>0.05).The results of the gut microbiota transferring experiment demonstrated an upregulation of gut barrier-related genes,including immunoglobulin Z/T(Ig Z/T),IL-6,IL-1βand IL-10,by the gut microbiota transferred from the BA300 group compared with the control(P<0.05).Feeding the BA300 diet directly to GF zebrafish resulted in enhanced expression of Ig M,Ig Z/T,lysozyme,occludin-2,IL-6 and IL-10(P<0.05).In conclusion,BAs can improve the gut barriers of fish through both direct and indirect effects mediated by the gut microbiota.

Poultry gut health and beyond

Intestinal health is critically important for the digestion and absorption of nutrients and thus is a key factor in determining performance.Intestinal health issues are very common in high performing poultry lines due to the high feed intake,which puts pressure on the physiology of the digestive system.Excess nutrients which are not digested and absorbed in the small intestine may trigger dysbiosis,i.e.a shift in the microbiota composition in the intestinal tract.Dysbiosis as well as other stressors elicit an inflammatory response and loss of integrity of the tight junctions between the epithelial cells,leading to gut leakage.In this paper,key factors determining intestinal health and the most important nutritional tools which are available to support intestinal health are reviewed.

Altered gut microbiota composition in children and their caregivers infected with the SARS‑CoV‑2 Omicron variant

Background Gut microbiota alterations have been implicated in the pathogenesis of coronavirus disease 2019(COVID-19).This study aimed to explore gut microbiota changes in a prospective cohort of COVID-19 children and their asymptomatic caregivers infected with the severe acute respiratory syndrome coronavirus type 2(SARS-CoV-2)Omicron variant.Methods A total of 186 participants,including 59 COVID-19 children,50 asymptomatic adult caregivers,52 healthy children(HC),and 25 healthy adults(HA),were recruited between 15 April and 31 May 2022.The gut microbiota composition was determined by 16S rRNA gene sequencing in fecal samples collected from the participants.Gut microbiota functional profling was performed by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States(PICRUSt)software.Results The gut microbiota analysis of beta diversity revealed that the fecal microbial community of COVID-19 children remained far distantly related to HC.The relative abundances of the phyla Actinobacteria and Firmicutes were decreased,whereas Bacteroidetes,Proteobacteria,and Verrucomicrobiota were increased in COVID-19 children.Feces from COVID-19 children exhibited notably lower abundances of the genera Blautia,Bifdobacterium,Fusicatenibacter,Streptococcus,and Romboutsia and higher abundances of the genera Prevotella,Lachnoclostridium,Escherichia-Shigella,and Bacteroides than those from HC.The enterotype distributions of COVID-19 children were characterized by a high prevalence of enterotype Bacteroides.Similar changes in gut microbiota compositions were observed in asymptomatic caregivers.Furthermore,the microbial metabolic activities of KEGG(Kyoto Encyclopedia of Genes and Genomes)and COG(cluster of orthologous groups of proteins)pathways were perturbed in feces from subjects infected with the SARS-CoV-2 Omicron variant.Conclusion Our data reveal altered gut microbiota compositions in both COVID-19 children and their asymptomatic caregivers infected with the SARS-CoV-2 Omicron variant,which further implicates the critical role of gut microbiota in COVID-19 pathogenesis.

Baseline gut microbiota and metabolome predict durable immunogenicity to SARS-CoV-2 vaccines

The role of gut microbiota in modulating the durability of cOVID-19 vaccine immunity is yet to be characterised.In this cohort study,we collected blood and stool samples of 121 BNT162b2 and 40 CoronaVac vaccinees at baseline,1 month,and 6 months post vaccination(p.v).Neutralisation antibody,plasma cytokine and chemokines were measured and associated with the gut microbiota and metabolome composition.

当归多糖对结直肠癌细胞顺铂耐药性的影响及作用机制

目的 探讨当归多糖对结直肠癌细胞顺铂耐药性的影响及作用机制。方法 将人结直肠癌细胞HT-15、顺铂耐药细胞株HT-15/DDP仅使用30μmol/L浓度的顺铂干预设为对照组,使用对应质量浓度1.0、1.5、2.0 mg/mL的当归多糖干预12 h后再加入30μmol/L浓度顺铂设为当归多糖组。通过脂质体细胞转染技术分别将miR-10b-5p inhibitor、TGFBR2 mimics转染至HT-15/DDP细胞中,再加入2.0 mg/mL当归多糖干预48 h,然后将其分为当归多糖(2.0 mg/mL)+miR-10b-5p inhibitor组、当归多糖(2.0 mg/mL)+TGFBR2 mimics组。MTT法检测细胞增殖能力;Transwell小室试验检测细胞迁移能力;流式细胞术检测细胞凋亡能力。RT-PCR检测miR-10b-5p、TGFBR2 mRNA表达水平;Western blot检测TGFBR2蛋白表达水平。结果 单独顺铂干预的对照组HT-15/DDP细胞增殖率、细胞迁移个数明显高于HT-15细胞(P<0.01);经不同质量浓度当归多糖预处理12 h后,可明显增强HT-15/DDP细胞对顺铂的敏感性,HT-15/DDP细胞增殖率、细胞迁移个数明显降低(P<0.01)。单独顺铂干预的对照组HT-15/DDP细胞凋亡率明显低于HT-15细胞(P<0.01);经不同质量浓度当归多糖预处理12 h后,明显增强了HT-15/DDP细胞对顺铂的敏感性,HT-15/DDP细胞凋亡率明显升高(P<0.01)。HT-15/DDP细胞miR-10b-5p、TGFBR2表达水平在各组间比较差异均具有统计学意义(P<0.01);不同剂量当归多糖组中HT-15/DDP细胞miR-10b-5p表达水平明显低于对照组,TGFBR2表达水平明显高于对照组(P<0.01),随着当归多糖剂量的增加miR-10b-5p表达水平逐渐降低,TGFBR2表达水平逐渐升高(P<0.01)。使用生物信息学数据库(TargetScan、miRanda)预测miR-10b-5p的靶基因,结果显示,TGFBR2是miR-10b-5p的候选靶基因。miR-10b-5p表达下调后,HT-15/DDP细胞中TGFBR2相对表达量明显高于对照组HT-15/DDP细胞中TGFBR2相对表达量(P<0.01)。当归多糖(2.0 mg/mL)+miR-10b-5p inhibitor组、当归多糖(2.0 mg/mL)+TGFBR2 mimics组的HT-15/DDP细胞增殖率、细胞增殖迁移个数明显低于当归多糖组(2.0 mg/mL),HT-15/DDP细胞凋亡率明显高于当归多糖组(2.0 mg/mL)(P<0.05)。结论 当归多糖可通过下调miR-10b-5p表达、上调TGFBR2表达逆转结直肠癌细胞顺铂耐药性,进而抑制肿瘤细胞增殖、迁移,促进细胞凋亡。

Swine gut microbiota and its interaction with host nutrient metabolism

Gut microbiota is generally recognized to play a crucial role in maintaining host health and metabolism.The correlation among gut microbiota,glycolipid metabolism,and metabolic diseases has been well reviewed in humans.However,the interplay between gut microbiota and host metabolism in swine remains incompletely understood.Given the limitation in conducting human experiments and the high similarity between swine and humans in terms of anatomy,physiology,polyphagy,habits,and metabolism and in terms of the composition of gut microbiota,there is a pressing need to summarize the knowledge gained regarding swine gut microbiota,its interplay with host metabolism,and the underlying mechanisms.This review aimed to outline the bidirectional regulation between gut microbiota and nutrient metabolism in swine and to emphasize the action mechanisms underlying the complex microbiomeehost crosstalk via the gut microbiotaegutebrain axis.Moreover,it highlights the new advances in knowledge of the diurnal rhythmicity of gut microbiota.A better understanding of these aspects can not only shed light on healthy and efficient pork production but also promote our knowledge on the associations between gut microbiota and the microbiomeehost crosstalk mechanism.More importantly,knowledge on microbiota,host health and metabolism facilitates the development of a precise intervention therapy targeting the gut microbiota.

生物发酵农作物秸秆及其在反刍动物饲料中的应用

我国农作物秸秆资源丰富,但大部分被直接还田或焚烧,造成资源浪费。农作物秸秆饲料化利用作为农作物秸秆利用途径之一,对缓解粗饲料资源紧张、促进畜牧业可持续发展具有重大意义。但因为秸秆粗纤维含量高和适口性差的特性,直接作为饲料利用,营养价值较低,生物发酵处理可以有效提高秸秆的营养价值和利用率。文章从农作物秸秆饲料化利用现状、生物发酵技术在农作物秸秆饲料化中的应用、生物发酵农作物秸秆在反刍动物生产上的应用研究等方面进行综述,为农作物秸秆的资源化利用提供参考依据。

姜酚和百里香酚对白羽肉鸡小肠形态结构和屏障功能的影响

[目的]本试验旨在研究日粮添加姜酚、百里香酚及其组合对白羽肉鸡小肠形态、免疫功能及肠道屏障的影响。[方法]将200只1日龄AA白羽肉鸡随机分为4组,每组5个重复,每个重复10只,试验期为42 d。4个处理组如下:对照组(Con组,基础日粮)、姜酚组(Gin组,基础日粮+60 mg·kg^(-1)姜酚)、百里香酚组(Thy组,基础日粮+30 mg·kg^(-1)百里香酚)及姜百组(Gin+Thy组,基础日粮+30 mg·kg^(-1)姜酚+15 mg·kg^(-1)百里香酚)。在试验期第42天,采集肉鸡的空肠和回肠制作切片并观察,取空肠和回肠黏膜以测定免疫球蛋白含量、细胞因子含量、抗氧化酶活性、紧密连接和抗氧化相关基因表达。[结果]与对照组相比,姜百组肉鸡回肠绒毛高度(VH)有增加的趋势(P=0.063),绒毛高度/隐窝深度(V/C)值显著提高(P<0.05);姜百组肉鸡空肠和回肠黏膜中分泌性免疫球蛋白A(sIgA)含量显著提高(P<0.05),空肠黏膜中白介素6(IL-6)和干扰素γ(IFN-γ)含量以及回肠黏膜中IL-6和白介素1β(IL-1β)含量显著降低(P<0.05);姜百组肉鸡空肠和回肠黏膜中总抗氧化能力(T-AOC)和谷胱甘肽过氧化物酶(GSH-Px)活性显著升高(P<0.05);姜百组肉鸡空肠黏膜中核因子E2相关因子2(Nrf2)、血红素加氧酶1(HO-1)、谷胱甘肽过氧化物酶(GPX4)和回肠黏膜中Nrf2、超氧化物歧化酶1(SOD1)、GPX4的mRNA相对表达量显著升高(P<0.05),空肠和回肠黏膜中的Occludin mRNA相对表达量显著增加(P<0.05)。[结论]日粮添加姜酚和百里香酚组合可以提高肉鸡的抗氧化能力和免疫功能,并通过改善肠道形态和肠道屏障促进肠道健康。

饲粮中添加蛋白酶对猪生长性能、营养物质消化率和血清生化指标影响的Meta分析

研究采用Meta分析,旨在评价饲粮中添加蛋白酶对猪生长性能、营养物质消化率和血清生化指标的影响。通过检索中国知网、PubMed和Web of Science数据库,筛选饲粮中添加蛋白酶对猪生长性能、营养物质消化率和血清生化指标影响的随机对照试验。自2013至2023年,筛选获得22篇文献纳入研究,所纳入总样本1818例,使用R包(Meta)进行相关数据分析。选择标准化均数差(SMD)作为效应指标。结果表明:相较于对照组,饲粮中添加蛋白酶显著提高了猪的平均日采食量(SMD=0.11,95%CI=0.01~0.21)和平均日增重(SMD=0.43,95%CI=0.28~0.57),降低了料重比(SMD=-0.33,95%CI=-0.48~-0.18),提高了饲粮中干物质(SMD=0.27,95%CI=0.15~0.39)和粗蛋白(SMD=0.42,95%CI=0.32~0.53)的消化率,降低了血清中尿素氮含量(SMD=-0.17,95%CI=-0.28~-0.05)。综上,饲粮中添加蛋白酶可以改善猪的生长性能,提高营养物质消化率,降低血清中尿素氮水平。

益生菌调控动物肠道健康的机制研究进展

益生菌是一类有益于宿主健康的微生物,具有提高动物生长性能、改善肠道健康等作用。在畜牧业全面禁止使用促生长类抗生素的形势下,益生菌类饲料添加剂能够作为抗生素的替代品,保障动物的健康养殖。本文从动物肠道营养物质消化吸收、微生物屏障、化学屏障、物理屏障和免疫屏障等方面出发,阐明了益生菌调控动物肠道健康的可能机制,以期为益生菌的科学应用提供依据。

碱性过氧化氢处理稻秸纤维对瘤胃体外发酵特性和微生物多样性的影响

本试验旨在评估一种碱性过氧化氢处理稻秸纤维的体外瘤胃降解率及其对瘤胃发酵参数和微生物多样性的影响。以普通稻秸为对照,将碱氧处理获得的稻秸纤维体外发酵72 h,并分别在4、8、12、18、24、36、48和72 h时测定产气量;在0.5、4、12、24、48和72 h时,每组取6个发酵瓶采集发酵液,用于测定挥发性脂肪酸(VFA)、氨态氮(NH_(3)-N)和菌体蛋白(MCP)含量,收集剩余底物,用于纤维降解率的测定;收集72 h发酵底物于-80℃保存,用于后续DNA提取和高通量分析。结果表明:1)在发酵72 h时,稻秸纤维的干物质降解率是稻秸的1.64倍(P<0.05),中性洗涤纤维、酸性洗涤纤维、纤维素和半纤维素的降解率均显著高于稻秸(P<0.05)。稻秸纤维干物质开始降解时间短于稻秸,稻秸纤维在发酵4 h时出现降解而稻秸在发酵12 h时出现降解。2)扫描电镜结果表明,与稻秸相比,稻秸纤维结构更加松散,微生物黏附数量更多,发酵72 h消化更完全。3)稻秸纤维的发酵总产气量、总挥发性脂肪酸含量以及丙酸和异戊酸含量均极显著高于稻秸(P<0.01),甲烷产量/总产气量比例和丁酸、异丁酸和戊酸含量以及乙酸/丙酸比例均显著或极显著低于稻秸(P<0.05或P<0.01)。在发酵72 h时,稻秸纤维的细菌总数和MCP含量极显著高于稻秸(P<0.01),NH_(3)-N含量极显著低于稻秸(P<0.01)。4)α多样性结果表明,稻秸纤维菌群多样性显著高于稻秸(P<0.05)。在门水平上,微生物差异分析结果表明,稻秸纤维和稻秸中相对丰度大于1%的菌门无显著差异(P>0.05);在属水平上,稻秸纤维中瘤胃球菌属(Ruminococcus)、产乙酸糖发酵菌属(Saccharofermentans)和普雷沃氏菌科UCG-001(Prevotellaceae_UCG-001)等的相对丰度显著低于稻秸(P<0.05),未培养的毛螺菌科(unculured_Lachnospiraceae)、Probable_genus_10、拟杆菌目F082(Bacteroidales_F082)和毛螺菌科UCG-009(Lachnospiraceae_UCG-009)的相对丰度显著高于稻秸(P<0.05)。综上所述,稻秸纤维比稻秸更容易被微生物降解并能生成更多的VFA等能量物质,可作为一种有潜力的产品用于反刍动物生产中。

不同包被缓释尿素的瘤胃缓释效果的评价

[目的]本文旨在通过体外批次发酵、瘤胃灌注和持续动态人工瘤胃模拟系统等不同方法评价包被缓释尿素的瘤胃缓释效果。[方法]体外发酵试验:选取1种普通尿素和4种商业包被缓释尿素,体外培养24 h,采集不同时间点(0、1、3、6、9、12、24 h)发酵液测定氨氮浓度,将筛选出缓释效果最好的缓释尿素用于进一步的研究。瘤胃灌注试验:12只体重(平均27.6 kg)相近的安装有瘤胃瘘管的育肥公湖羊,随机平均分为2组,分别向瘤胃中灌注剂量为日干物质采食量0.5%的普通尿素或日采食量0.55%的缓释尿素(等氮当量),灌注后不同时间点(0、1、3、6、9、12和24 h)采集瘤胃液,测定pH值和氨氮浓度。人工瘤胃试验:在基础日粮中分别添加3.5%的豆粕(普通日粮组)、0.5%的普通尿素(普通尿素组)和0.55%的缓释尿素(缓释尿素组),使用玉米补充普通尿素和缓释尿素组能量的缺乏;试验重复3次,每次持续7 d(4 d适应期和3 d采样期),采样期每天早上投料前后不同时间点采集发酵液和溢流液,测定发酵参数和微生物蛋白浓度。[结果]体外发酵试验:在发酵开始的9、12 h,缓释尿素A组的氨氮浓度显著低于普通尿素组和其余3个缓释尿素处理组(P<0.05)。体内瘤胃灌注试验:在灌注尿素后1 h,缓释尿素组瘤胃pH值和氨氮浓度显著低于普通尿素组(P<0.05),在灌注尿素后6 h,缓释尿素组的pH值显著高于普通尿素组(P<0.05)。人工瘤胃模拟试验:相比于其他2组,日粮添加缓释尿素显著提高了发酵液中丙酸和微生物蛋白的浓度(P<0.05);相比于普通日粮组,日粮添加缓释尿素显著降低了发酵液pH值(P<0.05)。[结论]不同包被缓释尿素的瘤胃缓释效果存在差异,体外发酵筛选出的缓释尿素A在动物瘤胃灌注条件下同样表现出较好的缓释效果。在人工瘤胃发酵试验中添加缓释尿素A能够改善瘤胃发酵,促进微生物蛋白的合成,但对生长性能和瘤胃菌群的影响仍需动物饲养试验做进一步的验证。

发酵全混合日粮对藏羊营养物质表观消化率、血清生化指标、屠宰性能及肉品质的影响

本文旨在探讨发酵全混合日粮(TMR)对育肥期藏羊营养物质表观消化率、血清生化指标、屠宰性能及肉品质的影响。选用14只5月龄、体重29 kg左右的健康藏羊公羊,随机分成2组,每组7个重复,每个重复1头。对照组饲喂未发酵TMR,试验组饲喂发酵TMR。预试期14 d,正试期70 d。结果表明:1)与对照组相比,试验组藏羊平均日采食量(ADFI)以及中性洗涤纤维(NDF)和半纤维素表观消化率显著提高(P<0.05)。2)与对照组相比,试验组藏羊血清谷丙转氨酶(ALT)活性、甘油三酯(TG)和总胆固醇(TC)含量、总抗氧化能力(T-AOC)以及谷胱甘肽过氧化物酶(GSH-Px)活性显著提高(P<0.05)。3)与对照组相比,试验组藏羊胴体重和屠宰率显著提高(P<0.05),腹脂重量和指数显著降低(P<0.05)。4)与对照组相比,试验组藏羊背最长肌红度(a^(*))值显著提高(P<0.05),且背最长肌总必需氨基酸含量显著升高(P<0.05),同时背最长肌总非必需氨基酸含量显著下降(P<0.05);其中,试验组背最长肌缬氨酸和异亮氨酸含量显著提高(P<0.05),而背最长肌甲硫氨酸、酪氨酸、天冬氨酸、丝氨酸和谷氨酸含量显著降低(P<0.05)。综上所述,在本试验条件下,对TMR进行发酵处理能够提高藏羊屠宰性能、NDF和半纤维素表观消化率以及机体抗氧化能力,降低腹部脂肪沉积,对背最长肌肉色及营养价值也具有一定的改善作用。

美洲大蠊提取物对便秘模型小鼠的影响

目的观察不同剂量美洲大蠊提取物对慢传输型便秘模型小鼠排便功能的影响。方法35只雄性C57BL/6J小鼠,随机分为对照组、模型组及美洲大蠊提取物高、中、低剂量组,每天给予盐酸洛哌丁胺灌胃造模及不同浓度的美洲大蠊提取物进行干预治疗,记录各组小鼠给药后粪便排泄数量及湿重;在实验结束前,收集各组小鼠粪便,采用16S rRNA分析其肠道菌群变化;同时测定各组小鼠首次排红便时间及小肠推进率。结果与对照组相比,模型组小鼠的粪便湿重、粒数,肠道推进率均降低;而排红便时间延长(P<0.01)。与模型组相比,各美洲大蠊治疗组小鼠的粪便湿重、粒数及小肠推进率增加,而排红便时间降低(P<0.05或P<0.01)。16S rRNA分析显示美洲大蠊提取物可明显提升便秘小鼠肠道粪便中Lachnospiraceae NK4A136和酸性拟杆菌、Alistipes、Rikenella microfusus DSM 15922细菌的丰度。结论美洲大蠊提取物能够缓解盐酸洛哌丁胺诱导的小鼠便秘,其作用机制与调节肠道菌群有关。

水公牛和荷斯坦奶公牛养分消化、瘤胃发酵及血液生化指标的比较研究

本试验旨在探究饲喂相同日粮条件下,比较水公牛与荷斯坦奶公牛养分表观消化率、瘤胃发酵参数和血液生化指标的不同。试验选取健康且状况良好的水公牛和荷斯坦奶公牛各6头,单栏饲养,自由采食和饮水,试验分为预试期16 d,采样期6 d,每天测定采食量,采样期分别采集瘤胃液、饲料、粪便和血液样品用于瘤胃发酵参数、养分消化率、血液生化等指标的测定。结果表明:荷斯坦奶公牛对日粮中干物质、有机物、粗蛋白、中性洗涤纤维和酸性洗涤纤维等养分摄入量极显著高于水公牛(P<0.01),水公牛对日粮中粗蛋白的消化率显著高于荷斯坦奶公牛(P<0.05),两组牛对日粮干物质、有机物、中性洗涤纤维、酸性洗涤纤维、粗脂肪的消化率无显著差异(P>0.05);水公牛组瘤胃pH值显著高于荷斯坦奶公牛组(P<0.05),而瘤胃总挥发性脂肪酸、乙酸、丁酸、异戊酸和戊酸含量显著低于荷斯坦奶公牛组(P<0.05),两组牛瘤胃液中氨态氮、丙酸和异丁酸浓度无显著差异(P>0.05);水公牛组血液中丙氨酸氨基转移酶、天冬氨酸氨基转移酶、白蛋白、碱性磷酸酶、尿素、甘油三酯和白蛋白/球蛋白比含量显著高于荷斯坦奶公牛组(P<0.05),而血液中总蛋白、球蛋白、总胆固醇含量显著低于荷斯坦奶公牛组(P<0.05),两组牛血液中γ-谷氨酰基转移酶、血糖含量无显著差异(P>0.05)。试验结果表明:在本试验日粮饲养条件下,荷斯坦奶公牛对于日粮养分摄入量以及瘤胃乙酸、丁酸等挥发性脂肪酸产量均大于水公牛,具有较好的增重潜力。