草鱼肠道微生物对食物改变适应性变化的研究

对草鱼(Ctenopharyngodon idellus)先饲喂人工饲料再饲喂苏丹草,运用PCR-DGGE的方法,比较了食物改变引起的草鱼肠道微生物菌群结构的变化过程。结果显示,饲喂同种饲料的草鱼后肠与前、中肠样品间菌群结构存在显著差异(TH0-F0=-2.268,P0.05;TH0-M0=-2.470,P0.05),饲喂不同种食物的相同肠段样品间菌群结构也存在着显著差异(P0.05)。微生物多样性指数显示,后肠样品Shannon指数H'一般不低于4.25,而前、中肠样品H'均未超过4.25。对后肠样品进一步研究发现,食物改变11 d之后,后肠微生物菌群基本达到稳定。结果表明,草鱼肠道不同部位内容物菌群结构不同,后肠样品具有更高的微生物多样性,并且食物的改变会对草鱼肠道微生物菌群产生快速而显著的影响。     

仔兔肠道菌群早期定植特征及其调控的研究进展

仔兔在断奶期的肠道菌群结构极易发生紊乱,从而引起腹泻造成大量死亡,严重阻碍了兔养殖业的发展。因此,建立健康稳定的兔肠道菌群对于降低兔腹泻的发生率具有极其重要的意义。本文系统综述了仔兔肠道菌群早期定植规律及其调控措施的研究进展,以期为缓解和阻止仔兔断奶腹泻提供理论参考。     

猪的肠道微生物与宿主营养代谢

肠道中栖息着数量庞大复杂多样的微生物菌群,肠道微生物在宿主健康中发挥着重要作用,既影响着饲料消化、营养物质吸收和能量供应,又调控着宿主正常生理功能及疾病的发生与发展.动物胃肠道不仅是消化器官,还是感应器官,肠道对营养物质的感应可以通过脑肠轴调节机体生理活动.肠道微生物还能代谢蛋白质产生宿主细胞不能合成的肽类物质,并通过小肠上皮的肽类转运系统影响机体代谢,因此可能存在微生物-肠道-大脑轴.肠道微生物还可以与机体形成宿主-微生物代谢轴,对动物机体营养物质代谢和免疫稳态起重要作用.饲粮对宿主代谢的改变,常伴随有肠道微生物区系的变化,肠道微生物的代谢可能通过微生物-肠道-大脑轴以及宿主-微生物代谢轴调节宿主很多生理过程,进而影响机体整体代谢.本文概述了猪肠道微生物区系与宿主肠道营养物质代谢的关系,以加深关于肠道微生物对机体代谢贡献的认识.     

复合益生素对生长育肥猪生产性能、盲肠菌群及代谢产物的影响

试验旨在研究饲粮中添加复合益生素(JS菌)对生长育肥猪生产性能、盲肠菌群、挥发性脂肪酸及蛋白质腐败产物的影响。试验选择120头体重10 kg左右的健康DLY仔猪,随机分为对照组、抗生素组、0.1%JS菌组和0.2%JS菌组,每组5个重复。结果表明:与对照组相比,添加0.2%JS菌显著提高试猪30~50 kg阶段的平均日增重和采食量(P0.05);添加0.1%JS菌显著提高试猪80~100 kg阶段的平均日增重(P0.05);从试验全期来看,抗生素组、0.1%JS菌组和0.2%JS菌组试猪平均日增重和采食量均有所提高,但各组间差异不显著(P0.05)。添加JS菌趋于增加盲肠内容物乳酸杆菌数量,减少大肠杆菌数量(P0.05),从而提高二者的比值,分析PCR-DGGE图谱发现添加JS菌对菌群多样性和相似性也有一定影响。与对照组相比,0.1%JS菌组和0.2%JS菌组盲肠内容物乙酸含量分别提高2.35倍和2.99倍,丁酸含量分别提高58.87%和62.10%,挥发性盐基氮含量分别降低31.91%和28.53%(P0.05)。在本试验条件下,添加JS菌对生长育肥猪的生产性能有一定改善,效果与抗生素基本相当,这可能与其对肠道健康的保护作用有关。     

猪肠道微生物组成、影响因素及其对重要经济性状的影响研究进展

肠道微生物在调节宿主生理机能、代谢和免疫功能等方面发挥着非常重要的作用,是影响猪健康和重要经济性状表型的重要因素之一。近年来,人们对猪肠道微生物的研究和了解越来越深入,了解猪肠道微生物组成将有助于为从肠道菌群方向入手改善猪群健康和提高生产性能提供参考。作者首先综述了不同发育阶段、不同肠道部位以及主要商品猪和中国地方猪肠道核心菌群组成;其次系统总结了宿主遗传背景、饲粮种类、性别、环境以及抗生素、益生菌和饲料添加剂使用等因素对猪肠道微生物组成的影响;最后概述了猪肠道微生物主要功能及其对饲料利用率、脂肪沉积、宿主行为和免疫炎症等方面的影响。     

Genetic relationships between efficiency traits and gut microbiota traits in growing pigs being fed with a conventional or a high-fiber diet

In pigs, the gut microbiota composition plays a major role in the process of digestion, but is influenced by many external factors, especially diet. To be used in breeding applications, genotype by diet interactions on microbiota composition have to be quantified, as well as their impact on genetic covariances with feed efficiency (FE) and digestive efficiency (DE) traits. This study aimed at determining the impact of an alternative diet on variance components of microbiota traits (genera and alpha diversity indices) and estimating genetic correlations between microbiota and efficiency traits for pigs fed a conventional (CO) or a high-fiber (HF) diet. Fecal microbes of 812 full-siblings fed a CO diet and 752 pigs fed the HF diet were characterized at 16 weeks of age by sequencing the V3-V4 region of the 16S rRNA gene. A total of 231 genera were identified. Digestibility coefficients of nitrogen, organic matter, and energy were predicted analyzing the same fecal samples with near infrared spectrometry. Daily feed intake, feed conversion ratio, residual feed intake and average daily gain (ADG) were also recorded. The 71 genera present in more than 20% of individuals were retained for genetic analyses. Heritability (h²) of microbiota traits were similar between diets (from null to 0.38 ± 0.12 in the CO diet and to 0.39 ± 0.12 in the HF diet). Only three out of the 24 genera and two alpha diversity indices with significant h² in both diets had genetic correlations across diets significantly different from 0.99 (P < 0.05), indicating limited genetic by diet interactions for these traits. When both diets were analyzed jointly, 59 genera had h² significantly different from zero. Based on the genetic correlations between these genera and ADG, FE, and DE traits, three groups of genera could be identified. A group of 29 genera had abundances favorably correlated with DE and FE traits, 14 genera were unfavorably correlated with DE traits, and the last group of 16 genera had abundances with correlations close to zero with production traits. However, genera abundances favorably correlated with DE and FE traits were unfavorably correlated with ADG, and vice versa. Alpha diversity indices had correlation patterns similar to the first group. In the end, genetic by diet interactions on gut microbiota composition of growing pigs were limited in this study. Based on this study, microbiota-based traits could be used as proxies to improve FE and DE in growing pigs.     

益生菌在恢复家兔肠道菌群平衡和解决腹泻中的作用

益生菌是一类有益于宿主健康的活性微生物,可以通过调节家兔肠道菌群的平衡和增强肠道屏障功能来发挥作用,能够抑制有害菌的生长,提高消化道内营养物质的吸收利用,增强免疫系统的功能,从而维持肠道健康。本文从益生菌对家兔肠道菌群的影响,益生菌治疗机制的探索等方面探讨益生菌在恢复家兔肠道菌群平衡和解决腹泻中的作用,分析了当前研究的局限性和未来研究方向,有助于推动益生菌在家兔腹泻治疗中的临床应用,为家兔肠道健康提供更全面的保障。     

中西太平洋柳叶鳗状幼体物种鉴定及其肠道微生物群落结构分析

调查野生柳叶鳗状幼体肠道微生物群落结构组成和功能分析对于预测仔鱼营养需求以及开口饵料的研发具有重要的科学和实践价值。本研究通过DNA条形码技术对2022年和2023年两次“淞航”号中西太平洋科考航次捕获到的柳叶鳗状幼体进行物种鉴定,并采用16S rDNA高通量测序技术对其肠道样本进行菌群测序,以分析肠道微生物群落结构,识别优势菌群及其相关功能。物种鉴定结果表明,捕获的16尾柳叶鳗状幼体中13尾鉴定至种水平,分别为大美体鳗(Ariosoma majus)、科氏龟草鳗(Thalassenchelys coheni)、大眼锥体糯鳗(Ariosoma megalops)、米克氏美体糯鳗(Ariosoma meeki)、Muraenidae sp. KY17-483、带尾裸胸鳝(Gymnothorax zonipectis);其它3尾只鉴定至属水平,包括突吻鳗属(Gymnothorax)和裸胸鳝属(Gnathophis)。测序发现,太平洋柳叶鳗状幼体的优势菌群主要是变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)和厚壁菌门(Firmicutes)。在属分类水平上,嗜冷菌属(Psychrobacter)和不动杆菌属(Acinetobacter)丰度占比较高。然而,不同物种以及不同站点之间肠道菌群结构存在一定差异。此外,通过对肠道微生物进行功能预测发现,代谢是相对丰度占比最高的一类。在代谢类别中,丰度最高的均为氨基酸的转运和代谢,说明柳叶鳗状幼体对于蛋白类物质有较高需求。本研究初步阐述了太平洋柳叶鳗状幼体肠道微生物菌群的多样性组成,为柳叶鳗状幼体的摄食习惯及人工繁殖鳗鲡仔鱼的开口饵料的研究提供一定的参考。     

Bacillus subtilis-Fermented Products Ameliorate the Growth Performance,Alleviate Intestinal Inflammatory Gene Expression,and Modulate Cecal Microbiota Community in Broilers during the Starter Phase under Dextran Sulfate Sodium Challenge

The aim of this study was to evaluate the effects of B. subtilis-fermented products (BSFP) on growth performance, intestinal inflammatory gene expression, and cecal microbiota community in broilers challenged with dextran sulfate sodium (DSS) in a 14-day experiment. A total of 32, 1-day-old male broiler chickens (Ross 308), were randomly divided into four groups of eight birds per group and reared individually (n=8). The treatments consisted of a control diet without supplementation and DSS challenge, control diet plus 1.5% DSS, control diet plus 1 g/kg BSFP in combination with 1.5% DSS, and control diet plus 3 g/kg of BSFP in combination with 1.5% DSS. The results showed that BSFP supplementation (1 and 3 g/kg) partially improved body weight and average daily gain in broilers under DSS challenge. Relative to DSS treatment alone, BSFP supplementation dose-dependently increased the body weight of broilers at 7 days of age, with the average daily gain being at 1 to 7 days of age. BSFP supplementation (1 and 3 g/kg) alleviated intestinal inflammatory gene expression in broilers under DSS challenge. The richness and evenness of bacterial species in cecal digesta increased in a dose-dependent manner in the groups treated with BSFP (1 and 3 g/kg) in combination with DSS challenge, compared with the control group. Unweighted principal coordinate analysis indicated distinct clusters separating the group treated with 3 g/kg of BSFP in combination with DSS challenge from the other three groups. The abundance of short-chain fatty acid-producing bacteria (genus Ruminococcaceae_unclassified) increased and that of mucindegrading bacteria (genus Ruminococcus torques group) decreased in the cecal digesta of broilers fed 3 g/kg of BSFP, compared with the control group. In conclusion, BSFP supplementation dose-dependently improved growth performance, reduced gut inflammation, and regulated the cecal microbiota of broilers exposed to DSS challenge during the starter phase.     

Supplementation of Selenium Nanoparticles-Loaded Chitosan Improves Production Performance,Intestinal Morphology,and Gut Microflora in Broiler Chickens

The current study aimed to evaluate the efficacy of selenium nanoparticles (SeNPs), combined or loaded with chitosan (COS), in broiler chickens reared under standard management protocols. The parameters under investigation were production performance, organ development, components of the intestinal barrier, and ileal microbial count. Two hundred and forty day-old chicks were raised in five groups, with each group containing eight replicates (n=6/replicate). The control group received a basal diet whereas the other four groups received basal diets supplemented with SeNPs (0.5 mg/kg), COS (200 mg/kg), SeNPs+COS (0.5 mg/kg SeNPs + 200 mg/kg COS), and SeNPs-loaded COS (SeNPs-L-COS) (200 mg/kg) respectively. On day 35, two birds/replicate were sampled to collect the viscera under investigation. The results revealed that dietary inclusion of SeNPs-L-COS increased (p<0.05) the body weight gain and improved (p<0.05) feed conversion ratio. Similarly, SeNPs-L-COS supplementation increased (p<0.05) the small intestinal villus surface area as well as the count of acidic goblet cells and intraepithelial lymphocytes when compared with the control group. Whereas the total goblet cell count was higher (p<0.05) in the small intestines of both the SeNPs+COS and SeNPs-L-COS groups. Microbial analysis of ileal contents also revealed an increase (p<0.05) in Lactobacilli species count with a concurrent decrease (p<0.05) in Escherichia coli count in the SeNPs-L-COS group when compared with the COS and control groups. Based on the results of the current trial, we can conclude that supplementation with SeNPs-L-COS is a superior combination for promoting the gut health and performance of broilers.