Effect of dietary encapsulated organic salts (Na‐acetate,Na‐butyrate,Na‐lactate and Na‐propionate) on growth performance,haemolymph, antioxidant and digestive enzyme activities and gut microbiota of juvenile narrow clawed crayfish,Astacus leptodactylus leptodactylus Eschscholtz, 1823

A 63‐day experiment was done to study the effects of four levels (5, 10, 20 and 50 g/kg) of encapsulated organic salts (Na‐acetate, Na‐butyrate, Na‐lactate and Na‐propionate) on the growth indices and haemato‐immunological responses of crayfish Astacus leptodactylus leptodactylus (4.38 ± 0.08 g). Crayfish were distributed at 51 1,000‐L tanks (17 treatments at triplicate). The highest values of final weight (27.86 g), specific growth rate (2.94% body weight per day) and survival rate (96%) were observed in the crayfish fed the 20 g/kg of encapsulated Na‐propionate diet (p < .05). The highest activities of phenoloxidase (7.4 U/min), superoxide dismutase (7.80 U/min) and lysozyme (9.40 U/min) were observed in the gut of crayfish fed the 20 g/kg of encapsulated Na‐propionate diet (p < .05), as well as the highest activities of alkaline protease (10.70 U/mg), lipase (9.10 U/mg), amylase (9.60 U/mg) and the lactobacillus count (p < .05). Broken line regression model of SGR and phenoloxidase activity suggested that the optimum dietary levels of encapsulated Na‐acetate, Na‐butyrate, Na‐lactate and Na‐propionate could be 30.7, 31.8, 31.4 and 33.5 g/kg, respectively, in crayfish reared in culture conditions.     

Abalone Viscera Protein Hydrolysate Modulation of Gut Microbiota in a Mouse Model of Alcohol induced Injury

In this study, the structural changes of gut microbiota in response to abalone viscera protein hydrolysate (AVPH) were examined in alcohol induced injured mice. The gut microbiota of mice without treatment (blank), alcohol treatment (control), and alcohol+AVPH treatment (sample) were profiled with Illumina sequencing of the V4 region of 16S rDNA genes. The sequencing results revealed that 705, 654, and 888 of Operational Taxonomic Units (OTUs) were determined in the blank, control, and sample groups, respectively. Compared with the control and blank groups, the AVPH had a higher diversity index and a larger number of reads subjecting to Bacilli (class), Lactobacillales (order), Lactobacillaceae (family), and Lactobacillus (genus) levels. However, insignificant difference of beta-diversity or principal component among control, blank, and sample groups was found. This study demonstrates that the in vivo oxidation inhibition pathway in alcohol induced injured mice by AVPH was not via modulating the gut microbiota structure.     

Research Advances on Intestinal Microflora Regulationin by Several Feed Additives in Piglets

In modern pig production,early weaning is a bottleneck problem which are restricting the development of pig industry.It can lead to early weaning syndrome in piglet,such as low appetite,growth inhibition,diarrhea and so on.One of the reasons induced these symptoms is impairment of intestinal mucosal barrier in piglets.The intestinal microflorais is one of the important parts of intestinal mucosal barrier.Therefore,study on the intestinal microflora of weaning piglets and nutritional regulations have been attracted more and more attentions,and it has an important influence on avoiding diarrhea,promoting the healthy growth and improving growth performance.The change of intestinal microflora in weaning piglets and research development of some common feed additives（microecologics,plant polysaccharide,acidulant,microelement,Chinese herbal medicine and plant extracts）for intestinal microflora were reviewed in this paper.     

Carbohydrates effects on nutrition and health functions in pigs

The greatest improvement in carbohydrates studies on pig nutrition and health is that carbohydrates are classified more clearly, which is based not only on their chemical structure but also on their physiological characteristics. Besides its primary energy source, different types and structures of carbohydrates are a benefit for nutrition and health functions in pigs, which are involved in promoting growth performance and intestinal functions, regulating the community of gut microbiota, and modulating the lipids and glucose metabolism. The underlying mechanism of carbohydrates regulates the lipids and glucose metabolism through their metabolites (short-chain fatty acids [SCFAs]) and mainly via the SCFAs-GPR43/41-PYY/GLP1, SCFAs-AMP/ATP-AMPK, and SCFAs-AMPK-G6Pase/PEPCK pathways. Emerging research had evaluated an optimal combination in different types and structures of carbohydrates, which could enhance growth performance and nutrient digestibility, promote intestinal functions, and increase the abundances of butyrate-producing bacteria in pigs. Overall, compelling evidence supports the notion that carbohydrates play important roles in both nutrition and health functions in pigs. Moreover, identifying the carbohydrates combinations will be of both theoretical and practical values for developing the technology of carbohydrates balance in pigs.     

Different impacts of native and exotic earthworms on rhizodeposit carbon sequestration in a subtropical soil

Earthworms are known to regulate the sequestration of soil and leaf litter carbon (C). However, their impacts on the more accessible rhizospheric C, which represents a major energy source for soil food webs and an essential factor for C sequestration, are still unclear. Previous studies indicate that earthworms regulate the dynamics of SOC and leaf litter-C by increasing C accessibility to microbiota. However, in the case of labile rhizodeposit-C, microbiota might not require any pre-conditioning by earthworms and may rapidly metabolize most of this root-derived C. Consequently, potential pathways by which earthworms may affect the fate of rhizodeposit-C would be to regulate the biomass and/or activity of rhizosphere microbiota and, further, to mineralize/stabilize microbial products. A ¹³CO₂ labelling experiment was performed to determine the impacts of four different earthworm species on the fate of tree rhizodeposit-C in a subtropical soil. We hypothesized that endogeic earthworm species, representing primarily geophagous species, would closely interact with soil microbiota and sequester the microbially metabolized rhizodeposit-C more efficiently than epigeic and anecic earthworm species. We found that irrespective of ecological group affiliation, the three native earthworms did not affect rhizodeposit-C sequestration. In contrast, the exotic endogeic species stimulated the immobilization of rhizodeposit-C in the biomass of root-associated bacteria and/or arbuscular mycorrhizal fungi and, further, accessed the microbiota-metabolized rhizodeposit-C more efficiently. As a consequence, the exotic endogeic earthworm species transiently tripled rhizodeposit-C retention in soil. We propose that the weak linkages between native earthworms and rhizodeposits-related microbiota limit earthworm impacts on rhizodeposit-C sequestration. However, the exotic endogeic species Pontoscolex corethrurus may potentially alter rhizodeposit-C dynamics in invaded areas by shifting rhizosphere microbial community composition. This work highlights a distinct mechanism by which earthworms can regulate C dynamics and indicates a significant contribution of invasive earthworm species to belowground processes.     

不同生长速度阿勒泰羊肠道菌群差异性研究

本文通过研究同一饲喂条件下，不同生长速度的阿勒泰羊肠道菌群差异，以及通过日粮影响生长速度后，肠道菌群物种组成的变化，旨在探讨肠道菌群与绵羊生长发育之间的关系。在300只6月龄羔羊中，按照日增重前10%和后10%筛选生长快和生长慢的雄性阿勒泰羊，分为高体重组和低体重组，高体重组随机选12只分为高体重能量日粮限饲组（HR）和高体重标准日粮对照组（HC），低体重组随机选12只分为低体重能量日粮增加组（LA）和低体重标准日粮对照组（LC），每组各6只。HR、HC、LC和LA组分别饲喂能量摄入为营养需要量75%、100%、100%和125%的日粮。预试期7 d，正试期30 d，记录体重，屠宰并采集相同部位的肠内容物，提取DNA，使用Illumina Miseq测序平台进行检测。研究结果显示，同一饲喂标准下，不同生长速度阿勒泰羊肠道菌群组成有差异，HC组厚壁菌门、放线菌门、Saccharibacteria门、疣微菌门和双歧杆菌属菌群丰度高于LC组，LC组变形菌门和拟乳菌属丰度高于HC组；在日粮调控生长速度的试验中，低能量水平日粮显著降低了高体重组体增重（P<0.05）；高能量水平日粮增加了低体重组的体增重（P<0.05）；不论促进或是抑制生长速度，肠道中厚壁菌门和拟杆菌门的物种丰度均升高，高丰度的Saccharibacteria门始终存在生长速度较快的组中，高丰度的拟乳菌属始终存在于生长速度较慢的组中。综合分析两部分试验结果可知，阿勒泰羊肠道中厚壁菌门和拟杆菌门的物种丰度变化可能与日粮和生长速度均有相关性，Saccharibacteria门的物种丰度变化与生长速度呈正相关，拟乳菌属的物种丰度变化与生长速度呈负相关。     

Recent advances in relationship between diversity of gut microbiota and health

Trillions of microbes inhabit the human intestine, forming a complex microecological community. It has been found that the gut microbiotas contribute nutrients and energy to the host, and they are also involved in the occurrence and development of human diseases. With the continuous development of related research, there is increasing evidence suggesting a close relationship between gut microbiota and human diseases. The discovery of this relationship affects the development of modern health care individually. In this review, we focus on the influence factors to the diversity of gut microbiota, which has influences on colorectal cancer, aging, obesity, immunity, drug effects and malnutrition.     

笼养密度对雪山鸡生产性能及盲肠微生物的影响

旨在探索笼养密度对雪山鸡生产性能、肉品质、福利指标及盲肠微生物的影响。本研究选用6周龄体重相近的健康雪山鸡母鸡180只,按单因素试验要求,设置高、中、低3组饲养密度进行后期笼养试验,每笼分别饲养4只、3只及2只,以此作为1个重复,每组20个重复,饲养至上市15周龄,屠宰,测定生产性能、屠宰性能及肉品质,并进行羽毛和步态评分、检测盲肠微生物菌群组成。结果表明：1）从11周龄到上市15周龄,低、中密度组雪山鸡体重显著高于高密度组（P<0.05）,15周龄腹脂重和腹脂率,低密度组显著高于中密度组（P<0.05）,且中密度组显著高于高密度组（P<0.05）,其余屠宰性能指标差异均不显著（P>0.05）。2）中、低密度组鸡只羽毛质量显著好于高密度组（P<0.05）,此外,高、中、低密度组的雪山鸡步态评分差异不显著（P>0.05）。3）雪山鸡盲肠内容物均以Firmicutes（厚壁菌门）、Proteobacteria（变形菌门）、Bacteroidetes（拟杆菌门）的菌群为主。3种饲养密度菌群差异不显著（P>0.05）,但中密度饲养模式下肉鸡盲肠内容物中特有OTUs较少,相对于高密度盲肠微生物区系而言,中、低密度盲肠微生物群落更趋于相近,有些差异菌群可能与体重及腹脂沉积相关,如Blautia菌属等。综合看来,对于雪山鸡而言,考虑采用中密度饲养模式能够获得较好的生产性能。     

β-葡聚糖对鱼类免疫调节作用的研究进展

为了维持鱼类健康并为养殖生产带来更好的效益,通常在养殖鱼类饲料中使用免疫增强剂作为饲料添加剂以提高鱼类的生产性能和疾病抵抗力。对多种鱼类的研究发现,饲喂β-葡聚糖能提高其免疫应答、对细菌与病毒的感染和环境压力的抵御力。因此,β-葡聚糖作为免疫增强剂在水产养殖中的应用在集约化养殖的今天显得至关重要。本文就β-葡聚糖的化学结构、β-葡聚糖调节鱼类免疫的机制以及影响β-葡聚糖生物活性的因素等方面进行综述,旨在为后续水产养殖中β-葡聚糖作为饲料添加剂的合理应用提供参考。     

饲粮中添加发酵豆粕对断奶仔猪粪便菌群多样性的影响

本试验采用高通量测序技术,研究饲粮中添加发酵豆粕对断奶仔猪粪便菌群多样性的影响。选取36日龄“杜×长×大”仔猪80头,随机分为A、B、C、D组,D组为对照组,饲喂基础饲粮;A、B、C组为试验组,分别在基础饲粮中添加5%、10%、15%的发酵豆粕。试验结束采集4组仔猪的粪便,采用Illumina MiSeq高通量测序技术对其中细菌的16SrRNA基因的V3~V4区序列进行测序。结果表明:1)菌群的平均有效序列数为47218条;在97%的相似水平下共产生了3581个操作分类单元(OTUs);共检测到12个门、21个纲、33个目、64个科、111个属和137个种。2)α多样性指数在各组间均无显著性差异(P>0.05),但B组的Shannon指数最高,菌群最丰富。β多样性分析表明,4组菌群在统计学上存在显著差异(P<0.05),分组效果较好。3)门水平的优势菌为厚壁菌门,科与属水平的优势菌分别为乳酸菌科和乳酸菌属。B组的厚壁菌门相对丰度显著高于D组(P<0.05),乳酸菌属相对丰度显著高于A、D组(P<0.05),但与C组间差异不显著(P>0.05)。4)菌群主要参与的代谢通路为糖类代谢、氨基酸代谢、能量代谢、核酸代谢、辅酶和维生素代谢。除核酸代谢外,其余4种代谢通路中,B组菌群的相对丰度最高并依次为C、A、D组。综上所述,在仔猪饲粮中添加10%的发酵豆粕,能增加肠道菌群的多样性,显著增加肠道中厚壁菌门、乳酸菌科和乳酸菌属等有益菌的相对丰度,维持肠道的健康,促进营养物质的代谢。