天然免疫活性多糖替代抗生素添加剂的作用研究

采用先进的微生物体外累积发酵产气法和分子生物学鉴定技术研究了天然多糖一香菇,银耳和黄芪多糖对鸡肠道微生物菌群及其发酵动力学的影响,观察了中药多糖作为抗生素替代品对鸡的抗病促生长作用以及它们对肠道微生态体系和免疫系统的影响。结果表明,中药多糖经微生物发酵产生挥发性脂肪酸（VFA）,使有益菌大量增生,同时发酵产生的酸性物质降低整个肠道pH值,抑制有害茼的生长;多糖还可减少氨气等有害气体产生,减少对环境的影响;多糖能显著提高鸡的细胞和体液免疫应答,增强动物防御系统的作用,可以部分替代抗生素添加刑应用于内仔鸡的生产。饲养试验表明,多糖和抗生素对健康鸡的促生长作用都不明显,而对感染鸡具有显著的抗病促生长作用。     

发酵中药在肉鸡养殖中的应用研究进展

中药发酵后生成的产物既有中药活性成分,又包含菌体及其代谢产物的生物活性物质,具有调节畜禽肠道内微生物菌群平衡、抑制有害微生物繁殖生长、增强机体免疫机能、防治疾病、提高饲料利用率与生长性能的作用,是目前较有潜力的抗生素替代产品。本文对近几年中药发酵产品在肉鸡养殖上的应用研究进展进行了梳理,以期对中药发酵的研究提供参考。     

多糖和寡糖的体外发酵特性及其对鸡盲肠微生物菌群的影响

本研究采用体外累积发酵产气法和16SrDNA指纹图谱鉴定技术研究了来自香菇、银耳和黄芪的天然免疫活性多糖(LenE,TreE和AstE)及酵母胞壁甘露寡糖(MOS)对鸡肠道微生物菌群及其发酵特性的影响。结果表明,三种多糖提取物的总糖含量均占干物质的60%以上,而MOS总糖含量在90%以上。多糖和寡糖具有不同的发酵模式;MOS、AstE和LenE三种糖的发酵模式相似,呈一阶段发酵模式;TreE呈两阶段的发酵模式。三种糖中,MOS和AstE发酵速度较TreE快。MOS和AstE在发酵后总VFA产量最高,pH最低;黄芪多糖发酵后产生较多的直链脂肪酸和较低的氨。这些多糖和寡糖提取物影响肠道微生物的活性和组成成分,体现在发酵模式和发酵终产物的显著改变上。以上研究结果表明,来自香菇、银耳和黄芪的天然免疫活性多糖(LenE,TreE和AstE)及酵母胞壁甘露寡糖(MOS)在体外发酵后,均具有显著改变鸡盲肠微生物发酵终产物的含量和盲肠微生物活性的作用。     

真菌多糖益生元干预家禽肠道微生物调控肠道屏障功能的研究进展

家禽肠道微生物作为肠道黏膜屏障的重要组成部分在宿主的肠道屏障功能维持和肠道健康稳定中发挥重要作用。益生菌和益生元是调控肠道微生物的有效手段,其中真菌多糖作为天然代谢产物,具有抗氧化、增强免疫等多种生物活性,是一种重要的潜在益生元,其在鸡体内无法直接消化利用,主要通过肠道微生物进行发酵降解,并产生相关代谢产物,真菌多糖与肠道微生物的相互作用会对肠道屏障功能产生积极影响。文章在简要概述家禽肠道微生物的定植和影响因素、家禽肠道黏膜屏障功能及其干预调控手段的基础上,重点阐述了潜在益生元真菌多糖干预家禽肠道微生物对肠道屏障功能的调控作用,为家禽肠道健康调控奠定理论基础,并为真菌多糖产品的开发提供参考。     

金霉素对肉仔鸡生长及肠道微生物繁殖的影响

金霉素是一种四环素类抗生素,具有广谱抗菌活性,对肉仔鸡具有促生长作用.有研究认为抗生素有促生长作用是因为其抑制了环境中的抗生长因子、降低肠壁厚度和促进营养吸收.更多研究者认为,口服抗生素可以有效抑制肠道微生物的繁殖,并促进动物的生长;然而长期口服抗生素对肠道微生物繁殖影响的研究结果不一致.本试验拟通过检测不同日龄肉仔鸡肠道中大肠埃希氏菌、乳酸菌和双歧杆菌繁殖情况,研究长期口服金霉素对肉仔鸡肠道微生物繁殖的影响.     

鸡饲料添加剂知多少

<正>抗生素添加剂。抗生素具有抑菌作用,一些抗生素添加入饲粮后,可抑制鸡肠道内有害菌的活动,具有抗多种呼吸、消化系统疾病,提高饲料利用率,促进增重和产蛋的作用,尤其在鸡处于逆境时效果更为明显。常用的抗生素添加剂有青霉素、土霉素、金霉素、新霉素、泰乐霉素等。在使用抗生素添加剂时,要注意几种抗生素交替作用,以免鸡肠道内的有害微生物产生抗药性而降低防治效果。为避免抗药性和药品残留量过高,应间隔使用,并严格控     

浅谈发酵液态饲料对养猪业的影响

发酵液态饲料是由干饲料与水或液态副食品混合,经一定时间发酵而成,其品质受微生物种类、数量、发酵温度和料水比等因素的影响。发酵液态饲料产生乳酸、乙酸、乙醇和戊醇等,可降低饲料p H、抑制肠道有害微生物繁殖及改善胃肠道菌群结构。断奶仔猪饲喂发酵液态饲料可有效帮助仔猪适应从母乳到饲料的过渡期,减缓断奶仔猪综合征。发酵液态饲料还能促进仔猪肠道绒毛的生长发育,提高绒毛/隐窝比,增强仔猪消化能力,有利于改善仔猪生长性能。育肥猪饲喂发酵液态饲料,对提高饲料转化率和日增质量作用有限,但发酵液态饲料可促进肠道后段色氨酸减少向粪臭素降解,可改善育肥猪生长环境和提高肥猪胴体品质。另外,仔猪饲喂发酵液态饲料有利于实现少用或禁用抗生素。研究将从发酵液态饲料的发酵方式、影响因素、优势和劣势等方面进行讨论以供参考。     

肉鸡肠道微生物及其调控

近年来,肉鸡肠道微生物已被广泛研究,它对宿主的健康和生产性能等方面发挥了重要的作用,尤其是在免疫防御以及营养生理中产生积极影响。随着促生长类抗生素的禁止使用,通过调控肠道微生物菌群改善肉鸡的生长与免疫成为解决抗生素替代问题的有效途径。本文从肉鸡肠道微生物的组成、分布、功能、影响因素及调控技术方面进行了综述。     

饲用抗生素的未来

饲用抗生素是指连续添加在饲料中，用来预防疾病、促进生长、提高饲料转化率和降低环境污染的抗生素（包括发酵提取、半合成、化学合成的抗微生物药物）。自从１９４６年Moore等发现抗生素在肉鸡饲料中添加具有促生长作用以后，抗生素就开始作为饲料添加剂，广泛应用于猪、鸡、鸭、水产动物等饲料中。半个世纪以来，为满足人类对安全、有效的动物性食品需求的持续增长，起了很大作用。从动物营养的角度来研究其促进生长的作用机理，是从发现金霉素的促生长效应开始，人们提出了使肠壁变薄，促进营养物质吸收、利用，降低肠道氨，降低病原菌…     

不同中药饲料添加剂复方促进肉鸡增重效果的比较

为研制一种新型鸡用抗病促生长中药饲料添加剂,按照不同原则分别拟订了4个复方,通过3批次动物试验,比较了4个复方的增重效果。结果表明,由黄芪、淫羊藿、山楂等组成的中药饲料添加剂,具有补气消食、和血助阳的作用,增重效果最显著,且优于抗生素。     

Performance, intestinal microflora, and wall morphology of weanling pigs fed sodium butyrate

Adding organic acids to piglet diets is known to be helpful in overcoming postweaning syndrome, and butyric acid is known to be the main energy source for the epithelial cells of the large intestine and the terminal ileum. This study investigated the effect of sodium butyrate (SB) on in vitro and in vivo swine microflora, piglet growth performance, and intestinal wall morphology. During a 24-h in vitro cecal fermentation, total gas production and maximal rate of gas production were reduced linearly by SB (P < 0.001). Ammonia in cecal liquor was increased linearly by SB after 4, 8, and 24 h of fermentation (P < 0.001). In the in vivo study, 48 piglets housed in individual crates were allotted to 4 treatment groups (12 animals per treatment) for 6 wk. Piglets received a basal diet with a) no addition (control), or with SB at b) 1,000 ppm, c) 2,000 ppm, or d) 4,000 ppm. After 6 wk, 6 animals per treatment were killed, and samples of intestinal content and mucosa were collected. Sodium butyrate did not improve the animal growth performance. In the cecum, SB increased pH and isobutyric acid concentration (linear, P < 0.05) and tended to increase ammonia concentration (P = 0.056). Intestinal counts of clostridia, enterobacteriaceae, and lactic acid bacteria as well as intestinal mucosal morphology were not affected by feeding SB. This study showed that SB influenced the cecal microflora in an in vitro system, reducing the total gas production but increasing ammonia concentrations. When fed to piglets, SB did not improve the animal growth performance, increased cecal pH, and tended to increase cecal ammonia concentrations. Further studies will be needed to better understand the mechanisms underlying the effects observed when SB is fed to piglets.     

Effect of gluconic acid on piglet growth performance, intestinal microflora, and intestinal wall morphology

Gluconic acid (GA) derives from the incomplete oxidation of glucose by some Gluconobacter strains. When fed to nonruminant animals, GA is only poorly absorbed in the small intestine and is primarly fermented to butyric acid in the lower gut. This study investigated the effect of GA on in vitro growth response and metabolism of swine cecal microflora and on animal growth performance, intestinal wall morphology, and intestinal microflora. During a 24-h in vitro cecal fermentation, total gas production and maximum rate of gas production were increased by GA (linear, P < 0.001). Ammonia in cecal liquor was reduced by GA after 4, 8, and 24 h of fermentation (quadratic, P < 0.01). After 24 h of fermentation, total short-chain fatty acids, acetic acid, propionic acid, n-butyric acid, acetic to propionic acid ratio, and acetic + butyric to propionic acid ratio were linearly increased by GA (P < 0.001). In the in vivo study, 48 piglets were divided into 4 groups and housed in individual cages for 6 wk. Piglets received a basal diet with a) no addition (control) or with GA addition at b) 3,000 ppm, c) 6,000 ppm, or d) 12,000 ppm. After 6 wk, 4 animals per treatment were killed, and samples of intestinal content and mucosa were collected. Compared with control, GA tended to increase average daily gain (+13 and +14% for GA at 3,000 and 6,000 ppm, respectively; P of the model = 0.11; quadratic, P < 0.05). Daily feed consumption and gain to feed ratio were not influenced by GA. Intestinal counts of clostridia, enterobacteriaceae, and lactic acid bacteria were not affected by GA. Gluconic acid tended to increase total short-chain fatty acids in the jejunum (+174, +87, and +74% for GA at 3,000, 6,000, and 12,000 ppm, respectively; P of the model = 0.07; quadratic, P = 0.07). Morphological evaluation of intestinal mucosa from jejunum, ileum, and cecum did not show any significant differences among treatments. This study showed that feeding GA influences the composition and activity of the intestinal microflora and may improve growth performance of piglets after weaning.     

Coccidiosis immunization: effects of mushroom and herb polysaccharides on immune responses of chickens infected with Eimeria tenella

An experiment was conducted to investigate the effects of polysaccharide extracts (E) of two mushrooms, Lentinus edodes (LenE) and Tremella fuciformis (TreE), and an herb, Astragalus membranaceus (AstE), on the immune responses of chickens infected with Eimeria tenella. A total of 180 broiler chickens were assigned to nine groups: three groups were fed with each of the extracts (LenE, TreE, and AstE), three groups were fed with the extracts and immunized with live oocyst vaccine (LenE+V, TreE+V, and AstE+V), a group was immunized with the vaccine only, and there were two controls (E. tenella-infected and noninfected groups). The oocyst vaccine was given at 4 days of age, and the extracts (1 g/kg of the diet) were supplemented from 8 to 14 days of age. At 18 days of age, all birds except those in the noninfected group were infected with 9 x 10(4) sporulated oocysts. The results showed that at 7 days postinfection (p.i.), birds fed the extracts without vaccination had lower body weight (BW) gain than those given the vaccine only. However, the extracts in conjunction with the vaccine significantly enhanced BW gain of the infected chickens compared with the vaccine group. Of the three extracts, LenE and TreE showed a better growth-promoting effect. The extracts largely increased oocyst excretion of droppings during the primary response postvaccination. The cecal peak oocyst output and lesion scores measured at 7 days p.i. were higher in the groups fed the extracts than in the group immunized with the vaccine only, whereas those of the groups fed with the extracts and immunized with the vaccine were not significantly different from the vaccine group. Of the three extracts, both LenE- and AstE-fed groups showed lower cecal oocyst output. Thus, as compared with the extracts, the live, attenuated vaccine showed better results with significantly increased immune response in coccidial infected birds. The polysaccharide extracts may prove useful against avian coccidiosis, and, particularly when they are used in conjunction with vaccine, they have shown preliminary promise against the experimental coccidial infection.     

Modulation of innate immunity in chickens induced by in vivo administration of baculovirus

Baculoviruses stimulate cytokine production in mammalian cells. They induce a strong innate immune response in animals and have adjuvant properties. The purpose of this work was to study the in vivo effect of baculovirus on chicken innate immune response. SPF chickens were inoculated intravenously with Autographa californica nuclear polyhedrosis virus (BV). Three hours later, chickens were bled, euthanized and their spleen, duodenum and cecal tonsils were excised in order to take samples for RNA extraction and real time PCR, and to isolate lymphocytes, which were stained and analyzed by flow cytometry. The results obtained showed that baculovirus inoculation up-regulates the expression of IFN-γ, IL-6 and LITAF in spleen cells. This result (IFN-γ) correlated with that obtained by ELISA which showed a very strong increase of IFN-γ in chicken plasma. Flow cytometry analysis revealed that BV inoculation induced in spleen an increase in the percentage of monocyte/macrophage population together with an increase in CD3(+)CD4(+) T lymphocytes. On the other hand, BV inoculation decreased the percentage of CD3(+)CD4(+) T lymphocytes and increased the percentage of NK cells in cecal tonsils. However, intraepithelial lymphocytes of the gut did not show differences between BV and control treated animals. Even though further studies in order to understand the mechanisms by which BVs affect the avian immune response are needed, results obtained in the present work demonstrate the ability of BVs to stimulate the innate immunity in chickens, modifying the expression pattern of related genes and the profile of the immune cells involved.     

乳酸菌菌体及全菌液制剂对雏鸡生长性能和盲肠菌群的影响

为了研究不同制备工艺及活菌数的乳酸菌制剂对雏鸡生长性能和盲肠菌群的影响,将格氏乳杆菌菌体和全菌液分别制成活菌制剂用于动物饲养试验。试验选用1日龄的AA肉仔公鸡360只,随机分成6组,每组5个重复,每个重复12只鸡。Ⅰ组和Ⅱ组分别饲喂基础日粮+0.5%和1%菌体制剂;Ⅲ组和Ⅳ组分别饲喂基础日粮+0.05%和0.1%的全菌液制剂(Ⅰ与Ⅲ、Ⅱ与Ⅳ试验组活菌数基本一致);Ⅴ组抗生素组,饲喂基础日粮+0.01%黄霉素;Ⅵ组为对照组,饲喂基础日粮。试验期28 d。结果表明:与对照组相比,日粮中添加乳酸菌制剂可明显改善生长性能,其中高剂量组显著(P<0.05)提高雏鸡日增重,极显著(P<0.01)降低饲料增重比;与抗生素组比,乳酸菌制剂能提高盲肠中乳酸菌数量,抑制大肠杆菌的繁殖;同一添加水平的乳酸菌菌体制剂与全菌液制剂应用效果无显著差异(P>0.05)。由此可知,雏鸡日粮中添加乳酸菌制剂具有促进雏鸡生长和改善盲肠菌群的作用。     

功能性寡糖对锦江黄牛瘤胃发酵及微生物生长效率的影响

本试验旨在研究不同水平的功能性寡糖对锦江黄牛瘤胃发酵及微生物生长效率的影响。采用体外批次培养法,在精粗比为 ２０∶８０的基础饲粮中添加甘露寡糖、果寡糖和大豆寡糖,各组功能性寡糖的添加水平分别为 ０（对照组）、０．８０％、１．００％和 １．２０％。结果表明,饲粮添加功能性寡糖对锦江黄牛瘤胃 ｐＨ无显著影响（Ｐ＞０．０５）,但显著增加培养液挥发性脂肪酸和菌体蛋白浓度（Ｐ＜０．０５）;每日微生物氮产量也有提高的趋势,但差异不显著（Ｐ＞０．０５）。建立微生物生长效率与功能性寡糖添加水平之间的二次曲线模型,当甘露寡糖添加水平为 １．１７％时,微生物生长效率最大,为 ５９．７２ｇ／ｋｇ;当大豆寡糖添加水平为 １．０３％时,微生物生长效率最大,为 ５９．５０ｇ／ｋｇ。综合本试验结果,功能性寡糖的添加水平在 １．００％ ～１．２０％之间更有利于锦江黄牛瘤胃微生物的生长。     

体外法研究米曲霉培养物对瘤胃发酵参数及微生物酶活性的影响

本试验旨在通过体外产气试验研究高酶活力的米曲霉培养物(AOC)对瘤胃发酵的影响。以米曲霉产酶特性为标准研制米曲霉培养物,体外法研究0、3、6、12 mg米曲霉培养物对瘤胃发酵和微生物酶活力的影响。结果表明:培养48 h的AOC酶活力最高(P<0.05);与对照组相比,添加6、12 mg AOC显著增加了24 h产气量、微生物蛋白浓度、总挥发性脂肪酸、乙酸和丙酸的含量(P<0.05),12 mg AOC组的氨态氮浓度显著高于其他各组(P<0.05)。6 mg AOC组微晶纤维素酶活性显著高于其他组(P<0.05),木聚糖酶活性显著高于对照组和3 mgAOC组(P<0.05);12 mg AOC组的羧甲基纤维素酶和淀粉酶活性显著高于对照组和3 mg AOC组(P<0.05)。综上所述,添加米曲霉培养物可通过提高瘤胃微生物酶活性而促进体外瘤胃发酵。     

Comparison of fermentation of selected fructooligosaccharides and other fiber substrates by canine colonic microflora

OBJECTIVE: To compare fermentation characteristics of fructooligosaccharides (FOS) and other fiber substrates that are commonly found in canine diets. SAMPLE POPULATION: Fecal samples from 3 adult dogs. PROCEDURE: The ability of fiber substrates to be used in microbial fermentation reactions was assessed by use of an in vitro fermentation system. Dogs were fed a commercially available food, and feces were collected for use as the microbial inoculum. Substrates used were beet pulp, cellulose, soy fiber, mannanoligosaccharides (MOS), FOS, and 4 inulin products (inulin 1, 2, 3, and 4). Each substrate was incubated anaerobically with fecal inoculum and growth media for 6, 12, and 24 hours, and production of short-chain fatty acids (SCFA) was measured. RESULTS: Total production of SCFA was higher for fermentation of the 4 inulin products and FOS, whereas fermentation of beet pulp, MOS, and soy fiber resulted in moderate concentrations of SCFA. Fermentation of cellulose produced the lowest concentrations of total SCFA without detection of butyrate or lactate. Butyrate production was greatest for fermentation of the 4 inulin products and FOS. Total lactate production was greatest for FOS and inulin 4. As expected, production of SCFA increased for all substrates as fermentation time increased. CONCLUSIONS AND CLINICAL RELEVANCE: Canine fecal microflora ferment FOS-containing substrates in a similar manner, with little fermentation of cellulose-based carbohydrates. Furthermore, results of an in vitro fermentation system indicate that fiber type affects the metabolic activity of microorganisms, thus influencing the amount and nature of the end products of fermentation.     

不同浓度肽对瘤胃发酵及微生物蛋白产量的影响

利用短期人工瘤胃发酵法研究奶牛瘤胃中肽浓度的变化对瘤胃发酵的影响,并探讨瘤胃适宜肽浓度值。试验按0、10、15、16g/L和20g/L氨基氮的肽浓度分为5个处理,每个处理3个重复,测定pH值、氨态氮值及微生物蛋白产量。结果表明:在各个时间点各组之间的pH均无显著差异(P>0.05)。发酵8h后,15、16g/L和20g/L3组的NH3-N值与对照组相比差异显著(P<0.05)。对于瘤胃微生物蛋白产量(MCP),在第4h和24h时,15g/L和16g/L组与0g/L和10g/L组分别相比,差异显著(P<0.05);在2h时,16g/L组与其他各组相比较,差异均不显著(P>0.05)。本试验条件下,人工瘤胃内适宜的肽浓度为16g/L。