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.     

Dietary organic acid and fiber sources affect performance,intestinal morphology,immune responses and gut microflora in broilers

This experiment was designed to investigate the effects of a dietary organic acid (OA) mixture and 2 fiber sources on performance, intestinal morphology, immune responses and gut microflora in broilers. A total of 390 one-day-old broiler chicks (Ross 308) were allocated to 6 dietary treatments with 5 replicate pens and 13 chicks each based on a factorial arrangement (2 × 3) in a completely randomized design. The experiment lasted 42 d. The following experimental diets and as well as their interaction were considered: a basal diet supplemented with or without OA (0 or 1 g/kg) and 2 fiber sources (sugar beet pulp [soluble fiber] or rice hull [insoluble fiber]; 0 or 30 g/kg). Dietary supplementation of OA increased daily weight gains of broilers across the entire rearing period (P < 0.05). The dietary fibrous materials did not affect the performance of broilers. Antibody titer against influenza disease virus was higher in birds fed diets containing rice hull compared with other experimental groups (P < 0.05). The population of Lactobacillus bacteria was greater in birds fed OA-added diets without or with 30 g/kg rice hull supplementation compared with other experimental groups (P < 0.05). In conclusion, dietary supplemental OA improved performance of broilers, and dietary supplemental OA with rice hull enhanced humoral immune responses.     

In vitro fermentation characteristics of selected oligosaccharides by swine fecal microflora

The objective of this study was to quantify the fermentation characteristics of oligosaccharides present in feed ingredients or isolated for dietary supplementation. Substrates studied included short-chain fructooligosaccharides, medium-chain fructooligosaccharides, long-chain fructooligosaccharides, raffinose, stachyose, soy solubles, granular and liquid forms of transgalactooligosaccharides, glucooligosaccharides, mannanoligosaccharides, and xylooligosaccharides. Three healthy pigs that had never received antibiotics served as sources of fecal inoculum. Each substrate was fermented in vitro; samples were taken at 0, 2, 4, 8, and 12 h, and pH change and short-chain fatty acid (SCFA) and gas production determined. Gas production at 12 h did not differ (P > 0.05) among all fructooligosaccharides, transgalactooligosaccharides, soy solubles, and xylooligosaccharides. Raffinose, stachyose, and raffinose + stachyose fermentation resulted in the greatest (P < 0.05) gas production at 12 h of all substrates tested. The rate of gas production was greatest (P < 0.05) for stachyose and least (P < 0.05) for glucooligosaccharides and mannanoligosaccharides. Substrate did not affect (P > 0.05) time to attain maximal rate of gas production. The pH at 12 h for all fructooligosaccharides and xylooligosaccharides did not differ (P > 0.05). The pH values at 12 h for raffinose, stachyose, and raffinose + stachyose were highest (P < 0.05) compared with all other substrates. Total SCFA production at 12 h was similar for all fructooligosaccharides and transgalactooligosaccharides, glucooligosaccharides, and soy solubles. Total SCFA production was greatest (P < 0.05) for xylooligosaccharides, stachyose, and raffinose + stachyose, and least (P < 0.05) for mannanoligosaccharides and raffinose. Stachyose fermentation resulted in the greatest (P < 0.05) rate and earliest time to attain maximal rate of SCFA production. All oligosaccharides studied were readily fermentable but varied in amount and type of SCFA produced. Fermentation of the pure forms of oligosaccharides contained in soy solubles resulted in greater gas production and higher pH compared with soy solubles. The oligosaccharides in the soy solubles matrix seemed to behave differently than their pure counterparts. The high rates of fermentation of most oligosaccharides tested indicate that they may serve as fermentable carbohydrate sources in the terminal small intestine or large intestine of swine.     

The gut microflora and the uptake of glucose from the small intestine of the chick

1. Chicks whose growth rate had been depressed either by a fully conventional flora or by association with a bile acid deconjugating strain of Streptococcus faecium and/or a filterable agent from chicken droppings showed no significant reduction in uptake of 3‐O‐methyl‐a‐D‐glucopyranose compared with germ‐free birds.

2. Association with a microflora increased the weight of the gut per unit length.     

Intestinal function and gut microflora of broiler chickens as influenced by cereal grains and microbial enzyme supplementation

A study was conducted to investigate the effect of the key cereal grains and a microbial enzyme supplement on broiler chicken performance, gut microflora and intestinal function. Ingestion of the barley-based diet was associated with low 28-day body weight, decreased feed intake and high FCR. The supplemental enzyme increased feed intake and weight gain of the chickens on a wheat-based diet. The pH of the gizzard and caecal contents varied with the grain type. Enzyme supplementation reduced ileal viscosity, particularly in birds that received the diet based on wheat. The birds on the barley-based diet had lower ileal digestibility of dry matter, protein and energy than those given maize and sorghum-based diets. The ileal digestibility of starch was increased by enzyme supplementation. Enzyme supplementation increased the number of total anaerobic bacteria in the gizzard of birds fed on sorghum and increased lactobacilli in the gizzard of those fed both sorghum and wheat. The birds fed the sorghum-based diet had the lowest counts of caecal total anaerobic bacteria and lactobacilli. Jejunal villus height and villus:crypt ratio of birds fed the barley-based diet were the lowest when compared with those fed the other diets. Enzyme application induced an increase in villus height and villus:crypt ratio of birds on wheat, crypt depth on barley and a reduction in crypt depth of chickens on the sorghum-based diets. The highest activity of maltase and the lowest activity of sucrase were observed in tissue from birds fed on maize and sorghum-based diets respectively. The differences in the performance of broilers on cereal grains could be explained by changes in intestinal morphology, enzyme activities and gut microflora as well as nutrient digestibility. The improved performance by supplemental enzyme in wheat-fed chickens was associated with beneficial changes in intestinal morphology and digesta viscosity.     

Adherence of salmonellae and native gut microflora to the gastrointestinal mucosa of chicks

Adherence of salmonellae to the mucosa of the cecum was demonstrated using scanning electron microscopy. In the absence of other microflora, adherence was also shown at all other levels of the alimentary tract tested. Comparative development of native gut microflora in the ceca was also investigated in chicks treated with selected fecal microflora and in untreated chicks using scanning electron microscopy. In the treated chicks, there was early colonization by adherent bacteria interconnected with fibers, forming a mat of microflora. This mat of microflora may be responsible for preventing colonization of salmonellae in the ceca.     

日粮中添加发酵饲料对育肥猪养分消化率及肠道菌群的影响

为研究日粮中添加不同水平的发酵饲料对育肥猪养分消化率及肠道菌群的影响,试验选用560头杜×长×大三元育肥猪[(75.37±2.65)kg],根据体重、性别随机分为7组,每组5个重复,每个重复16头,对照组饲喂育肥猪日粮,试验组分别在育肥猪日粮中添加5%或10%的发酵饲料A、B、C,饲喂21 d后每组选5头育肥猪肛门采集新鲜粪便测定肠道菌群多样性;并在饲喂第29天和第30天,各组每个重复连续收集粪便混合后测定养分消化率。结果表明:日粮中添加发酵饲料对育肥猪粗蛋白质、能量和干物质的消化率没有显著影响(P>0.05),相比对照组,饲喂发酵饲料组的粗蛋白质消化率有所提高(最高组提高2.9%);同时肠道菌群中乳杆菌属丰度有所增加,表明在日粮中添加一定比例的发酵饲料可以改善育肥猪养分消化率和肠道健康。     

In vitro fermentation of various fiber and starch sources by pig fecal inocula

Freeze-dried ileal effluent (1% wt/vol) from cannulated pigs fed rice-based diets with the inclusion of either animal protein (CON), animal protein plus potato starch (PS), animal protein plus sugar beet pulp (SBP), or animal protein plus wheat bran (WB) was incubated anaerobically at pH 6.0 in fermenters containing 5% (wt/vol) fecal slurry comprising mineral salts medium and 50 g/L of fresh feces from pigs fed the same diets as the cannulated pigs. Samples were collected from the fermenters at 0, 2, 4, 12, 24, and 48 h during in vitro fermentation for measuring nonstarch polysaccharides (NSP), starch, and short-chain fatty acids (SCFA). Results showed that the major SCFA produced were acetate, propionate, and butyrate. The inclusion of soluble dietary fiber (diet SBP) caused the highest concentrations of acetate, propionate, butyrate, and total SCFA, whereas the increase in the production of propionate resulting from the addition of insoluble dietary fiber (diet WB) only occurred at the initial stages during 48 h in vitro fermentation. At all sampling occasions (except for 4 h), the levels of butyrate were increased (P < 0.01) by resistant starch compared with fiber sources, showing that a higher level of butyrate can be achieved through microbial fermentation by potato starch. Lowered (P < 0.05) butyrate concentrations were observed with diet WB during in vitro fermentation. With the inclusion of fiber sources, the energy originating from SCFA was similar to that from NSP disappearance, whereas the values were lower (P < 0.05) from NSP disappearance than for SCFA generated without fiber sources supplemented. We conclude that more substrate is available in ileal effluent with the addition of soluble dietary fiber, and an increased level of butyrate could be achieved through microbial fermentation by resistant starch.     

梅山与长白母猪粪样微生物体外发酵八种纤维底物的特性比较

本研究旨在比较不同品种母猪(梅山猪与长白猪)粪样中微生物对不同纤维底物的体外降解能力,同时分析粪样中的主要纤维降解菌数量。采集梅山(n=5)和长白(n=5)母猪新鲜粪样作为发酵接种物,以果胶、纤维素、菊粉、麦壳、麸皮、木聚糖、玉米芯渣及苜蓿作为纤维底物进行体外发酵,测定产气量和发酵液挥发性脂肪酸(volatile fatty acid,VFA)浓度。粪样同时用于提取细菌总核酸,变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)和real-time PCR对菌群区系进行分析。体外发酵结果表明,从发酵后9 h至96 h结束,长白猪接种物各组的累积产气量、有机物校正产气量分别显著(P<0.05)和极显著(P<0.01)高于梅山猪,长白猪T_1/2和T_max显著低于梅山猪(P<0.05),且发酵终产物中乙酸和总VFA浓度显著高于梅山猪接种物(P<0.05),整个发酵过程中不同底物间累积产气量差异显著(P<0.05),累积产气量从高到低的组别依次为:菊粉>麸皮>果胶>苜蓿>麦壳>玉米芯渣>木聚糖>纤维素。DGGE分析表明,梅山与长白母猪粪样菌群图谱中存在许多共同条带。Real-time PCR定量分析表明,梅山母猪粪样中的总细菌的16S rRNA基因拷贝数显著高于长白母猪(P<0.05),而拟杆菌、产琥珀酸丝状杆菌、黄化瘤胃球菌和白化瘤胃球菌等纤维降解菌数量及其占总菌比例差异均不显著(P>0.05)。结果显示,尽管2个品种母猪粪样中纤维降解菌数量无显著差异,但是长白母猪粪样微生物体外发酵纤维底物的能力高于梅山母猪。     

Delivery routes for probiotics: Effects on broiler performance,intestinal morphology and gut microflora

Four delivery routes, via, feed, water, litter and oral gavage, were examined for their efficacy in delivering a novel probiotic of poultry origin, Lactobacillus johnsonii, to broilers. Seven treatments of 6 replicates each were allocated using 336 one-day-old Cobb broiler chicks. The treatments consisted of a basal diet with the probiotic candidate, L. johnsonii, added to the feed, and three treatments with L. johnsonii added to the drinking water, sprayed on the litter, or gavaged orally. In addition, a positive control treatment received the basal diet supplemented with zinc-bacitracin(Zn B, 50 mg/kg). The probiotic strain of L.johnsonii was detected in the ileum of the chicks for all four delivery routes. However, the addition of L.johnsonii as a probiotic candidate did not improve body weight gain, feed intake and feed conversion ratio of broiler chickens raised on litter during the 5-week experimental period regardless of the route of administration. The probiotic treatments, regardless of the routes of delivery, affected(P 0.05) the pH of the caecal digesta and tended(P = 0.06) to affect the p H of the ileal digesta on d 7, but the effect disappeared as the birds grew older. All probiotic treatments reduced the number of Enterobacteria in the caeca on d 21, and tended(P 0.054) to reduce it in the ileum and caeca on d 7 and in the ileum on d 21 compared with the controls. The probiotic also tended to increase the number of lactic acid bacteria and lactobacilli in the ileum and caeca on d 7, but this trend was not evident on d 21. The trend appeared most pronounced when the probiotic was delivered orally or via litter. The probiotic also decreased(P 0.05) the population of Clostridium perfringens rapidly from an early age to d 21 in the caeca, leading to a3-fold decrease in the number of C. perfringens between d 7 and 21. It also showed that the probiotic treatment presented the lowest number of C. perfringens in the caeca. Delivery of the probiotic through feed, water and litter increased(P 0.01) the weight of the pancreas on d 21, but the probiotic did not affect other morphometric parameters of the gut. Furthermore, the probiotic did not affect the p H and the concentrations of short chain fatty acids and lactic acid in either the ileum or caeca.     

Anti-nutritive effect of wheat pentosans in broiler chickens: roles of viscosity and gut microflora.

1. The mechanism of the anti-nutritive activity of isolated wheat pentosans was investigated by examining the roles of digesta viscosity and gut microflora in broiler chickens. 2. Wheat pentosans were isolated by alkaline extraction and purified by sequential treatment with pancreatin, alpha-amylase and lichenase, and high-speed centrifugation. Some of the pentosans were depolymerised using a beta-xylanase, which reduced the relative viscosity of the polysaccharides 4 fold. 3. Inclusion of 35 g alkali-extractable pentosans (containing 854 g arabinoxylans/kg DM) per kg diet significantly (P less than 0.05) depressed broiler performance and the viscosity of the digesta of these birds was significantly (P less than 0.05) higher than that of controls. Addition of the same amount of depolymerised pentosans had no significant effect on bird performance and had less effect on digesta viscosity. 4. Supplementation of the diet containing wheat pentosans (30 g/kg) with procaine penicillin (150 mg/kg) did not improve bird performance. 4. It is concluded that the wheat pentosans elicit their anti-nutritive activity predominantly through increasing the viscosity of digesta.     

复合维生素B对生长期山羊后段肠道菌群组成及肠黏膜的影响

本试验旨在研究日粮中添加复合维生素B对生长期山羊消化道微生物组成和肠黏膜结构的影响。试验选取10只4月龄波杂雌山羊（12.60±1.28） kg,随机分为对照组（control,CON）和复合维生素B处理组（vitamin B,VB）,CON组饲喂基础日粮（n=5）,VB组在基础日粮中添加复合维生素B（n=5）,预饲期2周,试验期11周,试验期间自由饮水。试验结束后屠宰采样,16S rRNA测序分析盲肠和结肠内容物微生物组成,检测肠道上皮组织形态结构和相关基因与蛋白的表达。通过菌群分类学分析发现,与CON相比,VB组山羊盲肠和结肠内容物菌群的α多样性指数无显著变化（P>0.05）;在门水平上,盲肠和结肠内容物菌群中厚壁菌门（Firmicutes）和拟杆菌门（Bacteroidetes）为优势菌门,VB组盲肠拟杆菌门丰度有升高趋势（0.05<P<0.1）,而螺旋菌门（Spirochaetes）丰度有降低趋势（0.05<P<0.1）;在目水平上,VB组盲肠Solirubrobacterales和Streptomycetales目菌群丰度显著下降（P<0.05）;在科水平上,VB组盲肠Christensenellaceae、Streptomycetaceae、Solirubrobacteraceae及结肠Christensenellaceae科菌群丰度显著下降（P<0.05）;在属水平上,VB组盲肠Lachnoclostridium属菌群丰度显著升高（P<0.05）,盲肠Bacillus、Nocardioides及结肠unidentified_Christensenellaceae和unidentified_Gammaproteobacteria属菌群丰度显著下降（P<0.05）。与CON相比,VB组山羊空肠绒毛高度（P<0.01）、隐窝深度（P<0.05）和绒毛高度/隐窝深度（V/C,P<0.05）均显著增加;回肠隐窝深度显著降低（P<0.05）,绒毛高度和V/C无显著变化（P>0.05）。实时荧光定量PCR结果显示,与CON相比,VB 组山羊盲肠上皮紧密连接和细胞增殖相关基因的表达均无显著变化（P>0.05）;而结肠黏膜上皮Occludin（P<0.05）、EGFR（P<0.01）、MIK67（P<0.05）和CCND（P<0.05）基因表达均显著上调;且VB组ZO-1蛋白表达显著上调（P<0.05）。综上表明,日粮中添加复合维生素B对生长期山羊肠道菌群多样性无显著影响,但可提高肠道中有益菌的丰度且降低有害菌的丰度,从而促进肠道绒毛的生长及紧密连接蛋白的表达,对山羊肠道健康和生长具有积极作用。     

Comparative studies on competitive exclusion of three isolates of Campylobacter fetus subsp. jejuni in chickens by native gut microflora

Resistance of young chicks to Campylobacter fetus subsp. jejuni was substantially increased by early exposure to native gut microflora. Protection was demonstrated against two human isolates and a chicken isolate of C. fetus subsp. jejuni. Significant protection against the chicken isolate was observed throughout a 91-day test period. Infection reached 100% (25/25) in the untreated group at 56 days of age and only 4% (1/25) in the group treated with native gut microflora. Campylobacter fetus subsp. jejuni was isolated from the ceca and less frequently from the gall bladder and liver of chicks that actively shed the bacteria. Cultures of feces from chicks reared on wood-shavings litter were often negative, suggesting that culturing litter as an indicator of infection has limited value.     

硒对热应激条件下放牧绵羊瘤胃发酵及瘤胃微生物区系的影响

为探讨热应激条件下补硒对放牧绵羊瘤胃发酵以及瘤胃微生物区系的影响,试验选择体重相近、健康的7～8月龄杜寒杂交羊10只,采用单因素完全随机试验设计,随机分成2组,每组5只.对照组不添加硒,试验组硒添加水平为0.2 mg/d(硒源为酵母硒).在夏季温度最高的初伏到中伏期间,以自然放牧方式饲养20 d后,颈静脉采集血液测定血...     

Prediction of clean mohair, fiber diameter, vegetable matter, and medullated fiber with near-infrared spectroscopy.

Four experiments were conducted in three separate years to test the utility of near-infrared spectroscopy (NIRS) to predict the clean mohair content of Angora goat fleece. Mohair fleece samples were obtained each year from yearling billies at the conclusion of the Angora Goat Performance Test conducted at the Texas A&M University Research Station, Sonora. In Exp. 1 (n = 293) and Exp. 2 (n = 256), fleeces were scanned with a Pacific Scientific (Silver Spring, MD) near-infrared spectrometer fitted with a fiber-optic probe, and calibrations were developed for clean mohair content. In Exp. 3, 59 mohair fleeces collected at the Texas A&M Research Station in San Angelo were sampled four times each. Each sample was scanned with the same spectrometer in reflectance mode fitted with a transport mechanism. This mechanism allowed the instrument to scan a 15-cm2 segment of the fleece sample. Conventional procedures to determine reference values for mohair yield, vegetable matter content, fiber diameter, and percentage of medullated and kemp fibers were conducted. Prediction equations were developed that related NIR spectra to reference values for yield and diameter parameters and were used to predict mohair characteristics for each fleece sample. The predicted and reference values were subjected to a simple analysis of variance to determine variation within and across samples. In Exp. 1, mohair base was related to NIR spectra with R2 = .46 and standard error of calibration (SEC) = 2.84%. In Exp. 2, similar repeatability errors for mohair base could be obtained for both reference- and NIRS-derived values. Fiber diameter and medullated fibers were poorly related to NIR spectra. When samples were scanned using the transport mechanism (Exp. 3), R2 and SEC were .82 and 1.19% for mohair base and .93 and .98 microm for fiber diameter, respectively. The CV for mohair base and diameter were 1.0 and 1.4%, whereas those for predicted mohair base and diameter were 1.4 and 3.4%, respectively. The increased variation within samples for predicted values represents sampling error and lack of fit between NIRS and the laboratory determined values. When the samples from Exp. 1 and 2 were rescanned with the NIRS transport (Exp. 4), R2 and SEC were .79 and 2.03% for mohair base and .52 and 3.49 microm for fiber diameter. The fiber optic probe would facilitate real-time analysis on the shearing floor, but our data indicate that the spectral limitations so far are too severe. A large sample device such as the transport gave excellent results for predicting mohair base and fiber diameter.     

Comparative in vitro fermentation activity in the canine distal gastrointestinal tract and fermentation kinetics of fiber sources

The current study aimed to evaluate the variation in fermentation activity along the distal canine gastrointestinal tract (GIT, Exp. 1). It also aimed to assess fermentation kinetics and end product profiles of 16 dietary fibers for dog foods using canine fecal inoculum (Exp. 2). For Exp. 1, digesta were collected from the distal ileum, proximal colon, transverse colon, and rectum of 3 adult dogs. Digesta per part of the GIT were pooled for 3 dogs, diluted (1:25, wt/vol), mixed, and filtered for the preparation of inoculum. A fructan, ground soy hulls, and native potato starch were used as substrates and incubated for cumulative gas production measurement as an indicator of the kinetics of fermentation. In addition, fermentation bottles with similar contents were incubated but were allowed to release their gas throughout incubation. Fermentation fluid was sampled at 4, 8, 12, 24, 48, and 72 h after initiation of incubation, and short-chain fatty acids and ammonia were measured. Results showed comparable maximal fermentation rates for rectal and proximal colonic inocula (P > 0.05). Production of short-chain fatty acids was least for the ileal and greatest for the rectal inoculum (P < 0.05). Therefore, for in vitro studies, fecal microbiota can be used as an inoculum source but may slightly overestimate in vivo fermentation. Experiment 2 evaluated the gas production, fermentation kinetics, and end product profiles at 8 and 72 h of incubation for citrus pectin, 3 fructans, gum arabic, 3 guar gums, pea fiber, peanut hulls, soy fiber, sugar beet fiber, sugar beet pectin, sugar beet pulp, wheat fiber, and wheat middlings. Feces of 4 adult dogs were used as an inoculum source. Similar techniques were used as in Exp. 1 except for the dilution factor used (1:10, wt/vol). Among substrates, large variations in fermentation kinetics and end product profiles were noted. Sugar beet pectin, the fructans, and the gums were rapidly fermentable, indicated by a greater maximal rate of gas production (R(max)) compared with all other substrates (P < 0.05), whereas peanut hulls and wheat fiber were poorly fermentable, indicated by the least amount of gas produced (P < 0.05). Sugar beet fiber, sugar beet pulp, soy fiber, and wheat middlings were moderately fermentable with a low R(max). Citrus pectin and pea fiber showed a similar low R(max), but time at which this occurred was later compared with sugar beet fiber, sugar beet pulp, soy fiber, and wheat middlings (P < 0.05). Results of this study can be used to formulate canine diets that stimulate dietary fiber fermentation along the distal GIT that may optimize GIT health and stimulate the level of satiety in dogs.     

Effects of different feed additives alone or in combination on broiler performance, gut microflora and ileal histology

1. The objectives of this experiment were to investigate the effects of different xylanases, alone or in combination with different organic acid and oligosaccharide sources, on bird performance, gut microflora and ileal histology. 2. Birds were given a diet based on a commercial formulation, which was split into 8 batches. Batch 1 contained the antibiotic growth promoter Avilamycin and acted as the positive control. To batch 2 the enzyme Allzyme PT was added and to batch 3 Allzyme PT was added with the organic acid and oligosaccharide mixture Avimos. To batch 4, Allzyme PT was added with the oligosaccharide mixture Biomos. To batch 5, yeast extract 2012 was added with the organic acid mixture Gustor and the enzyme xylanase XP20. To batch 6, yeast extract 2012 and feed acidifier Gustor were added as before, with the enzyme Avizyme 1300. Batches 7 and 8 both acted as negative experimental controls, with no added growth promoters. 3. A total of 64 birds were housed in individual wire cages in each of three consecutive experimental replicates (24 birds/treatment). Birds were fed ad libitum from 7 to 28 d and a 7-d excreta collection was carried out to determine apparent metabolisable energy (AME) content. 4. At 28 d, the birds were killed and viscosity of jejunal digesta supernatant and gizzard weight were determined. Samples were taken from the crop, ileum and caecum and analysed for viable presumptive lactic acid bacteria and coliforms. The overall microbial flora was determined using denaturing gradient gel electrophoresis of 16S ribosomal DNA followed by DNA sequence analysis in order to assign amplicons to a bacterial species. Ileal sections were also collected for histological analysis. 5. Total live weight gain (12%) and gain:feed (9%) were significantly improved for all diets containing additives, compared to the negative control diets. All diets containing xylanases gave significantly lower in vivo viscosity values than the positive and negative controls. Diet treatment significantly affected viable coliform numbers in the ileum and also viable lactobacilli in the ileum and caecum. A substantial proportion of the bacteria present in the GI tract (40%) belong to unknown species. No effects of diet treatment on histological measurements were observed in this study. 6. All the additive combinations studied were at least as effective as the antibiotic growth promoter and the results for Allzyme PT suggest that xylanase alone is as effective as any of the combinations studied.     

Effects of inulin on performance, egg quality, gut microflora and serum and yolk cholesterol in laying hens

1. The present study was conducted to investigate the effects of inulin on laying hens. A total of 360 Brown Nick laying hens were divided randomly into 6 groups of 60 with 6 replicates of 10 hens and fed on diets containing 0 (control), 0·1, 0·5, 1·0, 1·5 or 2·0% inulin during the 4-week trial. 2. Dietary supplementation of inulin reduced cholesterol concentration (mg/g yolk) and content (mg/egg) in eggs. Cholesterol content in eggs decreased linearly with increasing levels of dietary inulin level. 3. Supplementation of inulin in diets decreased coliform bacteria counts and pH in the caecum. The lowest coliform bacteria counts (6·30 ± 0·03 log10 cfu/g) and pH (6·47 ± 0·01) were obtained in the 2·0% inulin group, the two indices decreasing by 21·6% and 3·0% respectively, compared with the control group. Coliform bacteria count and pH were changed linearly in accordance with increasing levels of dietary inulin level. Caecal Bifidobacteria counts were increased in the 2·0%-inulin group. 4. Inulin supplementation of layer diets did not appear to have any adverse effects on laying rate, egg weight, feed intake, feed conversion efficiency, cracked-egg rate, eggshell thickness or Haugh unit compared with the control laying hens. 5. Therefore, dietary supplementation with inulin may lead to the development of low-cholesterol chicken eggs as demanded by health-conscious consumers.     

枯草芽孢杆菌对肉鸡肠道消化酶活性、黏膜结构及肠道菌群组成的影响

将216羽1日龄罗斯308肉鸡随机分成对照组和处理组,每组设3个重复,每个重复36羽。对照组饲喂基础日粮,处理组饲喂基础日粮加枯草芽孢杆菌制剂。饲养期42d。结果显示：与对照组相比,处理组肉鸡十二指肠内容物中胰蛋白酶、淀粉酶、脂肪酶和总蛋白水解酶的活性均显著提高（P〈0.05）;十二指肠、空肠和回肠绒毛高度显著增加（P〈0.05）,绒毛高度和隐窝深度的比值（VH/CD）显著升高（P〈0.05）;空肠和盲肠内容物中乳酸菌数量显著增加（P〈0.05）,大肠杆菌数量显著降低（P〈0.05）。结果表明,肉鸡日粮中添加适量的枯草芽孢杆菌能显著提高肉鸡消化酶活性,改善肉鸡肠黏膜结构及菌群组成,从而提高肉鸡的生长性能。