In vitro effects of inulin and soya bean oligosaccharide on skatole production and the intestinal microbiota in broilers

The experiment was conducted to investigate the in vitro effects of inulin and soya bean oligosaccharide (SBO) on the metabolism of L‐tryptophan (L‐try) to skatole production, and the intestinal microbiota in broilers. Treatments were as follows: caecal microbiota control (Cc), Cc + inulin, Cc + SBO, rectal microbiota control (Rc), Rc + inulin and Rc + SBO. Microbial suspensions were anaerobically incubated at 38°C for 24 hr. The results showed that concentrations of skatole and acetic acid were significantly lower in caecal microbiota fermentation broth (MFB) than those in rectal MFB (p < .05). Addition of inulin or SBO significantly decreased the concentrations of indole and skatole and rate of L‐try degradation (p < .05). Inulin groups had lower indole than SBO groups (p < .05). PCR‐DGGE analysis revealed that addition of inulin or SBO decreased the microbiota richness (p < .05), but no significant differences in Shannon index (p > .05). Four distinct bands were detected in inulin and SBO groups, which were related to two of Bacteroides, one of Firmicutes and Bifidobacteria. Six bands were detected only in control groups, which represented uncultured Rikenellaceae, Roseburia, Escherichia/Shigella dysenteriae, Bacteroides uniformis (T), Parabacteroides distasonis and Enterobacter aerogenes. Populations of Lactobacilli, Bifidobacteria and total bacteria in inulin groups were higher than those in control groups (p < .05). For SBO groups, only population of total bacteria increased (p < .05). However, there were no significant differences in Escherichia coli population among treatments (p > .05). These results suggest that reduced concentrations of skatole and indole in the presence of inulin and SBO may be caused by decrease in L‐try degradation rate, which were caused by change in microbial ecosystem and pH value. Uncultured B. uniformis (T) and E. aerogenes may be responsible for degradation of L‐try to skatole.     

Dietary protein level affects nutrient digestibility and ileal microbiota structure in growing pigs

This study aimed to determine whether dietary protein content influences pig health as indicated by ileal microbiota structure and coefficients of total tract apparent digestibility (CTTAD) of nutrients. Seventy‐two gilts, with an initial body weight of 29.9 ± 1.5 kg, were used in this 42‐day feeding study. Pigs were randomly allotted to one of three dietary treatments of corn‐soybean meal contained 14, 16 or 18% crude protein (CP). As dietary CP content decreased, the CTTAD of most essential amino acids (AAs), except for arginine and histidine, increased linearly, while those of most nonessential AAs decreased linearly. The concentration of total short‐chain fatty acids (SCFA) was higher in pigs fed the diet with 14% CP content than others. Ileal microbiota structure was changed by dietary treatments. In particular, at the phylum level, the relative abundance of Tenericutes in ileal digesta decreased as the dietary protein content reduced, while that of cyanobacteria increased. At the genus level, the relative abundance of Weeksella, Phaseolus acutifolius, Slackia, Sulfurimonas and Aerococcus showed significant differences among the three dietary treatments. In conclusion, ileal microbiota structure was changed by dietary protein content. Moderate reduction of protein intake can benefit gut health by enhancing the gut microbial fermentation and SCFA formation.     

Gut microbes limit growth in house sparrow nestlings (Passer domesticus) but not through limitations in digestive capacity

Recent research often lauds the services and beneficial effects of host‐associated microbes on animals. However, hosting these microbes may come at a cost. For example, germ‐free and antibiotic‐treated birds generally grow faster than their conventional counterparts. In the wild, juvenile body size is correlated with survival, so hosting a microbiota may incur a fitness cost. Avian altricial nestlings represent an interesting study system in which to investigate these interactions, given that they exhibit the fastest growth rates among vertebrates, and growth is limited by their digestive capacity. We investigated whether reduction and restructuring of the microbiota by antibiotic treatment would: (i) increase growth and food conversion efficiency in nestling house sparrows (Passer domesticus); (ii) alter aspects of gut anatomy or function (particularly activities of digestive carbohydrases and their regulation in response to dietary change); and (iii) whether there were correlations between relative abundances of microbial taxa, digestive function and nestling growth. Antibiotic treatment significantly increased growth and food conversion efficiency in nestlings. Antibiotics did not alter aspects of gut anatomy that we considered but depressed intestinal maltase activity. There were no significant correlations between abundances of microbial taxa and aspects of host physiology. Overall, we conclude that microbial‐induced growth limitation in developing birds is not driven by interactions with digestive capacity. Rather, decreased energetic and material costs of immune function or beneficial effects from microbes enriched under antibiotic treatment may underlie these effects. Understanding the costs and tradeoffs of hosting gut microbial communities represents an avenue of future research.     

内蒙古锡林郭勒冬季放牧蒙古牛肠道微生物多样性和功能预测分析

为探究内蒙古锡林郭勒冬季放牧蒙古母牛肠道微生物组成及其功能,采集同一地区冬季(11、12月和次年1月)放牧蒙古母牛(各20头)直肠粪便样品,利用16SrRNA测序技术对其肠道菌群多样性进行分析及PICRUSt(Phylogenetic investigation of communities by reconstruction of unobserved states,PICRUSt)功能预测。结果显示,60份样品平均每样品测得90 075条序列,通过聚类共获得3 975个操作分类单元(Operational taxonomic units,OTU),84.60%的OTU注释到门水平;29.56%的OTU注释到属水平;在门水平和属水平,冬季放牧蒙古牛肠道中优势物种分别为厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)、拟杆菌属(Bacteroides)和艾克曼菌属(Akkermansia);随着天气逐渐变冷,食物短缺,蒙古牛肠道中厚壁菌门(Firmicutes)减少,而拟杆菌门(Bacteroidetes)增多;聚类分析发现,11月和12月蒙古牛肠道微生物群落较为相似,而与次年1月相比有明显差异;PICRUSt功能预测发现,随着天气逐渐变冷,免疫系统、环境适应性及细胞运动性相关通路丰度降低,氨基酸代谢通路丰度增加。综上,蒙古牛肠道菌群在适应食物短缺的冬季发挥着重要作用。     

Effect of nutritional interventions with quercetin,oat hulls, β-glucans,lysozyme and fish oil on performance and health status related parameters of broilers chickens

ABSTRACT

1. An experiment was conducted to evaluate the effects of technical feed ingredients between 14 and 28 d of age on performance and health status of broilers (d 14–35) fed diets with a high inclusion rate of rapeseed meal as a nutritional challenge. It was hypothesized that the feed ingredients would improve health status related parameters.

2. A total of 1008 one-day-old male Ross 308 chicks were distributed over 36 floor pens and allocated to one of six iso-caloric (AME_N 13 MJ/kg) growing diets (d 15–28): a control and five test diets supplemented with quercetin (400 mg/kg), oat hulls (50 g/kg), β-glucan (100 mg/kg), lysozyme (40 mg/kg) or fish oil ω-3 fatty acids (40 g/kg), with six replicate pens per treatment.

3. Dietary inclusion of oat hulls and lysozyme resulted in a reduction in broiler performance during the first week after providing the experimental diets.

4. No effect of interventions on the microbiota diversity in the jejunum and ileum was observed. Ileal microbiota composition of birds fed oat hulls differed from the other groups, as shown by a higher abundance of the genus Enterococcus, mainly at the expense of the genus Lactobacillus.

5. In the jejunum, villus height and crypt depth of lysozyme-fed birds at d 28 were decreased compared to the control group. Higher total surface area of villi occupied by goblet cells and total villi surface area in jejunum (d 21 and 28) were observed in chickens fed oat hulls compared to other groups.

6. Genes related to the growth-factor-activity pathway were more highly expressed in birds fed β-glucan compared to the control group, while the genes related to anion-transmembrane-transporter-activity pathway in the quercetin- and oat hull-fed birds were less expressed. The genes differently expressed between dietary interventions did not seem to be directly involved in immune related processes.

7. It was concluded that the tested nutritional interventions in the current experiment only marginally effected health status related parameters.     

宏基因组测序分析野生林麝瘤胃、小肠和大肠微生物组成和抗生素抗性基因

本试验旨在研究野生林麝(Moschus berezovskii)瘤胃、小肠和大肠微生物组成和抗生素抗性基因。采集野生林麝消化道3个区段(瘤胃、小肠和大肠)的内容物进行宏基因组测序,并进行常规物种注释和抗生素抗性基因功能注释。结果表明:3个区段共有优势菌门为厚壁菌门(Firmicutes)和变形菌门(Proteobacteria);瘤胃中主要优势菌属为普雷沃氏菌属(Prevotella)、月形单胞菌属(Selenomonas),小肠中主要优势菌属为链球菌属(Streptococcus)、埃希氏菌属(Echerichia),大肠中主要优势菌属为梭菌属(Clostridium)、拟杆菌属(Bacteroides)。基因常规注释显示各个区段微生物基因在不饱和脂肪酸合成和抗生素抗性上差异较大。抗生素抗性基因注释显示macB、sav1866和bcrA绝对丰度最高,且都来自于大肠细菌;瘤胃中抗生素抗性基因绝对丰度最大的是Aminocoumarin_resistant_alaS,小肠中是adeG,大肠中是macB。通过对野生林麝消化道微生物组成分区段比对,发现瘤胃、小肠和大肠微生物组成和抗生素抗性基因分布存在较大差异,大肠和小肠中细菌与野生林麝的多重耐药性关系更密切。     

瘤胃微生物与宿主的互作及其对瘤胃上皮发育的影响

瘤胃上皮在挥发性脂肪酸的吸收和代谢中发挥着重要作用，但瘤胃上皮发育的机制尚不清楚。近年来研究报道，瘤胃微生物与宿主存在互作关系，瘤胃微生物可以通过与宿主的相互作用，在瘤胃上皮发育和代谢中发挥作用。然而，瘤胃微生物与宿主相互作用的调节机制在很大程度上是未知的。因此，本文总结了瘤胃微生物与宿主互作以及其促进瘤胃上皮发育的最新研究成果，以期从瘤胃微生物与宿主互作角度，分析瘤胃上皮发育机制，为进一步了解瘤胃上皮发育过程中瘤胃微生物与宿主之间的关系研究提供理论依据。     

西藏高原藏猪盲肠微生物群落结构与多样性的研究

本研究旨在探讨西藏高原放牧藏猪、舍饲藏猪与瘦肉型猪（杜×长×大，DLY猪）盲肠微生物的群落组成及多样性，从而部分揭示西藏高原藏猪肠道微生物的特异性。选用日龄相近的放牧藏猪、舍饲藏猪及DLY猪各5头，放牧藏猪由林芝本地农牧民采用传统方式放牧养殖，舍饲藏猪及DLY猪圈养并饲喂相同饲粮，160日龄时前腔静脉放血屠宰，采集盲肠食糜于液氮速冻待测。采用高通量测序技术测定样品16S rRNA V3-V4区域的基因序列。结果表明，在15个样本的16S rRNA基因V3-V4区测序共获得了659 904条有效序列，其中放牧藏猪213 031条、舍饲藏猪219 417条、DLY猪227 456条。放牧藏猪盲肠微生物OTU总数、Chao1指数、ACE指数及香农（Shannon）指数均显著高于舍饲藏猪与DLY猪（P<0.05），而舍饲藏猪与DLY猪无显著差异（P>0.05）。3个类型猪盲肠微生物共划分为13个门，56个属。厚壁菌门（Firmicutes）是3个类型猪相对丰度共同最高的门。放线菌门（Actinobacteria）与疣微菌门（Verrucomicrobia）在放牧藏猪中相对丰度显著高于其他2个类型猪（P<0.05），舍饲藏猪拟杆菌门（Bacteroidetes）相对丰度显著高于放牧藏猪与DLY猪（P<0.05）；放牧藏猪共有11个属相对丰度显著高于舍饲藏猪与DLY猪（P<0.05）。结果提示，放牧藏猪盲肠微生物群落结构与多样性具备自身独特性，为进一步开发藏猪资源提供参考。