Effects of formic acid and corn flour supplementation of banana pseudostem silages on nutritional quality of silage,growth,digestion,rumen fermentation and cellulolytic bacterial community of Nubian black goats

The objective of this study was to evaluate the effects of adding formic acid and corn flour supplementation to banana pseudostem silages on the nutritional quality of these silages,growth,digestion,rumen fermentation and cellulolytic bacterial community of Nubian black goats fed these silages.Banana pseudostem silage was prepared either conventionally without any additives(CON)or mixed with 0.6% formic acid(F),10% corn flour(C),or both(F+C).Four experimental diets containing 40% of the corresponding silages were designed with roughage to concentrate ratio of 50:50(dry matter(DM)basis).A total of 48 Nubian black castrated goats(body weight(BW),(22.64±1.82)kg;4-mon-old)were randomized into one of the four treatment groups with 12 replicates of one castrated goat per replicate for each treatment in a completely randomized design.Each group was fed on one of the four experimental diets for 40 days.A factorial arrangement of treatments of 2(formic acid levels:0 and 0.6%)×2(corn flour:0 and 10%)was adopted.Formic acid supplementation increased(P<0.05)average daily gain,as well as lactic acid,propionate and butyric acid and water-soluble carbohydrate concentrations,but decreased(P<0.05)the feed conversion rate,pH value,acetate/propionate ratio,and butyric acid concentration relative to the CON group.Corn flour supplementation increased(P<0.05)the apparent digestibility of crude protein,neutral detergent fiber,and non-fibrous carbohydrate and Fibrobacter succinogenes,Ruminococcus albus,and Butyrivibrio fibrisolvens populations,but decreased(P<0.05)the Ruminococcus flavefaciens population relative to the CON group.There were no F×C treatment interactions(P>0.05)for any of the other indices except for the apparent digestibility of non-fibrous carbohydrate(NFC)(P<0.05).The results demonstrated that adding 0.6% formic acid and 10% corn flour supplementation to banana pseudostem silages improved the nutritional quality of these silages and enhanced the growth performance of Nubian black castrated goats by improving apparent nutrient digestibility,and regulating ruminal fermentation and bacteria populations.

Comparison of rumen bacteria distribution in original rumen digesta, rumen liquid and solid fractions in lactating Holstein cows

Background： Original rumen digesta, rumen liquid and solid fractions have been frequently used to assess the rumen bacterial community. However, bacterial profiles in rumen original digesta, liquid and solid fractions vary from each other and need to be better established.Methods： To compare bacterial profiles in each fraction, samples of rumen digesta from six cows fed either a high fiber diet（HFD） or a high energy diet（HED） were collected via rumen fistulas. Rumen digesta was then squeezed through four layers of cheesecloth to separate liquid and solid fractions. The bacterial profiles of rumen original digesta, liquid and solid fractions were analyzed with High-throughput sequencing technique.Results： Rumen bacterial diversity was mainly affected by diet and individual cow（P 〉 0.05） rather than rumen fraction. Bias distributed bacteria were observed in solid and liquid fractions of rumen content using Venn diagram and LEf Se analysis. Fifteen out of 16 detected biomarkers（using LEf Se analysis） were found in liquid fraction, and these 15 biomarkers contributed the most to the bacterial differences among rumen content fractions.Conclusions： Similar results were found when using samples of original rumen digesta, rumen liquid or solid fractions to assess diversity of rumen bacteria; however, more attention should be draw onto bias distributed bacteria in different ruminal fractions, especially when liquid fraction has been used as a representative sample for rumen bacterial study.

The Preliminary Report on Rumen Protozoa Grazing Rate on Bacteria with a Fluorescence-Labeled Technique

Studies on the bacterial predation rate by rumen protozoa were carried out under laboratory conditions using a technique of fluorescence-labeled bacteria （FLB）. Four Xuhuai goats were used in this experiment to obtain rumen protozoa and bacteria. Two groups were designed as follows： One group was the whole bacteria which were labeled using fluorescence through removing free bacteria from rumen fluid （WFLB）; the other group was the bacteria which were labeled using fluorescence without removing free bacteria from rumen fluid （FLB）. The result indicated that the bacterial predation rates of rumen protozoa was 398.4 cells/（cell h） for the group WFLB, 230.4 cells/（cell h） for the group FLB, when the corresponding values expressed as bacteria-N, they were 2.15 pg N/（cell h） for the group WFLB, and 1.24 pg N/（cell h） for the group FLB, respectively. Extrapolating the assimilation quantity of nitrogen by ciliates on bacteria of Xuhuai goat, there were 103.2 mg N/（d capita） for the group WFLB, and 59.5 mg N/（d capita） for the group FLB, respectively. It was estimated that protein losses due to microbial recycling were 0.645 g pro/（d capita） for the group WFLB and 0.372 g pro/（d capita） for the group FLB, respectively. In addition, the fluorescence-labeled technique would be a potential assay for the determination of bacterial predation rate by rumen protozoa.

Isolation and characterization of superior rumen bacteria of cattle (<i>Bos taurus</i>) and potential application in animal feedstuff

Rumen of cattle harbors many microorganisms responsible for bioconversion of nutrients into a source of energy for the animals. In recent years many rumen microbes have been isolated and characterized by sequence analysis of 16S ribosomal RNA gene. Some of the microbes have also been recommended as feed additives for improving the overall growth or production of animals. Rumen bacteria which have potential application in animal feed stuffs were isolated and characterized in this experiment. Isolation was carried out from the rumen of cattle (Bos taurus) using techniques of serial dilutions and repeated tubing of the selectively enriched microbial cultures by using the specific media for rumen bacteria. All the isolates were then screened for in vitro gas production and cellulase enzyme activity and four superior isolates were selected and characterized. There were 18.00% to 23.00% increases in gas production on addition of these isolates to the rumen fluid of cattle and there was better cellulase enzyme activity. Two isolates were identified as Butyrivibrio fibrisolvens, one isolate as Streptococcus species and one isolate as Clostridium aminophilum. This indicated that, these isolates are superior and may have potential to be used as microbial feed additive in ruminants if fed in higher quantity.

不同处理对油菜秸秆营养品质及其牛瘤胃降解特性的影响

为研究不同处理对油菜秸秆营养价值及瘤胃降解动力学参数的影响,将油菜秸秆经高压、酶菌协同发酵、高压和酶菌协同发酵复合法处理,并测定其营养成分,并选用3头健康装有永久瘤胃瘘管的黑安格斯阉牛,采用尼龙袋法测定油菜秸秆(RS)、高压油菜秸秆(HPRS)、酶菌协同发酵高压油菜秸秆(SFHPRS)的主要营养成分在瘤胃中的降解率和动态降解模型参数。试验结果表明:SFHPRS的总能、粗蛋白质含量都显著高于RS和HPRS(P<0.05);酶菌协同发酵处理可以显著降低油菜籽秸秆中中性洗涤纤维、酸性洗涤纤维含量,提高相对饲用价值(RFV)、相对饲草品质(RFQ)及饲草分级指数(GI)(P<0.05)。RS、HPRS、SFHPRS的干物质、有机物、中性洗涤纤维和酸性洗涤纤维的72 h瘤胃降解率呈现出一致的规律,即SFHPRS>HPRS>RS,瘤胃消化0~72 h内SFHPRS的粗蛋白质瘤胃降解率显著高于RS、HPRS(P<0.05)。SFHPRS的干物质、有机物、粗蛋白质、中性洗涤纤维、酸性洗涤纤维的快速降解部分、有效降解率均显著高于RS、HPRS(P<0.05)。综上可知,本试验条件下,油菜秸秆进行酶菌协同发酵后,总能、粗蛋白质含量均有所提高,中性洗涤纤维、酸性洗涤纤维含量均显著下降。采用高压和酶菌协同发酵的复合法,能够更有效提高油菜秸秆饲料主要营养成分在瘤胃中的降解率,提升其营养价值。

不同pH对瘤胃细菌数量和菌群结构的影响

【目的】试验旨在研究瘤胃不同pH下瘤胃酸中毒相关细菌数量和瘤胃细菌菌群结构的变化。【方法】选取5头干奶期荷斯坦奶牛作为瘤胃液供体,调节瘤胃液pH分别为6.5、5.8、5.5、5.2和5.0。培养3 h后,采用qPCR技术测定瘤胃酸中毒相关细菌数量,采用16S rDNA高通量测序技术研究瘤胃细菌菌群结构的变化。【结果】(1)瘤胃pH对白色瘤胃球菌(Ruminococcus ablus)的相对数量没有影响(P>0.05),但显著影响了乳酸产生菌和乳酸利用菌的相对数量(P<0.05)。其中牛链球菌(Streptococcus bovis)相对数量随着pH的下降而升高,在pH 5.0处极显著高于其余各组(P<0.05);埃氏巨型球菌(Megasphaeraelsdenii)、反刍兽新月单胞菌(Selenomonas ruminantium)及乳酸杆菌(Lactobacillus species)随pH下降呈现先升高后下降的趋势,pH分别在pH 5.5或pH 5.2处达到最大值(P<0.05);(2)α多样性结果显示,瘤胃细菌数量和菌群的丰富度及多样性呈现随瘤胃pH下降先升高后下降的趋势,其中Chao1指数在pH 5.5处,Observed species和Shannon指数在pH 5.2处最高(P<0.05)。β多样性结果显示pH 6.5、pH 5.8处理组与pH 5.2、pH 5.0处理组的菌群构成有明显差异,pH 5.5处理组样本与其他4组样本距离较远,其菌群构成与其他4组具有差异;(3)在菌群组成上,瘤胃内主要菌门和属的菌群丰度随pH的降低也多有改变。pH 5.2、pH 5.0处理组和pH 6.5、pH 5.8处理组菌群结构有显著差异(P<0.05)。pH 6.5组与pH 5.8组的菌群组成差异不大(P>0.05),仅普雷沃氏菌科UGG-003菌属(Prevotellaceae UCG-003)和琥珀酸弧菌科UGG 002菌属(Succinivibrionaceae UCG 002)有差异;pH 5.0处理组与pH 5.2处理组的菌群组成较一致(P>0.05),仅在螺旋体门(Spirochaetota)、放线菌门(Actinobacteriota)、瘤胃菌属(Ruminococcus)和解琥珀菌属(Succiniclasticum)有差异(P<0.05);而pH 5.5处理组的菌群构成与其他4组有显著差异(P<0.05)。【结论】环境pH改变是瘤胃细菌遭受的一种严重干扰,会引起瘤胃内乳酸产生菌和乳酸利用菌的相对数量显著改变。瘤胃细菌数量、菌群丰富度和多样性也随瘤胃pH的下降表现出先升高后降低的趋势,其变化规律符合生态学中的“中度干扰假说”。

山谷型藏羊公羊瘤胃和粪便微生物多样性研究

为了研究青藏高原山谷型藏羊公羊胃肠道微生物组成结构,试验采集了10只放牧+补饲饲养方式下的周岁山谷型藏羊公羊的瘤胃和直肠内容物(指粪便),分别提取其基因组DNA,采用16S rDNA V3~V4扩增子高通量测序技术分析了瘤胃和粪便样品微生物门和属水平组成结构、标志微生物、α和β多样性及微生物功能。结果表明:山谷型藏羊瘤胃和粪便样品共得到5 383个分类操作单元(operational taxanomic units, OTUs),其中2 144个OTUs为瘤胃样品所特有,1 860个OTUs为粪便样品特有,1 379个为二者共有。瘤胃微生物优势菌门为厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)和浮霉菌门(Planctomycetes),相对丰度分别为53.2%、34.9%和3.1%;优势菌属为理研菌科_RC9_肠道菌群(Rikenellaceae_RC9_gut_group)和普式菌属_1(Prevotella_1),相对丰度分别为13.5%和12.0%。粪便微生物优势菌门为拟杆菌门、厚壁菌门和疣微菌门(Verrucomicrobia),相对丰度分别为47.4%、25.3%和16.9%;优势菌属为艾克曼菌属(Akkermansia)和克里斯滕森菌科_R7菌群(Christensenellaceae_R7_group),相对丰度分别为15.6%和7.3%。山谷型藏羊瘤胃和粪便样品的标志微生物均为拟杆菌门和厚壁菌门,且瘤胃和粪便样品微生物α和β多样性差异明显,主要功能均为碳水化合物代谢(carbohydrate metabolism)、氨基酸代谢(amino acid metabolism)、膜运输(membrane transport)与共同因子和维生素代谢(metabolism of cofactors and vitamins)等。说明山谷型藏羊瘤胃和粪便有各自独特的微生物组成结构。

饲喂含秸秆发酵饲料对育成牛瘤胃微生物组成和功能的影响

本研究旨在探究饲喂含秸秆发酵饲料对育成牛瘤胃微生物组成与功能以及代谢生理等方面的影响。选取36头8~11月龄、体重相近且健康的荷斯坦育成牛,随机分成2组,即在基础饲粮的基础上分别饲喂0 kg/d(对照组)、4 kg/d含秸秆发酵饲料(按干物质计,秸秆约占日粮16.0%;处理组),持续8周,每2周测定一次育成牛日增重情况,并在第8周时采集尾静脉血及瘤胃内容物,分析2组育成牛在表型以及瘤胃微生物区系上的差异。结果发现:饲喂含秸秆发酵饲料组育成牛日增重(0.991 kg/d)与对照组(1.080 kg/d)相比明显下降(p=0.042)。与对照组相比,饲喂含秸秆发酵饲料组瘤胃总挥发性脂肪酸浓度、血清中β-羟丁酸和甘油三酯浓度均显著升高(p<0.05),葡萄糖浓度显著降低(p<0.05);瘤胃细菌α多样性指数中,饲喂含秸秆发酵饲料组Sobs指数和香农(Shannon)指数显著升高(p<0.05),β多样性无显著差异(p>0.05)。饲喂含秸秆发酵饲料组中,与表型相关的核心菌种主要为厌氧支原体属;在微生物功能上,2组主要在碳水化合物代谢和氨基酸生物合成途径上存在显著差异。综上所述,饲喂含秸秆发酵饲料促进了育成牛瘤胃发酵,并在一定程度上影响其脂质代谢。本研究在瘤胃微生物组成与功能差异以及高效利用秸秆饲料的关键微生物挖掘上均有一定突破,为育成牛饲粮中非常规饲料的有效利用提供了实践依据。

单宁调控反刍动物瘤胃甲烷排放的研究进展

反刍动物排放的甲烷主要来源于瘤胃内饲料的发酵。受瘤胃内多种微生物的影响,甲烷的产生途径多样,调控机理复杂。降低饲料源瘤胃甲烷排放是提高饲料能量利用率和改善环境的有效措施之一。生产中常通过饲喂单宁添加剂或富含单宁的饲草来减少反刍动物的甲烷排放,因其来源、化学成分及添加剂量等因素的影响,单宁降低甲烷排放的效果有较大差异。本文综述了单宁对反刍动物瘤胃菌群代谢的影响,分析其降低甲烷排放的机制,探索单宁在瘤胃甲烷排放中的调控作用,旨在为降低反刍动物甲烷生成的营养调控措施提供参考。

Evaluation of ruminal methane and ammonia formation and microbiota composition as affected by supplements based on mixtures of tannins and essential oils using Rusitec

Background Dietary supplements based on tannin extracts or essential oil compounds(EOC)have been repeatedly reported as a promising feeding strategy to reduce the environmental impact of ruminant husbandry.A previous batch culture screening of various supplements identified selected mixtures with an enhanced potential to mitigate ruminal methane and ammonia formation.Among these,Q-2(named after quebracho extract and EOC blend 2,composed of carvacrol,thymol,and eugenol)and C-10(chestnut extract and EOC blend 10,consisting of oregano and thyme essential oils and limonene)have been investigated in detail in the present study with the semi-continuous rumen simulation technique(Rusitec)in three independent runs.For this purpose,Q-2 and C-10,dosed according to the previous study,were compared with a non-supplemented diet(negative control,NC)and with one supplemented with the commercial EOC-based Agolin^(R) Ruminant(positive control,PC).Results From d 5 to 10 of fermentation incubation liquid was collected and analysed for pH,ammonia,protozoa count,and gas composition.Feed residues were collected for the determination of ruminal degradability.On d 10,samples of incubation liquid were also characterised for bacterial,archaeal and fungal communities by high-throughput sequencing of 16S rRNA and 26S ribosomal large subunit gene amplicons.Regardless of the duration of the fermentation period,Q-2 and C-10 were similarly efficient as PC in mitigating either ammonia(-37%by Q-2,-34%by PC)or methane formation(-12%by C-10,-12%by PC).The PC was also responsible for lower feed degradability and bacterial and fungal richness,whereas Q-2 and C-10 effects,particularly on microbiome diversities,were limited compared to NC.Conclusions All additives showed the potential to mitigate methane or ammonia formation,or both,in vitro over a period of 10 d.However,several differences occurred between PC and Q-2/C-10,indicating different mechanisms of action.The pronounced defaunation caused by PC and its suggested consequences apparently determined at least part of the mitigant effects.Although the depressive effect on NDF degradability caused by Q-2 and C-10 might partially explain their mitigation properties,their mechanisms of action remain mostly to be elucidated.

大额牛瘤胃细菌Umcel-2蛋白的生物信息学分析

为了了解云南大额牛瘤胃细菌Umcel-2蛋白的生物学特性、结构及功能等特征,阐明大额牛瘤胃细菌Umcel-2蛋白高效降解纤维素的生物学功能,试验采用多种在线软件和工具对Umcel-2蛋白进行生物信息学分析研究。结果表明:Umcel-2蛋白分子式为C1983H2987N541O670S15,相对分子质量为4.56 kDa,属于一个定位于细胞质中,无跨膜区及信号肽的亲水型酸性稳定蛋白;Umcel-2蛋白含有1个保守区域pfam00150且属于糖苷水解酶家族5,二级结构由α-螺旋、无规则卷曲发挥主要功能,三级结构同源建模质量高且与芳基磷酸化-β-D-葡萄糖苷酶BglC相似;Umcel-2蛋白存在3个N端糖基化位点和49个磷酸化位点,且其活性位点由甘氨酸、丝氨酸、苏氨酸、亮氨酸和天冬酰胺等氨基酸组成,有利于提高其纤维素酶活性。系统进化树结果表明,Umcel-2蛋白与未培养生物AEX97596.1纤维素酶的纤维素酶蛋白高度同源,表现出内切葡聚糖酶和β-葡萄糖苷酶的纤维素酶活。研究表明,生物信息学方法预测瘤胃细菌Umcel-2蛋白具有较高的纤维酶活性,为瘤胃细菌高效降解纤维素的深入研究提供了参考。

Association of residual feed intake with abundance of ruminal bacteria and biopolymer hydrolyzing enzyme activities during the peripartal period and early lactation in Holstein dairy cows

Background: Residual feed intake(RFI) in dairy cattle typically calculated at peak lactation is a measure of feed efficiency independent of milk production level. The objective of this study was to evaluate differences in ruminal bacteria, biopolymer hydrolyzing enzyme activities, and overall performance between the most-and the leastefficient dairy cows during the peripartal period. Twenty multiparous Holstein dairy cows with daily ad libitum access to a total mixed ration from d-10 to d 60 relative to the calving date were used. Cows were classified into most-efficient(i.e. with low RFI, n = 10) and least-efficient(i.e. with high RFI, n = 10) based on a linear regression model involving dry matter intake(DMI), fat-corrected milk(FCM), changes in body weight(BW), and metabolic BW.Results: The most-efficient cows had ~ 2.6 kg/d lower DMI at wk 4, 6, 7, and 8 compared with the least-efficient cows. In addition, the most-efficient cows had greater relative abundance of total ruminal bacterial community during the peripartal period. Compared with the least-efficient cows, the most-efficient cows had 4-fold greater relative abundance of Succinivibrio dextrinosolvens at d-10 and d 10 around parturition and tended to have greater abundance of Fibrobacter succinogenes and Megaspheara elsdenii. In contrast, the relative abundance of Butyrivibrio proteoclasticus and Streptococcus bovis was lower and Succinimonas amylolytica and Prevotella bryantii tended to be lower in the most-efficient cows around calving. During the peripartal period, the most-efficient cows had lower enzymatic activities of cellulase, amylase, and protease compared with the least-efficient cows.Conclusions: The results suggest that shifts in ruminal bacteria and digestive enzyme activities during the peripartal period could, at least in part, be part of the mechanism associated with better feed efficiency in dairy cows.

Quantitative comparisons of select cultured and uncultured microbial populations in the rumen of cattle fed different diets

Background： The number and diversity of uncultured ruminal bacterial and archaeal species revealed by 16S rRNA gene firs） sequences greatly exceeds that of cultured bacteria and archaea. However, the significance of uncultured microbes remains undetermined. The objective of this study was to assess the numeric importance of select uncultured bacteria and cultured bacteria and the impact of diets and microenvironments within cow rumen in a comparative manner. Results： Liquid and adherent fractions were obtained from the rumen of Jersey cattle fed hay alone and Holstein cattle fed hay plus grain. The populations of cultured and uncultured bacteria present in each fraction were quantified using specific real-time PCR assays. The population of total bacteria was similar between fractions or diets, while total archaea was numerically higher in the hay-fed Jersey cattle than in the hay-grain-fed Holstein cattle. The population of the genus Prevotello was about one log smaller than that of total bacteria. The populations of Fibrobocter succinogenes, Ruminococcus flovefociens, the genus Butyrivibrio, and R. albus was at least one log smaller than that of genus Prevotello. Four of the six uncultured bacteria quantified were as abundant as F. succinogenes, R. flovefociens and the genus Butyrivibrio. In addition, the populations of several uncultured bacteria were significantly higher in the adherent fractions than in the liquid fractions. These uncultured bacteria may be associated with fiber degradation. Conclusions： Some uncultured bacteria are as abundant as those of major cultured bacteria in the rumen. Uncultured bacteria may have important contribution to ruminal fermentation. Population dynamic studies of uncultured bacteria in a comparative manner can help reveal their ecological features and importance to rumen functions.

Initial detection of the quorum sensing autoinducer activity in the rumen of goats in vivo and in vitro

Quorum sensing（QS） is a type of microbe-microbe communication system that is widespread among the microbial world, particularly among microorganisms that are symbiotic with plants and animals. Thereby, the cell-cell signalling is likely to occur in an anaerobic rumen environment, which is a complex microbial ecosystem. In this study, using six ruminally fistulated Liuyang black goats as experimental animals, we aimed to detect the activity of quorum sensing autoinducers（AI） both in vivo and in vitro and to clone the lux S gene that encoded autoinducer-2（AI-2） synthase of microbial samples that were collected from the rumen of goats. Neutral detergent fiber（NDF） and soluble starch were the two types of substrates that were used for in vitro fermentation. The fermented fluid samples were collected at 0, 2, 4, 6, 8, 12, 24, 36, and 48 h of incubation. The acyl-homoserine lactones（AHLs） activity was determined using gas chromatography-mass spectrometer（GC-MS） analysis. However, none of the rumen fluid extracts that were collected from the goat rumen showed the same or similar fragmentation pattern to AHLs standards. Meanwhile, the AI-2 activity, assayed using a Vibrio harveyi BB170 bioassay, was negative in all samples that were collected from the goat rumen and from in vitro fermentation fluids. Our results indicated that the activities of AHLs and AI-2 were not detected in the ruminal contents from six goats and in ruminal fluids obtained from in vitro fermentation at different sampling time-points. However, the homologues of lux S in Prevotella ruminicola were cloned from in vivo and in vitro ruminal fluids. We concluded that AHLs and AI-2 could not be detected in in vivo and in vitro ruminal fluids of goats using the current detection techniques under current dietary conditions. However, the microbes that inhabited the goat rumen had the potential ability to secrete AI-2 signaling molecules and to communicate with each other via AI-2-mediated QS because of the presence of lux S.

不同品种羔羊胃肠道微生物发育规律的比较研究

本试验旨在探究相同饲养条件下不同品种(道赛特羊、湖羊和小尾寒羊)羔羊瘤胃和直肠的细菌和真菌差异,为阐明不同品种羔羊胃肠道微生物发育规律和精准饲养管理提供基础数据。选取同一产房、胎次和性别相同的1日龄不同品种羔羊30只,其中道赛特羊、湖羊和小尾寒羊公羔各10只,相同饲养管理模式下进行120 d饲养试验。采集瘤胃液和粪便样品,测定细菌和真菌区系。结果表明:1)小尾寒羊瘤胃细菌的PD whole tree指数显著高于湖羊(P<0.05),湖羊直肠真菌的辛普森指数显著高于道赛特羊(P<0.05)。2)主坐标分析(PCoA)和相似性分析(ANOSIM)表明,不同品种羔羊在20、90日龄瘤胃细菌,70日龄直肠细菌,20、70、90日龄瘤胃真菌,90、120日龄直肠真菌中的群落均存在显著差异(P<0.05)。3)道赛特羊直肠细菌中螺旋体门和密螺旋体属相对丰度表现出升高的趋势(P=0.086)。小尾寒羊瘤胃细菌中理研菌科RC-9肠道群和克里斯滕森菌科R-7群相对丰度显著高于道赛特羊和湖羊(P<0.05),瘤胃真菌中子囊菌门相对丰度显著低于道赛特羊和湖羊(P<0.05),瘤胃细菌中普雷沃氏菌属相对丰度表现出降低的趋势(P=0.063)。综上所述,在相同饲养条件下,3个品种羔羊的胃肠道菌群的多样性和组成均存在差异,小尾寒羊具有较高的瘤胃细菌多样性,湖羊具有较高的直肠真菌多样性,道赛特羊直肠细菌中螺旋体门和密螺旋体属相对丰度较高,小尾寒羊瘤胃细菌中普雷沃氏菌属相对丰度较低以及理研菌科RC-9肠道群和克里斯滕森菌科R-7群相对丰度较高,胃肠道微生物区系结构差异可能是导致不同品种羔羊生产性能差异的原因之一。

Development of a Consolidated Anaerobic Digester and Microbial Fuel Cell to Produce Biomethane and Electricity from Cellulosic Biomass Using Bovine Rumen Microorganisms

Microbial fuel cells (MFCs) are bioelectrochemical systems that convert chemical energy contained in organic matter into electrical energy by using the catalytic (metabolic) activity of living microorganisms. Mediator-less two chamber H-type MFCs were constructed in the current study, using dairy digester microbial population as anode inocula to convert finely ground pine tree (Avicel) at 2% (w/v) to electricity. MFCs were placed at 37&deg;C and after the circuit voltage was stabilized on d9, bovine rumen microorganisms cultured anaerobically for 48 hrs in cellulose broth media were added to treatment group of MFC at 1% v/v dosage. MFC power and current across an external resistor were measured daily for 10 d. At the end of incubation on d19 head space gas and anode chamber liquid solutions were collected and analyzed for total gas volume and composition, and volatile fatty acids, respectively. Addition of enriched rumen microorganisms to anaerobic anode chamber increased cellulose digestibility and increased both CO2 and methane production;however, it decreased the methane to CO2 ratio. Over the experimental period, electricity generation was increased with rumen microorganism addition, and power density normalized to anode surface area was 17.6 to 67.2 mW/m2 with average of 36.0 mW/m2 in treatment, while control group had 3.6 to 21.6 (AVE 12.0) mW/m2. These observations imply that biocatalysis in MFCs requires additional cellulolytic activities to utilize structural biomass in bioenergy production.

不同月龄鲁西黑头羊瘤胃细菌多样性比较分析

瘤胃是反刍动物重要的消化器官,瘤胃微生物的组成及其多样性直接关系到反刍动物对饲料的消化利用。本研究通过测定不同月龄鲁西黑头羊瘤胃液微生物菌群多样性及组成结构,探索瘤胃微生物发育规律,为鲁西黑头羊高效饲养提供理论依据。结果表明:(1)Shannon指数和Simpson指数各组之间无显著性差异,ACE指数和Chao 1指数3月龄显著低于6月龄和12月龄;(2)拟杆菌门(Bacteroidetes)和厚壁菌门(Firmicutes)为优势菌门,普雷沃菌属(Prevotella)为瘤胃优势菌属,但各类群丰度在不同月龄间存在显著差异;(3)PCA分析显示,3月龄鲁西黑头羊瘤胃菌群个体间差异较小,6月龄与12月龄明显分离,表明菌群结构差异较大。综上,鲁西黑头羊瘤胃菌群在3月龄时相对稳定,随着月龄的增长,群落丰富度有所提高,表明3月龄时瘤胃功能仍在发育。

荷斯坦奶牛产犊前后瘤胃发酵参数及微生物区系变化规律的研究

本试验旨在研究奶牛产犊前后瘤胃发酵参数及微生物区系变化规律。选取20头年龄、体况、胎次、预产期及上一胎次泌乳量相近的健康荷斯坦待产奶牛,随机从中选取6头奶牛于产前7 d(-7 d)和产后7 d(+7 d)晨饲前采集瘤胃液,测定奶牛产犊前后瘤胃发酵参数和微生物组成。结果表明:1)奶牛在产后瘤胃液pH较产前极显著降低(P<0.01),瘤胃总挥发性脂肪酸、丙酸浓度较产前极显著增加(P<0.01),乙酸浓度较产前显著增加(P<0.05),瘤胃氨态氮浓度在产犊前后差异不显著(P>0.05),瘤胃微生物蛋白浓度在产后有降低趋势(0.05≤P<0.10)。2)16S rRNA高通量测序结果表明,与产前比较,产后奶牛瘤胃细菌Alpha多样性指数极显著降低(P<0.01)。在门水平上,奶牛产后瘤胃厚壁菌门、Patescibacteria、Kiritimatiellaeota、螺旋体门、纤维杆菌门、疣状菌门、黏胶球形菌门和WPS-2的相对丰度较产前极显著降低(P<0.01),变形菌门和蓝藻门相对丰度较产前极显著增加(P<0.01),放线菌门相对丰度较产前显著增加(P<0.05)。在属水平上,奶牛产后瘤胃普雷沃氏菌属_7、Shuttleworthia相对丰度较产前显著增加(P<0.05),瘤胃球菌属、厌氧弧菌属、理研菌科RC9肠道群、克里斯滕菌科R-7群、真杆菌群属、Candidatus_Saccharimonas、Papillibacter、Saccharofermentans相对丰度较产前极显著降低(P<0.01),欧氏菌属和嗜麦芽窄食单胞菌相对丰度较产前极显著增加(P<0.01)。3)ITS高通量测序结果表明,与产前比较,奶牛产后瘤胃真菌Chao1指数和ACE指数显著增加(P<0.05),香农指数和辛普森指数极显著降低(P<0.01)。在门水平上,奶牛产后被子植物门相对丰度极显著高于产前(P<0.01),子囊菌门和担子菌门相对丰度极显著低于产前(P<0.01),绿藻门相对丰度显著低于产前(P<0.05)。在属水平上,奶牛产后瘤胃棉属相对丰度极显著高于产前(P<0.01),曲霉属、藜属、枝顶孢属和Acremonium相对丰度极显著低于产前(P<0.01),Glycine、Wallemia、Nigrospora、青霉菌属相对丰度显著低于产前(P≤0.05),脱重霉属相对丰度产后有降低趋势(0.05<P<0.10)。由此可知,奶牛产犊前后瘤胃发酵存在显著性差异,且随着奶牛由妊娠末期进入泌乳初期,奶牛瘤胃细菌、真菌的丰富度和多样性均发生明显变化。

饲养方式对苏尼特羊生长性能、屠宰性能、肉品质和瘤胃菌群的影响

旨在研究不同饲养方式(放牧和舍饲)对苏尼特羊生长性能、屠宰性能、肉品质和瘤胃菌群的影响。选取健康的3月龄苏尼特羊24只,平均体重为(20.16±1.56)kg,随机分为2组,每组12只羊。对照组(舍饲组)饲喂基础饲粮,试验组(放牧组)采食天然牧草。预试期7 d,正试期90 d。结果表明:1)舍饲组苏尼特羊终末体重、平均日增重和胸围显著高于放牧组(P<0.05)。2)舍饲组苏尼特羊胴体重、净肉重、屠宰率和肉骨比显著高于放牧组(P<0.05)。3)舍饲组的背最长肌亮度(L*)值、蒸煮损失率和剪切力值显著高于放牧组(P<0.05),背最长肌pH24 h显著低于放牧组(P<0.05)。4)与放牧饲养相比,舍饲组的Shannon指数显著降低(P<0.05),门水平上,舍饲显著提高了瘤胃中拟杆菌门(Bacteroidetes)和变形菌门(Proteobacteria)的相对丰度,显著降低了瘤胃中厚壁菌门(Firmicutes)的相对丰度(P<0.05)。在属水平上,舍饲显著提高了瘤胃中普雷沃氏菌属_1(Prevotella_1)的相对丰度(P<0.05),显著降低了瘤胃中理研菌科_RC9_肠道群属(Rikenellaceae_RC9_gut_group)和丁酸弧菌属(Butyrivibrio_2)的相对丰度(P<0.05)。综上所述,舍饲降低了苏尼特羊的瘤胃菌群多样性,改善了育肥增重效果和屠宰性能,提高了苏尼特羊背最长肌的剪切力和蒸煮损失率,但劣化了羊肉的加工品质和食用口感。

复合菌制剂对芦苇青贮饲料发酵品质和瘤胃发酵特性的影响

本研究旨在探索复合菌制剂(同质乳酸杆菌/异质乳酸杆菌、枯草芽孢杆菌和黑曲霉菌及其配伍)对芦苇青贮饲料营养成分、发酵品质和瘤胃发酵特性的影响。以洞庭湖区生长期的芦苇为青贮原料,设5个组,分别为空白组(CK组)、乳酸菌组(LA组,添加植物乳杆菌、戊糖片球菌和布氏乳杆菌)、乳酸菌+枯草芽孢杆菌组(LA+BS组)、乳酸菌+黑曲霉菌组(LA+AN组)和乳酸菌+枯草芽孢杆菌+黑曲霉菌组(LA+BS+AN组),每组3个重复。乳酸菌添加量均为1.5×10^(8)CFU/kg青贮原料,黑曲霉菌和枯草芽孢杆菌添加量为1.0×10^(8)CFU/kg青贮原料(均以青贮原料鲜重为基础)。青贮60 d后,测定芦苇青贮饲料的营养成分和发酵品质,并通过体外发酵试验和体内降解试验评估其瘤胃发酵特性。结果表明:1)LA组、LA+BS组和LA+AN组干物质和粗灰分含量显著低于CK组(P<0.05),LA+BS组、LA+AN组和LA+BS+AN组粗蛋白质含量显著高于CK组和LA组(P<0.05)。2)各组青贮饲料感官评定得分均在60~70分,评级均为良好;LA+BS组和LA+AN组发酵品质综合得分较高,其中,LA+AN组氨态氮/总氮值、乙酸含量和乙酸/总酸值较CK组显著降低(P<0.05),乳酸含量和乳酸/总酸值较CK组显著提高(P<0.05)。3)LA+AN组体外发酵干物质消失率和总产气量显著高于其他组(P<0.05),发酵液中挥发性脂肪酸含量等体外发酵参数得到改善。4)LA+AN组和LA+BS+AN组8、24和48 h的瘤胃体内发酵干物质降解率显著高于其他3组(P<0.05)。综上所述,在本试验添加量下,乳酸菌和黑曲霉菌联用对芦苇青贮品质以及瘤胃发酵特性改善效果最好。