Oss Daniela B, Ribeiro Gabriel O, Marcondes Marcos I, Yang WenZhu, Beauchemin Karen A, Forster Robert J, McAllister Tim A
Departamento de Zootecnia, Universidade Federal de ViçosaViçosa, Brazil; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Ministério da EducaçãoBrasília, Brazil.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Ministério da EducaçãoBrasília, Brazil; Lethbridge Research and Development Centre, Agriculture and Agri-Food CanadaLethbridge, AB, Canada.
Front Microbiol. 2016 Dec 15;7:2032. doi: 10.3389/fmicb.2016.02032. eCollection 2016.
This study evaluated the effect of increasing the proportion of bison relative to cattle inoculum on fermentation and microbial populations within an artificial rumen (Rusitec). The experiment was a completely randomized design with a factorial treatment structure (proportion cattle:bison inoculum; 0:100, 33:67, 67:33, and 100:0) replicated in two Rusitec apparatuses ( = 8 fermenters). The experiment was 15 d with 8 d of adaptation and 7 d of sampling. Fermenters were fed a diet of 70:30 barley straw:concentrate (DM basis). True digestibility of DM was determined after 48 h of incubation from d 13 to 15, and daily ammonia (NH) and volatile fatty acid (VFA) production were measured on d 9-12. Protozoa counts were determined at d 9, 11, 13, and 15 and particle-associated bacteria (PAB) from d 13 to 15. Select bacterial populations in the PAB were measured using RT-qPCR. Fermenter was considered the experimental unit and day of sampling as a repeated measure. Increasing the proportion of bison inoculum resulted in a quadratic effect ( < 0.05) on straw, concentrate and total true DM disappearance and on straw and total neutral detergent fiber (aNDF) disappearance, with greater disappearances observed with mixed inoculum. There were no effect of source or proportion of inoculum on ADF disappearance ( > 0.05). Increasing bison inoculum linearly increased ( < 0.05) concentrate aNDF disappearance, total and concentrate N disappearance as well as total daily VFA and acetate production. A positive quadratic response ( < 0.05) was observed for daily NH-N, propionate, butyrate, valerate, isovalerate and isobutyrate production, as well as the acetate:propionate ratio. Increasing the proportion of bison inoculum linearly increased ( < 0.05) total protozoa numbers. No effects were observed on pH, total gas and methane production, microbial N synthesis, or copies of 16S rRNA associated with total bacteria, or . Increasing bison inoculum had a quadratic effect ( < 0.05) on , and tended to linearly ( < 0.10) increase and decrease ( < 0.05) copy numbers. In conclusion, bison inoculum increased the degradation of feed protein and fiber. A mixture of cattle and bison rumen inoculum acted synergistically, increasing the DM and aNDF disappearance of barley straw.
本研究评估了在人工瘤胃（Rusitec）中增加野牛接种物相对于牛接种物的比例对发酵和微生物种群的影响。试验采用完全随机设计，具有析因处理结构（牛：野牛接种物比例；0:100、33:67、67:33和100:0），在两个Rusitec装置中重复进行（ = 8个发酵罐）。试验为期15天，其中8天用于适应，7天用于采样。给发酵罐投喂70:30的大麦秸秆:精料日粮（干物质基础）。在第13至15天孵育48小时后测定干物质的真实消化率，并在第9至12天测量每日氨（NH）和挥发性脂肪酸（VFA）的产生量。在第9、11、13和15天测定原生动物数量，在第13至15天测定颗粒相关细菌（PAB）数量。使用RT-qPCR测量PAB中的特定细菌种群。将发酵罐视为实验单位，采样日作为重复测量。增加野牛接种物的比例对秸秆、精料和总干物质真实消失量以及秸秆和总中性洗涤纤维（aNDF）消失量产生二次效应（ < 0.05），混合接种物的消失量更大。接种物的来源或比例对酸性洗涤纤维（ADF）消失量没有影响（ > 0.05）。增加野牛接种物可使精料aNDF消失量、总氮和精料氮消失量以及每日总VFA和乙酸盐产量呈线性增加（ < 0.05）。观察到每日氨态氮、丙酸盐、丁酸盐、戊酸盐、异戊酸盐和异丁酸盐产量以及乙酸盐:丙酸盐比例呈正二次响应（ < 0.05）。增加野牛接种物的比例可使原生动物总数呈线性增加（ < 0.05）。未观察到对pH值、总气体和甲烷产量、微生物氮合成或与总细菌、 或 相关的16S rRNA拷贝数有影响。增加野牛接种物对 有二次效应（ < 0.05），并且倾向于使 呈线性增加（ < 0.10），使 拷贝数呈线性减少（ < 0.05）。总之，野牛接种物增加了饲料蛋白质和纤维的降解。牛和野牛瘤胃接种物的混合物具有协同作用，增加了大麦秸秆的干物质和aNDF消失量。
