摘要
The objective of this study was to examine the effect of humic substances (HS) on rumen fermentation, nutrient digestibility, methane (CH4) emissions, and the rumen microbiome of beef heifers fed a barley silage-based diet. The experiment was designed as a replicated 4 × 4 Latin square using 8 ruminally cannulated Angus × Hereford heifers. Heifers were offered a basal diet consisting of 60% barley silage and 40% concentrate (DM basis) with either 0 (control), 100, 200 or 300 mg granulated HS/kg BW. Each period was 28 d with 14 d of adaptation. Rumen samples were taken on d 15 at 0, 3, 6 and 12 h post feeding. Total urine and feces was collected from d 18 to 22. Blood samples were taken on d 22 at 0 and 6 h post feeding. Between d 26 and 28, heifers were placed in open-circuit respiratory chambers to measure CH4. Ruminal pH was recorded continuously during the periods of CH4 measurement using indwelling pH loggers. Intake was similar (P = 0.47) across treatments. Concentration of ammonia-N and counts of rumen protozoa responded quadratically (P P P P = 0.83); however, HS decreased the relative abundance of Proteobacteria (P = 0.04), and increased the relative abundance of Synergistetes (P = 0.01) and Euryarchaeota (P = 0.04). Results suggest that HS included at up to 300 mg/kg BW may improve N retention and CP digestibility, but there was no impact on CH4 production.
摘要译文
这项研究的目的是检查腐殖质（HS）对瘤胃发酵，营养消化率，甲烷（CH 4）排放以及牛肉小牛的瘤胃微生物组的影响。该实验被设计为复制的4×4拉丁正方形，使用8条液头插管的安格斯×赫里福德小母牛。小母牛的基础饮食由60％大麦青贮饲料和40％浓缩物（DM）组成，其0（对照），100、200或300 mg颗粒状的HS/kg BW。每个周期为28 d，适应14 d。喂食后0、3、6和12小时，在D 15上取出瘤胃样品。从D 18到22收集总尿液和粪便。在喂养后0和6小时，在D 22上采集血液样本。在D 26到28之间，将小母牛放在开路呼吸室中，以测量CH 4。在使用留置pH记录器的CH 4测量期间，连续记录瘤胃pH值。摄入量相似（p = 0.47）。氨-N的浓度和瘤胃原生动物的计数二次反应（p p p = 0.83）；然而，HS降低了蛋白杆菌的相对丰度（P = 0.04），并增加了协同作用（p = 0.01）和Euryarchaeota（p = 0.04）的相对丰度。结果表明，高达300 mg/kg BW的HS可能会提高N保留率和CP的消化率，但对CH 4产量没有影响。
S Terry; G Ribeiro; Jr; R Gruninger; M Hünerberg; P Sheng; A Chaves; K Beauchemin; J Burlet; ; T McAllister. 364 Effect of humic substances on rumen fermentation, nutrient digestibility, methane emissions and rumen microbiota in beef heifers.[J]. Journal of Animal Science, 2018,96(Sup3): 181-182