The study aimed to determine the effects of a postbiotic feeding program consisting of liquid and dry Saccharomyces cerevisiae fermentation product (SCFP) on ruminal fermentation, digestibility, and plasma metabolome of Holstein steers receiving a grain-based diet. Eight Holstein steers (Body weight; BW 467 ± 13.9 kg) equipped with rumen cannulas were used in a crossover design study, with 21 d per period and a 7 d washout period in between periods. Steers were stratified by initial BW and assigned to one of two treatments. The treatments were (1) Control, basal finishing diet only (CON); (2) SCFP, one-day feeding of liquid SCFP (infused into the rumen via the cannula at 11 mL/100 kg BW) followed by daily feeding of dry SCFP (12 g/d, top-dressed). Feed and spot fecal samples were collected during d 17 to 20 for determination of digestibility and fecal excretion of N, P, Cu, and Zn. Digestibility was measured using acid-insoluble ash as an internal marker. Blood samples were collected on d 21 before the morning feeding. Rumen fluid samples were collected on d 0, 1, 2, 3, 5 and 21 via rumen cannula. Results were analyzed with the GLIMMIX procedure of SAS 9.4 (SAS, 2023). Treatment did not affect DMI (P = 0.15) and digestibility (P ≥ 0.62). The fecal output and absorption of Zn, Cu, P, and N were not affected (P > 0.22) by treatment. On d 1, the liquid SCFP supplementation tended to reduce (P = 0.07) ruminal VFA concentration and increased (P < 0.01) the molar proportion of valerate. Feeding SCFP tended to increase total ruminal VFA on d 5 (P = 0.08) and significantly increased total VFA on d 21 (P = 0.05). Ruminal NH3-N was reduced (P = 0.02) on d 21 by supplementing SCFP. Treatment did not affect the production of proinflammatory cytokines, IL-1β (P > 0.19) and IL-6 (P > 0.12) in the whole blood in response to various toll-like receptor stimulants in vitro. Feeding SCFP enriched (P ≤ 0.05) plasma metabolic pathways, including citric acid cycle, pyrimidine metabolism, glycolysis/gluconeogenesis, retinol metabolism, and inositol phosphate metabolism pathways. In summary, supplementing liquid SCFP with subsequent dry SCFP enhanced ruminal total VFA production and reduced NH3-N concentration nitrogen in the rumen. Furthermore, feeding SCFP enriched several important pathways in lipid, protein, and glucose metabolism, which may improve feed efficiency of energy and protein in Holstein steers.

中文翻译：

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液体和干酿酒酵母发酵产品 (SCFP) 饲喂计划对接受谷物饮食的荷斯坦阉牛瘤胃发酵、总消化道消化率和血浆代谢组的影响


该研究旨在确定由液体和干燥酿酒酵母发酵产品 (SCFP) 组成的后生元喂养计划对接受谷物饮食的荷斯坦阉牛的瘤胃发酵、消化率和血浆代谢组的影响。交叉设计研究中使用了 8 头配备瘤胃插管的荷斯坦公牛（体重；体重；BW 467 ± 13.9 kg），每个周期 21 天，周期之间有 7 天的冲洗期。根据初始体重对公牛进行分层，并分配至两种处理中的一种。治疗方法为（1）对照，仅基础育肥饮食（CON）； (2) SCFP，一日饲喂液体 SCFP（通过插管以 11 mL/100 kg BW 注入瘤胃），随后每日饲喂干 SCFP（12 g/d，追肥）。在第 17 至 20 天期间收集饲料和斑点粪便样本，用于测定 N、P、Cu 和 Zn 的消化率和粪便排泄量。使用酸不溶性灰分作为内部标记来测量消化率。第 21 天早上喂食前采集血样。在第0、1、2、3、5和21天通过瘤胃插管收集瘤胃液样品。使用 SAS 9.4 (SAS, 2023) 的 GLIMMIX 程序分析结果。治疗不影响 DMI (P = 0.15) 和消化率 (P ≥ 0.62)。 Zn、Cu、P 和 N 的粪便排出量和吸收未受处理影响 (P > 0.22)。第 1 天，补充液体 SCFP 会降低 (P = 0.07) 瘤胃 VFA 浓度，并增加 (P < 0.01) 戊酸摩尔比例。饲喂 SCFP 往往会增加第 5 天的瘤胃总 VFA（P = 0.08），并显着增加第 21 天的总 VFA（P = 0.05）。通过补充 SCFP，第 21 天瘤胃 NH3-N 减少 (P = 0.02)。治疗不影响促炎细胞因子 IL-1β 的产生（P > 0.19) 和 IL-6 (P > 0.12) 在体外对各种 Toll 样受体兴奋剂的反应。饲喂 SCFP 富集（P ≤ 0.05）血浆代谢途径，包括柠檬酸循环、嘧啶代谢、糖酵解/糖异生、视黄醇代谢和磷酸肌醇代谢途径。总之，补充液体 SCFP 和随后的干燥 SCFP 提高了瘤胃总 VFA 产量并降低了瘤胃中 NH3-N 氮浓度。此外，饲喂 SCFP 丰富了脂质、蛋白质和葡萄糖代谢的几个重要途径，这可能会提高荷斯坦阉牛的能量和蛋白质的饲料效率。