Department of Animal Science, Iowa State University, Ames, IA.
J Anim Sci. 2018 Sep 7;96(9):3906-3915. doi: 10.1093/jas/sky247.
Thirty-six newly weaned, crossbred beef steers (323 ± 12 kg; SD) from a single-source were used in a 56-d study to examine the effects of a Saccharomyces cerevisiae fermentation product (SCFP; Original XPC, Diamond V, Cedar Rapids, IA) on total tract nutrient digestibility and response to a vaccination challenge. Twelve days after arrival, steers were blocked by body weight (BW) and randomly assigned to treatments: SCFP at 0 (CON), 14 (SCFP14), or 28 (SCFP28) g·steer-1·d-1. Steers were fed via bunks that measured individual intake and received ear tags (CowManager, Select Sires, Plain City, OH) that recorded rumination and activity. BWs were collected on days 1, 0, 14, 28, 42, 55, and 56. Titanium dioxide was fed as an indigestible marker to all steers from days 12 to 27, followed by consecutive day fecal samples, for determination of total tract nutrient digestibility. On day 34, steers received a Mannheimia haemolytica vaccination (One Shot, Zoetis, Kalamazoo, MI) to induce an acute phase protein response. Blood was collected from all steers on day 34 (prior to vaccination) and 3, 6, 9, 11, and 14 d post-vaccination. Data were analyzed using Proc Mixed of SAS (experimental unit = steer; n = 12 per treatment); the model included the fixed effect of treatment and block and the random effect of steer. Blood measures, ear tag, and dry matter intake (DMI) data for the 15-d vaccination period were analyzed as repeated measures. Contrast statements (CON vs. SCFP14; SCFP14 vs. SCFP28) were used to compare treatment means. Digestibility of dry matter (DM) and organic matter was greater for SCFP14 vs. SCFP28 (P ≤ 0.03). Steers fed SCFP14 exhibited greater crude protein digestibility compared with CON (P < 0.01). Steers fed SCFP14 exhibited greater DMI for 15 d post-vaccination (P = 0.02) and greater average daily gain from days 28 to 56 (P = 0.05) vs. SCFP28-fed steers. Post-vaccination, steers fed SCFP14 spent less time ruminating per kg of DM, neutral detergent fiber (NDF), and physically effective NDF consumed than CON or SCFP28 (P ≤ 0.07). Serum IL-8 and haptoglobin concentrations tended to be lesser for steers fed SCFP14 vs. SCFP28 (P ≤ 0.08). Ceruloplasmin concentrations were lesser on day 14 post-vaccination for steers fed SCFP14 vs. CON or SCFP28 (treatment × d; P = 0.004); there were no differences on other sampling days due to treatment. Although no overall performance benefit was noted, steers fed SCFP14 responded better to a vaccination challenge vs. SCFP28-fed steers.
三十六头新断奶的杂交肉牛（323±12kg；SD）来自单一来源，在 56 天的研究中，研究了酿酒酵母发酵产物（SCFP；Original XPC，Diamond V，Cedar Rapids，IA）对总肠道养分消化率和疫苗接种反应的影响。到达后 12 天，根据体重（BW）将牛分组，并随机分配到以下处理组：无 SCFP（CON）、添加 14g SCFP（SCFP14）或 28g SCFP（SCFP28）/头/天。牛通过料槽进食，单独记录采食量，并佩戴记录反刍和活动的耳标（CowManager，Select Sires，Plain City，OH）。BW 在第 1、0、14、28、42、55 和 56 天采集。从第 12 天到第 27 天，向所有牛饲喂二氧化钛作为不可消化标记物，然后连续采集粪便样本来确定总肠道养分消化率。在第 34 天，所有牛接受 Mannheimia haemolytica 疫苗接种（One Shot，Zoetis，Kalamazoo，MI）以诱导急性期蛋白反应。所有牛在第 34 天（疫苗接种前）和第 3、6、9、11 和 14 天采血。使用 SAS 的 Proc Mixed 分析数据（实验单位=牛；每个处理组 12 头）；模型包括处理和分组的固定效应和牛的随机效应。疫苗接种期 15 天的血液测量、耳标和干物质采食量（DMI）数据作为重复测量进行分析。使用对照语句（CON 与 SCFP14；SCFP14 与 SCFP28）比较处理均值。与 SCFP28 相比，SCFP14 组的干物质（DM）和有机物消化率更高（P≤0.03）。与 CON 相比，添加 SCFP14 的牛表现出更高的粗蛋白消化率（P＜0.01）。与 SCFP28 相比，添加 SCFP14 的牛在疫苗接种后 15 天表现出更高的 DMI（P=0.02）和从第 28 天到第 56 天更高的平均日增重（P=0.05）。与 SCFP28 相比，接种疫苗后添加 SCFP14 的牛每公斤 DM、中性洗涤纤维（NDF）和物理有效 NDF 的反刍时间更少（P≤0.07）。添加 SCFP14 的牛血清 IL-8 和触珠蛋白浓度往往低于 SCFP28（P≤0.08）。接种疫苗后 14 天，添加 SCFP14 的牛的铜蓝蛋白浓度低于 CON 或 SCFP28（处理×天；P=0.004）；由于处理没有差异，在其他采样日没有差异。尽管没有观察到整体性能的好处，但与 SCFP28 相比，添加 SCFP14 的牛对疫苗接种挑战的反应更好。
