Pogge D J, Drewnoski M E, Snider D, Rumbeiha W K, Hansen S L
J Anim Sci. 2016 Sep;94(9):3894-3901. doi: 10.2527/jas.2016-0657.
Angus-cross steers ( = 128) were used to examine the effects of supplementing ferric ammonium citrate (FAC; 300 mg ferric Fe/kg DM) to diets of 20, 40, or 60% dried distillers' grains plus solubles (DDGS) on growth performance, liver mineral and ruminal hydrogen sulfide (HS) concentrations, and carcass traits of finishing steers. Steers were blocked by initial BW (436 ± 10.6 kg) into pens of 4 and randomly assigned to 1 of 6 treatments ( = 5 or 6 pens per treatment) including a 20, 40, or 60% DDGS inclusion diet with (+) or without (-) 300 mg Fe/kg DM from FAC. Liver biopsies (d -9/-10 and 96) and HS measures (d 0, 7, 14, 21, and 95) were determined from 1 steer/pen. Steers were harvested on d 102 and carcass data were collected. A treatment × month effect ( ≤ 0.006) was noted for ADG and G:F, in which the 20-FAC ADG and feed efficiency were greater ( ≤ 0.02) between d 0 to 28 but lesser ( ≤ 0.04) from d 29 to 56 than that of the 20+FAC steers. Final BW linearly decreased ( < 0.01) as DDGS inclusion increased. Final BW tended to be greater ( = 0.10) in the 60+FAC steers than in the 60-FAC steers, whereas final BW was not different ( ≥ 0.32) due to FAC supplementation in the 20 or 40% DDGS diets. A quadratic effect was noted for DMI ( = 0.02), where 60% DDGS decreased DMI. Within the 20% DDGS diet FAC+ improved DMI ( = 0.03) but had no effect within 40 or 60% DDGS inclusion. Ruminal HS concentrations were not affected ( ≥ 0.25) by FAC, but increasing DDGS linearly increased ( < 0.01) ruminal HS values. Liver Cu was decreased ( < 0.01) by FAC across all DDGS inclusions and tended to linearly decrease ( = 0.06) with increasing DDGS inclusion, whereas liver Fe, Mn, and Zn were not altered ( ≥ 0.11) by DDGS inclusion. Liver Zn concentrations tended to be ( = 0.08) or were ( = 0.03) decreased by FAC supplementation within 20 and 40% DDGS, respectively. Increasing the inclusion of DDGS linearly decreased ( = 0.04) HCW and quadratically affected marbling score where the 40% DDGS had the greatest ( = 0.02) marbling scores. Supplementation of FAC within 60% DDGS improved ( ≤ 0.03) HCW and LM area. Marbling scores were greater ( ≤ 0.04) in 20+FAC and 40+FAC compared with 20-FAC and 40-FAC, respectively. In conclusion, although ruminal HS concentrations were not affected by FAC under the conditions of this study, supplementing FAC to diets containing 60% DDGS improved HCW and LM area, suggesting that FAC may be beneficial when dietary S concentrations exceed 0.5%.
安格斯杂交阉牛（n = 128）用于研究在含20%、40%或60%干酒糟及其可溶物（DDGS）的日粮中添加柠檬酸铁铵（FAC；300毫克铁/千克干物质）对育肥牛生长性能、肝脏矿物质和瘤胃硫化氢（HS）浓度以及胴体性状的影响。阉牛按初始体重（436±10.6千克）进行分组，每组4头，随机分配到6种处理中的1种（每种处理5或6组），包括含20%、40%或60% DDGS且添加（+）或不添加（-）300毫克/千克干物质FAC的日粮。从每组1头阉牛采集肝脏活检样本（第 -9/-10天和第96天）和进行HS测定（第0、7、14、21和95天）。阉牛在第102天屠宰并收集胴体数据。在平均日增重（ADG）和料重比（G:F）方面观察到处理×月份效应（P≤0.006），其中在第0至28天，20% DDGS添加FAC组的ADG和饲料效率更高（P≤0.02），但在第29至56天比20% DDGS未添加FAC组更低（P≤0.04）。随着DDGS添加量增加，末重呈线性下降（P<0.01）。60% DDGS添加FAC组的末重倾向于高于（P = 0.10）60% DDGS未添加FAC组，而在20%或40% DDGS日粮中添加FAC对末重无差异（P≥0.32）。在干物质采食量（DMI）方面观察到二次效应（P = 0.02），即60% DDGS降低了DMI。在20% DDGS日粮中添加FAC提高了DMI（P = 0.03），但在40%或60% DDGS添加量时无影响。瘤胃HS浓度不受FAC影响（P≥0.25），但随着DDGS添加量增加，瘤胃HS值呈线性增加（P< 0.01）。在所有DDGS添加水平下，FAC均降低了肝脏铜含量（P<0.01），且随着DDGS添加量增加有线性降低趋势（P = 0.06），而DDGS添加对肝脏铁、锰和锌含量无影响（P≥0.11）。在20%和40% DDGS日粮中添加FAC分别使肝脏锌浓度有降低趋势（P = 0.08）或显著降低（P = 0.03）。随着DDGS添加量增加，热胴体重（HCW）呈线性下降（P = 0.04），大理石花纹评分呈二次效应，其中40% DDGS组的大理石花纹评分最高（P = 0.02）。在60% DDGS日粮中添加FAC提高了（P≤0.03）HCW和腰大肌面积。与20% DDGS未添加FAC组和40% DDGS未添加FAC组相比，20% DDGS添加FAC组和40% DDGS添加FAC组的大理石花纹评分更高（P≤0.04）。总之，尽管在本研究条件下瘤胃HS浓度不受FAC影响，但在含60% DDGS的日粮中添加FAC提高了HCW和腰大肌面积，表明当日粮硫浓度超过0.5%时，FAC可能有益。
