Felix T L, Long C J, Metzger S A, Daniels K M
Department of Animal Sciences, University of Illinois, Urbana 61801
Department of Animal Sciences, The Ohio State University, Wooster 44691.
J Anim Sci. 2014 Jun;92(6):2503-10. doi: 10.2527/jas.2013-7156. Epub 2014 Mar 26.
The objective of these experiments was to determine adaptation by ruminants to dietary sulfur. In Exp. 1, lambs (n = 54; BW = 33.6 ± 0.4 kg) were allotted to 3 treatments: 1) 0% added dietary S (0%S), 2) 0.2% added dietary S (0.2%S), or 3) 0.4% added dietary S (0.4%S). Sulfur was added to the diet as Na(2)SO(4). Lambs fed the 0.2%S and 0.4%S diets had greater (P < 0.01) ADG and G:F compared to those fed the 0%S diet. There was time × diet interaction (P < 0.01) on ruminal hydrogen sulfide gas (H(2)S) concentrations. Ruminal H(2)S was not detected in lambs fed 0%S at any time. Ruminal H2S were not affected (P > 0.19) by diet on d 1 or 8; however, H(2)S were greater (P < 0.01) for lambs fed 0.2%S and 0.4%S than for lambs fed 0%S on d 15, 22, and 29 (0.2% was 931, 846, and 1,131 mg/L and 0.4% was 975, 737, and 1,495 mg/L on d 15, 22, and 29, respectively). These data suggest it takes at least 29 d for peak ruminal H(2)S to occur after exposure to Na(2)SO(4). In Exp. 2, lambs (n = 66; BW = 51.1 ± 0.4 kg) were allotted to 3 treatments: 1) 60% dried distillers grains with solubles (DDGS), 2) corn-based diet with Na(2)SO(4), or 3) corn-based diet with H(2)SO(4). All diets were formulated to contain 0.4%S. Lambs fed Na(2)SO(4) had greater (P < 0.05) ADG, DMI, and G:F than those fed H(2)SO(4) or 60% DDGS. A time × diet interaction occurred (P < 0.01) for ruminal H(2)S. There was no difference (P = 0.82) in H(2)S of lambs on d 1. However, at d 14 and 27 lambs fed supplemental Na(2)SO(4) had the lowest H(2)S concentrations while lambs fed 60% DDGS had the greatest (P < 0.01 on both d); lambs fed H(2)SO(4) were intermediate and different than both. These data suggest that at the same dietary S concentration, acidic S sources increased H(2)S and decreased DMI and ADG. In Exp. 3, Angus cross calves (n = 72; average initial BW = 324 ± 3 kg) were allotted to 3 treatments: 1) corn-based control d 0 through 85 (0%DDGS), 2) gradual step up to 60% DDGS diet (20% DDGS d 0 to 6, 40% DDGS d 7 to 13, 50% DDGS d 14 to 20, and 60% DDGS d 21 to 85; Step-up), or 3) 60% DDGS d 0 to 85 (60%DDGS). Overall, cattle fed 0%DDGS had increased (P < 0.05) DMI and ADG compared with those fed 60%DDGS or Step-up, and G:F was not affected (P = 0.42) by dietary treatment. On d 14, ruminal H(2)S concentrations were greater (P < 0.01) for cattle fed 60%DDGS and Step-up than for those fed 0%DDGS, and they did not differ (P ≥ 0.22) between DDGS-containing diets. These data illustrate that source of S impacts ruminal S metabolism and that S from DDGS is more readily reduced than S from Na(2)SO(4) or H(2)SO(4).
这些实验的目的是确定反刍动物对日粮硫的适应性。在实验1中，将羔羊（n = 54；体重 = 33.6 ± 0.4千克）分配到3种处理中：1）日粮中添加0%的硫（0%S），2）日粮中添加0.2%的硫（0.2%S），或3）日粮中添加0.4%的硫（0.4%S）。硫以Na₂SO₄的形式添加到日粮中。与饲喂0%S日粮的羔羊相比，饲喂0.2%S和0.4%S日粮的羔羊具有更高（P < 0.01）的平均日增重（ADG）和料重比（G:F）。瘤胃硫化氢气体（H₂S）浓度存在时间×日粮交互作用（P < 0.01）。在任何时间，饲喂0%S的羔羊瘤胃中均未检测到H₂S。在第1天和第8天，日粮对瘤胃H₂S没有影响（P > 0.19）；然而，在第15天、22天和29天，饲喂0.2%S和0.4%S的羔羊的H₂S含量高于饲喂0%S的羔羊（第15天、22天和29天，0.2%S组分别为931、846和1131毫克/升，0.4%S组分别为975、737和1495毫克/升）。这些数据表明，暴露于Na₂SO₄后，瘤胃H₂S峰值至少需要29天才能出现。在实验2中，将羔羊（n = 66；体重 = 51.1 ± 0.4千克）分配到3种处理中：1）60%干酒糟及其可溶物（DDGS），2）添加Na₂SO₄的玉米型日粮，或3）添加H₂SO₄的玉米型日粮。所有日粮均配制为含0.4%的硫。与饲喂H₂SO₄或60%DDGS的羔羊相比，饲喂Na₂SO₄的羔羊具有更高（P < 0.05）的ADG、干物质采食量（DMI）和G:F。瘤胃H₂S存在时间×日粮交互作用（P < 0.01）。第1天羔羊的H₂S含量没有差异（P = 0.82）。然而，在第14天和27天，饲喂补充Na₂SO₄的羔羊的H₂S浓度最低，而饲喂60%DDGS的羔羊的H₂S浓度最高（两天均P < 0.01）；饲喂H₂SO₄的羔羊处于中间水平，且与两者均不同。这些数据表明，在相同日粮硫浓度下，酸性硫源会增加H₂S含量，并降低DMI和ADG。在实验3中，将安格斯杂交犊牛（n = 72；初始平均体重 = 324 ± 3千克）分配到3种处理中：1）从第0天到85天的玉米型对照日粮（0%DDGS），2）逐步增加到60%DDGS的日粮（第0天至6天为20%DDGS，第7天至13天为40%DDGS，第14天至20天为50%DDGS，第21天至85天为60%DDGS；逐步增加组），或3）第0天到85天的60%DDGS日粮（60%DDGS组）。总体而言，与饲喂60%DDGS或逐步增加组的犊牛相比，饲喂0%DDGS的犊牛的DMI和ADG有所增加（P < 0.05），日粮处理对G:F没有影响（P = 0.42）。在第14天，饲喂60%DDGS和逐步增加组的犊牛的瘤胃H₂S浓度高于饲喂0%DDGS的犊牛（P < 0.01），且含DDGS的日粮之间没有差异（P ≥ 0.22）。这些数据表明，硫的来源会影响瘤胃硫代谢，并且来自DDGS的硫比来自Na₂SO₄或H₂SO₄的硫更容易被还原。
