Department of Animal Sciences, Purdue University, West Lafayette, IN.
Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN.
J Anim Sci. 2021 Jan 1;99(1). doi: 10.1093/jas/skaa385.
Energy values and amino acid (AA) digestibility of dried yeast (DY) and soybean meal (SBM) were determined in 2 experiments with growing pigs. Experiment 1 was conducted to determine the digestible energy (DE) and metabolizable energy (ME) in DY and SBM. Thirty barrows with a mean initial body weight (BW) of 20.6 kg (SD = 1.04) were assigned to 5 dietary treatments in a randomized complete block design with period and BW as blocking factors. A reference diet was prepared with corn, canola meal, and soybean oil as energy-contributing ingredients. Four additional diets were prepared by adding 5% and 10% DY or SBM at the expense of energy-contributing ingredients in the reference diet. The ratio of corn, canola meal, and soybean oil was kept consistent across the experimental diets. Each experimental period consisted of 5-d adaptation and 5-d quantitative collection of feces and urine. Test ingredient-associated DE or ME intake (kcal/d) was regressed against test ingredient intake [kg dry matter (DM)/d] to estimate the DE or ME in test ingredients as the slope of linear regression model. The DE in DY was estimated at 3,933 kcal/kg DM, which was not different from the estimated DE in SBM at 4,020 kcal/kg DM. Similarly, there was no difference between DY and SBM in the estimated ME (3,431 and 3,756 kcal/kg DM, respectively). Experiment 2 was conducted to determine the standardized ileal digestibility (SID) of AA in DY and SBM. Twenty-one barrows with a mean initial BW of 20.0 kg (SD = 1.31) were surgically fitted with T-cannulas at the distal ileum and assigned to 3 dietary treatments in a randomized complete block design with BW as a blocking factor. Two semi-purified diets containing DY or SBM as the sole nitrogen source and one nitrogen-free diet (NFD) were prepared. The NFD was used to estimate the basal ileal endogenous losses of CP and AA. Pigs were fed the 3 diets for 5 d as adaptation, followed by 2 d of feeding with ileal digesta collection. The SID of AA, except Gly and Pro, in DY was less (P < 0.05) than in SBM. The SID of indispensable AA in DY ranged from 64.1% for Thr to 85.2% for Arg, and those in SBM ranged from 83.9% for Thr to 91.8% for Arg. In conclusion, energy values of DY are not different from those of SBM, whereas AA in DY is less digestible than in SBM. The estimated DE and ME as well as the SID of AA in DY and SBM can be used in diet formulation for growing pigs using these ingredients.
本实验旨在确定干酵母（DY）和豆粕（SBM）的能量值和氨基酸（AA）消化率。选用 20.6kg 平均初始体重（BW）的 30 头生长猪，采用完全随机分组设计，以时间和 BW 为分组因素，分为 5 种日粮处理。基础日粮由玉米、菜粕和大豆油作为能量来源，4 种试验日粮是在基础日粮的基础上分别添加 5%和 10%的 DY 或 SBM。各试验日粮的玉米、菜粕和大豆油比例保持一致。每个试验期包括 5d 的适应期和 5d 的粪便和尿液定量收集。通过回归测试成分相关的 DE 或 ME 摄入量（kcal/d）与测试成分摄入量[kg 干物质（DM）/d]，以线性回归模型的斜率估计测试成分的 DE 或 ME。估计 DY 的 DE 为 3933kcal/kg DM，与 SBM 的 DE（4020kcal/kg DM）没有差异。同样，在 ME 方面，DY 和 SBM 之间也没有差异（分别为 3431 和 3756kcal/kg DM）。试验 2 旨在确定 DY 和 SBM 的 AA 标准回肠消化率（SID）。选用 21 头平均初始 BW 为 20.0kg（SD=1.31）的生长猪，在回肠末端安装 T 型瘘管，采用 BW 为分组因素的完全随机分组设计，分为 3 种日粮处理。2 种含有 DY 或 SBM 作为唯一氮源的半纯化日粮和 1 种无氮日粮（NFD）。NFD 用于估计 CP 和 AA 的基础回肠内源性损失。猪先适应 3 种日粮 5d，然后进行 2d 的回肠消化产物收集。除 Gly 和 Pro 外，DY 的 AA SID 均低于 SBM（P<0.05）。在 DY 中，必需 AA 的 SID 范围为 Thr 的 64.1%到 Arg 的 85.2%，在 SBM 中，其范围为 Thr 的 83.9%到 Arg 的 91.8%。总之，DY 的能量值与 SBM 没有差异，而 DY 的 AA 消化率低于 SBM。使用这些原料时，DY 和 SBM 的 DE 和 ME 估计值以及 AA 的 SID 可用于生长猪的日粮配方。
