Department of Animal and Food Sciences, University of Kentucky, Lexington.
Institute of Agricultural Sciences for Southern Vietnam (IASVN), Ho Chi Minh City, Vietnam.
J Anim Sci. 2020 Dec 1;98(12). doi: 10.1093/jas/skaa349.
Experiments were conducted to determine the relative bioavailability (RBV) of the calcium salt of the hydroxy analog of dl-methionine (MHA-Ca, 84%) to dl-methionine (dl-Met, 99%) as Met sources fed to pigs. In experiment 1, 42 crossbred barrows (initial BW of 15.0 ± 0.7 kg) were allotted to 7 treatments in an N-balance study. The basal diet (BD) was formulated to contain 15.4% CP and 0.22% Met (70% of requirement). Diets included (1) BD, (2) BD + 0.025% dl-Met, (3) BD + 0.050% dl-Met, (4) BD + 0.075% dl-Met, (5) BD + 0.038% MHA-Ca, (6) BD + 0.077% MHA-Ca, and (7) BD + 0.115% MHA-Ca. An increase in dietary inclusion rates of both Met sources linearly increased (P < 0.01) N retained (g/d) and N retention (% of intake). Using linear slope-ratio regression, the RBV value of MHA-Ca to dl-Met for N retained (g/d) was 63.0% on a product-to-product basis (75.0% on an equimolar basis). In experiment 2, 40 crossbred barrows (initial BW of 15.5 ± 1.5 kg) were allotted to 5 treatments in another N-balance study. The BD was formulated to contain 17.0% CP and 0.22% Met (70% of requirement). Diets included (1) BD, (2) BD + 0.030% dl-Met, (3) BD + 0.060% dl-Met, (4) BD + 0.046% MHA-Ca, and (5) BD + 0.092% MHA-Ca. Increasing levels of dl-Met or MHA-Ca increased N retained (g/d) and N retention (% of intake) linearly (P < 0.001) and quadratically (P < 0.05). Using linear slope-ratio regression, a product-to-product RBV value of MHA-Ca to dl-Met was 68.4% (81.4% on an equimolar basis) for N retained (g/d). In experiment 3, 276 pigs (12 barrow and 11 gilt replicates; initial BW of 7.09 ± 1.1 kg) were used in 3 diet preference studies. Pigs were randomly allotted to 1 of 3 treatment comparisons of feed choice: (1) BD (0.23% Met) or BD + 0.07% dl-Met; (2) BD or BD + 0.0825% MHA-Ca, and (3) BD + 0.07% dl-Met or BD + 0.0825% MHA-Ca. Pigs consumed a higher percentage (55 vs. 45%; P = 0.008) of their total feed intake from the diet supplemented with 0.07% dl-Met in Comparison 1, but a lower percentage (45 vs. 55%; P = 0.003) of their total feed intake from the diet supplemented with 0.0825% MHA-Ca in Comparison 2. There was no diet preference for dl-Met or MHA-Ca in Comparison 3. The observed Met source preference differences occurred in the barrow replicates but not in the gilt replicates. These results demonstrated the mean RBV of MHA-Ca to dl-Met of 65.7% on a product-to-product (wt/wt) basis or 78.2% on an equimolar basis and that a preference for Met sources was observed in barrows but not in gilts.
实验旨在确定 dl-蛋氨酸（dl-Met，99%）的羟基类似物钙盐（MHA-Ca，84%）作为蛋氨酸来源的相对生物利用率（RBV），并将其与 dl-Met 进行比较。在实验 1 中，将 42 头杂交阉猪（初始体重为 15.0 ± 0.7kg）分配到 7 种处理的氮平衡研究中。基础日粮（BD）的配方含有 15.4%CP 和 0.22%Met（满足 70%的需求）。日粮包括（1）BD，（2）BD+0.025%dl-Met，（3）BD+0.050%dl-Met，（4）BD+0.075%dl-Met，（5）BD+0.038%MHA-Ca，（6）BD+0.077%MHA-Ca，和（7）BD+0.115%MHA-Ca。两种蛋氨酸源的饲粮添加水平线性增加（P<0.01）氮保留（g/d）和氮保留率（摄入的百分比）。使用线性斜率比回归，MHA-Ca 与 dl-Met 相比，用于氮保留（g/d）的 RBV 值为 63.0%（等摩尔基础上为 75.0%）。在实验 2 中，将 40 头杂交阉猪（初始体重为 15.5 ± 1.5kg）分配到另一个氮平衡研究的 5 种处理中。BD 的配方含有 17.0%CP 和 0.22%Met（满足 70%的需求）。日粮包括（1）BD，（2）BD+0.030%dl-Met，（3）BD+0.060%dl-Met，（4）BD+0.046%MHA-Ca，和（5）BD+0.092%MHA-Ca。dl-Met 或 MHA-Ca 水平的增加线性（P<0.001）和二次（P<0.05）增加氮保留（g/d）和氮保留率（摄入的百分比）。使用线性斜率比回归，MHA-Ca 与 dl-Met 相比，用于氮保留（g/d）的 RBV 值为 68.4%（等摩尔基础上为 81.4%）。在实验 3 中，在 3 种饲料偏好研究中使用了 276 头猪（12 头阉猪和 11 头母猪重复；初始体重为 7.09 ± 1.1kg）。将猪随机分配到饲料选择的 3 种处理比较之一：（1）BD（0.23%Met）或 BD+0.07%dl-Met；（2）BD 或 BD+0.0825%MHA-Ca，和（3）BD+0.07%dl-Met 或 BD+0.0825%MHA-Ca。在比较 1 中，添加 0.07%dl-Met 的日粮的猪消耗了其总采食量的更高百分比（55%比 45%；P=0.008），而在比较 2 中，添加 0.0825%MHA-Ca 的日粮的猪消耗了其总采食量的更低百分比（45%比 55%；P=0.003）。在比较 3 中，猪对 dl-Met 或 MHA-Ca 没有饲料偏好。在阉猪重复中观察到的蛋氨酸源偏好差异，但在母猪重复中没有观察到。这些结果表明，MHA-Ca 与 dl-Met 的平均 RBV 为 65.7%（产品对产品（wt/wt）基础）或 78.2%（等摩尔基础），并且在阉猪中观察到了蛋氨酸源的偏好，但在母猪中没有观察到。
