Wageningen Livestock Research, Wageningen, The Netherlands.
Topigs Norsvin Research Center B.V., Beuningen, The Netherlands.
J Anim Sci. 2021 Jun 1;99(6). doi: 10.1093/jas/skab101.
The effects of birth weight (BiW; low BiW [LBW] vs. high BiW [HBW]) and estimated breeding value (EBV) for protein deposition (low EBV [LBV] vs. high EBV [HBV]) on N retention, N efficiency, and concentrations of metabolites in plasma and urine related to N efficiency in growing pigs were studied. At an age of 14 wk, 10 LBW-LBV (BiW: 1.07 ± 0.09 [SD] kg; EBV: -2.52 ± 3.97 g/d, compared with an average crossbred pig with a protein deposition of 165 g/d), 10 LBW-HBV (BiW: 1.02 ± 0.13 kg; EBV: 10.47 ± 4.26 g/d), 10 HBW-LBV (BiW: 1.80 ± 0.13 kg; EBV: -2.15 ± 2.28 g/d), and 10 HBW-HBV (BiW: 1.80 ± 0.15 kg; EBV: 11.18 ± 3.68 g/d) male growing pigs were allotted to the experiment. The pigs were individually housed in metabolism cages and were subjected to an N balance study in two sequential periods of 5 d, after an 11-d dietary adaptation period. Pigs were assigned to a protein adequate (A) or protein restricted (R, 70% of A) regime in a change-over design. Pigs were fed 2.8 times the energy requirements for maintenance. Nontargeted metabolomics analyses were performed in urine and blood plasma samples. The N retention (in g/d) was higher in the HBW than in the LBW pigs (P < 0.001). The N retention (in g/[kg metabolic body weight (BW0.75) · d]) and N efficiency, however, were not affected by the BiW of the pigs. The N retention (P = 0.04) and N efficiency (P = 0.04) were higher in HBV than in LVB pigs on the A regime but were not affected by EBV in pigs on the R regime. Restricting the dietary protein supply with 30% decreased the N retention (P < 0.001) but increased the N efficiency (P = 0.003). Nontargeted metabolomics showed that a hexose, free amino acids (AA), and lysophosphatidylcholines were the most important metabolites in plasma for the discrimination between HBV and LBV pigs, whereas metabolites of microbial origin contributed to the discrimination between HBV and LBV pigs in urine. This study shows that BiW does not affect N efficiency in the later life of pigs. Nitrogen efficiency and N retention were higher in HBV than in LBV pigs on the A regime but similar in HBV and LBV pigs on the R regime. In precision feeding concepts aiming to further optimize protein and AA efficiency in pigs, the variation in EBV for protein deposition of pigs should be considered as a factor determining N retention, growth performance, and N efficiency.
本研究旨在探讨初生重（BiW；低 BW [LBW] 与高 BW [HBW]）和蛋白质沉积的估计育种值（EBV；低 EBV [LBV] 与高 EBV [HBV]）对生长猪氮保留、氮效率以及与氮效率相关的血浆和尿液代谢物浓度的影响。在 14 周龄时，将 10 头 LBW-LBV（BW：1.07 ± 0.09 [SD] kg；EBV：-2.52 ± 3.97 g/d，与平均杂交猪的蛋白质沉积量 165 g/d 相比）、10 头 LBW-HBV（BW：1.02 ± 0.13 kg；EBV：10.47 ± 4.26 g/d）、10 头 HBW-LBV（BW：1.80 ± 0.13 kg；EBV：-2.15 ± 2.28 g/d）和 10 头 HBW-HBV（BW：1.80 ± 0.15 kg；EBV：11.18 ± 3.68 g/d）雄性生长猪分配到实验中。这些猪单独饲养在代谢笼中，并在 11 天的适应期后，进行了两次为期 5 天的氮平衡研究。采用转换设计，猪被分配到蛋白质充足（A）或蛋白质限制（R，A 的 70%）的方案中。猪的能量需求被喂食 2.8 倍以维持生命。在尿液和血浆样本中进行了非靶向代谢组学分析。HBW 猪的氮保留量（g/d）高于 LBW 猪（P < 0.001）。然而，猪的 BW0.75 的代谢体重）·d）和氮效率不受 BW 的影响。在 A 方案中，HBV 猪的氮保留量（P = 0.04）和氮效率（P = 0.04）高于 LBV 猪，但在 R 方案中，EBV 对猪的氮保留量和氮效率没有影响。用 30%的日粮蛋白质减少氮保留量（P < 0.001），但增加氮效率（P = 0.003）。非靶向代谢组学显示，在区分 HBV 和 LBV 猪时，血浆中最重要的代谢物是己糖、游离氨基酸（AA）和溶血磷脂酰胆碱，而尿液中微生物来源的代谢物有助于区分 HBV 和 LBV 猪。本研究表明，BW 不影响猪后期的氮效率。在 A 方案中，HBV 猪的氮效率和氮保留量高于 LBV 猪，但在 R 方案中，HBV 猪和 LBV 猪的氮效率相似。在旨在进一步优化猪的蛋白质和 AA 效率的精准饲养概念中，应考虑猪的蛋白质沉积 EBV 作为决定氮保留、生长性能和氮效率的因素。
