Department of Animal Science, Faculty of Science and Technology, Aarhus University, DK-8830 Tjele, Denmark.
J Anim Sci. 2013 Feb;91(2):772-82. doi: 10.2527/jas.2012-5635. Epub 2012 Nov 12.
Two experiments were conducted with the aim of studying how dietary fat source, reproductive stage (Exp. 1), and diurnal variation (Exp. 2) affect plasma ketone bodies in sows. In Exp. 1, 40 second-parity sows were fed 1 of 5 lactation diets from 7 d prepartum until 28 d postpartum, with low or high levels (3% or 8%) of dietary fats with different proportions of medium- and long-chain fatty acids. Blood was obtained by jugular venipuncture on d 3 and 7 prepartum, and d 1, 10, 17, and 28 postpartum, and concentrations of plasma beta-hydroxy butyric acid (BHBA), acetoacetate + acetone (AcAc+Ac), glucose, NEFA, lactate, acetate, and butyrate were determined. For 4 out of 5 treatments, plasma BHBA decreased slightly, whereas plasma AcAc+Ac remained stable. However, plasma BHBA (P < 0.01) and AcAc+Ac (P < 0.001) doubled after d 10 of lactation in sows fed 4% octanoic acid and 4% fish oil diet (4+4% FO; P < 0.001), compared with earlier in lactation (P < 0.001). Plasma AcAc+Ac was positively related to BHBA (P < 0.01), glucose (P < 0.05), and butyrate (P < 0.001), and negatively related to the acetate:butyrate ratio (P < 0.001). In addition, plasma BHBA was positively related to lactate (P < 0.01), acetate, and butyrate (P < 0.05). In Exp. 2, diurnal variations of plasma metabolites were studied in 5 sows sampled every second hour from a jugular catheter throughout a 24-h period on d 5 and 17 of lactation and analyzed as in Exp. 1. In addition, milk and urine samples were collected and analyzed for BHBA and AcAc+Ac. No diurnal variations in plasma BHBA or AcAc+Ac were observed and plasma AcAc+Ac was unchanged from d 5 to 17 of lactation (3.7 μM), whereas BHBA declined from 58 μM on d 5 of lactation to 52 μM on d 17 of lactation (P < 0.05). Minor amounts of AcAc+Ac were found in urine (8.6 μM) and this was not affected by days in milk, whereas the content of AcAc+Ac in milk and BHBA in milk and urine were less than the detection limit in 4 of 5 sows. In conclusion, dietary fat source affected plasma concentrations of ketone bodies, but the concentrations were much less than normally observed in dairy cows and, therefore, primary ketosis does not appear to be a major problem in sows. In addition, this study indicates that the intermediary metabolism of sows was challenged when sows were exposed to high fat diets in late gestation.
本研究旨在探讨饲粮脂肪源、繁殖阶段（试验 1）和日变化（试验 2）如何影响母猪的血浆酮体。在试验 1 中，40 头经产母猪从产前 7d 开始饲喂 5 种泌乳日粮中的 1 种，日粮的脂肪水平分别为 3%或 8%，脂肪源具有不同比例的中链和长链脂肪酸。在产前 3d 和 7d 以及产后 1d、10d、17d 和 28d 经颈静脉采血，测定血浆β-羟丁酸（BHBA）、乙酰乙酸+丙酮（AcAc+Ac）、葡萄糖、非酯化脂肪酸（NEFA）、乳酸、乙酸和丁酸浓度。对于 5 种处理中的 4 种，血浆 BHBA 略有下降，而 AcAc+Ac 保持稳定。然而，在母猪产后 10d 时，饲喂 4%辛酸和 4%鱼油日粮（4+4%FO）的母猪血浆 BHBA（P＜0.01）和 AcAc+Ac（P＜0.001）是泌乳早期的两倍（P＜0.001）。血浆 AcAc+Ac 与 BHBA（P＜0.01）、葡萄糖（P＜0.05）和丁酸（P＜0.001）呈正相关，与乙酸：丁酸比（P＜0.001）呈负相关。此外，血浆 BHBA 与乳酸（P＜0.01）、乙酸和丁酸（P＜0.05）呈正相关。在试验 2 中，在母猪产后第 5 天和第 17 天，通过颈静脉导管每隔 2 小时采集 5 头母猪的血液样本，在 24 小时内进行分析，如试验 1 所述。此外，收集并分析了牛奶和尿液样本中的 BHBA 和 AcAc+Ac。未观察到血浆 BHBA 或 AcAc+Ac 的日变化，并且在母猪产后第 5 天到第 17 天期间，血浆 AcAc+Ac 没有变化（3.7μM），而 BHBA 从泌乳第 5 天的 58μM 下降到第 17 天的 52μM（P＜0.05）。尿液中发现了少量的 AcAc+Ac（8.6μM），这不受泌乳天数的影响，而牛奶中 AcAc+Ac 和 BHBA 以及尿液中 AcAc+Ac 的含量在 5 头母猪中有 4 头低于检测限。总之，饲粮脂肪源影响了血浆酮体浓度，但浓度远低于奶牛的正常水平，因此，原发性酮病似乎不是母猪的主要问题。此外，本研究表明，当母猪在妊娠后期接触高脂肪日粮时，母猪的中间代谢受到了挑战。
