Our previously published paper demonstrated that fermented ammoniated condensed whey (FACW) supplementation improved feed efficiency and metabolic profile in postpartum dairy cows. The objective of this study was to further explore the effects of FACW supplementation on liver triglyceride content, hepatic gene expression and protein abundance, and plasma biomarkers related to liver function, inflammation, and damage. Individually fed multiparous Holstein cows were blocked by calving date and randomly assigned to postpartum (1 to 45 d in milk, DIM) isonitrogenous treatments: control diet (n = 20) or diet supplemented with FACW (2.9% dry matter of diet as GlucoBoost; Fermented Nutrition, Luxemburg, WI, replacing soybean meal; n = 19). Liver biopsies were performed at 14 and 28 DIM for analysis of mRNA expression, protein abundance, and liver triglyceride content. There was marginal evidence for a reduction in liver triglyceride content at 14 DIM in FACW-supplemented cows compared with the control group. Cows supplemented with FACW had greater mRNA expression of glucose-6-phosphatase at 14 DIM relative to control. Supplementation with FACW increased mRNA expression of pyruvate carboxylase (PC), but did not alter cytosolic phosphoenolpyruvate carboxykinase (PCK1), resulting in a 2.4-fold greater PC:PCK1 ratio for FACW-supplemented cows compared with control. There was no evidence for a FACW effect on mRNA expression of propionyl-CoA carboxylase nor on mRNA expression or protein abundance of lactate dehydrogenase A or B. Cows supplemented with FACW had lower plasma urea nitrogen compared with control. Plasma l-lactate was greater for FACW-supplemented cows compared with control at 2 h before feeding time at 21 DIM. There was no evidence for altered expression of IL1B or IL10, or blood biomarkers related to liver function and damage. Greater glucose-6-phosphatase and PC gene expression, together with greater blood glucose and similar milk lactose output, suggests that FACW increased the supply of glucose precursors, resulting in greater gluconeogenesis between 3 and 14 DIM. Greater hepatic PC:PCK1 ratio, together with previously reported decreased plasma β-hydroxybutyrate and the marginal evidence for lower liver triglyceride content at 14 DIM, suggests greater hepatic capacity for complete oxidation of fatty acids in FACW-supplemented cows compared with control. Overall, improvements in metabolite profile and feed efficiency observed with postpartum supplementation of FACW may be attributed to increased gluconeogenic and anaplerotic precursors, most likely propionate, due to modulated rumen fermentation.

我们之前发表的论文证明，发酵氨化浓缩乳清（FACW）补充剂可改善产后奶牛的饲料效率和代谢状况。这项研究的目的是进一步探讨FACW补充对肝脏甘油三酸酯含量，肝基因表达和蛋白质丰度以及与肝功能，炎症和损伤相关的血浆生物标志物的影响。单独喂养的多头荷斯坦奶牛在产犊日期之前被封锁，并被随机分配到产后（牛奶中1至45天，DIM）等氮处理：对照日粮（n = 20）或补充FACW的日粮（日粮干物质的2.9％作为GlucoBoost；威斯康星州卢森堡市的发酵营养食品，代替豆粕； n = 19）。在14和28 DIM进行肝活检，以分析mRNA表达，蛋白质丰度，和肝脏甘油三酸酯含量。与对照组相比，在补充FACW的母牛中，在第14天DIM时肝边缘甘油三酯含量降低的边缘证据很少。相对于对照组，补充FACW的母牛在14 DIM时具有更高的葡萄糖-6磷酸酶mRNA表达。补充FACW增加丙酮酸羧化酶（PC），但并没有改变胞质磷酸烯醇丙酮酸羧化激酶（PCK1），与对照组相比，添加FACW的母牛的PC：PCK1比高2.4倍。没有证据表明FACW对丙酰辅酶A羧化酶的mRNA表达或乳酸脱氢酶A或B的mRNA表达或蛋白质丰度有影响。补充FACW的母牛血浆尿素氮低于对照组。补充FACW的奶牛的血浆l-乳酸比21 DIM饲喂时间前2小时的对照组要大。没有证据表明IL1B或IL10的表达改变或与肝功能和损害有关的血液生物标志物。更高的葡萄糖6磷酸酶和PC基因表达，以及更高的血糖和相似的牛奶乳糖产量，表明FACW增加了葡萄糖前体的供应，导致3到14 DIM之间的糖异生作用更大。较高的肝PC：PCK1比值，再加上先前报道的血浆β-羟基丁酸酯含量降低，以及在14 DIM时肝甘油三酯含量降低的边缘证据，表明与对照组相比，FACW补充型母牛的肝脏完全脂肪酸完全氧化的能力。总体而言，产后补充FACW所观察到的代谢物谱和饲料效率的改善可能归因于瘤胃发酵的增加，糖原异生和无松动的前体，最可能是丙酸酯。