Zhou Z, Trevisi E, Luchini D N, Loor J J
Mammalian NutriPhysioGenomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana 61801; Department of Animal and Veterinary Sciences, Clemson University, SC 29634.
Istituto di Zootecnica Facoltà di Scienze Agrarie, Alimentari e Ambientali, Università Cattolica del Sacro Cuore, 29122, Piacenza, Italy.
J Dairy Sci. 2017 Aug;100(8):6720-6732. doi: 10.3168/jds.2016-12299. Epub 2017 May 24.
The liver functionality index (LFI) represents an assessment of transition cow metabolic health by measuring changes in biomarkers associated with liver plasma protein synthesis (albumin), lipoprotein synthesis (cholesterol), and heme catabolism (bilirubin). The present analysis was conducted to determine the role of peripartal rumen-protected Met or choline (CHOL) supplementation on LFI groupings, and to assess relationships with performance, inflammation, oxidative stress status, and plasma AA profiles. A cohort of 40 multiparous Holstein cows that were part of a randomized complete block design with 2 × 2 factorial arrangement of Met (Smartamine M, Adisseo NA, Alpharetta, GA) and CHOL (ReaShure, Balchem Inc., New Hampton, NY) level (with or without) were used. From -21 d to calving, cows received the same close-up diet and were assigned randomly to each treatment. From calving to 30 d, cows were on the same postpartal diet and continued to receive the same treatments until 30 d. Addition of Met was adjusted daily at 0.08% dry matter of diet and CHOL was fed at 60 g/cow per day. Liver (-10, 7, 20, and 30 d) and blood (-10, 4, 8, 20, and 30 d) samples were harvested for biomarker analyses. Cows were ranked retrospectively and assigned to low (LLFI, LFI <0) and high (HLFI, LFI >0) LFI groups regardless of Met or CHOL supplementation. Compared with cows in LLFI, close-up and lactation DMI, milk yield, milk fat yield, and milk protein yield were greater in HLFI cows. As expected, cows in LLFI had lower plasma cholesterol and albumin but greater bilirubin concentrations around parturition. Plasma haptoglobin concentration was also lower in HLFI cows, but plasma paraoxonase and hepatic total and reduced hepatic glutathione concentrations were greater. Although higher concentrations of His, Met, and Trp, as well as a tendency for greater Ile, were observed in HLFI cows, overall essential AA concentrations did not differ with LFI status. In contrast, overall concentrations of nonessential AA were greater in HLFI cows due to greater circulating concentrations of Ala, Asn, Gln, Pro, and Ser. Similarly, overall concentrations of total AA and total sulfur-containing compounds were greater in cows with HLFI. Feeding Met compared with CHOL led to a tendency for more cows classified as HLFI. Overall, results support the broader application of the LFI in the management of transition cows. In that context, the fact that precalving concentrations of compounds such as reduced glutathione, total sulfur-containing compounds, Met, Tau, and homocysteine differed between HLFI and LLFI independent of Met or CHOL feeding also underscores their potential for monitoring cows that might be at a greater risk of developing health problems after calving. Further studies on the applicability of these biomarkers to monitor transition success appears warranted.
肝脏功能指数（LFI）通过测量与肝脏血浆蛋白合成（白蛋白）、脂蛋白合成（胆固醇）和血红素分解代谢（胆红素）相关的生物标志物变化，来评估围产母牛的代谢健康状况。本分析旨在确定围产期添加瘤胃保护性蛋氨酸（Met）或胆碱（CHOL）对LFI分组的作用，并评估其与生产性能、炎症、氧化应激状态和血浆氨基酸谱的关系。选取40头经产荷斯坦奶牛，采用随机完全区组设计，Met（Smartamine M，安迪苏北美公司，佐治亚州阿尔法利塔）和CHOL（ReaShure，Balchem公司，纽约州新汉普顿）水平按2×2析因排列（添加或不添加）。从产前21天至产犊，奶牛采食相同的围产前期日粮，并随机分配至各处理组。从产犊至产后30天，奶牛采食相同的产后日粮，并持续接受相同处理至产后30天。Met的添加量按日粮干物质的0.08%每日调整，CHOL的饲喂量为每头奶牛每天60克。采集肝脏（产前10天、产后7天、20天和30天）和血液（产前10天、产后4天、8天、20天和30天）样本进行生物标志物分析。无论是否添加Met或CHOL，对奶牛进行回顾性排名，并分为低LFI组（LLFI，LFI<0）和高LFI组（HLFI，LFI>0）。与LLFI组奶牛相比，HLFI组奶牛围产前期和泌乳期的干物质采食量、产奶量、乳脂产量和乳蛋白产量更高。正如预期的那样，LLFI组奶牛在分娩前后血浆胆固醇和白蛋白水平较低，但胆红素浓度较高。HLFI组奶牛的血浆触珠蛋白浓度也较低，但血浆对氧磷酶以及肝脏总谷胱甘肽和还原型谷胱甘肽浓度较高。尽管HLFI组奶牛的组氨酸、蛋氨酸和色氨酸浓度较高，异亮氨酸也有升高趋势，但整体必需氨基酸浓度与LFI状态无关。相反，由于丙氨酸、天冬酰胺、谷氨酰胺、脯氨酸和丝氨酸的循环浓度较高，HLFI组奶牛的非必需氨基酸总体浓度更高。同样，HLFI组奶牛的总氨基酸和总含硫化合物总体浓度更高。与添加CHOL相比，添加Met使更多奶牛被归类为HLFI组。总体而言，结果支持LFI在围产母牛管理中的更广泛应用。在这种情况下，无论是否添加Met或CHOL，HLFI组和LLFI组奶牛产前谷胱甘肽、总含硫化合物、蛋氨酸、牛磺酸和同型半胱氨酸等化合物的浓度存在差异，这也突出了它们在监测产后可能有更大健康问题风险奶牛方面的潜力。对这些生物标志物监测围产成功适用性的进一步研究似乎是必要的。
