围产期日粮中添加鞣花酸对母羊生理代谢及产羔性能的影响

Effects of ellagic acid supplementation to peripartum diets on physiological metabolism and kidding performance of female goats

  • 摘要: 【目的】 探究围产期日粮中添加鞣花酸对母羊生理代谢及产羔性能的影响,并明确其对围产期母羊能量负平衡(NEB)状态的调控作用,为鞣花酸作为新型饲料添加剂应用于围产期母羊的精准营养调控与管理提供理论依据。【方法】 选取36只已妊娠122 d的健康贵州黑山羊母羊,随机分为对照组(CON,饲喂基础日粮)、低剂量组(LEA,基础日粮+70 mg/kg鞣花酸)、中剂量组(MEA,基础日粮+140 mg/kg鞣花酸)和高剂量组(HEA,基础日粮+210 mg/kg鞣花酸)。母羊分娩后,记录各组母羊的产羔数、活羔数、弱羔数和流产羔数,以及羔羊的初生体重、体高、体长、胸围和管围等指标;并于妊娠母羊产前21 d(d-21)、分娩当天(d0)及产后21 d(d21)3个时间点分别采集血样,用于测定血液生理生化指标、血清抗氧化指标及免疫指标;同时结合网络药理学分析鞣花酸代谢物尿石素A(UA)的作用靶点。【结果】 各处理组母羊在流产率、产羔率及羔羊成活率方面无显著差异(P>0.05,下同),但3个鞣花酸处理组的弱羔率显著低于CON组(P<0.05,下同)。围产期日粮中添加鞣花酸能有效提高羔羊初生体重、断奶体重及平均日增重(ADG),其中以HEA组的ADG最高,显著高于CON组和LEA组。补充鞣花酸对母羊血清葡萄糖(GLU)、非酯化脂肪酸(NEFA)和总蛋白(TP)的含量有显著影响,而对白蛋白(ALB)、甘油三酯(TG)和总胆固醇(TC)的含量影响不显著;同时能有效提高总抗氧化能力(T-AOC)水平和超氧化物歧化酶(SOD)活性,丙二醛(MDA)和活性氧(ROS)的含量则随鞣花酸添加剂量的增加呈显著下降趋势;母羊血清中的白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)及白细胞介素1β(IL-1β)水平随鞣花酸添加剂量的增加呈逐渐下降趋势,免疫球蛋白M(IgM)、免疫球蛋白G(IgG)及免疫球蛋白A(IgA)水平随鞣花酸添加剂量的增加呈逐渐上升趋势。基于网络药理学探析UA改善NEB状态的潜在机制,共获得184个UA缓解NEB状态的潜在靶点;进一步综合核心靶点网络与KEGG信号通路富集分析,最终筛选出5个UA缓解NEB状态的核心靶点(EGFR、HRAS、AKT1、IGF1R和RAF1),其中核心靶点AKT1与UA的结合能最低(-6.67 kcal/mol)。【结论】 鞣花酸在山羊体内经肠道微生物代谢转化为UA后,通过AKT1靶点调控机体的能量代谢与抗氧化应激反应,进而有效缓解围产期母羊的NEB状态,并间接促进羔羊的生长发育。实际生产中,围产期母羊日粮中的鞣花酸最适添加剂量为210 mg/kg。

     

    Abstract: 【Objective】 This study aimed to investigate the effects of ellagic acid (EA) supplementation to peripartum diets on physiological metabolism and kidding performance of female goats, and to clarify the regulatory role of EA in negative energy balance (NEB) of peripartum female goats, providing theoretical basis for applying EA as a novel feed additive in precise nutritional regulation and management of peripartum female goats. 【Method】 A total of 36 healthy pregnant female Guizhou black goats at 122 d of gestation were randomly divided into different groups:control group (CON, fed basal diet), low-dose EA group (LEA, basal diet + 70 mg/kg EA), medium-dose EA group (MEA, basal diet + 140 mg/kg EA), and high-dose EA group (HEA, basal diet + 210 mg/kg EA). After parturition, the litter size, live kid number, weak kid number, and aborted kid number of female goats in each group were recorded, as well as birth weight, height at withers, body length, chest circumference, and cannon bone circumference of kids. Blood samples were collected at the 21st d prepartum (d-21), day of parturition (d0), and the 21st d postpartum (d21) for the determination of blood physiological biochemical parameters, serum antioxidant indicators, and immune indicators; meanwhile, network pharmacology was used to analyze the action targets of urolithin A (UA), a metabolite of ellagic acid. 【Result】 There were no significant differences in abortion rate, kidding rate, and kid survival rate between treatment groups (P>0.05, the same below), however, the weak kid rate of the three EA supplementation groups was significantly lower than that of the CON group (P<0.05, the same below). EA supplementation to peripartum diets effectively increased kid birth weight, weaning weight, and average daily gain (ADG), with the HEA group showing the highest ADG, which was significantly higher than the CON and LEA groups. EA supplementation significantly affected serum glucose (GLU), non-esterified fatty acid (NEFA), and total protein (TP) contents of female goats, but had no significant effect on albumin (ALB), triglyceride (TG), and total cholesterol (TC) contents. Meanwhile, EA supplementation effectively enhanced total antioxidant capacity (T-AOC) level and superoxide dismutase (SOD) activity, but the contents of malondialdehyde (MDA) and reactive oxygen species (ROS) decreased significantly with the increase of EA dosage. The levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in serum of female goats gradually declined with increasing EA dosage, while the levels of immunoglobulin M (IgM), immunoglobulin G (IgG), and immunoglobulin A (IgA) gradually increased with increasing EA dosage. Based on network pharmacology, the potential mechanism of UA in alleviating NEB was investigated, with 184 potential targets for UA alleviating NEB; according to comprehensive core target network analysis and KEGG signaling pathway enrichment analysis, 5 core targets (EGFR, HRAS, AKT1, IGF1R, RAF1) for UA alleviating NEB were screened out, among which the core target AKT1 had the lowest binding energy with UA (-6.67 kcal/mol). 【Conclusion】 After being converted into UA by intestinal microorganisms in goats, EA can regulate energy metabolism and antioxidant stress via the AKT1 target, thereby effectively alleviating NEB in peripartum female goats and indirectly promoting the growth and development of kids. In practical production, the optimal EA dosage in the diet of peripartum does is 210 mg/kg.

     

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