Liver lipid dysregulation is one of the major factors in the decline of production performance in late-stage laying hens. Silymarin (SIL), a natural flavonolignan extracted from milk thistle, is known for its hepatoprotective and lipid-lowering properties in humans. This study evaluates whether SIL can provide similar benefits to late-stage laying hens. A total of 480 68-week-old Lohmann Pink laying hens were randomly assigned into 5 groups, each group consisting of 6 replicates with 16 hens each. The birds received a basal diet either without silymarin (control) or supplemented with silymarin at concentrations of 250, 500, 750, or 1,000 mg/kg (SIL250, SIL500, SIL750, SIL1000) over a 12-week period. The CON group exhibited a significant decline in laying rates from weeks 9 to 12 compared to the initial 4 weeks (P = 0.042), while SIL supplementation maintained consistent laying rates throughout the study (P > 0.05). Notably, the SIL500 and SIL750 groups showed higher average egg weight than the CON group during weeks 5 to 8 (P = 0.049). The SIL750 group had a significantly higher average daily feed intake across the study period (P < 0.05), and the SIL500 group saw a marked decrease in the feed-to-egg ratio from weeks 5 to 8 (P = 0.003). Furthermore, the SIL500 group demonstrated significant reductions in serum ALT and AST levels (P < 0.05) and a significant decrease in serum triglycerides and total cholesterol at week 12 with increasing doses of SIL (P < 0.05). SIL also positively influenced liver enzyme expression (FASN, ACC, Apo-VLDL II, FXR, and CYP7A1; P < 0.05) and altered the cecal microbiota composition, enhancing species linked to secondary bile acid synthesis. Targeted metabolomics identified 9 metabolites predominantly involved in thiamin metabolism that were significantly different in the SIL groups (P < 0.05). Our study demonstrated that dietary SIL supplementation could ameliorate egg production rate in late stage laying hens, mechanistically, this effect was via improving hepatic lipid metabolism and cecal microbiota function to achieve. Revealed the potentially of SIL as a feed supplementation to regulate hepatic lipid metabolism dysregulation. Overall, dietary 500 mg/kg SIL had the best effects.

中文翻译：

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日粮水飞蓟素通过改变晚期产蛋鸡的肝脏脂质代谢和盲肠微生物群功能及其代谢物来提高生产性能


肝脂失调是导致后期蛋鸡生产性能下降的主要因素之一。水飞蓟素 (SIL) 是一种从水飞蓟中提取的天然黄酮木脂素，以其对人类的保肝和降脂特性而闻名。本研究评估了 SIL 是否可以为后期产蛋鸡提供类似的益处。共480只68周龄罗曼粉红蛋鸡随机分为5组，每组6个重复，每组16只母鸡。这些鸡在 12 周内接受不含水飞蓟素（对照）的基础饮食，或补充浓度为 250、500、750 或 1,000 毫克/千克（SIL250、SIL500、SIL750、SIL1000）的水飞蓟素。与最初 4 周相比，CON 组从第 9 周到第 12 周的产蛋率显着下降 (P = 0.042)，而补充 SIL 在整个研究过程中保持一致的产蛋率 (P > 0.05)。值得注意的是，在第 5 周至第 8 周期间，SIL500 和 SIL750 组的平均蛋重高于 CON 组（P = 0.049）。在整个研究期间，SIL750 组的平均每日采食量显着较高（P < 0.05），而 SIL500 组的料蛋比从第 5 周到第 8 周显着下降（P = 0.003）。此外，随着 SIL 剂量的增加，SIL500 组在第 12 周时血清 ALT 和 AST 水平显着降低（P < 0.05），血清甘油三酯和总胆固醇显着降低（P < 0.05）。 SIL 还对肝酶表达（FASN、ACC、Apo-VLDL II、FXR 和 CYP7A1；P < 0.05）产生积极影响，并改变盲肠微生物群组成，增强与次级胆汁酸合成相关的物种。 靶向代谢组学鉴定出 9 种主要参与硫胺素代谢的代谢物，这些代谢物在 SIL 组中存在显着差异（P < 0.05）。我们的研究表明，日粮中添加SIL可以提高后期蛋鸡的产蛋率，从机制上讲，这种效果是通过改善肝脏脂质代谢和盲肠微生物群功能来实现的。揭示了 SIL 作为饲料补充剂调节肝脏脂质代谢失调的潜力。总体而言，膳食中 500 mg/kg SIL 的效果最好。