Abstract The objective of this study was to evaluate stearic acid supplementation (C18:0) on the production, composition, fatty acid profile and the expression of lipogenic genes in the mammary gland of late lactating ewes. We used 30 primiparous and multiparous Lacaune ewes with a mean body weight (BW) of 66.5 ± 9.4 kg and body condition score (BCS) of 3.0 ± 0.5 at late lactation (122 ± 12 DEL), producing 1.0 ± 0.3 kg of milk/day. The treatments were: Control and C18 (28 g/animal/d of C18:0). When compared with Control, C18:0 reduced silage dry matter intake (DMI) by 13.1% (P = 0.0003), milk production by 8.1% (P = 0.05), lactose production by 3.3% (P = 0.0004), and lactose content by 3.4% (P = 0.0002). There was no treatment effect on the production and content of fat, protein, and total solids. The gene expression of acetyl-CoA carboxylase alpha promoter 2 (ACACA PII) and fatty acid synthase (FASN) were reduced by 30% (P = 0.02) and 26.1% (P = 0.04), respectively. The C18:0 supplementation is not effective in increasing the fat content in late lactating dairy ewes and reduces DMI, milk production, lactose levels, and gene expression involved in fatty acid synthesis.

中文翻译：

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硬脂酸 (C18:0) 降低泌乳后期奶羊脂肪生成基因的表达和生产力

摘要 本研究的目的是评估补充硬脂酸 (C18:0) 对泌乳晚期母羊乳腺中脂肪生成基因的产生、组成、脂肪酸谱和表达的影响。我们使用了 30 头初产和经产 Lacaune 母羊，平均体重 (BW) 为 66.5 ± 9.4 kg，泌乳后期 (122 ± 12 DEL) 的身体状况评分 (BCS) 为 3.0 ± 0.5，产奶量为 1.0 ± 0.3 kg/日。处理是：对照和C18（28克/动物/天的C18:0）。与对照相比，C18:0 将青贮干物质摄入量 (DMI) 减少了 13.1% (P = 0.0003)、牛奶产量减少了 8.1% (P = 0.05)、乳糖产量减少了 3.3% (P = 0.0004) 和乳糖含量3.4% (P = 0.0002)。处理对脂肪、蛋白质和总固体的产生和含量没有影响。乙酰辅酶 A 羧化酶 α 启动子 2 (ACACA PII) 和脂肪酸合酶 (FASN) 的基因表达分别降低了 30% (P = 0.02) 和 26.1% (P = 0.04)。C18:0 补充剂不能有效增加泌乳后期奶羊的脂肪含量并降低 DMI、产奶量、乳糖水平和参与脂肪酸合成的基因表达。