Consequences of oocyte supplementation with l-carnitine may vary depending on species-specific cellular lipid profile, level of mitochondrial activity, or even on ipid availability in culture medium. This study aimed to evaluate l-carnitine supplementation on competence and gene expression of enzymes related to lipid metabolism in oocytes and cumulus cells from buffalo COCs matured in the presence or absence of fetal bovine serum (FBS). COCs were matured in vitro in FBS (10%) or bovine serum albumin fatty acid-free (BSA-FAF) (0.4%) and with or without supplementation with l-carnitine (3.03 mM). COCs matured in the presence of FBS or BSA-FAF were fertilized and cultured, then supplemented with l-carnitine during in vitro maturation or in vitro embryo culture. Finally, in vivo mature and immature COCs were included for gene expression analysis. COCs matured in culture medium with FBS in the presence of l-carnitine produced a lower blastocyst rate (p ≤ 0.05) compared to controls. In turn, the blastocyst rate from COCs matured with BSA-FAF in the presence of l-carnitine was similar to controls (p > 0.05), and higher than FBS + L-carnitine treated COCs (p ≤ 0.05). Addition of l-carnitine during embryo culture showed no differences in blastocyst production between experimental groups and controls (p > 0.05). In cumulus cells, gene expression of ACACA, SCD and FASN was upregulated in COCs matured in the presence of BSA-FAF + L-carnitine, while all genes in oocytes were significantly expressed upregulated by COCs matured in vivo, and only BSA-FAF + L-carnitine group showed similar expression of the FASN gene. In conclusion, the consequences of l-carnitine supplementation during in vitro maturation of buffalo COCs on oocyte competence vary depending on presence or absence of FBS in culture. With FBS, l-carnitine impairs oocyte competence, while in its absence, gene expression suggests adequate lipid metabolism and increased oocyte competence.

中文翻译：

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左旋肉碱对在胎牛血清或无脂肪酸牛血清白蛋白中成熟的水牛卵丘-卵母细胞复合物脂质代谢的影响

卵母细胞补充左旋肉碱的后果可能因物种特异性细胞脂质特征、线粒体活性水平，甚至培养基中脂质的可用性而异。本研究旨在评估补充左旋肉碱对来自在存在或不存在胎牛血清 (FBS) 的情况下成熟的水牛 COC 的卵母细胞和卵丘细胞中脂质代谢相关酶的能力和基因表达的影响。COC 在 FBS (10%) 或无牛血清白蛋白脂肪酸 (BSA-FAF) (0.4%) 和补充或不补充左旋肉碱 (3.03 mM) 中体外成熟。在 FBS 或 BSA-FAF 存在下成熟的 COC 受精和培养，然后在体外成熟或体外胚胎培养过程中补充左旋肉碱。最后，包括体内成熟和未成熟的 COC 用于基因表达分析。与对照组相比，在含有左旋肉碱的 FBS 培养基中成熟的 COC 产生较低的囊胚率 (p ≤ 0.05)。反过来，在左旋肉碱存在下用 BSA-FAF 成熟的 COC 的囊胚率与对照相似（p > 0.05），并且高于 FBS + L-肉碱处理的 COC（p ≤ 0.05）。在胚胎培养过程中添加左旋肉碱显示实验组和对照组之间的囊胚产量没有差异（p > 0.05）。在卵丘细胞中，在 BSA-FAF + L-肉碱存在下成熟的 COCs 中 ACACA、SCD 和 FASN 的基因表达上调，而卵母细胞中的所有基因在体内成熟的 COCs 中显着上调，只有 BSA-FAF +左旋肉碱组FASN基因表达相似。综上所述，在水牛 COCs 体外成熟过程中补充左旋肉碱对卵母细胞能力的影响取决于培养物中 FBS 的存在与否。对于 FBS，左旋肉碱会损害卵母细胞的能力，而在它不存在的情况下，基因表达表明足够的脂质代谢和增加的卵母细胞能力。