Heat Shock Affects Amino Acid Metabolism in Bovine Cumulus Cells and Denuded Oocytes During In Vitro Maturation

Increased heat levels can affect follicle development, oocyte maturation, and bovine fertility by disrupting amino acid (AA) metabolism and oocyte competence. This study aimed to explore the effect of heat shock on AA metabolism in bovine cumulus cells (CCs) or denuded oocytes (DOs). CCs and DOs were separately cultured for 24 h in vitro at 38.5 °C (control group), 39.5 °C (moderate heat shock-CC, MHS-CC group), or 40.5 °C (high heat shock-CC, HHS-CC group). AA levels were analyzed in 24-h in vitro maturation media using high-performance liquid chromatography. The findings indicated that the HHS-CC group consumed more AAs than the control (p = 0.04) or MHS-CC group (p = 0.03). Compared with the control and HHS-CC groups, the MHS-CC group exhibited elevated alanine levels (p = 0.02). The MHS-CC (p = 0.03) and HHS-CC (p = 0.03) groups exhibited significantly greater glutamine depletion than the control group. The HHS-DO group exhibited significant lysine depletion (p < 0.01) but produced more tryptophan than the control and MHS-DO groups (p = 0.02). In contrast to the control and MHS-DO groups, the HHS-DO group displayed a notably elevated level of appearance (p = 0.005) and net balance (p = 0.005) for all AAs. The findings imply that heat shock may alter the metabolism of certain AAs in CCs and DOs, thereby affecting the developmental competence of bovine oocytes.