As mentioned previously, mastitis in mammary gland leads to a decrease in milk quality, while milk fat is one of the key components of milk, and the HIF-1α/mTOR signaling pathway promotes the expression of FASN, which is a gene related to fatty acid synthesis from scratch, by regulating SREBP1, a key regulator of lipid synthesis-related gene transcription [37,38]. The gene discussed is FASN; the disease is mastitis.