The effects of flavonoids on female animal reproductive performance.

Flavonoids are polyphenolic secondary metabolites widely distributed in plants, exhibiting various biological activities such as antioxidant, anti-inflammatory, oestrogenic and metabolic regulatory effects. In recent years, their role in the regulation of female animal reproduction has attracted attention. This review summarises the structural characteristics, plant sources, forms of application and effects of flavonoids on reproductive function in female animals, with a focus on their roles in the hypothalamic-pituitary-varian axis, uterine receptivity and placental nutrient transport. Flavonoids primarily influence female reproductive function by regulating oestrogen receptor-related signalling, alleviating oxidative stress and inflammation, maintaining granulosa cell homeostasis, and promoting oocyte maturation and early embryonic development. There is already relatively direct production evidence regarding the improvement of reproductive performance in sows and placental function by certain isoflavonoids, whilst quercetin, luteolin and rutin, among others, are more commonly associated with ovarian protection, improved oocyte quality and the alleviation of damage. It should be noted that the effects of different flavonoid monomers or extracts are significantly influenced by animal species, dosage, timing of administration, physiological status and evaluation criteria. Current findings cannot be simply extrapolated to all female animal production practices; their safe dosages, critical administration windows and long-term efficacy still require further species-specific research for validation. This review indicates that flavonoids may serve as potential nutritional modulators for improving the reproductive microenvironment and alleviating reproduction-related damage, offering new insights into enhancing reproductive performance in female animals.