Advances and future directions in reproductive performance of major Chinese indigenous pig breeds in China

Chinese indigenous pig breeds exhibit remarkable adaptability, superior meat quality, tolerance to coarse feed and high resistance to environmental stress, making them crucial components in the conservation and sustainable utilization of China’s swine genetic resources. Reproductive performance is a key economic trait for assessing sow productivity, population growth potential and overall profitability in swine production, and has consistently been a central focus of genetic improvement in these indigenous breeds. Marked divergence in reproductive parameters, including total number born, number born alive, mean birth weight per piglet, age at sexual maturity, litter weight at weaning and number of teats, has been documented among Chinese indigenous pig breeds representing six major ecological types. Among these traits, total number born and number born alive emerge as the most informative indicators of prolificacy, and provide an important basis for evaluating reproductive potential and identifying valuable reproductive germplasm. In recent years, investigations into the reproductive performance of these breeds have progressively evolved from phenotypic evaluations to multifaceted approaches encompassing regulatory mechanisms of the hypothalamic–pituitary–gonadal axis, discovery of key candidate genes and multi-omics integration. Although pivotal genes, such as ESR, FSHβ, PRLR, RBP4, VEGFA and NR5A2, have been unequivocally demonstrated to be associated with porcine reproductive traits, significant challenges and opportunities remain in cross-breed comparative analyses, elucidation of fundamental molecular mechanisms, integration of multi-omics datasets and the successful translation of these findings into practical breeding strategies. This review systematically synthesizes the phenotypic characteristics, endocrine regulatory networks, critical candidate genes and advances in multi-omics research pertaining to the reproductive performance of the six principal ecological types of Chinese indigenous pig breeds. Moreover, it delineates prospective research avenues, with the objective of providing a theoretical foundation for the precise genetic enhancement of reproductive performance in Chinese indigenous pig breeds, as well as for the conservation and optimal utilization of their genetic resources.