Association of bone morphogenetic protein 15 and growth differentiation factor 9 with litter size in livestock: a review study

ABSTRACT. Litter size is one of the crucial factors in livestock production and is of high economic value, which is affected by ovulation rate, hormones, and growth factors. Growth factors play a multifaceted role in reproductive physiology. This review aims to investigate the association of bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) with litter size in livestock. The transforming growth factor β (TGF- β) superfamily includes more than 34 members; GDF9 and BMP15 are among the most significant factors for regulating fertility and litter size in most livestock species. Ovarian follicles release BMP15 and GDF9 that are involved in the maturation of primary follicles into the basal form, proliferation of granulosa and theca cells, steroidogenesis, ovulation, and formation of the corpus luteum. Besides, these factors are highly expressed in oocytes and are necessary for female fertility and multiple ovulation in several livestock species. Animals with two inactive copies of these factors are sterile, while those with one inactive copy are fertile. Thus, the present review provides valuable information on the association of BMP15 and GDF9 with litter size in livestock that can be used as biological markers of multiple ovulation or for improving fertility in livestock.

摘要：产仔数是畜禽生产中的关键性状之一，具有较高经济价值，其受排卵率、激素及生长因子共同调控。生长因子在生殖生理过程中发挥多维度作用。本综述旨在探究骨形态发生蛋白15（BMP15）与生长分化因子9（GDF9）和畜禽产仔数之间的关联。转化生长因子β（TGF-β）超家族包含34个以上成员，其中GDF9与BMP15是调控多数畜禽物种繁殖力与产仔数的核心因子之一。卵巢滤泡可分泌BMP15与GDF9，二者参与初级滤泡向基底形态的成熟过程、颗粒细胞与膜细胞的增殖、类固醇生成、排卵及黄体形成。此外，这些因子在卵母细胞中呈高表达状态，对雌性繁殖力及多种畜禽物种的多胎排卵不可或缺。携带该因子两份失活拷贝的动物会表现为不育，而仅携带一份失活拷贝的个体仍可正常繁育。因此，本综述提供了关于BMP15、GDF9与畜禽产仔数关联的宝贵信息，可作为多胎排卵的生物学标记物或用于提升畜禽繁殖力。