TRIENNIAL LACTATION SYMPOSIUM/BOLFA: Dietary regulation of allometric ductal growth in the mammary glands1,2

Abstract

Although mammary gland growth and development in females is a lifelong process, it builds on isometric and allometric phases of mammary growth to establish a complex ductal network before and during puberty. Only then can other phases of branching and alveologenesis, differentiation, lactation, and involution proceed. Although the ductal network of various species differs in its histomorphology, all glands undergo a common phase of allometric growth when the mammary ducts penetrate into the supporting stromal microenvironment. Perhaps not surprisingly, different aspects of diet and nutrition can influence this allometric growth, either directly or indirectly. In this review, we outline some of the fundamental aspects of how allometric ductal growth in the mammary glands of various species is influenced by diet and nutrition and identify opportunities and questions for future investigation.

Puberty is a critical window for the impact of diet on mammary gland development in the rabbit

“…The growth and differentiation of MEC are lengthy processes during the animal's lifespan (fetal, pre‐, and postpubertal periods) and reproductive cycles (pregnancy and lactation) and they occur under stage‐dependent hormonal and environmental control . It has already been shown that diet can influence mammary gland development and subsequent milk production . Moreover, data using rodent models have revealed that nutrition during early life, when the mammary tissue is undergoing proliferation and extensive modeling, can alter susceptibility to mammary tumor development .…”

“…In cattle, overfeeding during puberty exerts a negative effect on growth of the mammary parenchyma and subsequent milk potential . There is therefore considerable interest in understanding the importance of the pubertal period, because the mammary epithelium is rapidly invading the fat pad; it thus constitutes the starting point for later normal mammary functions in adulthood …”

“…3,4 It has already been shown that diet can influence mammary gland development and subsequent milk production. 5 Moreover, data using rodent models have revealed that nutrition during early life, when the mammary tissue is undergoing proliferation and extensive modeling, can alter susceptibility to mammary tumor development. 6,7 We previously showed in a rabbit model that an obesogenic diet (OD) initiated before puberty and pursued throughout puberty altered mammary gland development.…”

“…[24][25][26][27] There is therefore considerable interest in understanding the importance of the pubertal period, because the mammary epithelium is rapidly invading the fat pad; it thus constitutes the starting point for later normal mammary functions in adulthood. 5 The objective of the present study was therefore to determine the influence of an unbalanced diet, during the peripubertal period exclusively, on mammary development and function in early pregnancy. We used a previously developed model of rabbits fed a high-fat/high-sugar diet that had displayed alterations to mammary development.…”

TRIENNIAL LACTATION BIOLOGY SYMPOSIUM/BOLFA: The biology of lactation– from genes to cells to milk1

“…Recent findings showing a link between the feeding level of heifer calves and expression of estrogen receptors in their mammary tissue were described (Geiger et al, 2016). Dr. Russell C. Hovey (University of California, Davis, CA) more specifically discussed allometric ductal growth in mammary tissue of various animal species, and how it can be influenced by diet composition and plane of nutrition (Berryhill et al, 2017). He demonstrated that excess rate of BW gain or obesity can be detrimental for mammogenesis during the peripubertal period.…”