39 Colostrum intake promotes mammary cell proliferation in neonatal piglets

Abstract Abstract: Introduction Greater colostrum intake increases milk production during lactation in mature sows and cows. Although, we know that the number of mammary epithelial cells drives milk production during lactation, the mechanism however, is not clearly understood. Thus, we aimed to evaluate how neonate colostrum and formula intake administered at varying levels, affect epithelial and stromal cell proliferation in the neonatal mammary gland. Methods We randomly assigned piglets to one of six treatment groups: bottle-fed pooled colostrum at 20% (COL 20, n = 10) or 10% (COL 10, n = 10) of body weight, milk replacer at 20% (MR 20, n = 10) or 10% (MR 10, n = 10) of body weight, suckled ad libitum on the sow (SOS, n = 9), or not fed (zero hour, ZH, n = 8). All groups were euthanized 24 hours postnatally except ZH which were euthanized immediately after birth. Mammary tissues were obtained, fixed, and stained with Ki67 to identify proliferating cells using ImageJ and analyzed statistically with SAS software. Results Colostrum significantly increased epithelial cell proliferation (P = 0.05) compared to formula. Higher feeding dose also significantly increased epithelial cells (P = 0.0003) and stroma cells (P = 0.0005) than lower dose. Notably, stroma proliferation was significantly higher (P < 0.05) in COL 20 compared to other groups including COL 10, MR 20, MR 10, SOS and ZH. Conclusion These findings indicate that sufficient colostrum intake promotes proliferation of epithelial and stromal cells in the neonatal mammary gland, suggesting a potential role in enhancing the gland’s future lactation capacity. (Funded by USDA 2110002200)