Mammary Specific Transgenic Over-expression of Insulin-like Growth Factor-I (IGF-I) Increases Pig Milk IGF-I and IGF Binding Proteins, with no Effect on Milk Composition or Yield

摘要: IGF-I regulates lactation by stimulating mammary mitogenesis, inhibiting apoptosis, and partially mediating the effects of growth hormone on lactogenesis. Herein, performance during first second parity was assessed in transgenic swine (TG) that over-expressed human milk under control bovine α-lactalbumin promoter, regulatory regions signal peptide coding sequence. Milk samples were collected throughout (farrowing to d24) from TG sows non-transgenic littermates (CON) IGF-I, IGF-II, IGFBP determined. Colostral (<24 h postpartum) content 26-fold greater (p < 0.001) (949 ± 107 μg/L; range 228–1600 μg/L) than CON (36 17.8 50- 90-fold mature (d2-24 postpartum). There no effect content. IGF-II concentration unaffected over-expression. Low molecular weight (IGFBP-2 -5) higher = 0.02) early postpartum period, but did not differ milk. yield, determined weigh-suckle-weigh, similar as litter gain. nutrient composition significantly affected IGF Thus, specific over-expression increased content, impact swine.