Compensatory feeding of gestating gilts does not affect mammary development of their offspring at puberty
The goal of this project was to determine if feed restriction followed by compensatory feeding of gestating gilts affects mammary development and mammary gene expression of their female offspring at puberty. Gilts were fed a conventional (CTL; n = 5) or an experimental (TRT; n = 3) dietary regimen. The experimental regimen provided 70% (restriction) and 115% (compensatory) of the protein and DE contents provided by the CTL diet. The restriction diet was given during the first 10 wk of gestation followed by the compensatory diet until farrowing. Gilts were allowed to farrow and female offspring from these (11 CTL, 12 TRT) were weighed at birth, weaning (day 20), and puberty (day 211) at which time they were slaughtered and had their mammary glands collected and dissected. Parenchymal tissue samples were collected for molecular biology work and blood samples were obtained the day before slaughter to measure insulin-like growth factor 1 (IGF-1) concentrations. The MIXED procedure of SAS with treatment as main effect and sow as a randomized effect was used for statistical analyses. Piglets from TRT sows tended to weigh less at birth (1.31 vs. 1.53 kg, SEM = 0.05, P = 0.10) than piglets from CTL sows, but had similar BW at weaning and puberty (P > 0.10). Concentrations of IGF-1 at slaughter tended to be greater in gilts from TRT than in gilts from CTL sows (167 vs. 142 ng/mL, SEM = 9, P = 0.06). Amounts of parenchymal (534.9 vs. 542.4 g for TRT and CTL gilts, respectively, SEM = 45.0) and extra-parenchymal tissue as well as composition of parenchymal tissue (DM, protein, fat and DNA contents) were similar across treatments (P > 0.10). There were no differences in mRNA abundance for IGF1, IGF2, ornithine decarboxylase 1 (ODC1), prolactin receptor (PRLR), signal transducer and activator of transcription 5A (STAT5A) or 5B (STAT5A) in mammary parenchyma (P > 0.10). In conclusion, feed restriction and subsequent compensatory feeding of gestating gilts had no effects on mammary development or mammary gene expression of their female offspring at puberty.
Keywords: diet deprivation, diet over allowance, gestation, mammary development, offspring, sows