Effects of energy restriction during gilt development on milk nutrient profile, milk oligosaccharides, and progeny biomarkers.

An ongoing study at the University of Nebraska-Lincoln (which included 14 batches of gilts; n = 90 gilts/batch) demonstrated that energy restriction during the developmental period of a gilt increases longevity and may also have beneficial effects on progeny health and growth, particularly, parity 1 progeny. Therefore, we hypothesized that energy restriction during gilt development may affect milk nutrient profile, milk oligosaccharides (OS), and postnatal progeny biomarkers. During the development period, batch 14 gilts (n = 128, 8 gilts/pen) were fed 3 dietary treatments including the following: 1) Control diet formulated to NRC (2012) specifications (CTL); 2) Restricted (20% energy restriction via addition of 40% soy hulls; RESTR); and 3) CTL diet plus addition of crystalline amino acids equivalent to the SID Lys:ME of the RESTR diet (CTL+). All diets were fed ad libitum and applied in a 3-phase feeding regimen during gilt development (days 123 to 230 of age). Average daily feed intake was used to estimate daily metabolizable energy intake (Mcal/d) during each phase (Phase 1: 10.13, 6.97, 9.95; Phase 2: 11.25, 8.05, 10.94; and Phase 3: 9.47, 7.95,11.07) for CTL, RESTR, and CTL+, respectively. After 230 d of age, gilts were bred and fed a common diet. Milk samples were collected from batch 14 gilts (n = 7 per treatment) on days 0 and 14 postfarrowing for compositional analysis of N, CP, dry matter (DM), GE, insulin, and OS. Piglet blood samples (n = 6 piglets/gilt) were obtained on days 1 and 15 postfarrowing for quantification of glucagon-like peptide-2 (GLP-2) and insulin. No effects of developmental diet were observed for milk N, CP, DM, or GE; however, N, CP, DM, and insulin were increased (P < 0.05) on day 1 compared with day 14. A total of 61 different milk OS were identified. Milk OS profile was significantly different for neutral and acidic OS (P < 0.05) on day 0, but there were no significant differences on day 14. For piglet GLP-2, a treatment by day interaction was observed (P < 0.009); specifically, on day 1 GLP concentrations were greater (P < 0.001) in CTL+ compared with RESTR (6.73 vs. 1.21 ng/mL). For serum insulin, a treatment by day interaction was observed (P < 0.01); specifically, insulin in RESTR progeny was greater (P < 0.03) than CTL on day 1. In conclusion, nutritional management of the developing gilt may affect milk nutrient composition, milk OS profile, and piglet serum biomarkers.