Effects of Energy Restriction during Gilt Development on Characterization and Quantification of Milk Oligosaccharides

Current research at the University of Nebraska-Lincoln (including 14 batches of gilts) has shown that energy restriction during gilt development will increase sow longevity and may also have beneficial impacts with respect to litter performance. Milk oligosaccharides (OS) are structurally diverse carbohydrates comprised of monomers of glucose, galactose, N-Acetylglucosamine, N-Acetyl galactosamine, fucose, and sialic acid, which may support gut health and development in suckling neonates via prebiotic mechanisms (e.g., modulation of gut microbes and mucosal immunity). The objective of this work was to evaluate the effects of energy restriction during gilt development on oligosaccharides production in milk. During the development period (d 123 to 240 of age), gilts (n = 128, 8 gilts/pen) were fed dietary treatments including: 1) Control diet formulated to NRC (2012) specifications (CTL); 2) Restricted (20% energy restriction via addition of 40% soy hulls; RESTR). Diets were fed ad libitum and applied in a 3 phase feeding regimen. At 240 d of age gilts were bred and fed a common diet. For this analysis, milk samples were collected (n = 7/treatment) on d 0 and 14 post-farrowing (i.e., early and mid-lactation). Milk OS were characterized by Nano LC Chip QTOF MS and quantified by High Performance Anion Exchange Chromatography–Pulsed Amperometric Detection. Across the two diets (RESTR and CTL), 63 OS were identified (58.7, 25.4 and 15.9%, neutral, acidic OS and fucosyl, respectively). On d 0, CTL had greater neutral and less acidic OS (P < 0.05) compared to RESTR. Of the neutral OS quantified, RESTR had greater LNnT (a neutral OS) than CTL (P < 0.05). Also, both RESTR and CTL had an increase in fucosyl OS and decrease in acidic OS from d 0 to d 14 (P<0.05). Of the fucosyl OS quantified, samples from CTL had greater LNDFH-I (a fucosyl OS) than RESTR (P < 0.05) at d 0. Lastly, only the RESTR showed an increase in neutral OS over time. Total OS quantification was lower in the RESTR when compared to CTL (P < 0.05). Quantification of OS also decreased in both dietary treatments over time (P < 0.0001). In conclusion, nutritional management of the developing gilt may impact OS profile during lactation; however, more research is warranted to further OS understanding and to evaluate the effects of OS on gut health and litter performance.