title: Dietary sialic acid supplementation improves learning and memory in piglets.
abstract: BACKGROUND
  Sialic acid, a key component of both human milk oligosaccharides and neural tissues, may be a conditional nutrient during periods of rapid brain growth.
  
  
  OBJECTIVE
  We tested the hypothesis that variations in the sialic acid content of a formula milk would influence early learning behavior and gene expression of enzymes involved in sialic acid metabolism in piglets.
  
  
  METHODS
  Piglets (n = 54) were allocated to 1 of 4 groups fed sow milk replacer supplemented with increasing amounts of sialic acid as casein glycomacropeptide for 35 d. Learning performance and memory were assessed with the use of easy and difficult visual cues in an 8-arm radial maze. Brain ganglioside and sialoprotein concentrations and mRNA expression of 2 learning-associated genes (ST8SIA4 and GNE) were measured.
  
  
  RESULTS
  In both tests, the supplemented groups learned in significantly fewer trials than did the control group, with a dose-response relation for the difficult task (P = 0.018) but not the easy task. In the hippocampus, significant dose-response relations were observed between amount of sialic acid supplementation and mRNA levels of ST8SIA4 (P = 0.002) and GNE (P = 0.004), corresponding with proportionate increases in protein-bound sialic acid concentrations in the frontal cortex.
  
  
  CONCLUSIONS
  Feeding a protein-bound source of sialic acid during early development enhanced learning and increased expression of 2 genes associated with learning in developing piglets. Sialic acid in mammalian milks could play a role in cognitive development.
authors.affiliation: Human Nutrition Unit, School of Molecular and Microbial Biosciences, University of Sydney, Sydney, NWS, Australia.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Bing
authors.initials: B
authors.lastname: Yu
authors.forename: Muhsin
authors.initials: M
authors.lastname: Karim
authors.forename: Honghua
authors.initials: H
authors.lastname: Hu
authors.forename: Yun
authors.initials: Y
authors.lastname: Sun
authors.forename: Paul
authors.initials: P
authors.lastname: McGreevy
authors.forename: Peter
authors.initials: P
authors.lastname: Petocz
authors.forename: Suzanne
authors.initials: S
authors.lastname: Held
authors.forename: Jennie
authors.initials: J
authors.lastname: Brand-Miller
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight; D019587:Dietary Supplements; D006854:Hydrocortisone / Q000378:metabolism; D007858:Learning / Q000187:drug effects*; D008297:Male; D008568:Memory / Q000187:drug effects*; D009097:Multienzyme Complexes / Q000378:metabolism; D019158:N-Acetylneuraminic Acid / Q000008:administration & dosage* / Q000494:pharmacology*; D012799:Sialyltransferases / Q000378:metabolism; D013552:Swine
chemical_list: D000596:Amino Acids; D009097:Multienzyme Complexes; C482901:UDP-N-acetylglucosamine 2-epimerase - N-acetylmannosamine kinase; D012799:Sialyltransferases; C517012:ST8Sia IV protein, swine; D019158:N-Acetylneuraminic Acid; D006854:Hydrocortisone