Frontiers in Behavioral Neuroscience (Oct 2015)

Pre-weaning dietary iron deficiency impairs spatial learning and memory in the cognitive holeboard task in piglets

  • Alexandra eAntonides,
  • Alexandra eAntonides,
  • Anne C. Schoonderwoerd,
  • Anne C. Schoonderwoerd,
  • Gabi eScholz,
  • Brian M. Berg,
  • Brian M. Berg,
  • Rebecca E. Nordquist,
  • Rebecca E. Nordquist,
  • Franz Josef evan der Staay,
  • Franz Josef evan der Staay

DOI
https://doi.org/10.3389/fnbeh.2015.00291
Journal volume & issue
Vol. 9

Abstract

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Iron deficiency (ID) is the most common nutritional deficiency in humans, affecting more than two billion people worldwide. Early-life ID can lead to irreversible deficits in learning and memory. The pig represents a promising model animal for studying such deficits, because of its similarities to humans during early development. We investigated long-term effects of pre-weaning dietary iron deficiency in piglets on growth, blood parameters, cognitive performance and brain histology. Ten male sibling pairs of piglets were removed from the sow 4-6 days after birth. Ten piglets were given an iron dextran injection and were fed a control milk diet for 28 days (100 mg Fe/kg); their ten siblings were given a saline injection and fed an iron deficient milk diet (10 mg Fe/kg). Then, all piglets were fed a balanced commercial pig diet (190-240 mg Fe/kg). From 8 weeks of age, piglets were tested in a spatial cognitive holeboard task. In this task, 4 of 16 holes contain a hidden food reward, allowing measurement of working (short-term) memory and reference (long-term) memory (RM) simultaneously. All piglets received 40-60 acquisition trials, followed by a 16-trial reversal phase. ID piglets showed permanently retarded growth and a strong decrease in blood iron parameters during dietary treatment. After treatment, ID piglets blood iron values restored to normal levels. In the holeboard task, ID piglets showed impaired RM learning during acquisition and reversal. Iron staining at necropsy at 12 weeks of age showed that ID piglets had fewer iron-containing cells in hippocampal regions CA1 and dentate gyrus. The number of iron-containing cells in CA3 correlated positively with acquisition RM performance for all animals. Our results support the hypothesis that early ID leads to lasting cognitive deficits. The piglet as a model animal, tested in the holeboard, can be useful in future research for assessing long-term cognitive effects of early-life diets or diet-induced deficiencies.

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