Dietary protein deficiency influences the behavioural phenotypes of mammals. We studied whether protein deficiency during gestation and/or post-weaning heightened anxiety, reduced memory recall and influenced competitive ability in the African striped mouse Rhabdomys dilectus chakae. Mice were subjected to five protein diet treatments, which they received continuously, or were raised on one diet to weaning and switched to an alternate diet post-weaning (Day 16): 1) HP-HP: high protein (24%); first letter pair indicates maternal diet and the second pair indicates offspring diet post-weaning; 2) BP-BP: baseline protein (19%); 3) LP-LP: low protein (10%); 4) HP-LP: switched from high to low protein diet; and 5) LP-HP: switched from low protein to high protein diet. From Day 70, when mice were sexually mature, 20 individuals (10 males, 10 females) per treatment were subjected to three successive experiments, in which we tested their anxiety responses in: 1) an open field arena (time spent in the centre of the open field); 2) novel object recognition (time spent exploring a novel object); and 3) social interactions (excluding BP-BP) in age-matched same-sex dyadic encounters (aggressive, amicable and avoidance behaviours). LP-LP and LP-HP treatment mice spent the least amount of time in the centre of the open field, did not demonstrate object preference compared to the other treatments, and were the most aggressive in dyadic encounters. Our study shows that the systemic effects of protein-deficient diets during early life shapes the behavioural phenotype in R. d. chakae, possibly through early organisation of neuro-biological pathways or competition among littermates.
Keywords: Aggression; Early life influences; Episodic memory; Exploratory behaviour; Social interaction.
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