Authors: Eimear Murphy Lynn Kraak Jan van den Broek Rebecca E Nordquist Franz Josef van der Staay
Publish Date: 2014/12/20
Volume: 18, Issue: 2, Pages: 561-572
Abstract
Low birth weight LBW in humans is a risk factor for later cognitive behavioural and emotional problems In pigs LBW is associated with higher mortality but little is known about consequences for surviving piglets Alteration in hypothalamic–pituitary–adrenal axis function in LBW pigs suggests altered emotionality but no behavioural indicators have been studied Decisionmaking under uncertain conditions eg risk or ambiguity is susceptible to emotional influences and may provide a means of assessing longterm effects of LBW in piglets We tested LBW N = 8 and normalbirthweight NBW N = 8 male pigs in two decisionmaking tasks For decisionmaking under risk we developed a simple twochoice probabilistic task the Pig Gambling Task PGT where an ‘advantageous’ option offered small but frequent rewards and a ‘disadvantageous’ option offered large but infrequent rewards The advantageous option offered greater overall gain For decisionmaking under ambiguity we used a Judgement Bias Task JBT where pigs were trained to make an active response to ‘positive’ and ‘negative’ tone cues signalling large and small rewards respectively Responses to ambiguous tone cues were rated as more or less optimistic LBW pigs chose the advantageous option more often in later blocks of the PGT and were scored as less optimistic in the JBT than NBW pigs Our findings demonstrate that LBW pigs have developed different behavioural strategies with respect to decisionmaking We propose that this is guided by changes in emotionality in LBW piglets and we provide behavioural evidence of increased negative affect in LBW pigletsWe would like to thank Christine Oei for help with cortisol measurement Yorrit van der Staay for providing Fig 1 and Luca Melotti for advice on a draft of the article We would also like to thank Jan van Mourik Zias Lukasse and Dirk van der Heide for taking great care of our animals
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