Prenatal stress in pigs: impact on growth, behaviour, neuroendocrine and immune functions in the offspring

Abstract

Studies in different animal models and humans give evidence that stress experienced by pregnant mothers affects foetal development and has long-term consequences on many physiological systems and behaviour in the offspring, thus facilitating the risk for disorders later in life. In farm animals, housing conditions or inadequate management practices during gestation may be potential stressors for the mother, which could affect growth, vitality, health and welfare of the dam and its offspring, and can also have economic implications. This paper gives a survey of results from different studies in pigs on the impact of maternal stress during gestation on growth, behaviour, neuroendocrine and immune functions in the offspring. Different experimental models using either elevated maternal cortisol levels or stress paradigms are introduced and major results are presented. The survey reveals that also in pigs prenatal stress can impair growth and modify immune functions, stress reactivity and behaviour in the offspring. The materno-foetal cortisol regulation is a major determinant of the alterations in the offspring, and mid- and late gestation seems to be sensitive gestational periods of increased vulnerability to prenatal stress. Neuroendocrine and behavioural results indicate that prenatally stressed pigs can express an over-reactive phenotype characterised by an increased HPA axis reactivity, altered emotionality, more fearfulness in a novel environment and disturbed social behaviour. Further research in this area should focus on the potential consequences of prenatal stress in offspring used for breeding as reproductive and behavioural characteristics may be affected in the long-term.