Sham-Chewing in Sows Is Associated With Decreased Fear Responses in Their Offspring

Abstract

We hypothesized that sham-chewing expressed by the dam during gestation affects fetus programming. The goal of this study was to assess the effects of maternal sham-chewing on offspring welfare indicators, such as behavior and physiology. Sows that exhibited consistent sham-chewing on at least two of 6 days of observation (N = 7) were compared with sows that had never performed sham-chewing (non-sham-chewing sows; N = 4) during these 6 days. Salivary samples from sows and piglets were collected and cortisol concentrations were analyzed to assess the hypothalamic pituitary adrenal (HPA) axis activity as cortisol is a physiological indicator of welfare. Moreover, placental tissue was collected, right after farrowing, to assess cortisol and cortisone concentration. Piglet behavior and fear tests were performed after weaning (one couple per sow). In the fear tests, data was collected in an open field test to determine the states of fear indicators. Non-sham-chewing sows had lower concentrations of cortisol on days 91 and 92 of gestation in the morning. In addition to this, placental cortisol was higher among sham-chewing sows than non-sham-chewing sows. In the open field test, piglets born from non-sham-chewing sows demonstrated more latency to move in the arena and less activity, indicating more fear. Based on our data, we concluded that the expression of maternal sham-chewing is related to less fear in their offspring. Although stereotypies have been studied, attention has not been devoted to the effects of the prenatal period in considering a fetal reprogramming approach.

Stereotypic Behavior in Sows Is Related to Emotionality Changes in the Offspring

“…This increased movement in the test could be an indicator of more encouraged and explorative animals, showing a potential benefit for the offspring from sows with a high rate of stereotypies when gestation occurred in challenging environments. This result agrees with another study comparing the offspring of sham-chewing to non-shamchewing sows (34). We demonstrated in the same behavioral assessment tests that in the open field test, piglets born from nonsham-chewing sows demonstrated more latency to move in the arena and less activity, indicating more fear (34).…”

“…This result agrees with another study comparing the offspring of sham-chewing to non-shamchewing sows (34). We demonstrated in the same behavioral assessment tests that in the open field test, piglets born from nonsham-chewing sows demonstrated more latency to move in the arena and less activity, indicating more fear (34). An alternative explanation could be a response to increased anxiety in relation to novel social isolation.…”

“…Not all the elements showed by stereotypies in relation to the welfare of an animal and its offspring are clear, although there are many studies elucidating issues about this indicator. In another study (34), it is shown that maternal sham-chewing expressions are related to less fear in their offspring. However, we do not know whether the differences in the emotionality of the offspring are a consequence of the genetic (6) or personality (7,8) predisposition associated with stereotypies in the sows.…”

Donkey Skin Trade and Its Non-compliance With Legislative Framework

“…Animals' capacity to experience and express emotions has also been demonstrated ( 10 , 12 , 33 , 34 ) particularly their capacity to feel anxiety, fear ( 33 , 35 ), anhedonia ( 36 ), and motivation ( 37 ). Non-human animals can also change their behavior, based on previous experience and, like humans, can be more optimistic or pessimistic due their experiences, a response called cognitive bias ( 38 ).…”

How Epigenetics Can Enhance Pig Welfare?

“…The interaction among animals and their environments was an issue of discussion even before the theory of evolution through natural selection [ 72 ]. However, the role of genetic factors at the molecular level and their environmental interactions are still premature [ 38 , 73 , 74 , 75 , 76 , 77 ]. When the individual is exposed to an environmental experience, it is possible to determine what the epigenetic effects generated are [ 78 ], and methylation is a promising biomarker to detect and evaluate these effects [ 17 ].…”