Perinatal Flavour Learning and Adaptation to Being Weaned: All the Pig Needs Is Smell

Abstract

Perinatal flavour learning through the maternal diet is known to enhance flavour preference and acceptance of flavoured food in many species, yet still little is known about the mechanism underlying perinatal flavour learning. Previously we found positive effects of perinatal flavour learning on food intake, growth and behaviour of piglets postweaning, but no increased preference for the flavour. This suggests that flavour learning in pigs works through a reduction of weaning stress by the presence of the familiar flavour instead. The aim of this study was to investigate whether perinatal flavour learning reduces stress at weaning, and whether the effect is stronger when the familiar flavour is present in the food. Sows were offered an anethol-flavoured diet (Flavour treatment) or control diet (Control treatment) during late gestation and lactation. Flavour and Control piglets were provided with anethol either in their food (Food treatment) or in the air (Air treatment) after weaning. Preweaning and postweaning treatments did not affect food intake, preference or growth in the first two weeks postweaning but flavour treatment reduced the latency to eat (24 versus 35 hours, P = 0.02) and within-pen variation in growth (SD within-pen: 0.7 versus 1.2 kg, P<0.001). Salivary cortisol levels tended to be lower four and seven hours postweaning for Flavour piglets compared to Control piglets (4 hours: 2.5 versus 3.0 ng/ml, P = 0.05, 7 hours: 3.1 versus 3.4 ng/ml, P = 0.08). Flavour piglets played more and showed less damaging behaviours than Control piglets, indicating that the familiar flavour reduced stress around weaning. Few interaction effects were found between preweaning and postweaning treatment, and no effects of postweaning treatment. We conclude that in the newly weaned pig, perinatal flavour learning results in a reduction of stress when the familiar flavour is present, regardless of providing the flavour in the food or in the air.

Facilitating ‘learning from mom how to eat like a pig’ to improve welfare of piglets around weaning

“…This seemed to be the case at weaning of our pigs too. Piglets that were re-exposed to a familiar flavour they had experience perinatally after weaning, even when this flavour was just in the environment and not in the food, had lower cortisol levels, lower within-pen variation in growth and number of vocalizations, and more play behaviour (Table 1, Oostindjer et al, 2011b) that the piglets who were not familiar with the flavour. Other studies also show the merits of having a familiar flavour in the postweaning pen: a flavour associated with the mother during lactation (applied on the sow's mammary glands) had positive effects on postweaning behaviours, particularly aggressive behaviour (Fuentes et al, 2012).…”

Development of pigs raised in a group housing system for lactating sows and their litters

“…Other strategies that can ease the transition to the post-weaning situation, such as the presence of a familiar flavour in the weaner pen and facilitation of preweaning eating behaviour by learning from the sow, also decreased the level of manipulative behaviour within the first 2 weeks after weaning (Oostindjer et al, 2011a;Oostindjer et al, 2011b). Interestingly, in our study we found more long-term effects, as e.g.…”

“…Social facilitation of eating behaviour and social learning from the floor-fed sows and other piglets (Nicol and Pope, 1994;Morgan et al, 2001;Oostindjer et al, 2011a) may have stimulated early foraging in ML piglets, whereas SL piglets had limited possibilities to observe or participate in the sow's eating behaviour. The interest of ML piglets in the sows' feed, besides by having easier access, could be mediated by exposure to the flavours from the sows' diet in utero and via milk reviewed by Bolhuis et al, 2009;Oostindjer et al, 2009; also see Figueroa et al, 2013b).…”

“…For instance, MS housing may promote social development by providing contact between multiple sows and litters, similar to the social structure seen in feral pigs and wild boar. Moreover, an opportunity of MS housing that has received little attention so far is the stimulation of pre-weaning ingestive behaviour through learning from other piglets and sows, which may positively affect postweaning performance (Oostindjer et al, 2011a). Another advantage of MS systems is the possibility of keeping piglets in larger groups, without a need for the post-weaning mixing of unfamiliar piglets, which is one of the simultaneous stressors weanling piglets often have to cope with (Weary et al, 2008).…”

Prenatal Chemosensory Learning by the Predatory Mite Neoseiulus californicus

“…[3], [17]). Prenatal flavor learning through the maternal diet is associated with subsequent postnatal preference for this flavor in many other mammals, such as pigs [18], [19], mice [17], rabbits [20], rats [4], [21], dogs [5], cats [22] and lambs [1]. For example, prenatal exposure of dog embryos to aniseed flavor through the maternal diet induced a feeding preference for this flavor in pups [5].…”