The present work studies different learning strategies to increase the preference for flavours cues during lactation and after weaning. We propose that pigs may learn flavour preferences from their mother (Chapter 1 and 5), from trial and error tasks (Chapter 2 and 3) or from social interactions with conspecifics (Chapter 4), and that this learning may improve intake of new diets. Chapter 1 evaluate if piglets have the ability to prefer cues of maternal amniotic fluid after birth. During 7 minutes piglets couples were tested to prefer between maternal amniotic fluid, alien amniotic fluid and water or between a flavour added into late gestation maternal diet, a control flavour and water. The same prenatal strategy was used to study piglet’s preferences for flavoured or unflavoured creep feed during the suckling period. Suckling piglets preferred the amniotic fluid from their own mother over an alien amniotic fluid and also they preferred flavours cues given to the sows during the gestation period. However, prenatal flavour exposure did not created feed preferences during lactation. Chapter 2 study if piglets could learn by trial and error to prefer a new flavour cue. Animals were trained to drink (30min/day) one flavour (CS+) mixed into 2% protein solution (Soybean-Protein-Concentrate or Porcine-Digestible-Peptides; PDP) and another flavour (CS-) mixed into water during 6 alternate sessions. Animals preferred the CS+ over the CS- flavours at all test days. No differences were observed between proteins. In a second experiment a conditioned flavour preference also enhanced the attraction to a protein (PDP) when the flavour and protein were combined showing a synergy effect between the CS+ and US attraction. Chapter 3 evaluate flavour preferences conditioned by the post-ingestive effect of nutrients. Pigs were trained during 8d with one flavour (CS+) into PDP or sucrose solutions on odd days and another flavour (CS-) into 100 mM of monosodium glutamate (MSG) or 1% sucrose + 0.08% saccharine solutions on even days. Piglets showed higher intakes for CS+ than CS- explained because an associative learning between flavours and post-ingestive effects of nutrients. Chapter 4 describes social learning of feeding behaviour in pigs, in which a naive animal could learn specific flavour preferences by a close and brief contact with a conspecific. Piglets showed a preference for flavoured feed following social interactions (30 minutes) with an experienced demonstrator that ate that flavour before. However, higher intakes of demonstrators consumed flavoured feed were observed only when demonstrators and observers were familiar. Chapter 5 study the importance of milky flavour continuity in the post-weaning period and explore the influence of pre and postnatal exposure to PDP via maternal diet on the productive performance of post-weaned piglets fed a diet containing the same protein. No differences were found between the productive parameters of animals fed with dairy or PDP diets. However, animals showed a higher preference and acceptance for diets containing dairy products than for PDP diets (30 minutes choice and one feeder test). When the PDP was added to sows diets, post-weaned piglets tended to show higher ADFI and ADG than control piglets (15-33d after weaning). It is concluded that pigs may learn to prefer neutral flavours cues by a previous associative learning with a positive consequence. Flavour preferences learned through maternal transference, associative learning with nutrients and social interactions could increase pigs options to fit against new environment feed cues. These three ways of learning could act also together increasing the adaptive value of the learned feed.
Learning strategies to increase piglets feed intake after weaning
Jaime, F. H. (Author). 18 Dec 2012
Student thesis: Doctoral thesis
Student thesis: Doctoral thesis