title: Effect of handling on neurotransmitter profile in pig brain according to fear related behaviour.
abstract: Chemical neurotransmitters (NT) are principal actors in all neuronal networks of animals. The central nervous system plays an important role in stress susceptibility and organizes the response to a stressful situation through the interaction of the dopaminergic and the serotonergic pathways, leading to the activation of the hypothalamus-pituitary-adrenal axis (HPA). This study was designed to investigate: a) the effects of stressful handling of pigs at the slaughterhouse on the neurotransmitter profile in four brain areas: amygdala, prefrontal cortex (PFC), hippocampus and hypothalamus, and b) whether the alterations in the brain NT profile after stressful handling were associated with fear, determined by the tonic immobility (TI) test. In the first place, the characterization of the NT profile allowed to distinguish the four brain areas in a principal component analysis. The most crucial pathway involved in the reaction of pigs to a stressful handling was the serotonergic system, and changes were observed in the amygdala with a decrease in serotonin (5-HT) and total indoleamines, and in the hippocampus, where this pathway was activated. Fearful and non-fearful pigs did not show significant differences in their NT profile in control conditions, but when subjected to a stressful handling in the slaughterhouse, fearful animals showed a significant variation in the serotonin pathway and, in a lesser extent, the dopamine (DA) pathway. In conclusion, the existence of an underlying biological trait - possibly fearfulness - may be involved in the pig's response toward stressful challenges, and the serotonergic system seems to play a central role in this response.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Arroyo
authors.affiliation: IRTA, Animal Welfare Subprogram, Veïnat de Sies, s/n, 17121 Monells, Spain.
authors.forename: Ricard
authors.initials: R
authors.lastname: Carreras
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Valent
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain; Servei de Bioquímica Clínica Veterinària, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Peña
authors.affiliation: Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Mainau
authors.affiliation: IRTA, Animal Welfare Subprogram, Veïnat de Sies, s/n, 17121 Monells, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Velarde
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.
authors.forename: Josefa
authors.initials: J
authors.lastname: Sabrià
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain; Servei de Bioquímica Clínica Veterinària, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain. Electronic address: anna.bassols@uab.cat.
authors.forename: Anna
authors.initials: A
authors.lastname: Bassols
mesh_terms: D000588:Amines / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D005239:Fear / Q000502:physiology*; D006234:Handling, Psychological; D008297:Male; D018377:Neurotransmitter Agents / Q000378:metabolism*; D025341:Principal Component Analysis; D012149:Restraint, Physical; D013552:Swine
chemical_list: D000588:Amines; D018377:Neurotransmitter Agents
keywords: Brain; Dopamine; Pig; Serotonin; Stress; Tonic immobility