Vulnerability to dietary n-3 polyunsaturated fatty acid deficiency after exposure to early stress in rats Charles Francisco Ferreira a, b, c, ⁎, Juliana Rombaldi Bernardi c , Rachel Krolow b , Danusa Mar Arcego b , Gabriel Rodrigo Fries d , Bianca Wollenhaupt de Aguiar d , Gabrielle Senter c , Flávio Pereira Kapczinski d , Patrícia Pelufo Silveira a, c , Carla Dalmaz a, b a Programa de Pós-Graduação em Ciências Biológicas: Neurociências, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil b Laboratório de Neurobiologia do Estresse, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil c Núcleo de Estudos da Saúde da Criança e do Adolescente, Hospital de Clínicas de Porto Alegre (HCPA), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil d Laboratório de Psiquiatria Molecular. Serviço de Psiquiatria, Hospital de Clínicas de Porto Alegre (HCPA), Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil abstract article info Article history: Received 13 December 2012 Received in revised form 28 February 2013 Accepted 7 March 2013 Available online 26 March 2013 Keywords: n-3 PUFA deficiency Neonatal handling Maternal separation Sucrose preference test Locomotor activity Brain-derived neurotrophic factor (BDNF) The exposure to adverse events early in life may affect brain development. Omega-3 polyunsaturated fatty acid (n-3 PUFA) deficiency has been linked to the development of mood and anxiety disorders. The aim of this study was to examine the interaction between variations in the early environment (handling or maternal separation) and the chronic exposure to a nutritional n-3 PUFA deficiency on locomotor activity, sucrose preference, forced swimming test and on serum and hippocampal brain-derived neurotrophic factor (BDNF) levels. Rats were randomized into Non-handled (NH), Neonatal Handled (H) and Maternal Separated (MS) groups. Pups were removed from their dams (incubator at 32 °C on postnatal days (PND) 1–10) during 10 min/day (H) or 3 h/day (MS). On PND 35, males were subdivided into diets adequate or deficient in n-3 PUFA for 15 weeks. H and MS gained weight differently, and animals receiving the n-3 PUFA deficient diet gained less weight. MS displayed a higher food consumption and higher consumption of sucrose solution during the second hour of exposure to the sucrose preference test. No differences were observed in the swimming test. H group had increased locomotion and showed a higher response to amfepramone. No significant effect was observed on serum BDNF levels. BDNF protein levels were decreased in animals receiving the n-3 PUFA deficient diet. We observed that early life environment and a mild n-3 PUFA deficiency are able to affect several behavioral aspects (food and sucrose consumption and locomotor response), and lead to a differential hippocampal BDNF metabolism in adult life. © 2013 Elsevier Inc. All rights reserved. 1. Introduction Exposure to adverse events early in life may affect brain development profoundly, leading to long-lasting effects on neuronal structure and behavior and playing a role in the etiology of mood and anxiety disorders. Cognitive disturbances in later life are among the impairments of brain function that may be induced by early stress (Bremner and Narayan, 1998). Adverse early life environments, including loss of a parent, parental abuse or neglect, are also associated with traits of altered physiological and neurobiological functioning and long-term vulnerabil- ity to depression (Agid et al., 1999). In animal models, the early relation- ship between mother and infant is critical for optimal development of the offspring (Hofer, 1994). Several years ago, Levine (1957) and other researchers described the effects of postnatal handling on the develop- ment of behavioral and endocrine responses to stress. The handling procedure usually involves removing rat pups from their cages, placing the animals together in small containers, and returning them to their cages—and their mothers—some minutes later. As adults, handled rats exhibit attenuated fearfulness (decreased freezing and increased exploration) in novel environments (Benetti et al., 2007) and a less pronounced increase in the secretion of adrenal glucocorticoids in response to a variety of stressors (Meaney et al., 1991). On the other hand, early maternal separation (MS; separation of pups from their dams for longer periods) has been used to mimic early-life parental neglect in humans and is considered one of the most powerful stressors Pharmacology, Biochemistry and Behavior 107 (2013) 11–19 ⁎ Corresponding author at: Rua Ramiro Barcelos 2600 Anexo, Departamento de Bioquímica, UFRGS, CEP 90035-000, Porto Alegre/RS, Brazil. Tel.: + 55 51 3308 5569; fax: + 55 51 3308 5535. E-mail addresses: neurocientista@hotmail.com (C.F. Ferreira), juliana.bernardi@yahoo.com.br (J.R. Bernardi), krolowrachel@yahoo.com.br (R. Krolow), danusa_pf@hotmail.com (D.M. Arcego), gabrielrfries@gmail.com (G.R. Fries), biancawaguiar@gmail.com (B.W. de Aguiar), gabismed@gmail.com (G. Senter), flavio.kapczkisnki@gmail.com (F.P. Kapczinski), raty@cpovo.net (P.P. Silveira), carladalmaz@yahoo.com.br (C. Dalmaz). 0091-3057/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.pbb.2013.03.006 Contents lists available at SciVerse ScienceDirect Pharmacology, Biochemistry and Behavior journal homepage: www.elsevier.com/locate/pharmbiochembeh