Metabolic and behavioral effects of ractopamine at continuous low levels in rats under stress

• Autor(a) principal: Lopes, Edna
• Data de Publicação: 2015
• Outros Autores: Sousa, Raimundo Vicente de, Zangerônimo, Márcio Gilberto, Pereira, Andressa Naira de Jesus, Coelho, Mariana de Resende, Ferreira, Matheus Soares da Silva, Lima, Renato Ribeiro, Marcondes, Fernanda Klein, Napimoga, Marcelo Henrique, Pereira, Luciano José
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFLA
• Texto Completo: http://repositorio.ufla.br/jspui/handle/1/41779
• topic: β-adrenergic agonist; Ractopamine; Zootechnical performance; Metabolism; Elevated Plus-Maze Tests; Agonistas adrenérgicos beta-2; Ractopamina; Rato - Estresse; Desempenho zootécnico; Teste de labirinto em cruz elevado

This study aimed at evaluating the effect of ractopamine (RAC) on metabolism, zootechnical performance, body composition, and behavior in Wistar rats submitted to acute and chronic restrain stress. The oral dose of 5 mg/kg of RAC was administered in periods of 0, 7, 14, 21, and 28 days. The elevated plus-maze test (EPMT) was used for behavioral assessment. Blood, carcass and viscera characteristics were evaluated. Insulin-dependent glucose transporters (GLUT-4) were semi-quantified by Western Blot in epididymal adipocytes. RAC periods associated with chronic stress increased the GLUT-4 protein expression in adipose tissue in a time-dependent manner (P=0.01), i.e., the longer the RAC addition period, the higher the GLUT-4 concentration in chronically stressed animals (0=1.42; 7=1.19; 14=2.03; 21=1.59; 28=2.35). The stress periods combined with RAC increased the time spent in the opened arms of the maze (Chronic stress: 0=10.6; 7=8.7; 14=5.9; 21=12.3; 28=4.0; Acute stress 0=3.1; 7= 4.7; 14=7.5; 21=0.0; 28=2.8) (P=0.04). Chronic (entries on the closed arms [ECA]=3.60) and acute (ECA=3.80) stress reduced locomotive activity in the maze (P=0.03). The results suggested that stress could negatively affect the possible benefits offered by the RAC, mainly impairing the adipose tissue metabolism and behavior in the animals.