Óleos essenciais como substituintes de antibióticos promotores de crescimento em frangos de corte: perfil de soroproteínas e peroxidação lipídica

Essential oils are an alternative to growth promoters based on antibiotics used in animal diets, due to its antimicrobial potential, and immunomodulatory properties. Serum proteins electrophoresis and plasma lipid peroxidation were evaluated in broilers fed with diets supplemented with antibiotics or essential oils from oregano (Origanum vulgare L.), sage (Salvia officinalis L.), rosemary (Rosmarinus officinalis L.) and pepper (Capsicum frutescens L.) crude extract (OLES). The animals (n=910) were distributed within five treatment groups and seven replicates containing 26 birds each one: control group (diet without additives); the group receiving an antibiotic growth promoter diet (Tatb); and the groups T50, T100 and T150 (supplemented with 50, 100 and 150mg kg-1 of OLES, respectively). After 42 days, seven animals were randomly selected for serum proteins electrophoretic fractionation and plasma lipid peroxidation evaluation by thiobarbituric acid reactive species (TBARS) test. Total globulins (T150), betaglobulin fraction (Tatb and T150) and plasma TBARS levels in the groups that received OLES (P<0.05) presented a decrease in relation to the control group. These results suggests lower stimulus to the humoral immune response at the higher dose of OLES, as occurred in the antibiotic growth promoter group. Moreover, it suggests lower lipid peroxidation and, consequently, lower oxidative damage caused by OLES use in broiler chickens.