RESUMO
The aim of this study was to evaluate the antimicrobial activity and determine the minimum bactericidal concentration (MBC) of the essential oils derived from Origanum vulgare (oregano), Melaleuca alternifolia (tea tree), Cinnamomum cassia (cassia), and Thymus vulgaris (white thyme) against Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis. The study also investigated the ability of these different bacterial strains to develop adaptation after repetitive exposure to sub-lethal concentrations of these essential oils. The MBC of the essential oils studied was determined by disc diffusion and broth dilution methods. All essential oils showed antimicrobial effect against all bacterial strains. In general, the development of adaptation varied according to the bacterial strain and the essential oil (tea tree > white thyme > oregano). Therefore, it is important to use essential oils at efficient bactericidal doses in animal feed, food, and sanitizers, since bacteria can rapidly develop adaptation when exposed to sub-lethal concentrations of these oils.
La présente étude avait pour but d'évaluer l'activité antimicrobienne et de déterminer la concentration bactéricide minimale (CBM) des huiles essentielles dérivées d'Origanum vulgare (origan), de Melaleuca alternifolia (l'arbre à thé), de Cinnamomum cassia (cassia), et de Thymus vulgaris (thym blanc) contre Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus, et Enterococcus faecalis. L'étude visait également à examiner la capacité de ces différentes souches bactériennes à développer une capacité d'adaptation après une exposition répétée à des concentrations sub-létales de ces huiles essentielles. La CBM des huiles essentielles étudiées a été déterminée par des méthodes de diffusion en disque et de dilution en bouillon. Toutes les huiles essentielles ont démontré un effet antimicrobien contre toutes les souches bactériennes. En général, le développement de la capacité d'adaptation variait selon la souche bactérienne et l'huile essentielle (arbre à thé > thym blanc > origan). Il est donc important que les huiles essentielles soient utilisées à des doses bactéricides efficaces dans la nourriture animale, les aliments, et les assainisseurs, étant donné que les bactéries peuvent rapidement développer une adaptation lorsqu'exposées à des concentrations sub-létales de ces huiles.(Traduit par Docteur Serge Messier).
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Aditivos Alimentares/farmacologia , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia , Ração Animal , Animais , Farmacorresistência Bacteriana , Óleos de Plantas/química , Plantas/química , Plantas/classificaçãoRESUMO
An experiment was conducted to evaluate the addition of sodium butyrate, plant extracts and nucleotides on weanling pig performance, digestive content pH, organ morphometry, and intestinal epithelial histology. A total of 90 piglets at 21 days of age and an average initial weight of 6.35±0.34kg were used. The piglets were distributed in a randomized complete block design with five treatments, six replicates, and three animals per experimental unit. The treatments consisted of the following: Control: basal diet without antibiotic; Antibiotic: basal diet with 40mg kg-1 colistin sulfate and Additive: 1000, 1500 and 2000mg kg-1 of a combination of sodium butyrate + plant extracts + nucleotides. The experiment lasted 35 days, at which time one animal was slaughtered to assess pH of the digestive contents, morphometry of the organs and histology of the intestinal epithelium. No differences were found (P>0.05) in the performance, pH of the digestive contents, morphometry of the organs or histology of the intestinal epithelium by the analysis of orthogonal polynomials or contrasts. The combination of sodium butyrate, plant extracts and nucleotides not improved the productive characteristics of weanling pigs.
Foi conduzido um experimento para avaliar a adição de butirato de sódio, extratos vegetais e nucleotídeos sobre desempenho, pH do conteúdo digestório, morfometria dos órgãos e histologia do epitélio intestinal de leitões desmamados. Foram utilizados 90 leitões, com idade média de 21 dias e peso médio inicial de 6,35±0,34kg. Os leitões foram distribuídos em um delineamento em blocos casualizados completos, com cinco tratamentos, seis repetições por tratamento e três animais por unidade experimental. As dietas experimentais consistiam de: Controle - dieta basal sem antibiótico; Antibiótico - dieta basal com 40mg kg-1 de sulfato de colistina; Aditivo: 1000, 1500 e 2000mg kg-1 de uma combinação de butirato de sódio + extrato vegetal + nucleotídeos. No 35o dia de experimentação, foi eutanasiado um animal por gaiola (unidade experimental) para avaliar o pH do conteúdo digestório, morfometria de órgãos e histologia do epitélio intestinal. Não foram observadas diferenças (P>0,05) para desempenho, pH do conteúdo digestório, morfometria de órgãos e histologia do epitélio intestinal por meio das análises de polinômios ortogonais ou mesmo pelos contrastes. A combinação de butirato de sódio, extratos vegetais e nucleotídeos não melhorou as características produtivas de leitões desmamados.