Acknowledgments: The authors are grateful to CIENCIACTIVA from the “Consejo Nacional de Ciencia, Tecnología e Inovación Tecnológica” (CONCYTEC, Peru; Contract 278-2015-FONDECYT) and to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil) for Carmen M.S. Ambrosio Ph.D. scholarship. The current manuscript is part of the doctoral thesis (10.11606/T.11.2020.tde-18052020-151325) authored by Carmen M.S. Ambrosio at University of São Paulo.

The authors are grateful to the “Ministerio de Educación del Perú” from the Peruvian government for Carmen M.S Ambrosio M.Sc. scholarship, granted by the program “Programa Nacional de Becas y Crédito Educativo” (PRONABEC). Also, the author thanks CIENCIACTIVA for the recent Carmen M.S. Ambrosio Ph.D. scholarship, from the “Consejo Nacional de Ciencia, Tecnología e Inovación Tecnológica” (CONCYTEC-Peru; Contract 278-2015-FONDECYT).

Post-weaning diarrhea (PWD) is an often disease affecting piglets. It is caused mainly by enterotoxigenic Escherichia coli (ETEC) colonization in pig gut. Antibiotics has been used to prevent, combat and control PWD and its negative impact on the productivity of pig breeding sector. Nonetheless, antibiotics due to their wide antibacterial spectrum also can reach beneficial gut bacteria, such as Lactobacillus. Lately, essential oils (EOs) have emerged as a potential alternative to using antibiotics in animal breeding because of their effect on bacterial growth. Commonly, citrus EOs are by-products of food industry and the availability of these EOs in the worldwide market is huge. Thus, six commercials citrus EOs were evaluated on ETEC strains, as model of pathogenic bacteria, and on Lactobacillus species, as models of beneficial bacteria. In overall, citrus EOs exhibited a selective antib...