Antimicrobial effect of bothropstoxin-i in broilers Atividade antimicrobiana da bothropstoxin-i em frangos de corte

Bacterial resistance is a sanitary issue explained by indiscriminate use of nonprescription drugs, and antimicrobial use in food production for growth promotion. Bothropstoxin-I (BthTx-I) is a phospholipase A2 (PLA2) from Bothrops jararacussu venom, which has a known antimicrobial effect. The goal of this study was the unprecedented evaluation of in vivo antimicrobial activity of BthTx-I in broilers. Microbiological, biochemical, and histological parameters were determined using 84 21-day old broilers that were kept in cages with four birds each at a density of 625 cm2/broiler. The experiment was randomized by three treatments with seven repetitions of four broilers each that lasted seven days. The treatments were: 1) bacitracin zinc diet; 2) PLA2-BthTx-I; 3) without additives. The data obtained from the studied variables was subjected to analysis of variance and an F-test at the 5% significance level. Averages of each variable in each treatment were compared by Tukey’s test. Broiler bacterial cloacal counts showed that BthTx-I decreased the microbial population without reducing body weight, intestinal morphology, or liver or kidney histopathological damage. The toxin showed in vivo activity, being an alternative for better performance in the production of 1 Profa Dra, Instituto Federal do Triângulo Mineiro, IFTM, Uberaba, MG, Brasil. E-mail: anacarolinaportella@gmail.com 2 Bióloga, Instituto Butantan, São Paulo, SP, Brasil. E-mail: sarah_gi_menes@hotmail.com 3 Prof. Dr., Faculdade Pitágoras, Uberlândia, MG, Brasil. E-mail: lfbarbaresco@hotmail.com 4 Discente de Doutorado em Biologia Celular e Molecular Vegetal, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, ESALQ, USP, Piracicaba, SP, Brasil. E-mail: camila_perdoncini@hotmail.com 5 Prof. Dr., Centro Universitário do Triângulo, UNITRI, Uberlândia, MG, Brasil. E-mail: jprbueno@hotmail.com 6 Prof. Dr., Faculdade de Matemática, Universidade Federal de Uberlândia, UFU, Uberlândia, MG, Brasil. E-mail: ecg@ufu.br 7 Médico Veterinário da “Yes Nutrition”, Uberaba, MG, Brasil. E-mail: pfafreitas@gmail.com 8 Profs. Drs., Faculdade de Medicina Veterinária, UFU, Uberlândia, MG, Brasil. E-mail: maran@ufu.br; robson.antunes@ ufu.br 9 Profa Dra, Instituto de Genética e Bioquímica, UFU, Uberlândia, MG, Brasil. E-mail: vmravila@hotmail.com * Author for correspondence 267 Semina: Ciênc. Agrár. Londrina, v. 42, n. 1, p. 267-282, jan./fev. 2021 DOI: 10.5433/1679-0359.2021v42n1p267 Received: Apr. 17, 2020 Approved: Oct. 14, 2020 Silveira, A. C. P. et al. 268 Semina: Ciênc. Agrár. Londrina, v. 42, n. 1, p. 267-282, jan./fev. 2021 broiler chickens, because it acted by decreasing the microbial load of potentially pathogenic bacteria in the intestinal microbiota of the birds and did not cause muscle, liver or kidney damage at the assessed dosage.