Banca de DEFESA: LIZ MAGALHÃES WALTENBERG

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LIZ MAGALHÃES WALTENBERG
DATE: 28/02/2025
TIME: 13:00
LOCAL: Banca híbrida - LQEPV/DPA/IV/UFRRJ + google meet (https://meet.google.com/ozh-wycf-qfe)
TITLE:

In vitro evaluation of cinnamaldehyde activity and its combined effect with different synthetic ectoparasiticides against fleas and ticks.

KEY WORDS:

plant-based inputs; Ctenocephalides felis felis; Rhipicephalus sanguineus, fipronil, cypermethrin, chlorpyrifos.

PAGES: 85
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Parasitárias de Animais
SUMMARY:

Ticks and fleas are the most prevalent ectoparasites in the world. In Brazil, Rhipicephalus sanguineus (s.l.) and Ctenocephalides felis felis stand out. The control of these blood-sucking arthropods has predominantly been carried out through the use of chemical ectoparasiticides for decades. Their indiscriminate use generates enormous selective pressure, which accelerates the emergence of resistant populations to the available chemical classes. Moreover, most of these chemicals persist in the environment and cause toxic effects in animals and humans. Some natural compounds from plants have been shown to be effective in the control of ectoparasites and have demonstrated significant potential as an alternative to synthetic products, being promising candidates for combined use with chemical agents. This way, safety is increased, efficacy is maintained, and the use of synthetic molecules, as well as their environmental residues, is reduced. There are still no published studies on the effect of cinnamaldehyde and its combination with other synthetic molecules against C. felis felis and R. sanguineus (s.l.). The objective of this study was to evaluate the acaricidal and insecticidal activity of cinnamaldehyde in vitro against the immature and adult forms of C. felis felis and R. sanguineus (s.l.), as well as the effect of combining this phenylpropanoid with cypermethrin, chlorpyrifos, and fipronil against adults of the same flea and tick species. All developmental stages of C. felis felis and R. sanguineus were obtained from laboratory colonies. Initially, the activity of cinnamaldehyde in vitro was evaluated against the adult and immature stages of C. felis felis and R. sanguineus. To determine the mortality percentage, the different developmental forms were exposed to a filter paper impregnated with six concentrations of cinnamaldehyde diluted in acetone. All tests were performed with six repetitions, and parallel negative, placebo, and positive controls were carried out. The mortality evaluation was performed after 24 hours of exposure for all challenged stages, except for C. felis eggs and pupae, for which mortality was evaluated at 3 and 15 days post-exposure. With the mortality results obtained, lethal concentrations 50 and 90 were calculated for each developmental form. Following this, new challenges were performed, only with adult individuals, to determine the mortality percentage and the CL50 for cypermethrin, chlorpyrifos, and fipronil. Based on the CL50 values obtained for each parasite and each substance, cinnamaldehyde combinations with synthetic molecules in a 1:1 ratio were made. The CL50 and CL90 estimates were obtained through Probit analysis using the RStudio Team® program, and to determine the combination index between cinnamaldehyde with cypermethrin, chlorpyrifos, and fipronil, the CompuSyn version 1.0 program was used. For fleas, the CL50 obtained were 8.1; 15.7; 20.5; and 128.1 µg/cm² for the egg, larva, pupa, and adult stages, respectively. For R. sanguineus s.l., the CL50 were 57.4; 374.9; and 709.4 µg/cm². In the evaluation of the combined effect of cinnamaldehyde with cypermethrin, additive/synergistic effects were observed for fleas and ticks, while the combination of cinnamaldehyde with chlorpyrifos showed antagonistic effects for the same parasites. For the combination of fipronil with cinnamaldehyde, a synergistic effect was observed for fleas and an antagonistic effect for ticks. Based on the results obtained in this study, it can be concluded that cinnamaldehyde has insecticidal and acaricidal activity against the immature and adult stages of C. felis felis and R. sanguineus s.l., and that a synergistic effect was observed with the combination of cinnamaldehyde with cypermethrin for fleas and ticks, and with fipronil only for C. felis felis.

COMMITTEE MEMBERS:
Presidente - ***.088.737-** - DIEFREY RIBEIRO CAMPOS - UFRRJ
Interna - ***.630.647-** - BARBARA RAUTA DE AVELAR - UFRRJ
Interna - 1700427 - YARA PELUSO CID
Externa à Instituição - MARISA CAIXETA VALADÃO - UFV
Externa à Instituição - LORENDANE MILENA DE CARVALHO - UFRB