Banca de DEFESA: BRENA GAVA GUIMARAES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : BRENA GAVA GUIMARAES
DATE: 03/03/2023
TIME: 14:30
LOCAL: Google Meet - meet.google.com/tqg-zxgo-iif
TITLE:

Evaluation of insecticidal in vitro activity of essential oils against Haematobia irritans adults

KEY WORDS:

horn fly, cattle ectoparasites; natural products

PAGES: 71
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

Responsible for affecting livestock activity with economic losses due to its parasitism, the horn fly, Haematobia irritans, is literally annoying to cattle, because the incessant bites interfere on weight gain and leather quality, which directly harms the milk and meat production. These factors affect health and welfare of these animals, and the control of this ectoparasite is indispensable, done for a long time indiscriminately with synthetic insecticides, causing flies’ resistance to some of these drugs. To reduce the use of these synthetic molecules and then reduce damage to animals, humans and the environment, an alternative is essential oils (EOs) with a large spectrum of insecticidal action, however, few EOs have been tested against H. irritans. Therefore, the objective of this work was to evaluate the insecticidal activity of Eugenia caryophyllus (clove), Cinnamomum cassia (cassia cinnamon), Thymus vulgaris (white thyme) and Illicium verum (star anise) EOs on adult flies of H. irritans, and to determinate its lethal concentration (LC) values: LC₅₀ and LC₉₀. The EOs were obtained commercially, and their constituents were determined through gas chromatography. The major ones being respectively: eugenol, (E)-cinnamaldehyde, thymol and ocymene, and (E)-anethole. The specimens from naturally infested cattle from the field area of the Laboratory of Experimental Chemotherapy in Veterinary Parasitology (LQEPV) at the Universidade Federal Rural do Rio de Janeiro (UFRRJ) were exposed to filter paper discs (63.62cm²) impregnated with different concentrations of the EOs in Petri dishes (90x15mm). The evaluation of mortality were made 2 and 4 hours after exposure. The concentrations that showed 100% of mortality at the 2h evaluation were 11.79 and 15.72 µg/cm² for clove, 39.30 µg/cm² for cinnamon, 47.15 µg/cm² for thyme and 235.77 µg/cm² for anise. And at the 4h evaluation of 15.72 µg/cm² for clove, 15.72 and 39.30 µg/cm² for cinnamon, 31.44 and 47.15 µg/cm² for thyme, and 157.18 and 235.77 µg /cm² for anise. The LC₅₀ and LC₉₀ were statistically calculated using Probit analysis using the RStudio Team Software program with a 95% confidence interval (p≤0.05). The LC₅₀ of the EOs at 2 and 4h were: 5.04 and 5.27 µg/cm² for clove, 8.57 and 5.03 µg/cm² for cinnamon, 18.57 and 14.08 µg/cm² for thyme and 83 .91 and 71.88 µg/cm² for anise. The LC₉₀ at 2 and 4h were: 11.71 and 10.03 µg/cm² for clove, 19.26 and 11.22 µg/cm² for cinnamon, 27.41 and 18.80 µg/cm² for thyme and 132, 78 and 101.30 µg/cm² for anise. Except LC₅₀ of clove EO, all LCs after 4h of exposure reduced. Despite this, the oil that showed the greatest performance was clove EO, followed by cinnamon, thyme and anise. Concluding that all evaluated oils showed in vitro insecticidal activity against the horn fly.

COMMITTEE MEMBERS:
Presidente - 1173660 - FABIO BARBOUR SCOTT
Interna - 1700427 - YARA PELUSO CID
Externo ao Programa - ***.965.206-** - CAIO MÁRCIO DE OLIVEIRA MONTEIRO - UFG
Externo à Instituição - GUILHERME MARCONDES KLAFKE