Date of Graduation

5-2024

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor/Mentor

Hargis, Billy M.

Committee Member

Tellez, Guillermo

Second Committee Member

Caldwell, David J.

Third Committee Member

Latorre Cardenas, Juan D.

Keywords

Chickens; In vitro crop assay; Lippia organoides; Salmonella Enteritidis; Thymol chemotype

Abstract

The purpose of the present research was to evaluate the bactericidal activity of a microencapsulated Lippia origanoides essential oils (LOEOs) against Salmonella Enteritidis (SE) in an in vitro crop assay and in a prophylactic broiler chicken model using three low doses of the product: 75 ppm, 150 ppm and 300 ppm. Two trials of each assay were conducted. Day-of-hatch male Cobb-Vantress broiler chickens were randomly allotted to one of four groups: 1) positive control group; 2) 75 ppm LOEOs group; 3) 150 ppm LOEOs group; 4) 300 LOEOs group. Chicks were fed and watered ad libitum in heated brooder batteries in a controlled, age-appropriate environment. On day seven of age, all chickens were orally gavaged with 108 cfu of SE. Chickens were euthanized by CO2 exposure 24 hours after the SE challenge. Recovery of SE was evaluated in liver- spleen, and ceca (including cecal tonsils). None of the three microencapsulated LOEOs doses changed SE concentration (P > 0.05) in the in vitro crop assay. Similarly, no significant differences in SE were observed in the organ and intestinal colonization in broiler chicken trials. Therefore, the low concentrations of the microencapsulated LOEOs used do not reduce SE concentration in different poultry models. Further studies will be needed to optimize the formulation, delivery, models, and concentration of essential oils to control Salmonella infections in broiler chickens effectively.

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