Theses and Dissertations

ORCID

https://orcid.org/0000-0001-7978-3017

Advisor

Wamsley, Kelley G. S.

Committee Member

Wells, Jessica B.

Committee Member

Adhikari, Pratima A.

Committee Member

Brown, Andrew T.

Date of Degree

5-16-2025

Original embargo terms

Visible MSU Only 1 year

Document Type

Dissertation - Campus Access Only

Major

Agricultural Sciences (Poultry Science)

Degree Name

Doctor of Philosophy (Ph.D.)

College

College of Agriculture and Life Sciences

Department

Department of Poultry Science

Abstract

Functional feed additives, such as probiotics, prebiotics, and phytogenics, have seen increased usage in commercial poultry production due to their ability to improve growth performance, meat yield, and overall health status. Therefore, the objective of this research was to evaluate the efficacy of functional feed additives in broilers with or without an enteric challenge induced via a live coccidiosis vaccine (LCV). In the first study (Chapter II), broilers were raised on used litter without an LCV challenge and fed varying levels of a multi-strain Bacillus-based probiotic in the starter phase (1x or 2x dose). Reduced performance was observed in early phases; however, broilers fed the probiotic were able to compensate in later phases. Birds fed the 2x dose early had improved FCR ~2 points compared to a control and antibiotic diet. No differences were observed for health and managements metrics measured. In the second study (Chapter III), broilers were raised to 23 d and given a 10x dose of an LCV at d 14. Treatments included a positive (PC) and negative control (NC), zoalene (ZOA), a blend of yeast components (YC), a saponin (SAP), and their combination (YC+SAP). From d 0-14, YC, SAP, and YC+SAP had similar FCR as ZOA. Cumulative (d 0-21) BWG was improved in all treatments versus PC and ZOA and YC+SAP had similar FCR at the end of the study. In general, no differences were observed in lesion scores. In the last study (Chapter IV), 2 EXP were utilized, and broilers were supplemented with 2 levels of an alkaloid, sanguinarine (SAN60 and SAN120) versus a control (CON), and given a 10x LCV dose at d 14, as well as a 15x dose at d 42. Two different LCV were tested. In EXP 1, CON had reduced FCR throughout the EXP and no differences were observed for lesion scores following both LCV challenges. In EXP 2, CON and SAN120 improved BWG from d 0-21. The CON had the lowest cumulative FCR, but similar to birds fed SAN120. These studies demonstrate that functional feed additives may be viable solutions to enteric challenges faced in the poultry industry.

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