Available at: https://digitalcommons.calpoly.edu/theses/3090
Date of Award
6-2025
Degree Name
MS in Agriculture - Animal Science
Department/Program
Animal Science
College
College of Agriculture, Food, and Environmental Sciences
Advisor
Siroj Pokharel
Advisor Department
Animal Science
Advisor College
College of Agriculture, Food, and Environmental Sciences
Abstract
Essential oils (EOs) and prebiotics are increasingly utilized in the poultry industry as beneficial feed supplements that can help maintain gut health and microflora, promote production, and exhibit antimicrobial properties. This study aimed to investigate the effect of feeding EOs and prebiotics to late-stage laying hens and their impact on various metabolomic and physiological parameters. Sixty commercial caged Hy-Line W-80 White Leghorn laying hens were randomly allocated to one of four dietary treatments (15 hens/treatment) and fed ad libitum for twelve weeks. These treatments included 0% control (corn–soybean meal-based basal diet), 0.5% LOW (low EO-based basal diet), 1% HIGH (high EO-based basal diet) diets, and a 1% PRE (prebiotic-based basal diet). Weekly body mass and feed conversion ratio were measured. At the end of the twelfth week, a complete blood profile, metabolomic panels of cecal, serum, and liver samples, and bone strength tests were performed. Liver histopathology was also analyzed. Blood chemistry and bone strength were analyzed using SAS 9.4. All metabolomic data were analyzed using MetaboAnalyst software. Liver histopathology was scored on an ordinal basis, then analyzed using Kruskal-Wallis ANOVA with Dunn’s multiple comparisons test. Blood panels were lowered in prebiotic-treated hens. There was a stepwise decrease in Phosphorus and Calcium levels from control to prebiotic diets. The 0.5% low EO-based basal diet treated birds showed a significant increase (p < 0.05) in Lipemic Index compared to other diets. Cecal metabolites, aspulvinone E and coumestrol, were lowered in control hens and high EO-treated hens, respectively. Prebiotic-fed hens exhibited elevated levels of various significant serum metabolites. Liver metabolites as well as liver histopathology showed no significant differences between treatments (p > 0.05). Likewise, no significant differences were found between treatments for the bone strength. (p > 0.05). Additional research is necessary to determine the functional role of EOs and prebiotics as potential feed additives in the diets of late-stage laying hens.
data
Metabolomics serum data.csv (255 kB)
data
Metabolomics liver data.csv (291 kB)
data