The Effects Of Microencapsulated Vitamin And Trace Mineral Premixes And Red Osier Dogwood Extract On Growth Performance, Immune Response, And Gut Health Of Broiler Chickens In A Coccidiosis Vaccine Challenge Model

The poultry industry faces pressure to reduce antibiotic use while meeting rising demand for poultry products and controlling diseases such as coccidiosis, which cause significant global economic losses. Consequently, there is an urgent need for nutritional strategies to support gut health and immunity of broiler chickens. This thesis investigated the effects of two distinct dietary feed additives on growth performance, nutrient digestibility, immune response, and meat yield during a coccidiosis vaccine challenge using a 12x label dose of live coccidiosis vaccine in broiler chickens housed in bioassay cages. The first study evaluated the effects of red osier dogwood extract (RDE) inclusion (0%, 0.15%, and 0.30%) in 336 Ross 308 broilers. RDE linearly increased spleen weight without affecting bursa or liver weight, suggesting immune stimulation. While the 0.30% inclusion improved feed intake and body weight, the 0.15% level yielded the highest IgM titers and protein digestibility. Additionally, in the vaccinated group, 0.15% RDE resulted in superior villus height and villus height-to-crypt depth ratios compared to the higher dose. The second study utilized 560 Ross 308 broilers to examine the effects of microencapsulated vitamin and trace mineral premixes. Dietary treatments consisted of a corn-soybean meal basal diet supplemented with: a free-form vitamin and trace mineral premix (PA); microencapsulated premix A at 75% inclusion of the PA in the diet (M(PA75)); microencapsulated premix B (M(PB)); and microencapsulated premix B with phased reductions in the diet (M(PB66)), dosed at 91.4%, 83.3%, and 66.7% of the M(PB) inclusion in starter, grower, and finisher phases, respectively. Results indicated that microencapsulated premixes, even at reduced inclusion levels, significantly improved growth performance throughout the study compared to PA, and enhanced crude protein digestibility. Among the dietary treatments, M(PA75) produced the tallest jejunum villi. The vaccine challenge model did not result in coccidiosis, likely due to the bioassay cage limitation. However, both RDE and microencapsulated premixes are relevant tools for improving growth performance, protein digestibility, and gut morphology.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Animal Science

Grantor

University of Saskatchewan

Year dc:date.issued

2026

Author dc:creator

• Santos Reis Pereira, Italo

Advisor dc:contributor.advisor

• Adewole, Deborah

Committee members dc:contributor.committeemember

• Zhao, Xin
• Newkirk, Rex
• Gomis, Susantha
• Penner, Gregory

• Broiler
• Coccidiosis
• Gut health
• Immune response
• Performance
• Phytogenic feed additive
• Trace minerals
• Vitamins

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10388/17878

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/17878