Banca de DEFESA: PAMELLA PRYSCILA DE ALVARENGA BISSOLI MACIEL DE LIMA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : PAMELLA PRYSCILA DE ALVARENGA BISSOLI MACIEL DE LIMA
DATE: 27/02/2026
TIME: 13:00
LOCAL: Plataforma Google Meet
TITLE:

Analysis of the Intestinal Inflammatory Response and Cecal Content Microbiome of Poultry Challenged with Different Vaccine Doses of Eimeria spp.

KEY WORDS:

Eimeria tenella, Eimeria acervulina, Eimeria maxima, Coccidiosis, Cytokine expression, Gut health, Broilers

PAGES: 73
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Parasitárias de Animais
SUMMARY:

Avian coccidiosis is an intestinal disease caused by Eimeria spp. Seven species are of major importance in poultry production, particularly Eimeria tenella, Eimeria acervulina, and Eimeria maxima. Infection compromises the integrity of the intestinal epithelium, impairing nutrient absorption and the zootechnical performance of birds. The results of this dissertation demonstrate that both the challenge dose of Eimeria spp. and the post-infection period influence the immune response, intestinal integrity, and the composition of the cecal microbiota in broiler chickens. Gene expression analysis of markers associated with immune response and intestinal adhesion junctions showed that the higher parasite load induced more intense and prolonged immune responses, characterized by modulation of pro- and anti-inflammatory cytokines and regulation of genes related to epithelial adhesion junctions. A temporal pattern was observed, marked by early peaks of pro-inflammatory mediators followed by activation of regulatory mechanisms, suggesting an attempt by the host to control inflammation and restore intestinal homeostasis. However, exposure to the higher parasite load indicated a possible progressive suppression of the immune response, which may compromise efficient pathogen clearance and prolong tissue repair processes. In parallel, the cecal microbiota was predominantly modulated by time post-infection, showing a progressive increase in richness, evenness, and diversity up to 21 days post-infection, reflecting temporal changes in the intestinal microbial community. The effects of different Eimeria spp. doses on the microbiome were more specific, with the lower dose associated with greater microbial balance and reduced presence of opportunistic taxa, whereas the higher dose resulted in a reduction of genera considered beneficial and an increase in potentially pathogenic taxa. These findings indicate that modulation of the intestinal microbiota occurs primarily as a function of time, while the influence of dose is more specific rather than proportional to the Eimeria spp. challenge dose. Overall, this work demonstrates that the interaction between infectious dose and post-infection time is critical for understanding the immunological mechanisms and microbial alterations associated with coccidiosis in broiler chickens. The results contribute to the improvement of control, management, and prevention strategies for coccidiosis in poultry production.

COMMITTEE MEMBERS:
Presidente - 3701492 - HUARRISSON AZEVEDO SANTOS
Externa ao Programa - 1400897 - ALICIA ZEM FRAGA - UFRRJExterno ao Programa - 3470547 - JEAN KAIQUE VALENTIM - UFRRJExterno ao Programa - 1121773 - TULIO LEITE REIS - UFRRJExterna à Instituição - DAYSE LIMA DA COSTA ABREU - UFF
Externo à Instituição - NELSON RODRIGO DA SILVA MARTINS - UFMG
Externo à Instituição - THOMAS SALLES DIAS - UFF