Final Examination for the Degree of PhD - Quail Das

Date and Time


Webex meeting - by invitation sent from candidate; send email to candidate for invite 


Examining Committee
Dr. Iris Joye, Chair
Dr. Massimo Marcone, Advisor
Dr. Moussa Diarra, Advisory Committee Member
Dr. Gisele LaPointe, Department Member
Dr. Michele Jay-Russell, UC Davis, External Examiner


Berry pomace products possess antimicrobial properties due to their functionally bioactive molecules; however, the underlying mechanism of actions are poorly understood. This research investigates the antimicrobial activity of cranberry extracts (KCOH) and its sub-fractions against Salmonella enterica. Salmonella serovars show more sensitivity to flavonols and anthocyanin sub-fractions than KCOH. Transcriptional studies revealed that exposure of S. Enteritidis at sub-inhibitory concentrations of KCOH reduces expression major operon encodes structural components of Salmonella Pathogenicity Islands. While berries are beneficial in promoting human health, incorporation of such berry products in broiler chicken diets are scarce. The potential of cranberry (CP) and blueberry (BP) pomaces and their byproducts as alternatives to antimicrobial growth promoters were examined on day-old male Cobb500 broilers’ growth performance and gut microbiota for a 30-day trial. In the first chicken trial (n=2800), at day 21, ethanolic extracts of cranberry pomaces (COH) resulted in better performance by increasing body weight (BW) and feed efficiency (FE), while CP feeding at 1% (CP1) decreased the prevalence of necrotic enteritis (NE) and coccidiosis compared to bacitracin (BACI) treatment (P < 0.05). qPCR studies showed the immunomodulatory effects of CP by reducing the expression of proinflammatory cytokines in liver (IL-4, IFN-γ), while inducing the expression of anti-inflammatory cytokines IL-4, 13 in spleen, and IL- 10 in bursa. 16S rRNA analysis showed higher relative abundances (RA) of Clostridiales in COH and BACI fed birds, while Lactobacillaceae and Bacteroidetes were abundant in CP1 and BP1 treated birds of ceca. In the second trial, the basal diet was enriched with animal protein using a group of birds vaccinated (n=1350) and a non-vaccinated (n=1350) against coccidiosis. Overall, BACI induced the best growth performance in vaccinated group, while no effect of treatments was observed in nonvaccinated group at 10 to 20 days of age. CP1 feeding provides similar incidences of coccidiosis and NE compared to BACI in non-vaccinated birds. Metagenomic analysis revealed a significant variation among different feed treatments. Both BACI and BP supplementations led to increased RA of Enterobacteriaceae and Streptococcaceae, in the vaccinated group, while RA of Lactobacillaceae, was increased in the non-vaccinated group with the CP treatment.

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