Encapsulated butyric acid as a functional ingredient in canine health

Short-chain fatty acids are known to exert beneficial effects in the intestinal tract of humans and animals (Guilloteau et al., 2010; Bedford and Gong, 2017; Kim et al., 2025). Butyric acid is recognized to play a large role in maintaining gut immunity and gut barrier function, and it also contributes to broader systemic effects including metabolic regulation, anti-inflammatory activity, oxidative stress reduction, and epigenetic modulation (Guilloteau et al., 2010; Zhang et al., 2021b; Recharla et al., 2023). This study examined whether encapsulated butyric acid supplementation could influence gastrointestinal (GI) health markers in adult dogs challenged with 25 mg/BWPO q12h metronidazole. Thirty-two beagles were fed a commercially available complete and balanced diet to meet the nutritional requirements of adult canines. The selected commercial diet minimized the inclusion of functional ingredients to not affect variables of interest in this study. Gelatin capsules containing butyric acid salt embedded in a fat matrix via spray-freezing (EBA) were orally administered post-feeding, in accordance with experimental treatment assignments. The experimental treatment groups consisted of butyric acid supplemented at 0 mg/d (EBA 0; empty capsule), 250 mg/d (EBA 1), or 500 mg/d (EBA 2) prior to, or 500 mg/d (EBA 3) initiated after the antibiotic challenge (n=8/treatment). The total experimental period was 77 days, with the first 14 days as diet adaptation to the control diet prior to baseline collections. Total fecal collections were performed on days 10-14 and days 31-35, while fresh fecal samples were collected on days 0, 14, 21, 35, 49, and 63 and blood samples were collected on days 0, 14, 21, and 63. An antibiotic challenge was performed on days 14-21. Food was offered twice per day to maintain body weight and body condition score. Data was analyzed in SAS 9.4 using PROC MIXED for continuous outcomes and PROC GLIMMIX for non-normal variables such as fecal score and fecal pH. Fixed effects included treatment, day, and their interaction, with dog as a random effect and day specified as a repeated measure. Assumptions were checked with the Shapiro-wilk test; when violated, data were log- or square-root transformed, and outliers (> ± 3 SD) were removed to improve residual distribution. Planned linear contrasts assessed dose-response relationships, and Tukey-adjusted least square means were used for multiple comparisons. Statistical significance was set at P < 0.05. Apparent total tract nutrient digestibility was unaffected by EBA before or after antibiotic administration; however, acid-hydrolyzed fat digestibility decreased linearly as EBA concentration increased following the challenge (P = 0.0417). Fecal output, fecal pH, fecal score, and major fermentative metabolites did not differ among treatments. A treatment × day interaction was detected for 2,3-dimethylindole (P = 0.0263), with EBA 1 being significantly higher than EBA 2 on day 14. Treatment influenced blood urea nitrogen (BUN), total protein, and globulin (P < 0.05). Total protein and BUN each demonstrated negative quadratic responses, with total protein lowest and BUN highest at intermediate doses, whereas globulin declined linearly with increasing EBA. No other serum chemistry or complete blood count variables differed notably among treatments. Microbial community composition was stable across treatments, and no differences were detected at the phylum, family, or genus level. Alpha and Beta diversity metrics showed pronounced day-related shifts, particularly on day 21 as that was at the end of the antibiotic challenge, but no treatment effects were seen. Fecal tight junction proteins, calprotectin, and IgA similarly did not differ among treatments. Overall, EBA was well tolerated and did not result in negative effects on dogs’ health. However, EBA supplementation did not alter digestive, microbial, or immunological responses to antibiotic challenge. Metronidazole produced clear, time-dependent disruptions in microbial diversity, followed by natural recovery that occurred similarly across all treatments. Functional metabolites, gut barrier markers, apparent total tract digestibility, and fecal microbial composition remained largely unchanged, indicating that EBA neither mitigated dysbiosis nor enhanced resilience under these experimental conditions.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Animal Sciences

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Hinz, Emma

Contributors dc:contributor

• de Godoy, Maria R.C.
• Swanson, Kelly S
• Oba, Patricia Massae

• antibiotic
• dog
• gastrointestinal tract
• fecal biomarkers
• fecal metabolites
• gut health
• gut microbiota
• nutrition
• short-chain fatty acids
• tight junction proteins

Statement dc:rights

• Copyright 2025 Emma Hinz

Language dc:language

en

Handle dc:identifier

https://hdl.handle.net/2142/132817

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/132817