Nutritional evaluation of vegan dog foods in healthy adult dogs and the cecectomized rooster model

Roberts, Leah J.

Permalink

https://hdl.handle.net/2142/120124 Copy

Description

Title

Nutritional evaluation of vegan dog foods in healthy adult dogs and the cecectomized rooster model

Author(s)

Roberts, Leah J.

Issue Date

2023-05-04

Director of Research (if dissertation) or Advisor (if thesis)

Swanson, Kelly S

Committee Member(s)

• de Godoy, Maria R. C.
• Fahey Jr., George C.

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• canine nutrition
• nutrient digestion
• pet food
• rooster model

Abstract

As the needs, desires, and beliefs of pet owners change, so too does the pet food market. In recent years, numerous dog owners have begun searching for alternatives to extruded kibble, which has led to an increase in alternative dietary options such as freeze-dried, raw, mildly-cooked, human-grade, and vegan. Vegan diets are increasing in popularity, but to our knowledge, no in vivo studies have been performed to evaluate them. Therefore, the goal of this research was to evaluate mildly-cooked, human-grade, vegan dog food in vivo, which involved performing two studies, one of which utilized the cecectomized and conventional rooster models, and another that utilized the dog model. The objective of study one was to investigate the amino acid (AA) digestibility and nitrogen-corrected true metabolizable energy (TMEn) of mildly-cooked human-grade vegan dog foods using the precision-fed cecectomized rooster and conventional rooster assays. The objective of study two was to determine the apparent total tract digestibility (ATTD) of mildly-cooked human-grade vegan dog foods and their effects on blood metabolites and fecal microbiota, characteristics, and metabolites of adult dogs. In both studies, three commercial dog foods were tested. Two were mildly-cooked human-grade vegan dog diets provided by Bramble. Those two recipes were The Cowbell (BC) and The Roost (BR). The third diet was a chicken-based extruded dog diet, which was abbreviated as (CT) for control. All data were analyzed using the Mixed Models procedure of SAS (version 9.4). In study one, all three diets were dried and ground, and then fed to cecectomized roosters to determine AA digestibility and to conventional roosters to determine TMEn. The majority of indispensable and dispensable AA across all diets had digestibilities higher than 80%, with a few exceptions (BC: histidine, lysine, threonine, and valine; BR: histidine). The only difference in indispensable AA digestibility among diets was observed with tryptophan, with its digestibility being higher (P=0.0163) in CT than BC. TMEn values were higher (P=0.006) in BC and BR (4.55 and 4.66 kcal/g dry matter, respectively) than that of CT (3.99 kcal/g dry matter). The TMEn/GE was also higher (P=0.0193) in BR than CT. Metabolizable energy (ME) estimates using Atwater factors accurately estimated the energy content of CT, but modified Atwater factors and the predictive equations for ME recommended by the National Research Council underestimated energy content. All calculations underestimated the measured TMEn values of BC and BR, with Atwater factors being the closest. In study two, twelve healthy adult female beagles (7.81 ± 0.65 kg; 7.73 ± 1.65 y old) were used in a replicated 3x3 Latin Square design. The study consisted of three experimental periods, with each composed of a 7-day diet adaptation phase, 15 days of consuming 100% of the diet, a 5-day phase for fecal collection for ATTD measurement, and 1 day for blood collection for serum chemistry and hematology. During the fecal collection period, a fresh sample was collected for fecal scoring and dry matter, pH, metabolite, and microbiota measurements. All three diets were shown to be highly digestible, with all macronutrients having digestibility values above 80%. The vegan diets had higher (P<0.001) ATTD of fat, but lower (P<0.05) ATTD of organic matter than the extruded diet. Dogs consuming the vegan diets had lower circulating cholesterol (P<0.001), triglyceride (P<0.001), and platelet (P<0.009) concentrations and lower (P<0.010) blood neutrophil percentages than dogs consuming the extruded diet. Dogs consuming vegan diets had lower (P<0.001) fecal dry matter percentages, lower (P<0.001) fecal phenol and indole concentrations, and higher (P=0.05) fecal short-chain fatty acid concentrations than those consuming the extruded diet. Fecal bacterial alpha and beta diversities were not different (P>0.05) among diets, but dogs consuming vegan diets had altered (P<0.05) relative abundances of nearly 20 bacterial genera when compared with those consuming the extruded diet. In conclusion, the mildly-cooked human-grade vegan dog foods evaluated in both studies performed well. In study one, the majority of AA were highly digestible, but the TMEn data suggested that existing energy equations underestimate the ME of mildly-cooked human-grade vegan diets. In study two, the mildly-cooked human-grade vegan diets resulted in desirable fecal characteristics and serum chemistries, high ATTD, positive changes to serum lipids and fecal metabolites, and changes to the fecal microbial community, including an increase in Bifidobacterium, Megamonas, and Parasutterella, and a decrease in Adlercreutzia, Blautia, and Turicibacter.

Graduation Semester

2023-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Leah Roberts

Owning Collections