Alternative diet formats and novel protein ingredients for use in canine and feline diets

Smola, Meredith Ann

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https://hdl.handle.net/2142/129565 Copy

Description

Title

Alternative diet formats and novel protein ingredients for use in canine and feline diets

Author(s)

Smola, Meredith Ann

Issue Date

2025-04-24

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

Swanson, Kelly K

Doctoral Committee Chair(s)

Swanson, Kelly K

Committee Member(s)

• Fahey, Jr., George C
• Stein, Hans H
• Parsons, Carl M
• de Godoy, Maria R. C.

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• protein
• raw diet
• mealworm
• fermented soybean
• yeast
• digestibility
• canine
• feline

Abstract

As the global population continues to grow, food sustainability is an increasingly important challenge. Along with the search for alternative proteins, including fermented ingredients, insects, and brewed yeast-based proteins, there is increased demand for innovative pet food formats that undergo different processing methods. Because there are 10 indispensable amino acids (AA) for dogs and cats, dietary protein sources must not only provide nitrogen but also the necessary amounts of each AA. As alternative proteins and processing methods reach the pet food industry, it is important to conduct sufficient testing so that diet quality and pet health are maintained. The purpose of this dissertation was to evaluate alternative proteins and diet formats for pet foods by using the precision-fed cecectomized rooster model and conducting canine nutrition studies. The first aim was to determine the apparent total tract macronutrient digestibility (ATTD) of raw and kibble diets, and test their effects on the serum metabolites, hematology, and fecal characteristics, metabolites, and microbiota of adult dogs. Adult beagle dogs were used in a replicated 4x4 Latin square design (n = 12/treatment) to test: Frozen Stella’s Super Beef Dinner (FD), Stella & Chewy’s Red Meat Raw Blend Kibble (RBK), Purina Pro Plan Adult Complete Essentials Shredded Blend Beef & Rice (PP), and Blue Wilderness Rocky Mountain Recipe with Red Meat (BW). Greater (P<0.05) macronutrient digestibility, firmer stools, and greater (P<0.05) fecal dry matter and pH were observed in dogs fed FD. Fecal output, fecal short-chain fatty acid (SCFA) concentrations, and fecal valerate concentrations were higher (P<0.05) in dogs fed RBK. Serum markers also differed, with FD leading to higher (P<0.05) cholesterol concentrations and BW leading to higher (P<0.05) triglyceride concentrations. Fecal microbiota populations were affected, as beta diversity identified clustering by diet and the relative abundances of 3 bacterial phyla and over 30 bacterial genera being altered. The second aim was to measure the AA composition, AA digestibility, and protein quality of yellow mealworm-based ingredients using the precision-fed cecectomized rooster assay. Cecectomized roosters were randomly allotted to one of three test ingredients (n = 6/group): 1) defatted yellow mealworm flour without cuticles (TM); 2) defatted yellow mealworm flour with cuticles (TMc); and 3) whole yellow mealworm pulp (TMp). Standardized ileal AA digestibilities and digestible indispensable AA score (DIAAS)-like values were determined and limiting AA were identified based on dog and cat nutrient requirements or recommendations. All ingredients were highly digestible, with all indispensable AA digestibilities being >90%, with the exception of histidine (89.55%) and valine (89.36%) for TMc. Histidine digestibility was higher (P<0.05) for TM and TMp than for TMc. Isoleucine, leucine, lysine, and valine digestibilities were higher (P<0.05) for TMp than TMc. The DIAAS-like values were highest for TM, which scored high enough to be considered a high-quality protein source for most guidelines and life stages, with DIAAS-like values for TMc and TMp being slightly lower. For dogs and growing puppies, methionine + cystine was the limiting AA depending on reference guideline and life stage. For cats and growing kittens, arginine, threonine, or methionine + cystine were the limiting AA. The third aim was to measure the AA composition, AA digestibility, and protein quality of fermented soybean-based ingredients using the precision-fed cecectomized rooster assay. Cecectomized roosters were randomly allotted to one of five test ingredients (n = 6/ingredient): 1) autoclaved soybeans (ASB); 2) fermented soybeans (FSB); 3) fermented soybeans + Lactococcus lactis subsp. lactis ATCC 11454 (FSBP); 4) fermented soybean meal (FSBM); and 5) fermented soybean meal + L. lactis (FSBMP). Standardized ileal AA digestibilities and DIAAS-like values were determined and first limiting AA were identified. All ingredients had acceptable AA digestibilities, with all indispensable AA digestibilities being >80%, with the exception of histidine (79.32%), lysine (73.47%), and valine (79.02%) for ASB. All AA digestibility values were different, with FSBP being the most digestible and ASB being the least digestible. The DIAAS-like values were highest for FSBP, which met the criteria for a high-quality protein source for adult cats and a good-quality protein source for growing puppies, with DIAAS-like values for other ingredients being lower. For adult and growing dogs, methionine, methionine + cystine, or threonine were the first limiting AA depending on reference guideline and life stage. For adult and growing cats, phenylalanine + tyrosine, threonine, methionine, or methionine + cystine were first limiting. The fourth aim was to evaluate the safety, efficacy, gastrointestinal tolerance, ATTD and palatability of brewed chicken protein (BCP; Saccharomyces cerevisiae expressing a chicken protein). Adult beagle dogs were used in a completely randomized design (n = 8/treatment). After a 2-wk acclimation phase, baseline measurements were collected and then dogs were allotted to the following treatments and fed for 26 wk: control diet based on chicken by-product meal and brewers rice (0% BCP; Control), 15% BCP (Low), 30% BCP (Medium), or 40% BCP (High). Palatability was assessed by comparing dry diets coated 0% vs. 1% BCP in 20 adult dogs. Consumption of BCP did not affect BW, body condition score, physical examination parameters, food intake, serum chemistry, hematology, and urinalysis parameters. The ATTD of dry matter, organic matter, and crude protein were greater (P<0.05) for the High diet, while the ATTD of fat was greater (P<0.05) for the Control diet than the Medium and High diets. Fecal output was lower (P<0.0001) and fecal dry matter was lower (P<0.001) for dogs fed the High diet. Fecal metabolites were altered by treatment, with acetate concentrations being lower (P<0.05) and propionate concentrations tending to be higher (P = 0.06) in dogs fed BCP. Fecal isobutyrate, isovalerate, indole, total phenol and indole, and ammonia concentrations were lower (P<0.001) and fecal valerate concentrations were higher (P<0.0001) in dogs fed BCP. Fecal bacterial alpha diversity was lower (P<0.05) in dogs fed BCP. Fecal bacterial beta diversity was also affected by treatment, with those fed Control being different than those fed BCP. The relative abundance of over 20 fecal bacterial genera were affected by BCP consumption. The palatability test showed that 1% BCP was strongly preferred (P<0.05; 2.93:1 consumption ratio) over the control. The fifth aim was first to measure the AA digestibilities of individual protein-based ingredients and ingredient mixtures using the precision-fed cecectomized rooster assay and second to determine if the values from the individual ingredients were additive and predictive of those for mixtures. Cecectomized roosters were randomly allotted to one of seven test ingredients (n = 6/group): 1) dehydrated egg (EGG); 2) pea protein (PP); 3) corn-gluten meal (CGM); 4 and 5) mixtures of PP:EGG at a ratio of 75:25 (PP75) or 25:75 (PP25); 6 and 7) mixtures of CGM:EGG at a ratio of 75:25 (CGM75) or 25:75 (CGM25). All test ingredients had high standardized ileal AA digestibilities, with all indispensable AA digestibilities being >85% with the exception of lysine (72.45%) for CGM. There were no differences between measured and predicted AA digestibility values for all protein mixtures, except histidine (2.92% difference) and serine (2.63% difference) in CGM25. These data demonstrate that AA digestibilities obtained from individual ingredients are additive and predictive of those in ingredient mixtures when using the cecectomized rooster assay.

Graduation Semester

2025-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129565

Copyright and License Information

Copyright 2025 Meredith Smola

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