Determination of macronutrient composition, amino acid digestibility, and overall protein quality of select novel dietary proteins for use in canine and feline nutrition

Gomez, Victoria A.

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https://hdl.handle.net/2142/115758 Copy

Description

Title

Determination of macronutrient composition, amino acid digestibility, and overall protein quality of select novel dietary proteins for use in canine and feline nutrition

Author(s)

Gomez, Victoria A.

Issue Date

2022-04-29

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

de Godoy, Maria R. C.

Committee Member(s)

• Parsons, Carl M.
• Fahey, Jr. , Georgy 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)

• protein
• amino acid digestibility
• cecectomized rooster
• protein quality
• novel protein

Abstract

Protein is an important component of companion animal diets as it is provides the foundation for normal bodily functions by supplying indispensable and dispensable amino acids (AA). The forms in which dietary protein is incorporated into diets is through common animal and plant-based ingredients such as beef, chicken, fish, and soybean based products. However, novel proteins have become a point of interest in the pet food market due to several factors including, the demand for more diverse products, owners prioritizing ingredient quality, and the ethos of purchasing pet foods that use sustainable ingredients. Despite the increased consumer attention towards novel protein sources, there is limited information in the literature regarding their chemical composition, AA profile, and AA digestibility. Therefore, the aim of this research was to analyze the macronutrient and AA composition of mammalian proteins (yak, wild boar, camel, and kangaroo as compared to beef), avian proteins (goose, quail, duck, and emu as compared to chicken), aquatic and reptile proteins (whitefish, carp slurry, eel, spirulina, and rattlesnake, as compared to salmon), and non-animal proteins (cricket meal, chocho, pumpkin seed powder, and hemp powder as compared to soybean meal) as well as to determine the standardized AA digestibility by using the precision-fed cecectomized rooster assay. This assay more accurately measures AA digestibility in the ileum by removing the ceca from roosters which minimizes the effect of microbial fermentation on AA. For this assay, the roosters are fasted and then tube fed 25g to 30g of substrate. The excreta is collected after 48 hours and analyzed for AA digestibility. Protein quality was further assessed by calculation of digestible indispensable amino acid (DIAAS-like) scores to compare against the nutrient profiles of the Association of American Feed Control Officials (AAFCO) and recommended allowances of the National Research Council (NRC) for adult dogs and cats at maintenance. For mammalian proteins, it was determined that each substrate was highly digestible by the roosters as no standardized AA digestibility values were below 81%. Based on DIAAS-like scores, tryptophan and threonine were consistently the lowest scoring AA when compared with AAFCO and NRC references for both dogs and cats. Using NRC and AAFCO DIAAS-like values for adult cats, kangaroo, yak, and camel were scored as high-quality proteins as these ingredients contained no first-limiting AA as scores were all greater than 100%. For avian proteins, the standardized indispensable AA digestibility values from precision-fed cecectomized rooster assay ranged from 64.1% to 99.2% which determines the avian proteins to be moderate to highly digestible. Across all protein sources, tryptophan was the first-limiting AA, except for methionine being first-limiting in goose when compared with AAFCO nutrient profiles for dogs and cats. When compared to chicken, emu and goose were observed to be of higher quality for adult dogs using AAFCO and NRC comparisons. In contrast, chicken was the highest quality protein overall and was absent of any first-limiting AA according to DIAAS-like scores. In aquatic and reptile proteins, the standardized AA digestibility values for each ingredient were all greater than 80% and were considered to be highly digestible. Rattlesnake was consistently low quality for dogs and cats using AAFCO and NRC comparisons with tryptophan as first-limiting AA. Carp slurry and spirulina were determined to be high quality based on AAFCO and NRC comparisons; however, these proteins received moderate scores using NRC recommended allowance for adult dogs as the reference protein. In plant and insect proteins, standardized AA digestibility values were observed to be highly digestible, except for lysine in pumpkin seed powder (77.2%). Methionine was most often the first-limiting AA for dogs using NRC and AAFCO references. Cricket meal contained no limiting AA for cat AAFCO and NRC comparisons. In general, this research indicates that the novel proteins tested herein are of moderate to high quality. Data collected from these studies also provide justification for further in vivo research to determine future use of these ingredients in more complex dietary matrices of treats and complete and balanced diets for companion animal.

Graduation Semester

2022-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Victoria Gomez

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