Evaluation of select novel dietary fiber-rich ingredients and their functionality in companion animal nutrition

Finet, Shannon E.

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https://hdl.handle.net/2142/122249 Copy

Description

Title

Evaluation of select novel dietary fiber-rich ingredients and their functionality in companion animal nutrition

Author(s)

Finet, Shannon E.

Issue Date

2023-11-30

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

de Godoy, Maria R C

Doctoral Committee Chair(s)

de Godoy, Maria R C

Committee Member(s)

• Swanson, Kelly S
• Fahey, George C
• Parsons, Carl M
• Loman, Brett R

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• dietary fiber
• dogs
• cats
• gastrointestinal health
• miscanthus
• hemp

Abstract

Dietary fiber and fiber-rich ingredients are used as functional components of pet food and can modulate animal physiological response. Fibrous ingredients exhibit great versatility, with the unique composition of each ingredient and their physicochemical properties determining their functionality. Therefore, the present studies were conducted to examine the functionality of novel fiber-rich ingredients in canine and feline nutrition. The first aim was to evaluate miscanthus grass as a dietary source of insoluble fiber and its effects on the palatability, digestibility, and physiological response in adult canines. The second aim was to assess the functional properties of the fiber-rich ingredient, ground, whole hemp seeds, including protein quality and physiological response in adult canines. The third aim was to gain a better understanding of the idiosyncrasies of the canine and feline gut microbiome, and their specific response to traditional and novel dietary fiber interventions. To evaluate miscanthus grass (MF) as a dietary fiber source in extruded canine diets, 6 complete and balanced diets similar in nutrient composition were formulated to include either cellulose (CO), beet pulp (BP), MF, or a blend of MF and tomato pomace, MF and resistant starch, or MF and fructooligosaccharide as the primary fiber sources. Twelve adult female beagles were randomly assigned to one of the 6 treatment diets in a replicated 6 x 6 Latin square design with each treatment period consisting of 21 d. Dogs fed BP had greater fecal total short-chain fatty acid concentration than the CO treatment (P < 0.05), while the dogs fed diets containing MF were intermediate. In a two-bowl palatability trial, no significant preference was observed between the extruded diets containing MF and CO (P > 0.05). However, a significant preference for the extruded diet containing BP over the diet containing only MF was observed (P < 0.05). The α-diversity of fecal microbial communities was not impacted by treatment (P > 0.05), but β-diversity indicated that dogs fed the BP diet differed from the other treatment groups (P < 0.05). To determine the nutritional properties of whole hemps seeds, the chemical composition and fatty acid profile of four different hemp seed varieties (NWG 452, NWG 331, NWG 2730, X-59) were measured. The protein quality and true metabolizable energy of these varieties were assessed using a precision-fed rooster assay. The seed varieties were similar in macronutrient composition, with only small variations in acid hydrolyzed fat, crude protein, total dietary fiber and gross energy content, as well as amino acid and long-chain fatty acid profiles. All essential amino acids were present in concentrations that exceeded the NRC (2006) recommended allowances for adult dogs and cats at maintenance with the exception of tryptophan which was determined to be the first limiting amino acid. The long-chain fatty acid profile presented a favorable ratio of omega-6 to omega-3 fatty acids of close to 3.5:1. The results of the rooster assay indicated no significant difference in the standardized amino acid digestibility of the indispensable amino acids among the seed varieties (P > 0.05). A significant difference in the true metabolizable energy corrected for nitrogen was observed among the seeds (P < 0.05), following the pattern of higher acid hydrolyzed fat and lower total dietary fiber content resulting in higher metabolizable energy. Based on these findings, baked chews including different levels of ground, whole hemp seed were formulated to evaluate the physiological effects of daily supplementation in adult beagles. Three chews, similar in macronutrient composition, were developed and included a cellulose control, low hemp inclusion (25%), and high hemp inclusion (50%). Thirty adult beagle dogs were used in a complete randomized design, with 10 dogs assigned to each treatment. The dogs were supplemented with the chews at a level of 10% of their energy intake daily for 28 d. Regardless of the level of hemp seed inclusion, daily supplementation did not present any negative physiological effects in these healthy adult dogs. The hemp seed ingredient utilized in this study was confirmed to be devoid of, or have undetectable levels of select cannabinoids. The animals remained clinically healthy with no changes to normal blood chemistry or signs of gastrointestinal intolerance. Voluntary physical activity levels also did not differ among the groups (P > 0.05). The hemp seed inclusion chews had similar concentrations of insoluble dietary fiber as the cellulose control and resulted in similar levels of fecal fermentative end-products and relative abundance of individual microbial taxa in the feces (P > 0.05). To characterize the similarities and differences in the gut microbial composition of dogs and cats and how they respond to various dietary fiber interventions, microbiota composition was analyzed from fecal samples collected during 4 feline and 4 canine feeding trials. These trials were completed to evaluate extruded kibble diets including 4 novel fiber sources, avocado meal, soybean hulls, sorghum, and miscanthus grass, and 3 traditionally utilized fiber containing ingredients in companion animal diets, cellulose, beet pulp, and corn. The treatment diets for the 4 sets of trials were consistent across both species, utilizing the same formula, ingredient sources, and processing methods. When comparing the 2 species overall, cats had a higher level of α-diversity compared with dogs (P < 0.05) and were also significantly different in terms of β-diversity (P < 0.05). Differentially abundant taxa for dogs included 23 families and 36 genera, primarily within the families Bacteroidaceae, Fusobacteriaceae, Erysipelotrichaceae, and Lachnospiraceae. For cats, the differentially abundant taxa were more diverse, belonging to 27 families and 42 genera, including Atopobiaceae, Coriobacteriaceae, and Veillonellaceae which were unique to this species. Among the evaluated fiber sources, beet pulp resulted in the most variation and inclusion of unique differentially abundant taxa, especially in cats. In conclusion, the novel fiber-rich ingredients, miscanthus grass and whole hemp seed, could be used as alternative sources of insoluble dietary fiber in canine nutrition. In dogs, the consumption of these fibrous ingredients did not result in detrimental effects to animal health, or fecal quality. Diets with a high inclusion of miscanthus grass were well digested, and no adverse physiological response was observed with the daily supplementation of ground, whole hemp seeds. Both ingredients were similar in fiber profile to the traditional dietary fiber source, cellulose, and feeding of these novel fiber sources resulted in similar outcomes in composition of gut microbial community and fecal fermentative end-product concentration as cellulose controls. In addition to providing dietary fiber, hemp seeds can also be a source of polyunsaturated fatty acids and highly digestible plant protein, although require complementary protein sources to prevent deficiencies in a complete and balanced diet for dogs and cats. Finally, while many similarities exist among the microbiome of dogs and cats, differences in response to dietary fiber interventions can be observed on multiple taxonomic levels, highlighting the need for data describing effective microbial modulation in species-specific models.

Graduation Semester

2023-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Shannon E. Finet

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