Effects of diet on the body composition, voluntary physical activity, blood hormones and metabolites, and fecal characteristics of adult cats undergoing weight gain and weight loss conditions

Opetz, Danielle L.

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https://hdl.handle.net/2142/122122 Copy

Description

Title

Effects of diet on the body composition, voluntary physical activity, blood hormones and metabolites, and fecal characteristics of adult cats undergoing weight gain and weight loss conditions

Author(s)

Opetz, Danielle L.

Issue Date

2023-11-28

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

Swanson, Kelly S.

Doctoral Committee Chair(s)

C. de Godoy, Maria R.

Committee Member(s)

• Fahey, Jr., George C.
• Pan, Yuan-Xiang

Department of Study

Nutritional Sciences

Discipline

Nutritional Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

feline obesity, obesity, companion animal, feline microbiota, feline nutrition, 16S rRNA gene sequencing

Abstract

Obesity is the most prevalent form of malnutrition, plaguing many humans and companion animals worldwide, with increasing incidence year after year. The excessive deposition of body fat results in numerous diseases, negatively impacting nearly every body system, resulting in decreased longevity and quality of life. Therefore, understanding the pathophysiological changes in individuals undergoing weight gain and weight loss conditions may help in the development of prevention or management strategies. Given the size of the problem, obesity studies have been frequently conducted in humans and companion animals. While many have evaluated the health implications of obesity, a gap exists in regard to the effects of dietary format and/or nutrient modification on metabolic responses. The consequent responses and changes elicited by gut microbiota communities during weight gain or loss are also poorly studied, especially in felines. Therefore, this dissertation aimed to test the effects of commercially available diets differing in nutrient composition or moisture content in adult cats during weight gain and weight loss conditions. We hypothesized that diets specially formulated for weight loss would minimize the detrimental effects of obesity (e.g., reduce blood lipids and markers of oxidative stress), maximize positive impacts (e.g., alter BCS and blood hormone concentrations and beneficially alter and/or modulate the fecal microbiota populations), all while providing beneficial outcomes (e.g., decreased risk of disease exacerbation and obesity-associated comorbidities), key elements that may serve as intervention strategies and improve feline health. The first aim was to determine the effects of restricted feeding and weight loss on body composition, voluntary physical activity, blood hormones and metabolites, and gastrointestinal microbiota of overweight cats. Twenty-two overweight adult spayed female and neutered male cats [body weight (BW) = 5.70 ± 1.0 kg; body condition score (BCS) = 7.68 ± 0.6; age = 4 ± 0.4 yr] were used in a longitudinal weight loss study. A control diet (OR) was fed during a 4-wk baseline to identify intake needed to maintain BW. After baseline (wk 0), cats were allotted to OR or a test diet (FT) and fed to lose ~1.0% BW/wk for 24 wk. Body weight, body composition, and voluntary physical activity were measured and fecal and blood samples were collected over time. Restricted feeding of both diets led to weight and fat mass loss, lower BCS, and lower blood triglyceride and leptin concentrations. Cats fed the FT diet had a greater reduction in blood triglycerides and cholesterol than cats fed the OR diet. Restricted feeding and weight loss reduced fecal short-chain fatty acid, branched-chain fatty acid, phenol, and indole concentrations. Fecal valerate concentrations were affected by diet, with cats fed the OR diet having a greater reduction than those fed the FT diet. Fecal bacterial alpha diversity was not affected, but fecal bacterial beta diversity analysis showed clustering by diet. Restricted feeding and weight loss affected relative abundances of 7 fecal bacterial genera, while dietary intervention affected change from baseline relative abundances of 2 fecal bacterial phyla and 20 fecal bacterial genera. The second aim was to determine the effects of overfeeding and weight gain on apparent total tract digestibility (ATTD), gastrointestinal transit time (GTT), blood hormones, serum metabolites, hematology, fecal microbiota populations, and voluntary physical activity of cats. Eleven lean adult spayed female cats (BW = 4.11 ± 0.43 kg; BCS = 5.41 ± 0.3; age = 5.22 ± 0.03 yr) were used in a longitudinal weight gain study. After a 2-wk baseline phase, cats were allowed to overeat for 18 wk. Fecal and blood samples were collected, and voluntary physical activity was measured using accelerometers over time. The ATTD of dry matter, organic matter, crude protein, fat and gross energy and GTT decreased with overfeeding and weight gain. Fecal bacterial alpha diversity measures were unchanged, but fecal bacterial beta diversity was impacted with overfeeding and weight gain. The relative abundances of 16 bacterial genera, including Bifidobacterium, Collinsella, and Erysipelatoclostridium were affected by overfeeding and weight gain. The third aim was to determine the effects of restricting the intake of diets differing in moisture content on weight loss, body composition, voluntary physical activity, serum markers of metabolism and inflammation, and fecal microbiota populations of overweight cats. Twenty-four overweight adult spayed female and male cats [BW = 5.51 ± 0.92 kg; BCS = 8.44 ± 0.53; muscle condition score (MCS) = 2.75 ± 0.50] were used in a longitudinal weight loss study. A control diet (Purina Cat Chow) was fed during a 4-wk baseline to identify intake needed to maintain BW. After baseline (wk 0), cats were allotted to one of two weight loss diets (DRY or CAN) and fed to lose 1.5% BW per wk for 18 wk. BW, body composition, and voluntary physical activity were measured, while fecal and blood samples were collected over time. Restricted feeding and subsequent weight loss resulted in reduced body, fat, and lean mass, with increased lean:fat ratio. Diet treatment significantly affected voluntary physical activity in the light:dark ratio and a significant diet*week interaction was observed, where those fed the CAN diet increased and those fed the DRY decreased activity counts from baseline measures. Serum leptin, insulin, SOD, and active ghrelin concentrations all were impacted with restricted feeding and weight loss, but were not affected by diet. Fecal bacterial alpha diversity measures increased with restricted feeding and weight loss and fecal bacterial beta diversity was altered by time in all cats, with wk 0 being different than wk 6, 12, and 18. Change from baseline relative abundances of 3 fecal bacterial phyla and over 30 fecal bacterial genera were impacted or tended to be impacted by dietary treatment. In conclusion, our results demonstrate that restricted feeding promoted controlled and safe weight and fat loss, reduced blood lipids and oxidative stress markers, and shifted fecal scores, metabolites, and microbiota. It also showed that overfeeding and subsequent weight gain reduced nutrient digestibility, reduced GTT, and caused changes to the fecal microbial community of adult domestic shorthair cats. Additionally, some dietary differences were noted, highlighting the importance of ingredient and nutrient composition in weight loss diets for cats.

Graduation Semester

2023-12

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/122122

Copyright and License Information

Copyright 2023 Danielle L. Opetz

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