Nitrogen metabolism, macronutrient digestibility, and fecal fermentative end-products in domestic cats fed extruded, raw beef-based and cooked beef-based diets

Kerr, Katherine R.

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Description

Title

Nitrogen metabolism, macronutrient digestibility, and fecal fermentative end-products in domestic cats fed extruded, raw beef-based and cooked beef-based diets

Author(s)

Kerr, Katherine R.

Issue Date

2010-05-18T18:55:42Z

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

Swanson, Kelly S.

Department of Study

Nutritional Sciences

Discipline

Nutritional Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Domestic Cat
• Nitrogen Metabolism
• Digestibility
• Fermentative End-Products
• Blood Metabolites
• Raw Meat Diet
• Cooked Meat Diet
• Extruded Diet

Abstract

The objective of this study was to determine differences in nitrogen (N) metabolism, nutrient digestibility, fecal and urine characteristics, and serum chemistry of domestic cats fed raw and cooked beef-based diets versus a high-protein extruded diet. Nine adult female domestic shorthair cats were utilized in a crossover design. Dietary treatments included an extruded diet [HP; ~57% crude protein (CP)], a raw beef-based diet (RB; ~53% CP), and a cooked beef-based diet (CB; ~52% CP). Cats were housed individually in metabolic cages and fed to maintain body weight. The study consisted of three 21-day periods: days 0-16 were used for diet adaptation; fecal and urine samples were collected on days 17-20; and blood samples were collected on day 21. Food intake was measured daily. During the collection phase, total feces and urine were collected. A fresh urine sample was also collected for urinalysis and acidified for N determination. In addition to total fecal collection, a fresh fecal sample was collected for determination of ammonia, short-chain fatty acid (SCFA), and branched-chain fatty acid (BCFA) concentrations. All feces were scored upon collection using a scale ranging from 1 (hard, dry pellets) to 5 (watery, liquid that can be poured). Blood was analyzed for serum chemistry. Total tract apparent dry matter (DM), organic matter (OM), CP, fat and gross energy (GE) digestibilities were higher (P<0.05) in cats fed the RB and CB versus cats fed HP. Nitrogen metabolism differed among treatments. Nitrogen intake and fecal N were lower (P<0.05) in cats fed the RB and CB versus cats fed HP, while urinary N was not different among groups. Differences were also noted in fecal fermentative end-product concentrations. Total fecal SCFA concentrations did not differ among dietary treatments; however, molar ratios of SCFA were modified by diet, with cats fed RB and CB having an increased (P<0.05) proportion of fecal propionate and decreased (P<0.05) proportion of fecal butyrate as compared to cats fed HP. Fecal concentrations of ammonia, isobutyrate, valerate, isovalerate, and total BCFA were higher (P<0.05) in cats fed HP compared to cats fed RB and CB. Our results suggest that cooking a raw iii meat diet does not significantly decrease macronutrient digestibility or alter N metabolism, yet may minimize risk of microbial contamination. Given the increasing popularity of feeding raw diets and the metabolic differences noted in this experiment, further research focused on the adequacy and safety of raw beef-based diets in domestic cats is justified.

Graduation Semester

2010-5

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© Katherine R. Kerr

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