Year of Publication

2006

Document Type

Thesis

College

Agriculture

Department

Animal Science

First Advisor

David L. Harmon

Abstract

This experiment was conducted to determine if changing the amount of ideal aminoacids (meaning the amount of amino acids necessary to supply all the animal's needswithout excesses or deficiencies of any single amino acid), in relation to caloric intakewill change nitrogen metabolism and weight loss in obese mature dogs. Informationprovided by this experiment can be used to formulate canine diets emphasizing weightloss in older animals.Six moderately obese mature female crossbred hounds were fed diets varying in theirratio of lysine:calories (Lysine % : Mcal ME/g) (2.2, 3.0, and 3.8) in a 3 x 3 replicatedLatin square design. Increasing the lysine:calorie of the diets linearly increased theamount of nitrogen absorbed. It did not, however, significantly affect blood chemistryvalues. Protein turnover exhibited a positive linear trend with increasing ratio and proteindegradation showed a strong quadratic change with the lowest point of degradationoccurring with the diet containing a 3.0 lysine:calorie ratio. Plasma urea and creatinineexcretion demonstrated quadratic tendencies with the two highest values occurring withthe diets containing lysine:calorie of 2.2 and 3.8, reflecting changes in muscle proteinbreakdown while nitrogen was retained in the body. Caloric restriction did not result inloss of lean mass as much as a loss of fat mass. By increasing the quality of protein fedas a percentage of caloric intake, lean muscle mass was conserved during periods ofcaloric restriction.

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