Effect of dietary protein on lean body wasting in dogs: correlation between loss of lean mass and markers of proteasome-dependent proteolysis.
J Anim Physiol Anim Nutr (Berl)
; 87(11-12): 408-20, 2003 Dec.
Article
em En
| MEDLINE
| ID: mdl-14633050
ABSTRACT
To determine the effect of dietary protein intake on lean body wasting in adult canines a study was undertaken to investigate the Ubiquitin Proteasome (UP) pathway and concurrent changes in lean and fat body mass of canines fed variable sources and concentrations of dietary protein. Purpose-bred, intact female canines (56) between the ages of 2 and 3 years were fed either 12 or 28% protein diet for 10 weeks. Each diet contained variable amounts of corn gluten meal and chicken protein sources in ratios of 100 0, 67 33, 33 67 and 0 100 per cent (w/w), respectively. All diets were isocaloric with calories coming from protein fat carbohydrate at the respective ratios of 12 40 48% for the 12% diets, and 28 40 32% for the 28% diets. Standard dual energy X-ray absorptiometry was performed to assess total body lean and fat mass at weeks 0 and 10 of the dietary trial. Muscle biopsies were also taken and processed for protein determination and standard gel electrophoresis with subsequent Western blotting for 20S proteasome and PA700 regulatory cap subunit p31. Statistical analysis revealed a moderate degree of correlation between increasing quantities of corn gluten, which is low in essential amino acids (i.e. lysine, tryptophan), and increasing loss of lean body mass over the 10-week study (R = 0.56). Furthermore, a moderate degree of correlation was observed between increasing concentrations of corn gluten protein and decreased expression of the p31 subunit of the 26S proteasome (R = 0.49). Additionally, the dogs consuming the 12% protein diets had a significant increase in fat mass regardless of the protein source. These findings suggest that lean body wasting in adult canines can be associated with the consumption of low protein diets consisting of predominantly corn gluten, which is likely due to imbalances or subclinical deficiencies of specific essential amino acids, and that low protein diets may augment accumulation of adipose tissue. Although the mechanisms remain unclear, alteration of molecular targets of skeletal muscle proteolysis, specifically involving the UP pathway occur.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cisteína Endopeptidases
/
Proteínas Alimentares
/
Tecido Adiposo
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Músculo Esquelético
/
Cães
/
Complexos Multienzimáticos
Limite:
Animals
Idioma:
En
Revista:
J Anim Physiol Anim Nutr (Berl)
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Estados Unidos