Metabolic Evidence for Adaptation to a High Protein Diet in Rats

Abstract

This study was designed to assess the effects of long-term adaptation to a high protein diet on energy intake, body weight gain, body composition and splanchnic metabolic indicators in rats. For this purpose, adult male Wistar rats were fed either a 50 g/100 g dry matter (DM) protein diet (P50 group) or a 14 g/100 g DM protein diet (P14 group) for 21 d. These two groups were compared with a P14 pair-fed (P14-pf) group that consumed the same daily energy as the P50 group. The energy intake of the P50 group was 16 +/- 1% less than that of the P14 group (P < 0.05), and the P50 group had significantly lower body weight. The P50 group had significantly less adipose tissue compared with both P14 and P14-pf rats. The activities of the brush border membrane enzymes, neutral aminopeptidase and gamma-glutamyl transferase, were significantly higher in the P50 group than in the P14 rats. Similarly, the activities of alanine aminotransferase, arginase and serine dehydratase were significantly higher in the liver of P50 rats compared with P14 rats. Both amino acid transporter system A and X(A,G-) activities, measured in freshly isolated hepatocytes, were significantly higher in the P50 group (8- and 1.5-fold, P < 0.05, respectively) compared with the P14 group. The 1.5-fold increase in the steady-state activity of X(A,G-) was accompanied by a doubling of EAAT2 mRNA, involved in the system X(A,G-). This study provides confirmation that specific biochemical and molecular adaptive processes of the splanchnic area are involved in the response to variations in the protein content of the diet.

Effect of oral oleoyl-estrone on adipose tissue composition in male rats

“…13 The lipid content of the tissue recovered, including liver and muscle lipid, did not account for even half of total body lipids, which suggests that in male Zucker lean rats a very large part of these lipids is dispersed in other locations, probably as infiltrated WAT in other tissues. In larger Wistar male rats, the mass of the adipose tissue recovered accounted for a higher percentage of body weight than that found here, 26 which suggests that strain and size may also be critical factors in the distribution and overall mass of WAT.…”

Effects of Boiled Fish (Silurus glanis, Heterotis niloticus, Cyprinus carpio and Oreochromis niloticus) Ingestion on the Growth of Young Male and Female Wistar Albino Rats

“…In addition, the hydrated environment would favour Maillard reaction and, therefore reduce the flavours. These results corroborate those obtained by [16][17][18][19][20] where the hydrated medium led to protein loss because of the Maillard reaction during the heat treatment ( Table 5). …”

“…Indeed, the quality of a protein is bad if the PER is lower than 1.5; intermediary if it's between 1.5 and 2; and good or very good when this value is higher than 2 (Friedman, 1996). These values are higher than those obtained (PER ranging between 0.9 and 2.1) on leguminous plants and 3 on egg [15][16][17][18][19]. …”

“…The brush border enzymes of the small intestine are sensitive at the level of protein contribution [16].…”

High-protein diet during gestation and lactation affects mammary gland mRNA abundance, milk composition and pre-weaning litter growth in mice

“…In obese and diabetic individuals, a higher utilization of fat reserves and improved glucose homeostasis was reported while subjected to diets containing higher protein contents (Farnsworth et al, 2003;Layman et al, 2003). Similar results were obtained in rats fed HP diets with reduced carbohydrate content (Jean et al, 2001; -E-mail: metges@fbn-dummerstorf.de Lacroix et al, 2004). Reports on the impact of an increased dietary protein intake during gestation and lactation on maternal and foetal/offspring health and development are scarce and the results obtained are inconsistent (Daenzer et al, 2002;Zhang et al, 2005;Thone-Reineke et al, 2006).…”