The Effects of Age and Adiposity on Casein Digestibility and Tissue Protein Synthesis in Rats

Age and adiposity can impact the digestibility of dietary proteins metabolic response to their ingestion. The objective was evaluate effects age on casein protein synthesis in tissues organs. Wistar rats 1 month (n = 15) 10 months at arrival were fed ad libitum with a standard diet or High Fat obtain normal high levels. Four groups constituted 7/8): 2 months/normal adiposity, months/high 11 adiposity. At end intervention, they for week before test meal. consumed 4g meal containing 15N-labeled (Prodiet® 85B). Six hours after ingestion, euthanized. Intravenous injection massive dose 13C-valine prior euthanasia used determine rate liver, kidneys, skin muscle. Body composition evaluated digestive contents collected measure digestibility. No weight difference between same observed. However, significant noted, surge body fat 3% young 7% older rats. Digestibility increased higher level (P 0.04). In rats, it 94.1 ± 1.1% lean 95.2 1.7% 94.5 2.2% 95.8 0.7%, respectively. Significant < 0.01) observed muscle fractional (FSR), decreasing increasing it. FSR 10.1 2.1%/day 12.0 3.0%/day respectively, these values being 6.2 1.5%/day 10.6 2.0%/day skin, younger exhibited as 11.1 2.6%/day 12.6 3.7%/day 8.3 2.3%/day 8.2 2.7%/day differences found liver kidneys. Protein decreased while This is consistent an improvement ribosomal activity intermediate state obesity. although moderate, could have contributed anabolism response. Ingredia.