The assessment of protein quality of carp (Cyprinus carpio) diets

Protein quality of carp diets was assessed by five methods: 1. True digestibility, true NPU, BV (as percentage) and PER were determined for approximately iso-energetic diets containing ca.38% protein from 4 different sources. Fish meal gave values of 94.0, 72.5, 77.0, and 1.21 respectively; egg 93.0, 65.4, 70.3, 1.26; Pruteen 68.4, 63.6, 68.40, 1.36; and Casein 91.0, 56.90, 62.5, 1.33. 2. Blood urea were determined and found to be significantly increased with increasing protein concentration in the diet. 3. Ammonia excretion rate was determined; it increased with a decline in protein quality, being greater on groundnut, rapeseed meal, and sunflower diets than on fishmeal, cottonseed meal, and pruteen. 4. Protein sources were incubated in vitro with digestive fluids of fish. Protein digestibilities for fishmeal diets containing 14 and 27% protein were 90.2 and 93.0% respectively; casein (18 and 36%), 91.5 and 93.2%; soybean (10 and 20%), 84.2 and 85.3% ; sunflower (8 and 16%), 64.2 and 66.1%; and fish meal plus soybean meal (ca. 18.2%) 86.5. 5. Plasma free amino acids were individually determined at 0, 6, 24 and 48 h after force-feeding diets containing 15 and 30% protein from six different sources. Total free AA were highest at 24 h for casein and fishmeal, and at 48 h for egg, soybean, rapeseed and sunflower. The 24 h essential amino acid indices (EAAI) for the six diets at 15% protein were, in the same order, 93.0, 100, 100, 86.4, 62.4, and 97.2. At 30% protein, the 24 h EAAI were 78.5, 84.3, 100, and 83.8 for casein, fishmeal, egg, and rapeseed respectively.

Reduced postprandial proinsulinaemia and 32-33 split proinsulinaemia after a mixed meal in type 2 diabetic patients following sensitization to insulin with pioglitazone

Objective: Reduced insulin sensitivity associated with fasting hyperproinsulinaemia is common in type 2 diabetes. Proinsulinaemia is an established independent cardiovascular risk factor. The objective was to investigate fasting and postprandial release of insulin, proinsulin (PI) and 32-33 split proinsulin (SPI) before and after sensitization to insulin with pioglitazone compared to a group treated with glibenclamide. Design and patients: A randomized double-blind placebo-controlled trial. Twenty-two type 2 diabetic patients were recruited along with 10 normal subjects. After 4 weeks washout, patients received a mixed meal and were assigned to receive pioglitazone or glibenclamide for 20 weeks, after which patients received another identical test meal. The treatment regimes were designed to maintain glycaemic control (HbA1c) at pretreatment levels so that ß-cells received an equivalent glycaemic stimulus for both test meals. Measurements: Plasma insulin, PI, SPI and glucose concentrations were measured over an 8-h postprandial period. The output of PI and SPI was measured as the integrated postprandial response (area under the curve, AUC). Results: Pioglitazone treatment resulted in a significant reduction in fasting levels of PI and SPI compared to those of the controls. Postprandially, pioglitazone treatment had no effect on the insulin AUC response to the meal but significantly reduced the PI and SPI AUCs. Glibenclamide increased fasting insulin and the postprandial insulin AUC but had no effect on the PI and SPI AUCs. Conclusions: Sensitization to insulin with pioglitazone reduces the amount of insulin precursor species present in fasting and postprandially and may reduce cardiovascular risk. © 2007 The Authors.

A high-fat meal induces low-grade endotoxemia:evidence of a novel mechanism of postprandial inflammation

Background: Bacterial endotoxin is a potently inflammatory antigen that is abundant in the human gut. Endotoxin circulates at low concentrations in the blood of all healthy individuals, although elevated concentrations are associated with an increased risk of atherosclerosis. Objective: We sought to determine whether a high-fat meal or smoking increases plasma endotoxin concentrations and whether such concentrations are of physiologic relevance. Design: Plasma endotoxin and endotoxin neutralization capacity were measured for 4 h in 12 healthy men after no meal, 3 cigarettes, a high-fat meal, or a high-fat meal with 3 cigarettes by using the limulus assay. Results: Baseline endotoxin concentrations were 8.2 pg/mL (interquartile range: 3.4–13.5 pg/mL) but increased significantly (P < 0.05) by ≈50% after a high-fat meal or after a high-fat meal with cigarettes but not after no meal or cigarettes alone. These results were validated by the observations that a high-fat meal with or without cigarettes, but not no meal or smoking, also significantly (P < 0.05) reduced plasma endotoxin neutralization capacity, which is an indirect measure of endotoxin exposure. Human monocytes, but not aortic endothelial cells, were responsive to transient (30 s) or low-dose (10 pg/mL) exposure to endotoxin. However, plasma from whole blood treated with as little as 10 pg endotoxin/mL increased the endothelial cell expression of E-selectin, at least partly via tumor necrosis factor-α–induced cellular activation. Conclusions: Low-grade endotoxemia may contribute to the postprandial inflammatory state and could represent a novel potential contributor to endothelial activation and the development of atherosclerosis.