Thèse de doctorat en Nutrition humaine
Sous la direction de Daniel Tomé.
Soutenue en 2008
Pas de résumé disponible.
Variations in quantity and quality of milk protein intake : metabolic consequences
The aim of this work was to explore the metabolic consequences of 1- the long-term ingestion of a high-protein diet, based on total milk protein (TMP) and 2-the ingestion of milk protein after current industrial treatments such as filtering and heating processes. We showed that rats given a high-protein diet (HP-50% protein) over a period of 6 and 9 months exhibited large differences on a broad range of parameters, when compared to rats given a normal-protein diet (NP-14% protein). No major alterations of the hepatic or renal function were found in HP rats. Moreover, HP rats showed a sharp reduction in adipose tissue and lower basal concentrations of triglycerides, glucose, leptin, and insulin. We also determined the in vivo bioavailability of industrially treated milk proteins by giving seven [15N]-labelled meals containing either micellar casein (CAS), milk soluble protein isolate (MSPI), and microfiltered milk (MF) or heated [high temperature short time pasteurized (HTST), higher temperature, shorter time pasteurized (HHST), ultrahigh temperature-treated (UHT), and spray-dried (SPRAY)] milks to male Wistar rats. Except spray drying, heating did not affect protein bioavailability. Moreover, the biological value of purified protein fractions was lower than that seen in products containing TMP. Five of the seven previous products (MF, CAS, MSPI, HTST, UHT) were also tested in man. Postprandial protein retention of MSPI or UHT was then markedly lower than that of MF and HTST. These differences seemed to be driven by a modulation of digestive kinetics. In conclusion, both of these studies confirm or offer new opportunities for the development of clinical nutrition.
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