The increasing demand for food and especially for proteins, leads to the search for alternative protein. The valorization of co-products, such as meat co-products little valorized in human food, is from this point of view a promising way, in line with the principle of circular economy. The present study aimed to evaluate the nutritional quality of two protein ingredients of bovine origin, co-products of the fat rendering process. To do so, their true ileal digestibility (TID), their digestible indispensable amino acid score (DIAAS) and the postprandial plasma amino acid (AA) kinetics were determined. Ten growing pigs were surgically inserted an ileal T-cannula and a catheter in the jugular vein. After recovery, they received each over a 2.5-day period and following a cross-over design two experimental diets based either on Greasy Greaves Recovered Proteins (GGRP) or on Water Recovered Proteins (WRP)], followed by a protein-free diet for endogenous protein loss evaluation. Titanium dioxide (3 g/kg) was used as an undigestible marker. Digesta and blood samples were collected during the 9 hours following meal ingestion and total N and AA contents were analysed by the Dumas method or by ion-exchange chromatography, respectively. Data were statistically analysed using linear models. The TID of total N was not significantly different between WRP and GGRP (84.2±3.2 and 81.2±2.3%, respectively; mean ± SD). The primary limiting AA was tryptophan for both protein ingredients, with a DIAAS much higher for GGRP (74%) than for WRP (18%). The kinetics of AA release differed between proteins, with postprandial plasma AA concentration reaching its maximal value earlier for WRP (3 hours) than for GGRP (5 hours). GGRP has a nutritional quality suitable to meet the needs of old children, adolescents and adults, while WRP should be supplemented with other protein sources rich in essential AAs to fulfill the AA requirements.