Replacing cereals with food leftovers could reduce feed-food competition and keep nutrients and
energy in the food chain. Former food products (FFPs) are industrial food leftovers no more intended
for human but still suitable as alternative and sustainable feedstufs for monogastric. In this study,
omics approaches were applied to evaluate the impact of dietary FFPs on pig liver proteome and
plasma peptidome. Thirty-six Swiss Large White male castrated pigs were randomly assigned to three
dietary treatments [control (CTR), 30% CTR replaced with salty FFP (SA), 30% CTR replaced with
sugary FFP (SU)] from the start of the growing phase (22.4 ± 1.7 kg) until slaughtering (110 ± 3 kg). The
low number of diferentially regulated proteins in each comparison matrix (SA/SU vs. CTR) and the
lack of metabolic interaction indicated a marginal impact on hepatic lipid metabolism. The plasma
peptidomics investigation showed low variability between the peptidome of the three dietary groups
and identifed three possible bioactive peptides in the SA group associated with anti-hypertension and
vascular homeostasis regulation. To conclude, the limited modulation of liver proteome and plasma
peptidome by the SA and SU diets strenghtened the idea of reusing FFPs as feed ingredients to make
pig production more sustainable.