PSXI-21 - Inclusion of former food products in post-weaning piglets’ diet: impact on the fatty acid profile of subcutaneous adipose tissue and on serum metabolites

Abstract: Livestock production is facing the feed-food competition, use of natural resources and environmental sustainability. To address these issues, the use of food leftovers in animal nutrition could satisfy the principles of circular economy. Among the different food leftovers, former food products (FFPs) consist mainly of unsold/defective food from industrial production (i.e. bread, croissants, biscuits, chips). FFPs can be classified in sugary confectionary FFPs (FFPs-C) and salty bakery FFPs (FFPs-B). The aim of this study was to assess the impact of the inclusion of FFPs into post-weaning piglets’ diet on the fatty acid profile of subcutaneous adipose tissue and on serum metabolites. Thirty-six post-weaning female piglets (Large White × Landrace, BW 8.52 ± 1.73 kg) were assigned to a standard diet (CTR), or with a 30% replacement (w/w) of conventional cereals with FFPs-C or FFPs-B for 42 days. Growth performance and feeding behaviour were measured. Subcutaneous abdominal fat samples were collected from 12 selected piglets after slaughtering. Gas chromatography was performed on feed samples from control diet and experimental diets and on adipose tissue samples. Untargeted metabolomics was performed on blood samples (d 0 and d 42) using UHPLC/MS-MS. Data were analyzed with the software MetaboAnalyst (version 5.0). The inclusion of FFPs did not alter growth performance and feeding behaviour. The CTR diet had higher PUFA level than FFPs diets. In FFPs diets, the fatty acid profile was equally distributed among SFA, MUFA, and PUFA. The ω-6/ω-3 ratio was higher in FFPs-C diets than CTR and FFPs-B diets. The subcutaneous adipose tissue showed no differences between groups for SFA level. The MUFA level was reduced in CTR compared to FFPs groups, whereas PUFA level was reduced in FFPs-C group compared to FFPs-B and CTR groups. The ω-6/ω-3 ratio was lower in FFPs-C group compared to CTR and FFPs-B groups. The untargeted metabolomics identified a total of 104 metabolites, with 2 significantly different between groups. Specifically, the serum concentration of theobromine and caffeine was higher in FFPs groups compared to CTR. To conclude, piglets were able to rebalance the fatty acids profile despite the differences observed in the diets. The metabolic status was not strongly altered by the inclusion of 30% FFPs in the diet. Thus, FFPs could be safely applied in post-weaning pig diets. Further studies are needed to assess the effect of FFPs on pig physiology and metabolic status in growing phase pigs and for a longer feeding time. (funded by ASSO Project- Regione Lombardia)