Sugary and salty former food products in pig diets affect energy and nutrient digestibility, feeding behaviour but not the growth performance and carcass composition

Former foodstuff products (FFPs) are promising alternative ingredients for reducing the waste of natural resources and the environmental impact of food production. This study investigates the effects of salty and sugary FFPs on growth performance, apparent total tract digestibility (ATTD), and growing-finishing pigs' empty body and carcass composition. Thirty-six Swiss Large White male castrated pigs were assigned to three growing (G) and finishing (F) diets: (1) standard diet (ST), 0% FFPs; (2) 30% conventional ingredients replaced by sugary FFPs (SU); and (3) 30% conventional ingredients replaced by salty FFPs (SA). Faecal samples from 24 selected pigs were collected to assess the ATTD of gross energy, crude fibres, and CP. The BW was measured weekly, while feed intake was determined daily. Average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), and ATTD were calculated for both the growing and finishing periods. Pigs' body composition was determined at ≥20 and ≥98 kg using dual-energy X-ray absorptiometry. In the growing but not finishing period, the FCR was lower (P 0.05) ADG, ADFI, FCR, or BW at slaughter. In both the growing and finishing periods, the gross energy ATTD was higher (P 0.05) effects on the parameters related to the pigs' body composition (e.g., average daily fat weight gain). Finally, the carcasses of the SU group had the thickest belly fat, even though the total fat content was similar among the groups. This study confirms that including FFPs has no detrimental effects on growth performance or live body/carcass composition in growing and finishing pigs