THE USE OF SALTY AND SUGARY FORMER FOOD PRODUCTS IN GROWING AND FINISHING PIG DIETS: EFFECTS ON GROWTH PERFORMANCE, NUTRIENT DIGESTIBILITY, BEHAVIOUR, GUT HEALTH, MEAT QUALITY AND FEED SAFETY

One of the biggest challenges in recent years is ensuring global food security while minimizing the utilization of natural resources, whose availability is limited. Animal feed production is among the factors that contribute to worsen the food-feed competition. Thus, researchers in animal nutrition are looking for alternative feed sources to conventional ingredients. This thesis focused on the use of Former Food Products (FFPs) as alternative ingredients in growing and finishing pigs’ diets. In particular, the first part of this thesis investigated the effects of FFPs on growth performance, nutrients digestibility, feeding and social behaviour, giving an overview about animal health and welfare. The central part addressed the effects on gut health considering the microbiota composition and physiology of the small intestine and the effects on selected serum metabolites and insulin secretion. Moreover, the effects on meat quality traits, carcass composition and sensory characteristics of the loins were evaluated. In the last part, the safety issues linked to the use of FFPs were investigated. FFPs samples were thus analysed in relation to the presence of presumed remnants of packaging materials. For this purpose, a method involving stereomicroscopy coupled with µFT-IR spectroscopy was used. The results obtained from the in vivo trial involving thirty-six growing-finishing pigs, confirmed that the inclusion of 30% of salty and sugary FFPs had no detrimental effects on growth performance, apparent total tract digestibility and feeding or social behaviour. Gut health has been preserved and metabolic profile as well. As a positive outcome, no adverse effects on pork quality traits and sensory characteristics were shown, however the fatty acid profile of the meat and backfat was slightly altered. Regarding the presumed remnants of packaging materials, the contamination level of the FFPs analysed samples was always below the European safety limits and the novel approach demonstrated that packaging remnants were mainly represented by cellulose. The findings confirmed the potential of including these alternative feed ingredients throughout the entire pig production cycle emphasizing their sustainability in reducing food waste and simultaneously ensuring both product quality and safety.