Salty vs. sugary food industry leftovers in post-weaning piglets: effects on gut microbiota and intestinal volatile fatty acid production

Awareness of the need to improve the sustainability of livestock production by reducing the loss of natural resources has increased significantly. This study investigated effects of two categories of food industry leftovers (i.e. “former foodstuff” (FFPs)) on pig gut microbiota and intestinal volatile fatty acid (VFA) production. Thirty-six female post-weaning piglets (28 days old, Large White x Landrace, 6.5 ± 1.1 kg) were separated into three groups and fed a conventional diet (CTR) or a diet in which cereals were partially replaced (30% w/w) by sugary confectionery products(FFPs-C) orsalty bakery products(FFPs-B), respectively. After 42 days of dietary treatments, faeces were collected from the rectal ampulla, snap-frozen, and used for next-generation sequencing to analyse the composition and alpha and beta diversity indexes of the microbial population. The concentration of VFAs in the intestinal content collected at the slaughterhouse was also analysed. Neither the FFPs-C or FFPs-B diets influenced the abundance or biodiversity indexes of the microbial community. The experimental diets had no impact on the production of VFAs in the intestine. In contrast, the FFPs-C and FFPs-B diets slightly influenced the gut microbiota. FFPs could thus be used as a promising alternative to traditional ingredients in pig diets; however, additional analyses are needed to further investigate the presence of potentially pathogenic bacteria. Effects of using such ingredients during the fattening period on other markers of gut health and on product quality also need to be investigated.