Effects of bakery/confectionary former food products as cereal substitute on growth performance and gut microbiota in post-weaning piglets

Former Foodstuffs (FFPs) are products that have lost their commercial value on the human consumption market, due to for example production errors. However, their nutritional value for animal feed purposes is not at all affected. Consequently, biscuits, bread, chocolate bars, pasta, savoury snacks and sweets, high in energy content in the form of sugar, starch, oil or fat can be considered an appealing alternative feed ingredient. Although FFPs composition, may vary to a large extent, they have been indicated as energy sources mainly. Accordingly, in this study, conventional cereal grains have been partially replaced by FFPs in post-weaning piglet’s diets in order to investigate the effects of these alternative feed ingredients on growth performance and gut microbiota. The diets were iso-energetic (16 MJ/kg DM) and iso-nitrogenous (20.5% DM), and contained all essential amino acids in the recommended amounts. After an adaptation period (7d), post-weaning piglets (n=12, 28d old) were housed for 12d in individual pen and assigned to two experimental groups: CRT, receiving a standard diet and FFP, receiving a diet in which 30% of conventional cereals (wheat, barley, corn) were substituted by 30% FFPs. Both diets were in grounded forms and piglets had ad libitum access to the feed and fresh water throughout the whole trial. Individual feed intake was recorded daily, piglet’s bodyweight (BW, kg) was recorded on d1, 5, 9 and 12 of the experiment. Average daily gain (ADG kg/day), average daily feed intake (ADFI kg/day) and Feed Conversion Ratio (FCR kg/kg) have been calculated. Raw data means were analyzed by IBM SPSS Statistics version 25 software (SPSS Inc.). In order to characterize gut microbiota composition, bacterial DNA has been extracted from stool samples, and the 16s rRNA gene has been sequenced by Next Generation Sequencing approach. At the end of the experiment no differences in BW, ADG, ADFI, have been observed between groups. Conversely, piglets on the FFP diet showed a better FCR (P<0.05). The gut microbiota did not show differences in microbial taxa composition, while further investigations are necessary to clarify the effects of FFPs on gut bacterial abundance and biodiversity.