Evaluation of Lactobacillus plantarum and Lactobacillus reuteri as feed additives for swine

In swine farming, effective alternatives capable to reduce antibiotic consumption are needed to cope with the increasing concern of antibiotic resistance. In this perspective, functional feed additives, such as probiotics, are able to sustain the health status and reduce the risk of diseases development, that have become a fundamental tool to prevent pathological conditions in livestock. The aim of this study was to evaluate Lactobacillus plantarum and Lactobacillus reuteri in vitro for their functional characteristics and in vivo for their effect on animal performance and health. Firstly, L. plantarum 4.1 and L. reuteri 3X7, isolated from swine by Biotecnologie BT were genetically characterized by PCR reaction. Subsequently, their resistance to pH, temperature and digestive process were evaluated. Furthermore, the Lactobacilli mucosa adhesion ability was assessed on IPEC-J2 cell line. For the in vivo trial, 350 weaned piglets (28±2d) were randomly divided into four experimental groups receiving basal diet respectively supplemented with: i) CTRL no supplementation; ii) PLA 2×108 CFU/g of L. plantarum; iii) REU 2×108 CFU/g of L. reuteri; iv) PROBIO 1×108+1×108 CFU/g for both bacterial strains. Growth performance and faecal consistency using a four-point scale (faecal score 0–3; considering diarrhoea ≥2) were recorded individually. Faecal samples were collected for the evaluation of main bacterial families, and blood serum aliquots were obtained for the assessment of metabolic parameters. In vitro characterization revealed a great resistance to a wide range of pH (3,4,5,7) for both species. At pH 2 a statistically significant reduction of bacterial growth was observed (p < .05). Both species showed good tolerance to a wide temperature range, while at 60 and 70°C a statistically significant reduction of bacterial growth was observed (p < .05). Both species survived well to all the steps of the digestion process. The LiCl treatment strongly inhibited the adhesion ability of L. reuteri (p < .001), while it showed no significant effects for L. plantarum strain. Piglets supplemented with Lactobacilli significantly decreased the faecal score (p < .0001) during the experimental period. L. plantarum and L. reuteri revealed interesting functional proprieties and health-improving effects as functional feed additives for weaned piglets. Acknowledgements The research study was done in the frame of FOODTECH PROJECT (ID 203370, co-funded by Lombardy Region and ERDF.