Effect of a Bacillus spp. mix combined with a potato-derived substrate on performance and faecal parameters of post-weaned piglets

Bacillus subtilis, B. licheniformis and Heyndrickxia (formerly Bacillus) coagulans are well known probiotics offering benefits for piglets during the weaning process. This study aimed to evaluate the efficiency of a mix of these strains combined with a by-product of potato processing product. The experiment was conducted using 88 piglets for 42 days post-weaning (DPW). Piglets were weaned at 28 days of age and directly received ad libitum access to a second age diet supplemented (PRO) or not (CO) with the probiotic mix at a concentration of >2.109 CFU/kg diet. The piglet's performance was calculated on a weekly basis. Four times per week, faecal consistency was scored for each pen comprising 4 piglets. Faeces samples (of the 2 heaviest piglets per pen) were collected weekly to determine dry matter (DM), short chain fatty acid content and microbiota profile by 16S rRNA analysis. PRO average daily gain increased by 12% (p=0.026) at 14 DPW and tended to increase by 8% (p=0.077) at 21 DPW with an equal feed conversion ratio (FCR, p=0.827 and p=0.966 respectively) compared to CO. At 42 DPW, the FCR of PRO was increased by 2.5% (p=0.019) due to an increase of the total feed consumption (p=0.027). The DM and the butyrate ratio of the faeces tended to be improved in PRO piglets in week 1 (respectively p=0.066 and p=0.085) and the DM was still improved in week 3 (p=0.028). However, PRO pen faecal consistency score was slightly more unfavourable. Twenty-six amplicon sequence variants (ASVs) were modulated by the mix. To conclude, the probiotic mix had an effect on piglets and its use seems more appropriate at the beginning of the post-weaning period.