Effect of different dosages of sodium butyrate and niacin on growth, faecal microbiota and Vitamin B metabolism in weaned piglets

Our study aimed to evaluate the effects of different dosages of sodium butyrate and niacin on the growth performance, faecal Vitamin B and microbiota in weaned piglets.Seventy-two weaned piglets (Duroc × Landrace × Yorkshire, age of 21 days) were randomly assigned to one of six treatments (12 pigs/treatment); the control (CT) group was administered a basal diet. The groups in which concentration ratios of sodium butyrate to niacin were 100: 1, 100: 2, 100: 4, 100: 8 and 100: 16 (BN1, BN2, BN4, BN8 and BN16) were administered a basal diet supplemented with 2000 mg kg-1 sodium butyrate and 20, 40, 80, 160 or 320 mg·kg-1 niacin. After 14-day treatment, the samples were collected. The results showed that feed conversion rate (FCR) was reduced and average daily gain (ADG) was increased in BN2 (p < 0.05). The diarrhoea index of pigs decreased with the low supplement. Additionally, compared with the CT group, other groups significantly increased (p < 0.05) the abundance of Firmicutes (BN4, phylum), Lactobacillaceae (BN8, family), Megasphaera (BN8, genus) and Lactobacillus (BN8, genus). Furthermore, the sodium butyrate and niacin supplementation influence Vitamin B1, Vitamin B2, pyridoxine, niacin, nicotinamide and Vitamin B12 (p < 0.05). Correlation analysis of the association of micro-organisms with Vitamin B indicated that changes of Vitamin B metabolism have a potential correlation with alterations of faecal microbiota in weaned piglets.The results indicated that adding sodium butyrate and niacin in the diet could promote the performance and improve the faecal microbiota and Vitamin B metabolism in weaned piglets.Our study might provide clues to the research of correlations between faecal bacteria and faecal Vitamin B, and these findings will contribute to the direction of future research in weaned piglets.