Supplementation with niacinamide in normal- and low-protein diets: effects on immunity, antioxidant capacity, and intestinal microbiota in growing-finishing pigs

Reducing dietary protein requires amino acid supplementation to maintain growth, as low-protein diets can otherwise impair pig performance. Currently, studies are investigating the effects of nicotinamide on immune function, antioxidant capacity, and intestinal microbiota.

Objective: This study aimed to investigate the effects of dietary nicotinamide supplementation on the antioxidant capacity, immune function, and intestinal microbiota of pigs, aiming to provide insights into improving the health of pigs fed low-protein diets.

Method: Forty barrows (37.0±1.0 kg) were randomly allocated to one of four dietary treatments (n=10 per group). The diets in the two phases consisted of a basal diet with 30 mg/kg nicotinamide, a basal diet with 360 mg/kg nicotinamide, a low-protein diet with 30 mg/kg nicotinamide, and a low-protein diet with 360 mg/kg nicotinamide. On days 70–71, blood, jejunum and colon mucosa, and colon tissue samples were collected.

Results: Dietary addition of 360 mg/kg nicotinamide decreased IL-12, malondialdehyde, IgG and IgM contents in the plasma and increased total superoxide dismutase activity and total antioxidant capacity in the colonic mucosa. Supplementing the diet with 360 mg/kg nicotinamide increased mRNA expression of the nucleotide-binding oligomerization domain containing 2 and nuclear factor erythroid 2-related factor 2 and protein expression of nuclear factor kappa-B and toll-like receptor 4 in the colonic mucosa. The concentrations of acetic acid and butyric acid in the colonic contents and the abundance of Actinobacteriota in the colon at the phylum level were significantly decreased by feeding low-protein diets. Additionally, the addition of 360 mg/kg nicotinamide to diets increased the Sobs, Ace, and Chao indices of colonic microorganisms in pigs.

Conclusion: The rational use of nicotinamide can improve inflammatory status, enhance antioxidant capacity and intestinal barrier function, and increase colonic microbial diversity in growing-finishing pigs.

Lan T, Cai M, Wang S, Lu Y, Tang Z, Tang Q, Gao J, Xu Y, Peng X, Sun Z. Effects of adding niacinamide to diets with normal and low protein levels on the immunity, antioxidant, and intestinal microbiota in growing-finishing pigs. The Journal of Nutritional Biochemistry. 2025; 136: 109809. https://doi.org/10.1016/j.jnutbio.2024.109809