Quantum dot butyrate: a novel strategy to improve performance, nutrient digestibility and gut barrier function in broilers

Restriction of antibiotic growth promoters in poultry increased the search for safe alternatives to improve growth, gut health, and immunity. Sodium butyrate (SB) as a feed additive enhances intestinal integrity and function, but its rapid dissociation and absorption in the upper gut limit its utility. The present study was carried out to determine the effects of quantum dot butyrate (QdotB), a targeted and controlled-release alternative for broilers. Carbon quantum dots (CQDs) were synthesized and conjugated with SB to generate QdotB. A total of 240 one-day-old cobb-430 broiler chicks were divided into five groups: control (CON), sodium butyrate powder (0.5 kg/MT feed) (SB), CQD (0.5 mL/L water), 0.5 mL/L QdotB, and 1.0 mL/L QdotB. Growth performance, nutrient digestibility, intestinal morphology, the gut pH, tight junction gene expression, the cecal microbiota, and the immune response were measured for 35 days. Compared with CON and SB, QdotB supplementation, especially at a concentration of 1.0 mL/L, significantly improved (P < 0.05) body weight gain and the feed conversion ratio. Nutrient digestibility of dry matter (DM) and crude protein (CP) was increased by QdotB supplementation but had no influence on ether extract or fiber digestibility. QdotB reduced the pH of the duodenal, jejunal, and ileal digesta; increased the VH (villus height) and VH/CD (crypt depth) ratios; and increased the expression of tight junction genes (claudin-1 and ZO-1). The QdotB supplementation increased the Lactobacillus count, reduced the total viable count (TVC), and reduced the Escherichia coli (E. coli) count. The QdotB also significantly increased the hemagglutination inhibition (HI) titer against Newcastle disease virus (NDV) compared with that of CON- and SB-supplemented birds. The findings of the present study suggest that, compared with traditional SB, QdotB supplementation improved growth performance, nutrient utilization, and gut health in broilers. This new nanocarrier-based method has potential as an environmentally friendly antibiotic alternative in sustainable poultry production.