Abstract Preliminary results demonstrated that dietary supplementation with non-nutritive sweeteners (NNS) enhanced growth performance and intestinal development in weaned pigs by improving morphology and strengthening gut barrier function. While the beneficial effects of neotame (NEO) and sucralose (SCL) are evident, the underlying mechanisms remain unclear. Therefore, the objective of this study was to evaluate the effects of dietary NEO and SCL supplementation on colonic microbiome composition and diversity in weaned pigs. A total of 288 pigs (6.21 ± 0.45 kg; PIC 800 x Yorkshire) were weaned at 21 ± 1 days and randomly allotted to 4 dietary treatments in a randomized complete block design (12 replicates/treatment; 6 pigs/pen), with initial body weight as the blocking factor. The dietary treatments were: (1) Control (CON): basal nursery diet; (2) SCL: CON + 150 mg/kg SCL; (3) NEO: CON + 30 mg/kg NEO; (4) CBX: CON + 50 mg/kg carbadox (antibiotic). Pigs were fed the experimental diets for 28 days in 2 phases (Phase 1: day 0 to 14; Phase 2: day 15 to 28). Colonic digesta samples were collected from 24 pigs (6 pigs/treatment) on days 0, 14, and 28 post-weaning. Total microbial DNA was extracted and sequenced at the Michigan State University Genomic Core targeting the V4 region of the 16S rRNA gene using the AVITI PE150 platform. Sequence data were processed using DADA2 within QIIME2, with taxonomy assigned using the SILVA 138.2 database. Functional prediction was performed using PICRUSt2, and downstream analyses were conducted in R to assess microbial composition, alpha and beta diversity, and differential abundance. SCL, NEO, or CBX did not affect alpha diversity (Chao1, Shannon indices); however, significant differences (P 0.05) were detected across sampling days, reflecting the expected temporal shifts in microbial structure during post-weaning development. Bray-Curtis PCoA and PERMANOVA further confirmed that sampling day was the primary factor influencing microbial community divergence (P 0.05). At the taxonomic level, Pigs fed SCL lowered Eubacteriaceae (P 0.05), Oribacterium (P 0.10), and Bifidobacterium (P 0.10) on day 14 compared to CON. Pigs fed NEO have lower Lactobacillus (P 0.10), and higher Aminicella (P 0.05) and Tyzzerella (P 0.10) on day 14 compared to the CON. In conclusion, dietary supplementation with NEO, SCL, or CBX exerted minimal effects on colonic microbial composition, diversity, and predicted functional profiles in weaned pigs. These results suggest that the growth-promoting benefits of NNS are likely independent of microbiome modulation and may instead involve host-mediated mechanisms influencing intestinal development and metabolism.
Jansen et al. (2026) studied this question.