Abstract Zinc oxide (ZnO) at pharmacological doses (1000 to 3500 ppm) improves intestinal health of weaned piglets. However, long-term use can cause toxicity, antibiotic resistance, and environmental contamination. Thus, there is a need for safe, sustainable, and equally effective alternatives. Therefore, the objective was evaluate the bacterial community composition and intestinal morphology of weaned piglets supplemented with zinc proteinate (ZnProt-Bioplex® Zn), mannan-rich fraction (MRF-Actigen®) and a patented mixture of sodium butyrate, prebiotics and minerals (Viligen™ (VIL)), supplied by Alltech Inc., São Pedro do Ivaí, PR, Brazil, as a replacement for high levels of ZnO. 275 mixed-sex piglets (Landrace × Large White, PIC 337 × DanBred 90) weaned at 21 days of age, distributed in a CRD with 5 treatments, 11 replicates containing 5 animals each. The analyzed period was from 0 to 11 days, with feed and water provided ad libitum. Treatments were: T1 – basal diet (BD) + 3000 ppm ZnO + 100 ppm Zn as zinc sulfate (ZnOF); T2 – BD +ZnProt (100 ppm Zn)(ZnProt); T3 – BD + ZnProt (100 ppm Zn) + 800 g/ton MRF (ZnProt+MRF800); T4 – BD + ZnPro (100 ppm Zn) + 800 g/ton MRF + 600 g/ton VIL (ZnProt+MRF800+VIL600); and T5 – BD + ZnProt (100 ppm Zn) + 800 g/ton MRF + 1200 g/ton VIL (ZnProt+MRF800+VIL1200). At 11 days post-weaning, one animal per experimental unit, with a weight close to the average, was euthanized for duodenum, jejunum, ileum, and cecal digesta collection. Histological slides were prepared, and images were obtained using an EVOS™ M5000 optical microscope (10x). Subsequently, 20 villus heights (VH) and 20 crypt depths (CD) per segment and experimental unit were measured using ImageJ 1.50i, and the VH:CD ratio was calculated. ANOVA was used for data, with Tukey and Dunnett tests (5%). The cecal bacterial community composition was identified by sequencing the V3–V4 region of the 16S rRNA gene and data were processed using the DADA2 package, ASV taxonomy was assigned using the SILVA database (v.138.1), and analyses were performed with the mctoolsr, vegan, and ggplot2 packages. No differences (P 0.05) were observed in VH, CD, and VH:CD in duodenum and ileum. However, in jejunum, T4 promoted greater VH and a higher VH:CD ratio than ZnOF (P 0.05), not differing (P 0.05) from the other treatments (Tukey). When evaluating diversity indices (Richness, Shannon and Simpson), heatmap, and principal coordinates analysis, ZnOF maintained a more diverse community and lower Escherichia/Shigella abundance; however, the beneficial microbiota population (Lactobacillus) was also lower. In general, low levels of ZnProt with MRF and VIL additives promoted a higher beneficial bacteria population, similar and potentially protective. It is concluded that the additives ZnPro+MRF800+VIL600 or VIL1200 enhanced intestinal morphology and positively modulated the cecum bacterial community
Fonseca et al. (Wed,) studied this question.