Effect of Black Corn Anthocyanin-Rich Extract (Zea mays L.) on Cecal Microbial Populations In Vivo (Gallus gallus)

Abstract

Black corn has been attracting attention to investigate its biological properties due to its anthocyanin composition, mainly cyanidin-3-glucoside. Our study evaluated the effects of black corn extract (BCE) on intestinal morphology, gene expression, and the cecal microbiome. The BCE intra-amniotic administration was evaluated by an animal model in Gallus gallus. The eggs (n = 8 per group) were divided into: (1) no injection; (2) 18 MΩ H₂O; (3) 5% black corn extract (BCE); and (4) 0.38% cyanidin-3-glucoside (C3G). A total of 1 mL of each component was injected intra-amniotic on day 17 of incubation. On day 21, the animals were euthanized after hatching, and the duodenum and cecum content were collected. The cecal microbiome changes were attributed to BCE administration, increasing the population of Bifidobacterium and Clostridium, and decreasing E. coli. The BCE did not change the gene expression of intestinal inflammation and functionality. The BCE administration maintained the villi height, Paneth cell number, and goblet cell diameter (in the villi and crypt), similar to the H₂O injection but smaller than the C3G. Moreover, a positive correlation was observed between Bifidobacterium, Clostridium, E. coli, and villi GC diameter. The BCE promoted positive changes in the cecum microbiome and maintained intestinal morphology and functionality.

Keywords: cyanidin; goblet cells; intestinal barrier; phenolic components.

Figure 1

Flowchart of the black corn extract procedure.

Figure 2

The effect of intra-amniotic black corn extract administration on the bacterial population from cecal content. The relative abundance is expressed in arbitrary units (AU). Values are means ± SED, n = 5 animals/group. BCE: black corn extract; C3G: cyanidin-3-glucoside. The treatment groups not indicated by the same letter are different (p < 0.05) by the post-hoc Duncan test. Squares without any letters: no difference among the treatments (p > 0.05).

Figure 3

Effect of intra-amniotic administration of black corn extract on duodenal gene expression related to (A): intestinal inflammation biomarkers; (B): intestinal barrier biomarkers; (C): intestinal functionality biomarkers. Values are means (AU: arbitrary units) ± SED, n = 5 animals/group. BCE: black corn extract; C3G: cyanidin-3-glucoside. The treatment groups not indicated by the same letter are different (p < 0.05) by the post-hoc Duncan test. Squares without any letters: no difference among the treatments (p > 0.05). TNFα: tumor necrosis factor-alpha; NF-κβ1: nuclear factor kappa beta-1; IL-1β: interleukin 1 beta; AMPK: AMP-activated protein kinase; OCLN: occludin; CDX2: caudal-related homeobox transcriptional factor 2; VDAC: voltage-dependent anion channel; CRBP2: cellular retinol-binding protein-2; LRAT: lecithin retinol acyltransferase; ZnT1: Zinc transporter 1.

Figure 4

Effect of intra-amniotic administration of black corn extract on goblet cells: (A–D): villi goblet cell characteristics; (E–H) crypt goblet cell characteristics. Values are means ± SED, n = 3 animals/group. Treatment groups not indicated by the same letter are different (p < 0.05) by Kruskal–Wallis and a post-hoc of Dunn’s test. Mixed goblet cells are acidic and neutral. BCE: black corn extract; C3G: cyanidin-3-glucoside; GC: goblet cell.

Figure 5

Correlation between intestinal biomarkers, bacterial population, and histological parameters. Colors from blue to red represented the p-value of the Spearman’s rank correlation coefficient. Blue: negative and red: positive correlation. * Significant correlation p < 0.05. TNF−α: tumor necrosis factor-alpha; NF−κB: nuclear factor kappa beta; IL−1β: interleukin 1 beta; MUC2: mucin 2; OCLN: occludin; CDX2: caudal-related homeobox transcriptional factor 2; VDAC: voltage-dependent anion channel. GC: goblet cells; #: number.