Beneficial Effects of Non-Encapsulated or Encapsulated Probiotic Supplementation on Microbiota Composition, Intestinal Barrier Functions, Inflammatory Profiles, and Glucose Tolerance in High Fat Fed Rats

Abstract

Development of obesity-associated comorbidities is related to chronic inflammation, which has been linked to gut microbiota dysbiosis. Thus, modulating gut microbiota composition could have positive effects for metabolic disorders, supporting the use of probiotics as potential therapeutics in vivo, which may be enhanced by a microencapsulation technique. Here we investigated the effects of non-encapsulated or pectin-encapsulated probiotic supplementation (Lactobacillus paracasei subsp. paracasei L. casei W8^®; L. casei W8) on gut microbiota composition and metabolic profile in high-fat (HF) diet-fed rats. Four male Wistar rat groups (n = 8/group) were fed 10% low-fat, 45% HF, or HF with non-encapsulated or encapsulated L. casei W8 (4 × 10⁷ CFU/g diet) diet for seven weeks. Microbiota composition, intestinal integrity, inflammatory profiles, and glucose tolerance were assessed. Non-encapsulated and pectin-encapsulated probiotic supplementation positively modulated gut microbiota composition in HF-fed male rats. These changes were associated with improvements in gut barrier functions and local and systemic inflammation by non-encapsulated probiotics and improvement in glucose tolerance by encapsulated probiotic treatment. Thus, these findings suggest the potential of using oral non-encapsulated or encapsulated probiotic supplementation to ameliorate obesity-associated metabolic abnormalities.

Keywords: glucose tolerance; gut microbiota; inflammation; intestinal epithelial barrier; microencapsulation; probiotics.

Figure 1

Non-encapsulated or encapsulated probiotic supplementation had no protective effects on obesity phenotype. Bodyweight (A), adiposity index: Fat pad weight/BW (%) (B) and energy intake (C) of rats fed an LF, HF, HF/Pro, or HF/Pca diet for seven weeks. Values are means ± SEMs; n = 8/group. ^a,b,c means with different letters are statistically significant, * indicates p < 0.05. HF, high fat; HF, high fat; HF/Pca, HF with supplemented with encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); HF/Pro, HF supplemented with non-encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); LF, low fat.

Figure 2

Encapsulation of probiotic bacteria improved glucose intolerance. Glycemia (A,B) and insulinemia (C,D) were measured during an OGTT (2 mg/kg) in rats fed an LF, HF, HF/Pro, or HF/Pca diet for seven weeks. Values are means ± SEMs; n = 8/group. ^a,b,c means with different letters are statistically significant, p < 0.05. HF, high fat; HF/Pca, HF with supplemented with encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); HF/Pro, HF supplemented with non-encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); LF, low fat.

Figure 3

Non-encapsulated or encapsulated probiotic supplementation led to compositional changes in gut microbiota. Microbial composition at the phylum (A), class (B), order (C), family (D) genus I, and species (F–I) of rats fed an LF, HF, HF/Pro, or HF/Pca diet for seven weeks. n = 8/group. Asterisk (*) or ^a,b,c means with different letters are statistically significant, p < 0.05. All phylogenic levels present with abundance >1% are represented. HF, high fat; HF/Pca, HF with supplemented with encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); HF/Pro, HF supplemented with non-encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); LF, low fat.

Figure 4

Compositional changes in gut microbiota by non-encapsulated or encapsulated probiotic supplementation were associated with changes in serum concentration of SCFAs (A) with no significant difference in gene expression of GLP-1 in the ileum (B) of rats fed an LF, HF, HF/Pro, or HF/Pca diet for seven weeks. Values are means ± SEMs; n = 8/group. ^a,b,c means with different letters are statistically significant, p < 0.05. GLP-1, glucagon-like peptide 1; HF, high fat; HF/Pca, HF with supplemented with encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); HF/Pro, HF supplemented with non-encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); LF, low fat; SCFA, short chain fatty acid.

Figure 5

Non-encapsulated probiotic supplementation improved markers of gut integrity and inflammation. Gene expressions of MUC2 (A) and inflammatory markers (B) in the ileum, serum LBP (C), and gene expression of macrophage infiltration markers (D) in mesenteric fat of rats fed an LF, HF, HF/Pro, or HF/Pca diet for seven weeks. Values are means ± SEMs; n = 8/group. ^a,b,c means with different letters are statistically significant, p < 0.05. CD68, cluster of differentiation 68; HF, high fat; IL-1β, interleukin-1 beta; IL-6, interleukin-6; LBP, lipopolysaccharides-bind protein; LF, low fat; MCP1, monocyte chemoattrantant protein 1; MUC2, mucin 2; HF/Pca, HF with supplemented with encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); HF/Pro, HF supplemented with non-encapsulated L. casei W8 (4 × 10⁷ cfu/g diet); TNFα, tumor necrosis factor alpha.