Effects of dietary intake of potatoes on body weight gain, satiety-related hormones, and gut microbiota in healthy rats

Abstract

Potatoes, as a prominent staple food, have exerted diverse intestinal health benefits, but few studies have addressed the gut microecology modulatory effects of consuming potatoes in realistic quantities. The objective of this study was to evaluate the effects of ingesting potatoes in different doses on body weight gain (BWG), food intake, short chain fatty acids (SCFAs), fecal microbiota, gut hormones, and colon morphology of healthy rats. Male Sprague-Dawley rats of 6-8 weeks old were randomized to five groups and fed AIN-93 G or diets containing graded concentrations of potato powder (low, medium, high, and higher) for 7 weeks. Accordingly, the final body weight was significantly lower for rats fed the high and/or higher potato diets than their control counterparts (P < 0.05). Potato intervention caused a significant dose-dependent increment in full cecum, and SCFAs production. The relative abundance of "S24-7" (order Bacteroidales), Bifidobacterium, "NK3B31" (family Prevotellaceae), Parasutterella, and Ruminococcus_1 increased in high and higher potato diets. Furthermore, a Spearman's correlation analysis revealed that Parasutterella was negatively correlated with BWG, triglyceride (TG), and low-density lipoproteins (LDL). The maximum number of goblet cells, longest crypt depth, and highest level of PYY were found in the distal colon of rats fed higher potato diets. The results suggested that potato powder could provide the potential for hopeful impact on weight control.

Fig. 1. Periodic acid–Schiff staining of distal colon tissue showing intact crypts with goblet cells. The blue lines (T1–T7) represent the length of crypt depth. Magnification: ×200.

Fig. 2. Potato intake modulated the structures of the gut microbiota. (A) Principal co-ordinate analysis (PCoA) based on unweighted UniFrac distances of microbial 16S rRNA sequences from the V3–V4 region in distal colon contents at week 7; (B) the Firmicutes/Bacteroidetes (F/B) ratio in rats after fed different diets for 7 weeks.

Fig. 3. Fecal microbiota composition of Sprague-Dawley rats after 7 weeks on a control diet (CO), low (PL), medium (PM), high (PH) and higher concentration of potato group (PHer). (A) Phylum level; (B) genus level.

Fig. 4. Linear discriminant analysis (LDA) scores for differentially abundant genera between rats fed with different diets: CO vs. PH (A); CO vs. PHer (B); PH vs. PHer (C). LDA effect size (3.5-fold) was set as the threshold to determine the significance. CO: rats fed with an AIN-93 G diet; PH: rats fed with a high concentration of potato diet; PHer: rats fed with a higher concentration of potato diet.

Fig. 5. Correlation analysis between fecal microbiota and host biochemical characteristics at genus level. The red-white-green color in the right histogram stands for R-value of Spearman's correlation between the genus and host biological characteristics. SCFAs: short chain fatty acids; BCFAs: branched-chain fatty acids; HDL: high-density lipoproteins; LDL: low-density lipoproteins; TG: triglyceride; BWG: body weight gain. ***P < 0.001; **P < 0.01; *P < 0.05.