An Alteration in the Cecal Microbiota Composition by Feeding of 1-Kestose Results in a Marked Increase in the Cecal Butyrate Content in Rats

Abstract

Functional food ingredients, including prebiotics, have been ardently developed for improving the intestinal environment. Fructooligosaccarides (FOS), including fructans, are the well researched and commercialized prebiotics. However, to our knowledge, few studies have been conducted on the physiological effects of each component of FOS as prebiotics. 1-Kestose, a component of FOS, is composed of one glucose and two fructose molecules, and is considered as a key prebiotic component in short-chain FOS. In the present study, we examined the effects of dietary 1-kestose using 0.5–5% 1-kestose diets on cecal microbiota composition and cecal contents of short-chain fatty acids and lactate in rats. The findings indicate that dietary 1-kestose induced cecal hypertrophy and alterations in the cecal microbiota composition, including a marked increase in the cell number of Bifidobacterium spp. These alterations were associated with significant increases in acetate and lactate, and a marked increase in butyrate in cecal contents. Furthermore, dietary 1-kestose induced a significant decrease in serum insulin concentration in rats fed 2.5–5% 1-kestose diet. These findings suggest a potential of 1-kestose to be a prebiotic for improving the metabolism of the host.

Experimental Determination of the Threshold Dose for Bifidogenic Activity of Dietary 1-Kestose in Rats

“…The bifidogenic activity was significantly stronger with 1-kestose than nystose and FOSs in vitro [5]. In our previous study, we demonstrated that 1-kestose showed a dose-dependent relationship with bifidogenic activity in rats [6]. Since 1-kestose naturally occurs in several foods, such as banana, peach, artichoke, onion, barley and wheat [3], and only trace levels of 1-kesotse are consumed in the regular diet, its ability to exert prebiotic effects has drawn attention to its use as a supplement to a regular diet.…”

“…The pellet form AIN-93G diet and the AIN-93G-based experimental diets were purchased from CLEA Japan (Tokyo, Japan). Equivalent amount of sucrose (0.1%, 0.2% or 0.3%) in AIN-93G were replaced with 1-kestose in the experimental diets ( Supplementary Table S1) [6].…”

“…Measurements of cecal microbiota populations were conducted using quantitative real-time PCR (qPCR) at Technosuruga Laboratory Co., Ltd. (Shizuoka, Japan). Details of the analyses were described previously [6]. Primers sequences for 16S rRNA analysis are shown in Supplementary Table S2 [10][11][12].…”

“…Currently, while the prebiotic activities of FOSs, galactooligosaccharides and inulin-type fructans have been widely tested (dose-dependent effects or threshold doses in healthy subjects [7][8][9]), the Foods 2020, 9, 4 2 of 5 optimal dose of 1-kestose has not been adequately established. Since our previous finding confirmed that a 0.5% 1-kestose dietary supplementation was sufficient to increase the population of Bifidobacterium in rat cecal contents [6], this study investigated the minimum effective dose of 1-kestose to modulate beneficial microbes in rats.…”

Comment on Experimental Determination of the Threshold Dose for Bifidogenic Activity of Dietary 1-Kestose in Rats. Foods 2020, 9, 4

“…by traditional cell counting on agar plate other than qPCR amplification [3]. It is obvious the citation is incorrect.Then, we found the above primers in another paper, which came from the same research group, in which a similar experiment was conducted investigating the effect of 1-kestose within a range of 0.5-5.0% [4]. In this paper, the primers have the same sequences but different names (Bif LM26F/Bif 228R).…”