Frozen Autoclaved Sorghum Enhanced Colonic Fermentation and Lower Visceral Fat Accumulation in Rats.

Samanthi W Pelpolage,Koichi Nakano,Kyu-Ho Han,Hiroki Bochimoto,Tetsuo Hamamoto,Michihiro Fukushima,Ryuji Nagata,Atsushi Yoshida,Kenichiro Shimada,Michiyo Hoshizawa,Naoki Fukuma

doi:10.3390/nu12082412

Abstract

As raw sorghum is not able to influence considerable colonic fermentation despite its higher resistant starch (RS) content, our study aimed to investigate the effects of frozen autoclaved sorghum on colonic fermentation. Fischer 344 rats were fed frozen cooked refined (S-Rf) and whole (S-Wh) sorghum diets and were compared against α-corn starch (CON) and high amylose starch (HAS) fed rats for zoometric parameters, cecal biochemical and microbiological parameters. Sorghum fed rats exhibited significantly lower feed intake and visceral adipose tissue mass compared to CON. Bacterial alpha diversity was significantly higher in the sorghum fed rats compared to HAS and the two sorghum fed groups clustered together, separately from HAS and CON in the beta diversity plot. Serum non-High Density Lipoprotein cholesterol and total cholesterol in S-Rf group were significantly lower compared to CON, while total fecal bile excretion was also significantly higher in the two sorghum fed groups. Lower visceral adiposity was correlated with lower feed intake, RS content ingested and cecal short chain fatty acid (SCFA) contents. Thus, higher RS inflow to the colon via frozen autoclaved sorghum might have influenced colonic fermentation of RS and the resultant SCFA might have influenced lower adiposity as manifested by the lower body weight gain.

Highlights

Decreased incidence of non-communicable diseases such as obesity and related co-morbidities has been linked with the beneficial effects of gut microbial fermentation of dietary resistant polysaccharides and fermentation metabolites [1]
Albeit that a clear reason could not be identified for the reduced appetite, the resistant starch (RS) content ingested via diet was found to influence a reduced calorie intake, as well as a higher cecal short chain fatty acid (SCFA) content
Lower body weight was only associated with reduced calorie intake, while lower visceral fat accumulation was associated with both lower calorie intake and SCFA contents

Summary

Introduction

Decreased incidence of non-communicable diseases such as obesity and related co-morbidities has been linked with the beneficial effects of gut microbial fermentation of dietary resistant polysaccharides and fermentation metabolites [1]. Adenosine monophosphate kinase (AMPK) activation in adipose tissue by SCFA is known to decrease lipogenic flux, triglyceride catalysis, and increase fatty acid oxidation and reduce the free fatty acid release into and, its availability in, plasma [2]. Resistant starch (RS) has a negligible contribution in terms of caloric supply, but it mediates more beneficial biochemical reactions upon reaching the colon [4]. Being an anaerobic fermentation process, it yields SCFA as the main by-products that are known as signaling molecules, which mediate many biochemical reactions in the adipose tissue, liver, brain axis and the intestine itself [5]. The SCFA mediated upregulated or downregulated biochemical processes are known to exert beneficial health effects on the host, such as prevention of colon cancers, homeostasis of lipid and glucose metabolism, and prevention of fat accumulation, overweight and obesity, etc. The SCFA mediated upregulated or downregulated biochemical processes are known to exert beneficial health effects on the host, such as prevention of colon cancers, homeostasis of lipid and glucose metabolism, and prevention of fat accumulation, overweight and obesity, etc. [6,7]

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