Soluble polysaccharide and biomass of red microalgaPorphyridiumsp. alter intestinal morphology and reduce serum cholesterol in rats

Abstract

The present study investigated the effects of the red microalga Porphyridium sp. on gastrointestinal physiology and lipid metabolism in male Sprague-Dawley rats. Diets containing dietary fibre from pelleted red microalgal cells (biomass) or their sulfated polysaccharide, pectin or cellulose (control) were fed to rats for a period of 30 d. All three fibre-supplemented diets increased the length of both the small intestine and colon, with a significantly greater effect in rats fed the algal polysaccharide. The polysaccharide also increased mucosa and muscularis cross-sectional area of the jejunum, and caused hypertrophy in the muscularis layer. The algal biomass significantly lowered gastrointestinal transit time by 44 % in comparison with the control rats. Serum and mucosal cholecystokinin levels were lower in rats on the pectin and polysaccharide diets, while cholecystokinin levels in rats fed algal biomass were not different from those in the control animals. In comparison with the control diet, all the experimental diets significantly lowered serum cholesterol levels (22–29 %). Feeding of non-fermentable algal polysaccharide or biomass significantly increased faecal weight and bile acid excretion compared with pectin-fed or control rats. The algal polysaccharide and biomass were thus shown to be potent hypocholesterolaemic agents active at low concentrations in the diet. Both metabolic and morphological changes were observed following consumption of algae, suggesting several possible mechanisms by which the alga affects lipid metabolism. The results presented in the present study encourage the use of red microalga as a functional food.

Acute and subchronic safety assessment of Porphyridium purpureum biomass in the rat model

“…There are no published reports of P. purpureum-producing toxins. Further, few earlier reports on feeding of P. purpureum biomass in chickens and rats did not show any toxic signs (Ginzberg et al 2000;Dvir et al 2000). In addition, the quality of P. purpureum biomass was ensured by using potable water and closed LDPE bioreactors for cultivation.…”

“…Similarly, in the present study, a decrease in cholesterol and triglyceride levels of rats was observed. A number of recent studies have shown that algae possess a cholesterol and lipid-lowering ability and demonstrated the potential health benefits of incorporating algae or algal by-products into the diet (Belay 2002;Dvir et al 2000;Ginzberg et al 2000). Moreover, the minimum recommended dietary intake of n-3 PUFA as prescribed by WHO and FAO is 250 mg day −1 , while the American Heart Association has recommended up to 500 mg day −1 for a healthy adult (Lichtenstein et al 2006).…”

“…Although several in vitro and in vivo studies have proved the nutritional potential of P. purpureum (Ginzberg et al 2000), complete long-term feeding studies are limited (Dvir et al 2000). Hence, the present work was taken up to study the effect of long-term feeding of P. purpureum biomass in an experimental animal model and to evaluate its effect on the various physiological and biochemical parameters.…”

The extracellular proteoglycan produced by Rhodella grisea

“…), pharmacological (drug delivery matrix) and medicinal (antiviral, hypocholesterolemic, antithrombotic, immunomodulatory activities, etc.) applications [2][3][4][5][6][7].…”

The extracellular polysaccharide of Porphyridium sp.: an NMR study of lithium-resistant oligosaccharidic fragments

“…25 These polysaccharides could be used as hypocholesterolemic or antiviral agents, potential pharmacological effects are expected in immune modulatory and antithrombotic activities, another application was described as oral drug delivery matrix. [26][27][28][29] Elucidating the structure of a complex carbohydrate requires first its fragmentation into characteristic oligosaccharidic units. In the present paper, the polysaccharide from Porphyridium sp.…”