Prebiotic and Immunomodulatory Properties of the Microalga Chlorella vulgaris and Its Synergistic Triglyceride-Lowering Effect with Bifidobacteria

Ivana Hyrslova,Ladislav Curda,Tomas Branyik,Jana Smolova,Martina Huttl,Ivo Doskocil,Barbora Stankova,Gabriela Krausova,Antonin Kana,Hana Malinska

doi:10.3390/fermentation7030125

Abstract

The microalga Chlorella and strains of Bifidobacterium have been used in human or animal food supplements for decades because of their positive health effects. The presented study assessed different properties of C. vulgaris and its combination with bifidobacteria with the aim to develop new functional foods. The growth of four bifidobacteria strains in milk and whey supplemented with 1.0% (w/v) C. vulgaris and the immunomodulatory effects of aqueous Chlorella solutions (0.5%, 1.0%, and 3.0%) on human peripheral mononuclear cells were evaluated. Furthermore, synergistic effects on lipid metabolism of rats fed a high-fat diet with Chlorella and B. animalis subsp. lactis BB-12® were analysed. Chlorella had a positive growth-promoting effect on the tested bifidobacteria (p < 0.05), and significantly increased the secretion of inflammatory cytokines (tumor necrosis factor-α, interleukin-10, and interleukin-6), depending on the concentration of Chlorella (p < 0.05). After 8 weeks, significant synergistic effects of Chlorella and bifidobacteria on triglyceride levels in rat heart, liver, and serum were observed (p < 0.05). These results demonstrate that various combinations of Chlorella and bifidobacteria have significant potential for the development of new fermented products, dependent on the algal species, probiotic strain, application form, and concentrations for acceptable sensory quality for consumers.

Highlights

Our results demonstrate that Chlorella and bifidobacteria used in various combinations have significant synergistic potential for the development of new fermented products with positive health effects
Prebiotic activity was evaluated by determining the bacterial counts of four selected bifidobacterial strains, changes in pH, and production of lactic and acetic acids (Tables 2 and 3) after fermentation of whey and bovine milk with 1.0% (w/v) Chlorella powder supplementation
The pH values correlated with increased concentrations of lactic and acetic acids produced by bifidobacteria (Table 3)

Summary

Introduction

Chlorella vulgaris as a food supplement acts as a source of nutritionally-valuable substances, including proteins, carbohydrates, vitamins, pigments, antioxidants, and unsaturated fatty acids. Chlorella and Arthrospira (Spirulina), the most consumed microalgae, accumulate high-quality proteins with a balanced amino acid profile according to WHO recommendations for essential amino acids [1]. Commercial prebiotics are generally carbohydrate compounds that act as substrates for probiotic microorganisms. The most important carbohydrate in Chlorella cells, in terms of its usefulness for living organisms, is β-1,3-glucan, which is a branched polysaccharide of β-D-glucose units. The most important carbohydrate in Chlorella cells, in terms of its usefulness for living organisms, is β-1,3-glucan, which is a branched polysaccharide of β-D-glucose units. β-1,3-glucan is

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