The Antibacterial and Immunomodulatory Effects of Carbohydrate Fractions of the Seaweed Gracilaria persica

Abstract

INTRODUCTION Algae contain diverse photosynthetic organisms that grow in aquatic environments. According to their morphology and chemical composition, marine macroalgae or seaweeds are classified into green algae (Chlorophyta), brown algae (Phaeophyta), and red algae (Rhodophyta) [1]. They have various bioactive organic and inorganic components with beneficial applications, such as feeding and health protection of humans and animals [2, 3]. Due to the emergence of antibiotic-resistant strains of bacteria, the medicinal plants might play an alternative role in the treatment of infectious diseases. The biological and pharmacological evaluation of seaweeds has led to discovering several natural or semi-synthetic drugs in recent years [4]. In response to harsh environmental conditions, algae produce various secondary metabolites [3, 5] that have bactericidal effects against some of the Grampositive and Gram-negative bacteria [6]. In addition, brown, red, and green seaweed extracts have been reported to have antioxidant, antiviral [7], antifungal [8], cytotoxic [9], and larvicidal properties [10]. The anti-inflammatory compounds of the seaweeds can be also used for medicinal applications [11]. The Gracilaria species grow in the tropical regions throughout the world. These Algae produce sulfated polysaccharides. The polysaccharide backbone of

Algae as an alternative source of protein in poultry diets for sustainable production and disease resistance: present status and future considerations

“…Additionally, a carbohydrate fraction derived from the red seaweed Gracilaria persica displayed direct antimicrobial effects against six bacterial pathogens, including Staphylococcus aureus , E. coli , Methicillin-resistant Staphylococcus aureus , Salmonella typhimurium , Pseudomonas aeruginosa , and Aeromonas hydrophila , while also inducing a humoral immune response against sheep red blood cells ( 56 ). Water extracts of red seaweeds Gelidium latifolium , Hypnea musciformis , Jania rubens , Jania spp., and Laurencia obtusa exhibited potent in vitro antimicrobial activity against Gram-negative pathogenic bacteria such as E. coli , Klebsiella spp., and P. aeruginosa ( 90 ). Furthermore, chickens fed Laminaria japonica at 1, 3, and 5% levels inhibited E. coli counts while increasing Lactobacillus counts in ceca ( 91 ).…”

A Review of the Varied Uses of Macroalgae as Dietary Supplements in Selected Poultry with Special Reference to Laying Hen and Broiler Chickens

“…Red and brown seaweeds have prebiotic-like properties that alter the metabolic activities of beneficial microflora and reduce the prevalence of pathogenic bacteria [61]. Moreover, a carbohydrate fraction extracted from the red seaweed Gracilaria persica exhibited direct anti-microbial effects against six bacterial pathogens including Staphylococcus aureus, E. coli, Methicillin-resistant Staphylococcus aureus (MRSA), Salmonella typhimurium, Pseudomonas aeruginosa and Aeromonas hydrophila and induced a humoral-immune response against sheep red blood cells (SRBC) [62]. Likewise, phlorotannin extracts isolated from two brown seaweeds A. nodosum and Fucus serratus were effective at killing three foodborne pathogens, E. coli O157, Salmonella agona, and Streptococcus suis, without negatively affecting the pig intestinal cells (in vitro) [63].…”