The Use of κ-Carrageenan in Egg Yolk Free Extender Improves the Efficiency of Canine Semen Cryopreservation

κ-Carrageenan is a plant polysaccharide derived from red seaweeds reported to possess potential medicinal and antioxidants activities. The present study aimed to identify the cryoprotective effects of κ-carrageenan on the quality of frozen-thawed canine semen. Twenty-eight ejaculates were collected and diluted in a Tris egg-yolk-free extender supplemented with various concentrations of κ-carrageenan (0.0%, 0.1%, 0.2%, 0.3%, and 0.5%). The addition of κ-carrageenan to the extender at a 0.2% concentration induced a significant increase in the total motility (TM) and the rapid progressive motility (RPM) of canine sperm. Among the experimental groups, the highest percentage of sperms with intact acrosomes was found in the 0.5% κ-carrageenan group (p < 0.05). Apoptosis levels were significantly lower in the 0.1% and 0.2% κ-carrageenan treatment. Moreover, sperm in the κ-carrageenan supplemented group showed a significantly higher expression of antiapoptotic (Bcl-2) and lower expression of NADPH oxidase (NOX5), spermine synthase (SMS), and spermine oxidase (SMOX) genes than those in the control group. In conclusion, the addition of κ-carrageenan to the freezing extender improved the overall efficiency of frozen-thawed dog spermatozoa.

Red Seaweed Pigments from a Biotechnological Perspective

Algae taxa are notably diverse regarding pigment diversity and composition, red seaweeds (Rhodophyta) being a valuable source of phycobiliproteins (phycoerythrins, phycocyanin, and allophycocyanin), carotenes (carotenoids and xanthophylls), and chlorophyll a. These pigments have a considerable biotechnological potential, which has been translated into several registered patents and commercial applications. However, challenges remain regarding the optimization and subsequent scale-up of extraction and purification methodologies, especially when considering the quality and quantity needs, from an industrial and commercial point of view. This review aims to provide the state-of-the-art information on each of the aforementioned groups of pigments that can be found within Rhodophyta. An outline of the chemical biodiversity within pigment groups, current extraction and purification methodologies and challenges, and an overview of commercially available products and registered patents, will be provided. Thus, the current biotechnological applications of red seaweeds pigments will be highlighted, from a sustainable and economical perspective, as well as their integration in the Blue Economy.

Iota-Carrageenan Prevents the Replication of SARS-CoV-2 in a Human Respiratory Epithelium Cell Line in vitro

Iota-carrageenan is a sulfated polysaccharide extracted from red seaweeds, which, formulated into a nasal spray, has already been proven safe and effective in viral upper respiratory infections. In Calu-3, a human respiratory epithelium cell line, we explored the activity of a formula of iota-carrageenan and sodium chloride against SARS-CoV-2. In this study, the assayed formula, already approved as a nasal spray for human use, effectively inhibited SARS-CoV-2 infection, providing a more substantial reference for clinical studies or developments.

Assessment of Heavy Metal Contamination in Red Seaweeds from the Coastal Areas of Zanzibar by Using EDXRF Technique

The content of Mn, Zn, Ni, Cu, Fe, and Pb in 10 samples of Kappaphycus alvarezii (cottonii) and 10 samples of Eucheuma denticulatum (spinosum) from 15 different sites in the intertidal coastal area of Zanzibar were determined by using EDXRF. The heavy metals assessed in both species decreased in the order of Fe >Mn > Zn >Pb> Cu > Ni. In general, the cottonii samples in Unguja had significantly higher (p ≤ 0.05) concentrations of Fe, Zn, Ni, Cu and Pb than the spinosum samples, but the latter had significantly higher levels of Mn. Similarly, the cottonii samples in Pemba had significantly higher (p ≤ 0.05) concentrations of Ni, Cu and Pb than the spinosum samples, but the latter had significantly higher levels of Fe and Zn. The concentrations of heavy metals in cottonii and spinosum in the present study were noticed lower compared to publish results. The results from this study revealed that, the heavy metals contaminations in cottonii and spinosum along the coastal area in Zanzibar were mainly caused by effluents that directly flow into marine environments. Hence, serious measures should be taken to reduce the flow of waste effluents into the marine ecosystem.

Assessment of Antioxidant Capacity and Phytochemical Composition of Brown and Red Seaweeds Sampled off Red Sea Coast

Seaweeds are becoming a viable source of biologically active composites with a hopeful application as nutraceuticals, functional food components, and medicinal agents. In the present study, the antioxidant capacity and biochemical compositions of four seaweeds; Polycladia indica and Turbinaria ornata (Phaeophyceae) and Laurencia obtusa and Sarconema scinaioides (Rhodophyceae), were estimated. The results indicated that T. ornata showed the maximum value of total phenolic compound (TPC), flavonoid content, β-carotene, carbohydrate and has maximum percentage of DPPH radical scavenging capacity, total antioxidant capacity (TAC), and total reducing capacity (TRC) (72.48%, 15.02%, and 53.24% inhibition, respectively), while the highest contents of ascorbic acid, lipid, calcium, and zinc were observed in L. obtusa. P. indica showed the highest protein contents, dietary fibers, sodium, potassium, magnesium, and total amino acids. Glutamic, aspartic, proline, and methionine were the most frequent amino acids in the four selected seaweeds. Brown seaweeds (T. ornata and P. indica) attained the highest percent of the total polyunsaturated (ω6 and ω3) essential fatty acids. The biochemical content of these seaweed species, as well as their antioxidant properties, make them interesting candidates for nutritional, pharmacological, and therapeutic applications.

An Assessment of Selected Nutritional, Bioactive, Thermal and Technological Properties of Brown and Red Irish Seaweed Species

Irish edible brown (Himanthalia elongata—sea spaghetti, Alaria esculenta—Irish wakame) and red seaweeds (Palmaria palmata—dulse, Porphyra umbilicalis—nori) were assessed for nutritional (proximate composition; salt; pH; amino acid; mineral and dietary fibre contents); bioactive (total phenolic content (TPC) and in vitro antioxidant activity (DPPH and FRAP)); thermal (thermogravimetric analysis (TGA)); and technological (water holding capacity (WHC), oil holding capacity (OHC) and swelling capacity (SC)) properties. Red seaweeds had higher (p < 0.05) protein levels, whereas brown seaweeds possessed higher (p < 0.05) moisture, ash, insoluble and total dietary fibre contents. Nori had the lowest (p < 0.05) salt level. Seaweed fat levels ranged from 1 to 2% DW. Aspartic and glutamic acids were the most abundant amino acids. The total amino acid (TAA) content ranged from 4.44 to 31.80%. Seaweeds contained numerous macro (e.g., Na) and trace minerals. The TPC, DPPH and FRAP activities followed the order: sea spaghetti ≥ nori > Irish wakame > dulse (p < 0.05). TGA indicated maximum weight loss at 250 °C. Dulse had the lowest (p < 0.05) WHC and SC properties. Dulse and nori had higher (p < 0.05) OHC than the brown seaweeds. Results demonstrate the potential of seaweeds as functional food product ingredients.

Chondracanthus teedei var. lusitanicus: The Nutraceutical Potential of an Unexploited Marine Resource

Presently, there is a high demand for nutritionally enhanced foods, so it is a current challenge to look at new raw food sources that can supplement beneficially the human diet. The nutritional profile and key secondary metabolites of red seaweeds (Rhodophyta) are gaining interest because of this challenge. In this context, the possible use of the red seaweed Chondracanthus teedei var. lusitanicus (Gigartinales) as a novel nutraceutical source was investigated. As a result, we highlight the high mineral content of this seaweed, representing 29.35 g 100 g−1 of its dry weight (DW). Despite the low levels of calcium and phosphorus (0.26 and 0.20 g 100 g−1 DW, respectively), this seaweed is an interesting source of nitrogen and potassium (2.13 and 2.29 g−1 DW, accordingly). Furthermore, the high content of carbohydrates (56.03 g 100 g−1 DW), which acts as dietary fibers, confers a low caloric content of this raw food source. Thus, this study demonstrates that C. teedei var. lusitanicus is in fact an unexploited potential resource with the capability to provide key minerals to the human diet with promising nutraceutical properties.

328 The Potential Role of Two Red Seaweeds That Promote Anti-methanogenic Activity and Rumen Fermentation Profiles Under Laboratory Conditions

Ruminal methane (CH4) production results from carbohydrate fermentation by ruminal microbiota (methanogens) to produce CH4, volatile fatty acids (VFA), carbon dioxide (CO2), nitrous oxide (N2O), and hydrogen (H2) in a reduction pathway. The aims of this study were to assess the effects of two red seaweed (RSW) species (Asparagopsis taxiformis and A. armata; collected from Messina, Italy). The two RSW were identified by DNA barcoding and genetic data were deposited in BOLD Systems (REAPP006-21, REAPP004-21, respectively). The two RSW were used at dietary inclusion levels (0, 2, and 4% as-fed basis) in an anaerobic in vitro study (39°C for 48-h) to examine greenhouse gas (GHG) production and VFA profiles. Gases were collected using an ANKOM Gas Production system and analyzed for CH4 and N2O by gas chromatography. Asparagopsis taxiformis contained higher levels of bromoform (201 vs. 7.0 mg/kg DM), iodine (4820 vs. 3260 ppm), and crude protein (16 vs. 15.6% DM), than A. armata, which contained higher levels of acid detergent fiber (ADF; 7.7 vs. 19.0%) and neutral detergent fiber (NDF; 13.2 vs. 19.2%), respectively. RSW supplementation increased total gas, butyrate and valerate production (P &lt; 0.01), while production of CH4 (mg/g DM), acetate (A), propionate (P), A/P ratios and in vitro dry matter digestibility (IVDMD; % DM) were reduced (P &lt; 0.01) as RSW supplementation increased. In the presence of A. taxiformis, production of N2O (µg/g DM), tended to be less (P = 0.1) at 2% DM, but increased (P &lt; 0.01) N2O production with A. armata at the 2 and 4% DM. Therefore, it may be possible to suppress methanogenesis both directly and indirectly by addition of RSW. To efficiently use seaweeds as feed ingredients with nutritional and environmental benefits, more research is required to determine the mechanisms underlying seaweed and dietary substrate interactions.