Food production is facing challenging times due to the pandemic, and climate change. With production expected to double by 2050, there is a need for a new paradigm in sustainable animal feed supply. Seaweeds offer a highly valuable opportunity in this regard. Seaweeds are classified into three categories: brown (Phaeophyceae), red (Rhodophyceae), and green (Chlorophyceae). While they have traditionally been used in aquafeed, their demand in the feed market is growing, parallelly increasing according to the food demand. Additionally, seaweeds are being promoted for their nutritional benefits, which contribute to the health, growth, and performance of animals intended for human consumption. Moreover, seaweeds contain biologically active compounds such as polyunsaturated fatty acids, antioxidants (polyphenols), and pigments (chlorophylls and carotenoids), which possess beneficial properties, including antibacterial, antifungal, antiviral, antioxidant, and anti-inflammatory effects and act as prebiotics. This review offers a new perspective on the valorization of macroalgae biomass due to their nutritional profile and bioactive components, which have the potential to play a crucial role in animal growth and making possible new sources of healthy food ingredients.

Plant extracts of fifteen plants of ethnomedicinal use in Mexico were analyzed to provide scientific knowledge of their medicinal properties through the evaluation of different biological activities such as anti-hemolytic, antioxidant, and cytotoxic effects in normal cells. Therefore, methanolic extracts were obtained from each of the plants by the Soxhlet extraction. The hemolytic activity in human erythrocytes was evaluated, as was their potential to protect the erythrocyte membrane against the 2,2′-azobis (2-methylpropionamidine) dihydrochloride (AAPH) and 1,1–diphenyl–2–picryl hydrazyl (DPPH) radicals. Finally, the toxicity of the extracts in normal cell cultures of African green monkey kidney cells (Vero) and peripheral blood mononuclear cells (PBMC) was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction method. Most of the extracts showed low hemolytic activity and high anti-hemolytic activity as well as high selectivity indices (SI) and antioxidant effects. Extracts of H. inuloides, J. dioica, and J. spicigera induced cell proliferation of the Vero cells. K. daigremontiana, A. adstringens, S. mexicanum, J. spicigera, L. tridentata, and M. tenuiflora extracts showed PBMC cell proliferation. In the present study, it was observed that the evaluated extracts did not present hemolytic activity, and some presented low toxicity when Vero and PBMC cell cultures were exposed. In conclusion, traditionally used plants possess beneficial health properties, and it is hoped that this study will serve as a basis for understanding the biological effects of traditionally used plants and may complement future studies.

Fungal diseases caused by Fusarium spp. significantly threaten food security and sustainable agriculture. One of the traditional strategies for eradicating Fusarium spp. incidents is the use of chemical and synthetic fungicides. The excessive use of these products generates environmental damage and has negative effects on crop yield. It puts plants in stressful conditions, kills the natural soil microbiome, and makes phytopathogenic fungi resistant. Finally, it also causes health problems in farmers. This drives the search for and selection of natural alternatives, such as bio-fungicides. Among natural products, algae and cyanobacteria are promising sources of antifungal bio-compounds. These organisms can synthesize different bioactive molecules, such as fatty acids, phenolic acids, and some volatile organic compounds with antifungal activity, which can damage the fungal cell membrane that surrounds the hyphae and spores, either by solubilization or by making them porous and disrupted. Research in this area is still developing, but significant progress has been made in the identification of the compounds with potential for controlling this important pathogen. Therefore, this review focuses on the knowledge about the mechanisms of action of the fatty acids from macroalgae, microalgae, and cyanobacteria as principal biomolecules with antifungal activity, as well as on the benefits and challenges of applying these natural metabolites against Fusarium spp. to achieve sustainable agriculture.

The production of biomolecules by microalgae has a wide range of applications in the development of various materials and products, such as biodiesel, food supplements, and cosmetics. Microalgae biomass can be produced using waste and in a smaller space than other types of crops (e.g., soja, corn), which shows microalgae’s great potential as a source of biomass. Among the produced biomolecules of greatest interest are carbohydrates, proteins, lipids, and fatty acids. In this study, the production of these biomolecules was determined in two strains of microalgae (Chlamydomonas reinhardtii and Chlorella vulgaris) when exposed to different concentrations of nitrogen, phosphorus, and sulfur. Results show a significant microalgal growth (3.69 g L⁻¹) and carbohydrates (163 mg g⁻¹) increase in C. reinhardtii under low nitrogen concentration. Also, higher lipids content was produced under low sulfur concentration (246 mg g⁻¹). It was observed that sulfur variation could affect in a negative way proteins production in C. reinhardtii culture. In the case of C. vulgaris, a higher biomass production was obtained in the standard culture medium (1.37 g L⁻¹), and under a low-phosphorus condition, C. vulgaris produced a higher lipids concentration (248 mg g⁻¹). It was observed that a low concentration of nitrogen had a better effect on the accumulation of fatty acid methyl esters (FAMEs) (C16-C18) in both microalgae. These results lead us to visualize the effects that the variation in macronutrients can have on the growth of microalgae and their possible utility for the production of microalgae-based subproducts.

Microalgae are a promising solution in shrimp farming overexploitation. This study assessed the efficacy of microalgae as a food additive for Penaeus vannamei growth and their effect on immune system stimulation against Vibrio parahaemolyticus. Three diets were formulated with 0, 1, and 3% (DC, D1, and D3, respectively) of a mixture of three different microalga species, Tetraselmis suecica, Dunaliella salina, and Chaetoceros muelleri, and growth, survival, and post-harvest quality in shrimp culture were evaluated. Two bioassays were performed: a 60-day feeding trial and an immersion infection bioassay against V. parahaemolyticus. D1 was the best treatment and significantly different to DC (P ≤ 0.05), achieving a food conversion factor of 1.24 ± 0.11 and 1.85 ± 0.38; specific growth rate 1.58 ± 0.03% d-1 and 1.35 ± 0.11% d-1; and weight gain of 5.68 ± 0.32 g and 4.79 ± 0.33 g, respectively. Protein content in shrimp muscle was positively increased by microalgae inclusion, achieving 20.8 ± 0.2% (D1) to 21.7 ± 0.3% (D3), 19.2 ± 0.1% (DC). In the infection bioassay, D1 and D3 reached a 100% survival rate, and histological damage in the hepatopancreas was not observed, suggesting immune system stimulation. These results indicated that microalgae added to food are an excellent source of proteins, carbohydrates, lipids, and promoters of antimicrobial activity that allowed additional protection against mortality caused by V. parahaemolyticus.