Evaluation of Microalgae as Immunostimulants and Recombinant Vaccines for Diseases Prevention and Control in Aquaculture

Abstract

Microalgae are often used as nutritional supplements for aquatic animals and are widely used in the aquaculture industry, providing direct or indirect nutrients for many aquatic animals. Microalgae are abundant in nature, of high nutritional value, and some of them are non-toxic and rich in antioxidants so that they can be explored as a medicinal carrier for human or animals. Natural wild-type microalgae can be adopted as an immunostimulant to enhance non-specific immune response and improve growth performance, among which Haematococcus pluvialis, Arthrospira (Spirulina) platensis, and Chlorella spp. are commonly used. At present, there have been some successful cases of using microalgae to develop oral vaccines in the aquaculture industry. Researchers usually develop recombinant vaccines based on Chlamydomonas reinhardtii, Dunaliella salina , and cyanobacteria. Among them, in the genetic modification of eukaryotic microalgae, many examples are expressing antigen genes in chloroplasts. They are all used for the prevention and control of single infectious diseases and most of them are resistant to shrimp virus infection. However, there is still no effective strategy targeting polymicrobial infections and few commercial vaccines are available. Although several species of microalgae are widely developed in the aquaculture industry, many of them have not yet established an effective and mature genetic manipulation system. This article systematically analyzes and discusses the above problems to provide ideas for the future development of highly effective microalgae recombinant oral vaccines.

Efficient Transient Expression of Recombinant Proteins Using DNA Viral Vectors in Freshwater Microalgal Species

“…Algal cells are known to be natural green factories that can emerge as excellent organisms with highly valuable and significant products through gene transformations ( Georgianna and Mayfield, 2012 ; Dyo and Purton, 2018 ). These eukaryotic microorganisms, which are regarded as safe, unlike the bacterial system, are capable of undergoing complex protein folding and modifications to form active proteins that are specifically important for human use as antigens and antibodies ( Ma et al, 2020 ). Each system needs to be evaluated for its attributes before developing an oral vaccine delivery platform ( Rosales-Mendoza et al, 2016 ).…”

Plant-Produced Vaccines: Future Applications in Aquaculture

“…Genetic engineering technologies in microalgae offer the possibility of producing "functional feed additives" with no need for complex post-expression conditions, such as purification, cold chain, and injection (Kwon et al, 2019). Chlamydomonas reinhardtii, Dunaliella salina, cyanobacteria, and other microalgae have been processed to express antigen genes in chloroplasts for the prevention and control of infectious diseases (Ma et al, 2020b). Although several species of microalgae have been widely used in the aquaculture industry, many of them have not yet become established as an effective and mature genetic manipulation system.…”

Physicochemical Evaluation of Edible Cyanobacterium Arthrospira platensis Collected from the South Atlantic Coast of Morocco: A Promising Source of Dietary Supplements

“…erefore, we could confirm that A. platensis indigenous to the Moroccan Atlantic coast at Laayoune is a promising source of food supplement due to their high values concerning proteins, unsaturated fats, carbohydrates, minerals, vitamins, and pigments and their low values regarding heavy metals and saturated fats. A. platensis is reported to be of high nutritional value and pharmacological and biological potentials so that they can be used for medicinal purposes for humans or animals [46]. In addition to their nutritional and pharmacological properties, A. platensis has a biofuel production potential, and therefore, it can significantly contribute to economic performance [47].…”