Comparative study on the effect of dietary β-carotene and phycocyanin extracted from Spirulina platensis on immune-oxidative stress biomarkers, genes expression and intestinal enzymes, serum biochemical in Nile tilapia, Oreochromis niloticus

The synergistic effect of dielectric barrier discharge plasma and phycocyanin on shelf life of Oncorhynchus mykiss rainbow fillets

This study aimed to evaluate the efficacy of dielectric barrier discharge treatment (DBD) combined with phycocyanin pigment (PC) in extending the shelf life of Oncorhynchus mykiss rainbow fillets stored at 4 ± 0.1 °C. Microbiological, physicochemical, sensory and antioxidant properties were assessed over an 18-day storage period. The combined DBD and PC treatment significantly inhibited total viable counts and Psychrotrophic bacteria counts compared to the rest of the samples throughout storage. While Total Volatile Nitrogen concentrations remained below international standard until day 18, they exceeded this threshold in control sample by day 9. DBD treatment notably reduced Trimethylamine levels compared to controls (p < 0.05). PC and DBD combined inhibited DPPH and ABTS radical scavenging capacities by 80% and 85%, respectively, while demonstrating heightened iron-reducing antioxidant activity compared to controls. Analysis of 24 fatty acids indicated that PC mitigated DBD's adverse effects, yielding superior outcomes compared to controls. The ratio of n-3 to n-6 fatty acids in all samples met or fell below international standard. Thus, the combined use of DBD and PC shows promise in extending fillet shelf life by over 15 days at 4 °C.

Effect of photoperiod on serum biochemistry, electrolytic balance, acute phase response and histopathology of butter catfish, Ompok bimaculatus (Bloch, 1794)

The present study was executed to evaluate the effect of photoperiod on serum biochemical parameters (glucose, cortisol, ALT, AST and LDH), electrolytic balance (Sodium and potassium), acute phase response (CRP) and histopathology (liver, kidney and skin) of an endangered high valued catfish, Ompok bimaculatus. Catfish (21.00 ± 1.53 cm and 30.00 ± 2.31 g) from the acclimatized stock were randomly distributed to six 120 × 45 × 60 cm3 FRP tanks (n = 20 fish per tank) and exposed to 1500 lx light intensity under different photoperiods [24:0 light: dark (L: D), 15L: 9D, 12L: 12D, 9L: 15D, 0L: 24D and a natural photoperiod (control)], and fed at a daily rate of 2% of bodyweight, twice a day for 60 days. Serum glucose, cortisol and enzymes including aspartate transaminase (AST), lactate dehydrogenase (LDH), alanine transaminase (ALT), and acute phase reactant, such as C-reactive protein (CRP) increased significantly (P < 0.05) in continuous light (24L: 0D), continuous dark (0L: 24D) and short day (9L: 15D) photoperiods, whereas in 15L: 9D and 12L:12D photoperiods, those were in decreasing trend. Serum electrolytes, i.e. potassium level was elevated and sodium level was declined in 24L: 0D, 0L: 24D and 9L: 15D photoperiod groups. Moreover, significant histological alterations in the liver, kidney and skin tissue were also evidenced in the experimented catfish. Typical polygonal hepatocytes with normal blood vessels in liver and normal organization of kidney were seen in catfish of 15L: 9D group. Histological analysis of other groups displayed nuclear degeneration, karyorrhexis, karyolysis, melanomacrophages, nuclear hypertrophy, sinusoid dilation and vacuolar degeneration in liver and hyaline droplets accumulation, granular degeneration, fragmentation of glomerulus and focal necrosis of epithelial cells in kidney. Additionally, general structure of the skin was observed in control group as well as in 15L: 9D group. Contrarily, in 24L: 0D group increased number of mucous cells and vacuoles was observed in the skin of butter catfish. In 9L: 15D and 0L: 24D photoperiods, O. bimaculatus exhibited ruptured epithelial cells, enlarged alarm cells, fat cells, necrotic cells and vacuoles in the skin tissue. The present study depicted that 15L: 9D photoperiod can induce better health of catfish, O. bimaculatus, which, in turn, can help farmers to increase the production of this high valued catfish in future.

The Effects of Laurencia caspica Algae Extract on Hemato-Immunological Parameters, Antioxidant Defense, and Resistance against Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus)

Natural immune stimulants are among the most effective chemicals for boosting immunity and fish welfare. This study aims to investigate the effects of red macroalgae extract (Laurencia caspica) on hematological, immunological, antioxidant, biochemical, and disease resistance against S. agalactiae in Nile tilapia for 50 days. For this purpose, fishes were assigned to four dietary treatments group in which the base meal was supplemented with 0.5%, 1%, and 2% of L. caspica extract. On days 25 and 50 of the experiment, samples were taken to investigate the hematological, immunological, biochemical, and antioxidant parameters. The white blood cells (WBCs), hemoglobin, and neutrophils significantly increased after 50 days of feeding with the L. caspica extract, but until the 25th day, no significant difference was observed among the treatments except for hemoglobin. Immunological parameters (including Immunoglobulin M [IgM] and complement 3 [C3]) were significantly higher in treated groups compared to control both 25 days and 50 days posttreatment. However, on the 25th day, no significant difference was noticed between treatments and control in the case of lysozyme activity. Alkaline phosphatase (ALP) and alanine aminotransferase (ALT) considerably increased in comparison to the control group on the 50th day, but no significant difference was observed on the 25th day. In addition, feeding with L. caspica significantly increased the antioxidant enzyme activities on the 25th day (L. caspica 1% and 2% in peroxidase [POD] and superoxide dismutase [SOD] in all groups) and 50th day (catalase [CAT], SOD and L. caspica 1% and 2% in POD) in the spleen. The survival rate of fish challenged with Streptococcus agalactiae was considerably greater than the control group. Finally, it can be concluded that L. caspica extract is an immunological stimulant that induces fish resistance to S. agalactiae.

Extraction and purification of phycobiliproteins from algae and their applications

Microalgae, macroalgae and cyanobacteria are photosynthetic microorganisms, prokaryotic or eukaryotic, living in saline or freshwater environments. These have been recognized as valuable carbon sources, able to be used for food, feed, chemicals, and biopharmaceuticals. From the range of valuable compounds produced by these cells, some of the most interesting are the pigments, including chlorophylls, carotenoids, and phycobiliproteins. Phycobiliproteins are photosynthetic light-harvesting and water-soluble proteins. In this work, the downstream processes being applied to recover fluorescent proteins from marine and freshwater biomass are reviewed. The various types of biomasses, namely macroalgae, microalgae, and cyanobacteria, are highlighted and the solvents and techniques applied in the extraction and purification of the fluorescent proteins, as well as their main applications while being fluorescent/luminescent are discussed. In the end, a critical perspective on how the phycobiliproteins business may benefit from the development of cost-effective downstream processes and their integration with the final application demands, namely regarding their stability, will be provided.

Effects of Tomato Paste By-Product Extract on Growth Performance and Blood Parameters in Common Carp (Cyprinus carpio)

This research examined different growth performances and blood parameters of common carp (Cyprinus carpio) consuming diets supplemented with tomato paste by-product extract (TPE). Five diets with different concentrations of TPEs, 0% (TPE0) 0.5% (TPE0.5), 1% (TPE1), 2% (TPE2), and 5% (TPE5) were supplied to 300 common carp (8.38 ± 0.18 g) (60 fish per group) each day during the 60-day feeding trial. The relative and specific growth rates of fish-fed supplemental diets increased significantly, while the feed conversion ratio significantly decreased (p < 0.05). TPE considerably increased the erythrocyte count (RBC), hemoglobin content (Hb), and hematocrit (Hct) (p < 0.05), according to hematological analyses of blood samples collected after the feeding experiment. The blood biochemical findings indicate that using 1% or more extracts considerably reduced the serum glucose, cholesterol, and triglyceride ratios while significantly increasing the total protein, albumin, and globulin ratios in common carp (p < 0.05). Based on the findings of the study, it was concluded that the 2% extract generated from tomato paste by-products in common carp diets could be utilized as a growth-promoting product without any negative effects on blood parameters linked to feeding in carp.

Bioactive immunostimulants as health-promoting feed additives in aquaculture: A review

Bioactive immunostimulants could be derived from different sources like plants, animals, microbes, algae, yeast, etc. Bioactive immunostimulants are the most significant role to enhance aquatic production, as well as the cost of this method, which is effective, non-toxic, and environment-friendly. These immunostimulants are supportive to increase the immune system, growth, antioxidant, anti-inflammatory, and disease resistance of aquatic animals' health and also improve aquatic animal feed. Diseases are mainly targeted to the immune system of aquatic organisms in such a way that different processes of bioactive immunostimulants progress are considered imperative techniques for the development of aquaculture production. Communicable infections are the main problem for aquaculture, while the mortality and morbidity connected with some outbreaks significantly limit the productivity of some sectors. Aquaculture is considered the mainly developing food production sector globally. Protein insists is an important issue in human nutrition. Aquaculture has been an exercise for thousands of years, and it has now surpassed capture fisheries as the most vital source of seafood in the world. Limited study reports are available to focal point on bioactive immunostimulants in aquaculture applications. This review report provides information on the nutritional administration of bioactive immunostimulants, their types, functions, and beneficial impacts on aquatic animals' health as well as for the feed quality development in the aquaculture industry. The scope of this review combined to afford various kinds of natural derived bioactive molecules utilization and their beneficial effects in aquaculture applications.

Metabolomics-Guided Comparison of Pollen and Microalgae-Based Artificial Diets in Honey Bees

Managed honey bee colonies used for crop pollination are fed artificial diets to offset nutritional deficiencies related to land-use intensification and climate change. In this study, we formulated novel microalgae diets using Chlorella vulgaris and Arthrospira platensis (spirulina) biomass and fed them to young adult honey bee workers. Diet-induced changes in bee metabolite profiles were studied relative to a natural pollen diet using liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) metabolomics. Untargeted analyses of pollen- and microalgae-fed bees revealed significant overlap, with 248 shared features determined by LC-MS and 87 shared features determined by GC-MS. Further metabolomic commonalities were evident upon subtraction of unique diet features. Twenty-five identified metabolites were influenced by diet, which included complex lipids, essential fatty acids, vitamins, and phytochemicals. The metabolomics results are useful to understand mechanisms underlying favorable growth performance as well as increased antioxidant and heat shock protein gene expression in bees fed the microalgae diets. We conclude that the tested microalgae have potential as sustainable feed additives and as a source of bee health-modulating natural products. Metabolomics-guided diet development could eventually help tailor feed interventions to achieve precision nutrition in honey bees and other livestock animals.

Dietary Salvia officinalis leaves enhances antioxidant-immune-capacity, resistance to Aeromonas sobria challenge, and growth of Cyprinus carpio

The current perspective is a pioneer to assess the efficacy of Salvia officinalis leave powder (SOLP) on growth, intestinal enzymes, physiological and antioxidant status, immunological response, and gene expression of Common carp (Cyprinus carpio). We also looked into fish resistance after being challenged with Aeromonas sobria, a pathogenic zoonotic bacteria. Fish (N = 120) were fed four different experimental diets in triplicate for 8 weeks. The control diet (SOLP0 - without SOLP); meanwhile, the other three diets included SOLP of 2, 4, and 8 g kg^-1 concentrations (SOLP2, SOLP4, and SOLP8), respectively. Findings demonstrated that fish fed SOLP4 and SOLP8 diets had better growth performance and improved digestion by noticeable enhancing lipase and amylase enzymes activity than other groups. Additionally, the antioxidant (superoxide dismutase and glutathione peroxidase) and immune activities (immunoglobulin M, nitric oxide, and antiprotease) clarified a significant increase (p < 0.05) in SOLP4 and SOLP8 groups. Enriched diets with SOLP4 and SOLP8 exhibited better expression of splenic genes (IL-1β, IL-6, IL-10, TLR-2, and SOD), intestinal genes (Slc26a6) and (PepT1 or Slc15a1), and muscular genes (IGF-1 and SOD), while MSTN was down-regulated. After 8 weeks of the experimental trial, C. carpio challenged by A. sobria exhibited the highest cumulative mortality (66.67%), while SOLP8-dietary intervention showed the best results in enhancing the fish resistance against A. sobria by lessening mortalities to 13.33% followed by SOLP4 diet (20%). The outcomes indicate that the expression of splenic, muscular, and intestinal genes confirm the efficacy of SOLP on enhancing growth, digestion, and immune-antioxidant status, and recommend the potential use of SOLP especially at 4 g kg^-1 level as a valuable natural economic diet additive in C. carpio culture for sustaining aquaculture.

Synergistic Effects Between Dietary Zinc Form Supplementation and Dietary Protein Levels on Performance, Intestinal Functional Topography, Hemato-biochemical Indices, Immune, Oxidative Response, and Associated Gene Expression of Nile Tilapia Oreochromis niloticus

The present study investigates the effect of different dietary protein levels suboptimum level (25%) and optimum level (35%), different Zn forms bulk zinc oxide (BZnO) or nanoparticles zinc oxide (NZnO), and their interaction on performance, intestinal topography, hematology, serum biochemical, antioxidant-immune responses, and related gene expression of Nile tilapia. Six experimental diets were formulated to contain approximately 25% and 35% crude protein and supplemented with Zn forms with 0 (normal level in ingredients), 60 mg kg^-1 BZnO and 60 mg kg^-1 nanoparticles of NZnO. Nile tilapia, Oreochromis niloticus, fingerlings (7.53 ± 0. 06 g) were fed on one of tested diets in triplicates with 5% of total biomass three times a day for 84 days. Results showed that, fish fed diet containing 35% crude protein and supplemented with NZnO form recorded the highest final body weight (FBW), weight gain (WG), and specific growth rate (SGR). However, no significant (P > 0.05) differences were recorded in FBW, WG, SGR, feed conversion ratio (FCR), and protein efficiency ratio (PER) between fish fed diet containing 35% crude protein without Zn supplementation and fish fed diet containing 25% crude protein supplemented with NZnO form. Either fish fed diet containing 25% or 35% crude protein and supplemented with NZnO exhibited the highest values of villi height/width. The highest absorption surface area (ASA) was obtained in fish fed diet containing 25% or 35% crude protein and supplemented with BZnO. Hemoglobin (Hb), hematocrit (Hct), and red blood cell count (RBCs) highest values were obtained for fish fed diet containing protein level 35% supplemented with NZnO. Fish fed diet containing protein level 35% and supplemented with NZnO had the lowest value of alanine amino transferase (ALT) and aspartate amino transferase (AST). The highest globulin value was recorded for fish provided with diet containing 35% crude protein and supplemented with BZnO followed by those fed diet containing 35% crude protein and supplemented with NZnO. Fish fed diet containing protein level 25% with NZnO supplementation recorded the highest super oxide dismutase (SOD), catalase (CAT), glutathione reductase (GSH), and glutathione peroxidase (GP_X), with decreasing malondialdehyde (MAD) values. The highest values of immunoglobulin g (IgG), immunoglobulin M (IgM), complement 4 (C4), and complement 3 (C3) were obtained for diet containing 35% crude protein and supplemented with NZnO form. Growth hormone gene (GH) was upregulated in fish fed 25% dietary protein without Zn supplementation, while it was downregulated in fish fed 25% dietary protein and supplemented with NZnO. Transcription of insulin-like growth factor-1 (IGF-I) gene recorded the highest value for fish fed 35% crude protein and supplemented with BZnO. This is although the diet of 35% crude protein + NZnO induced significant (IGF-I) gene expression compared with 25% crude protein with or without BZnO. Therefore, nano zinc is useful as a feed supplement for Nile tilapia (Oreochromis niloticus).

The Effects of Dietary Arthrospira platensis on Oxidative Stress Response and Pigmentation in Yellow Catfish Pelteobagrus fulvidraco

In aquaculture, fish are often exposed to several stress conditions, which will cause oxidative disorder and bring about health and quality problems. Arthrospira platensis contains abundant bioactive ingredients, which are beneficial for animal health. This study was conducted to investigate the effects of A. platensis on pigmentation, antioxidant capacity, and stress response after air exposure of fish. A total of 120 yellow catfish Pelteobagrus fulvidraco (initial weight 70.19 ± 0.13 g) were divided into three tanks per treatment and fed diets supplemented with 0 g kg−1 A. platensis (CON) and 20 g kg −1 A. platensis (AP) for 65 days. The results indicated that dietary A. platensis had no effects on the growth of yellow catfish. The AP diet significantly reduced lactic acid (LD) and cortisol levels stimulated by air exposure stress (p < 0.05). Dietary A. platensis significantly increased plasma superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities and glutathione (GSH) contents, and the relative expression levels of sod and cat, to protect against oxidative stress caused by air exposure (p < 0.05). The AP diet significantly improved the relative expression level of nrf2 (nuclear factor erythroid-2 related factor 2), while the relative expression level of keap1 (kelch-like ECH associated protein 1) was downregulated, and the protein levels of liver Nrf2 were significantly increased after air exposure stimuli (p < 0.05). Dietary A. platensis significantly increased skin lutein contents, increased skin redness, yellowness and chroma (p < 0.05), and improved body color abnormalities after oxidative stress caused by air exposure stimuli. Skin yellowness was associated with lutein contents and the expression levels of some antioxidant genes to varying degrees. Overall, dietary A. platensis could be utilized as a feed additive to activate the antioxidant response, as well as alleviate oxidative stress and pigmentation disorder induced by air exposure.

Health benefits of microalgae and their microbiomes

Microalgae comprise a phylogenetically very diverse group of photosynthetic unicellular pro‐ and eukaryotic organisms growing in marine and other aquatic environments. While they are well explored for the generation of biofuels, their potential as a source of antimicrobial and prebiotic substances have recently received increasing interest. Within this framework, microalgae may offer solutions to the societal challenge we face, concerning the lack of antibiotics treating the growing level of antimicrobial resistant bacteria and fungi in clinical settings. While the vast majority of microalgae and their associated microbiota remain unstudied, they may be a fascinating and rewarding source for novel and more sustainable antimicrobials and alternative molecules and compounds. In this review, we present an overview of the current knowledge on health benefits of microalgae and their associated microbiota. Finally, we describe remaining issues and limitation, and suggest several promising research potentials that should be given attention.

The effects of dietary stachyose as prebiotic on immunity and anti-oxidant related genes’ expression and lipid metabolism in zebrafish (Danio rerio)

An 8-week feeding trial was conducted to examine the efficacy of stachyose as a prebiotic on immune parameters, antioxidant-/immune-related genes’ expression, and lipid metabolism of zebrafish. Three hundred zebrafish (0.45 ± 0.08 g) were fed four diets containing different stachyose levels at 0, 1, 2 and 4 g kg-1, respectively. After eight weeks of the feeding trial, immunity, anti-oxidant defence and lipid metabolism were tested. It was observed that the addition of stachyose to the diet induced no significant influence (P>0.05) in SOD, GPX, and CAT, gene’s expression, compared to the control diet. The inclusion of stachyose resulted in no significant changes in immune gene expression (Lyz, IL-1, IL-6, and TNF) in zebrafish (P>0.05) compared to the control diet. Total cholesterol, triglyceride and LDL (low-density lipoprotein) significantly (P<0.05) decreased with the addition of 2 and 4 g kg-1 stachyose, while fish fed the control diet and 1 g.kg-1 recorded the highest significant value of LDL (P<0.05). Fish fed diet, either control or diet supplemented with 0.5 g kg-1 stachyose, recorded the lowest HDL value (P<0.05) compared to other treatments. In conclusion, stachyose can be potentially used as a feed additive to modulate lipid metabolism. However, this prebiotic couldn’t benefit immune parameters and anti-oxidant defence.

Nano Zinc Versus Bulk Zinc Form as Dietary Supplied: Effects on Growth, Intestinal Enzymes and Topography, and Hemato-biochemical and Oxidative Stress Biomarker in Nile Tilapia (Oreochromis niloticus Linnaeus, 1758)

Five isonitrogenous diets were formulated to comprise two forms of zinc (Zn): convention zinc oxide named Bulk-ZnO or zinc oxide nanoparticles (Nano-ZnO) supplemented at two levels 30 and 60 mg kg^-1 compared to the control diet. Nile tilapia, Oreochromis niloticus, fingerlings (5.02-5.05 g) were fed tested diets two times a day for 84 days. The results displayed that the best growth and digestive enzyme activity (P < 0.05) were noticed in fish fed 60 mg kg^-1 Nano-ZnO. Moreover, significant (P < 0.05) improvement in intestinal topography was observed in 60 mg kg^-1 Nano-ZnO group versus other treatments. Furthermore, fish fed 30 mg kg^-1 Nano-ZnO recorded the best values of hematological indices (P < 0.05). The alanine and aspartate aminotransferase (ALT and AST) values were lower, while total serum protein, albumin, and globulin contents were clearly higher in fish fed diet that contained 30 mg kg^-1 Nano-ZnO versus other groups. The significant highest values of oxidative enzyme activity escorted with lower malondialdehyde value recorded of fish fed diet supplemented with 60 mg kg^-1 Nano-ZnO. The results indicated that inclusion of Nano-ZnO at 60 mg kg^-1 was the recommended source to enhance growth, feed utilization, amylase and lipase enzymes activity, intestinal morphology, hemato-biochemical, and oxidative response biomarkers of Nile tilapia compared with Bulk-ZnO in commercial tilapia feeds.

Impacts of Aegle marmelos fruit extract as a medicinal herb on growth performance, antioxidant and immune responses, digestive enzymes, and disease resistance against Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus)

An experiment was conducted to investigate the effects of Aegle marmelos fruit (AMF) extract on the growth performance, biochemical parameters, immune response, antioxidative capacity, and digestive enzyme activity of Nile tilapia (Oreochromis niloticus). Fish were fed a diet supplemented with AMF at concentrations of 0 (AMF0; control), 5 (AMF5), 10 (AMF10), 15 (AMF15), or 20 (AMF20) g/kg for 8 weeks. The results show that the final body weight, weight gain, specific growth rate, average daily gain, and feed conversion ratio were significantly higher in fish fed AMF15 and AMF20 compared to those fed the control diet (P < 0.05). Moreover, significant increases in antioxidant enzyme activities and non-specific immune responses were observed in groups fed AMF15 and AMF20. Interestingly, the level of cholesterol decreased with increasing AMF concentrations in the diet. As dietary AMF levels increased, digestive enzyme activities significantly improved. After the feeding trial, fish were injected intraperitoneally with Streptococcus agalactiae, and the 14-day cumulative mortality was calculated. A high survival rate after challenge with S. agalactiae was observed in all groups that received AMF-supplemented feed. Therefore, the present study suggests that supplementing the diet of Nile tilapia with AMF at a concentration of 20 g/kg could encourage their growth, improve their immunity and antioxidant status, and provide strong protection against S. agalactiae.

Role of Food Antioxidants in Modulating Gut Microbial Communities: Novel Understandings in Intestinal Oxidative Stress Damage and Their Impact on Host Health

Dietary components have an important role on the structure and function of host gut microbial communities. Even though, various dietary components, such as carbohydrates, fats, proteins, fibers, and vitamins, have been studied in depth for their effect on gut microbiomes, little attention has been paid regarding the impact of several food antioxidants on the gut microbiome. The long-term exposure to reactive oxygen species (ROS) can cause microbial dysbiosis which leads to numerous intestinal diseases such as microbiota dysbiosis, intestinal injury, colorectal cancers, enteric infections, and inflammatory bowel diseases. Recently, it has been shown that the food derived antioxidant compounds might protect the host from intestinal oxidative stress via modulating the composition of beneficial microbial species in the gut. The present review summarizes the impact of food antioxidants including antioxidant vitamins, dietary polyphenols, carotenoids, and bioactive peptides on the structure as well as function of host gut microbial communities. Several in vitro, animal model, and clinical studies indicates that food antioxidants might modify the host gut microbial communities and their health status. However, still further clarification is needed as to whether changes in certain microbial species caused by food additives may lead to changes in metabolism and immune function.

Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids

Acute inflammation is a key component of the immune system’s response to pathogens, toxic agents, or tissue injury, involving the stimulation of defense mechanisms aimed to removing pathogenic factors and restoring tissue homeostasis. However, uncontrolled acute inflammatory response may lead to chronic inflammation, which is involved in the development of many diseases, including cancer. Nowadays, the need to find new potential therapeutic compounds has raised the worldwide scientific interest to study the marine environment. Specifically, microalgae are considered rich sources of bioactive molecules, such as carotenoids, which are natural isoprenoid pigments with important beneficial effects for health due to their biological activities. Carotenoids are essential nutrients for mammals, but they are unable to synthesize them; instead, a dietary intake of these compounds is required. Carotenoids are classified as carotenes (hydrocarbon carotenoids), such as α- and β-carotene, and xanthophylls (oxygenate derivatives) including zeaxanthin, astaxanthin, fucoxanthin, lutein, α- and β-cryptoxanthin, and canthaxanthin. This review summarizes the present up-to-date knowledge of the anti-inflammatory and anticancer activities of microalgal carotenoids both in vitro and in vivo, as well as the latest status of human studies for their potential use in prevention and treatment of inflammatory diseases and cancer.