Fish Pigmentation Research Articles

Harnessing Hue: Advances and Applications of Fish Skin Pigmentation Genetics in Aquaculture

Fish exhibit a broad spectrum of colors and patterns facilitated by specialized cells known as chromatophores. The vibrant coloration of fish, controlled by complex genetic and environmental interactions, serves critical roles in ecological functions such as mating, predation, and camouflage. This diversity not only makes fish an invaluable model for exploring the molecular mechanisms of pigmentation but also significantly impacts their economic value within the aquaculture industry, where color traits can drive marketability and breeding choices. This review delves into the sophisticated biological processes governing fish pigmentation and discusses their applications in enhancing aquaculture practices. By exploring the intersection of genetic regulation, environmental influences, and advanced breeding techniques, this review highlights both the scientific understanding and practical applications of fish coloration, providing a bridge between basic biological research and its application in commercial aquaculture.

Whole genome resequencing reveals the genetic basis of albino phenotype in an ornamental fish, Channa asiatica

Body color is one of the most noticeable phenotypic and economic characteristics in fish. Fish exhibit a diverse array of body color mutations influenced by factors such as artificial selection and natural mutations. Elucidating the genetic mechanisms of these color variants in fish is crucial for developing new breeds with higher ornamental value. In this study, we identified a nonsense mutation in csf1ra (c. 1249 C>T) with whole genome resequencing technology, and which may potentially contribute to the albino phenotype in Channa asiatica. The albino individuals exhibited a substantial decrease in the expression level of csf1ra compared to that of the wild individuals. To unravel the underlying mechanism of csf1ra, we delved into comparative transcriptomic and gene expression analyses. Our findings suggest that csf1ra may impact tyrosine kinase activity. Furthermore, csf1ra may not only regulate the expression levels of genes (sox9, ephb6, and wnt9) involved in melanin-based pigmentation but also influence genes (ampd3, ak1, and bco1) associated with non-melanin-based pigmentation. Our study investigated the genetic basis of the albino mutant of C. asiatica and provided new insights into the function of csf1ra in fish pigmentation.

Unveiling the molecular mechanisms of pigmentation control in Queen Loach, Botia dario (Hamilton, 1822): Insights from sesame seed and marigold-induced antityrosinase effects.

Fish pigmentation study can reveal understandings in dermatological research based on functional genomics. Cultured ornamental fish becomes dull coloured and antityrosinase activity through sesame seed may enhance skin colour, which has not been studied. Botia dario is an indigenous fish, having ornamental and aesthetic value and can be studied as a model for fish pigmentation genetics. In this study, fish specimens were fed with 15% marigold petal meal along with 5, 10 and 15% w/w sesame seed in diet. Pigmentation genes, that is, tyr, tyrp1a, asip1, gnaq, kitlga, mc1r, mitf, pax7a, rab38, slc7a11, sox9a, sox10, csf1r, bcdo2 and gsta2 in skin and immunogens, that is, il20, nramp, tlr9 and trail in kidney were studied. Gene expression in tissues revealed enhanced pigmentation and immunity as well as the role of tyr, tyrp1a and asip1 in pigmentation. Immunogenes and blood parameters confirmed the best pigmentation diet. Colorimetric analysis also showed the enhancement of pigmentation. Insights from sesame seed and marigold-induced antityrosinase effects will be applied in aquaculture to develop natural, dietary formulations that will enhance pigmentation in ornamental fish, leading to improved skin colour and market value.

Differential expression and alternative splicing analyses of multiple tissues reveal albinism-associated genes in the Wels catfish (Silurus glanis)

Albinism is a widespread departure from a typical body colouration due to altered melanin production. The Wels catfish (Silurus glanis) is among the largest freshwater fish species in the world, and albino individuals occur both in the wild and in aquaculture. Here, we performed transcriptome-wide analysis of albino and normally pigmented S. glanis using four tissues (skin, dorsal fin, whole eye and liver) to identify genes associated with albinism by exploring patterns of differential expression (DE) and differential alternative splicing (DAS). Multi-tissue analyses revealed a large number of genes in skin (n = 1355) and fin (n = 614) tissue associated with the albino phenotype in S. glanis, while the number of DE genes in eye and liver tissues was lower (n = 188, n = 189, respectively). Several DE genes across multiple tissues were detected as the most promising candidates (e.g., hsp4, hsp90b1, raph1, uqcrfs1, adcy-family and wnt-family) potentially causally linked to the albino phenotype in Wels catfish. Moreover, our findings supported earlier observations of physiological differences between albino and normally pigmented individuals, particularly in energy metabolism and immune response. In contrast, there were only a few pigmentation-related genes observed among DAS genes (4 in skin, 2 in fin), the overlap between DAS and DE genes was low (n = 25) and did not include known pigmentation-related genes. This suggests that DAS and DE in Wels catfish are, to a large extent, independent processes, and the observed alternative splicing cases are probably not causally linked with albinism in S. glanis. This work provides the first transcriptome-wide multi-tissue insights into the albinism of Wels catfish and serves as a valuable resource for further understanding the genetic mechanisms of pigmentation in fish.

ENHANCEMENT OF COLOR OF PLATY FISH (Xipophorus maculates) BY USING CARROT PEELS AS SOURCE OF CAROTENOIDS

Color is one of the major factors which determine the price of aquarium fish in the market world over. Ornamental fishes are acceptable to buyers if they have striking and vibrant colors. The pigmentation of fish results from the pigments in the feed. People involved in the trade of ornamental fish are constantly exploring methods of enhancing skin coloration for which the use of dietary supplements with carotenoids is recommended. The aim of this research was to develop a feed using a cheap source of carotenoid for enhancing the skin color of Platy fish which could reduce the feed cost of aquarium fish hobbyists. In this study, carrot peel was used as a carotenoid source very successfully and the fish skin color was enhanced.

Balitora anlongensis, the first cavefish species of the genus Balitora (Teleostei, Balitoridae) from Guizhou Province, southwest China

This work describes a new species, Balitora anlongensissp. nov., collected from a cave at Xinglong Town, Anlong County, Guzihou, China. Phylogenetic trees reconstructed based on two mitochondrial and three nuclear genes show that the new species represents an independent evolutionary lineage with large genetic differences, 7.1%–12.0% in mitochondrial gene cytochrome b and 9.2%–12.1% in cytochrome oxidase subunit 1, from congeners. Morphologically, the new species can be distinguished from the 18 species currently assigned to the genus Balitora by a combination of characters, most clearly by having two pairs of maxillary barbels; 8½ branched dorsal-fin rays; 5½ branched anal-fin rays; pectoral fin not reaching pelvic fin origin; dorsal-fin origin in front of pelvic fin origin; eye small (eye diameter approximately equal to outer maxillary barbel length); and fins lacking pigment in live fish. The new species represents the first record of Balitora inhabiting caves in China and increases the number of species in the genus Balitora in its present concept from 18 to 19. The study suggests that more evidence is needed to further clarify the taxonomic composition of the genus Balitora.

Transcriptomic analysis of colour dimorphism of Opsariichthys bidens provides insights into the mechanism of male colour

Opsariichthys bidens (O. bidens) is a fish species native to China. It has become a popular ornamental fish because of its interesting colour dimorphism. Its colour pattern is unique; however, with the exception of model species, such as zebrafish, the molecular mechanisms of most fish colour patterns remain unclear. In the present study, we compared and analysed the transcriptomic data of the skin and anal fins of male and female O. bidens. A total of 9028 differentially expressed genes (DEGs) were identified, of which 5259 were upregulated and 3769 were downregulated in males. Compared with known pigmentation genes, Mitf, Tyr, Tyrp1, Dct, Pnp4a, Alx4a, Gch1, and Csf1r were identified as potential genes related to colour dimorphism. Second, we tracked the process of colour development in male O. bidens and found that there were three stages in the formation of body colour. We explored the distribution, migration, and expression patterns of genes related to pigment cells at each stage using microscopic imaging, transmission electron microscopy, enzyme-linked immunosorbent assay, and high-performance liquid chromatography. Melanophores, xanthophores, and iridophores were found to be distributed on the skin or anal fins of O. bidens. It was inferred that this unique body colour pattern is caused by the differentiation and migration of pigment cells at specific stages. This discovery provides a basis for studying the molecular mechanisms of pigmentation in ornamental fish and will contribute to the genetic selection and breeding of O. bidens in ornamental fish cultures in the future.

Carotenoids as a Dietary Supplement for Enhancing Pigmentation and Colouration in Ornamental Fishes: A Review

Due to the rising demand for aquarium fish, the ornamental fish-keeping business has significantly increased its contribution to fisheries. The sector requires little investment and is socially and environmentally acceptable. Fish's skin colour, which is influenced by their diet and nutrition, is a major determinant of their market value. Fish have vivid colouring because they consume plants and animals that are naturally rich in pigment. Dietary carotenoids and coloration are intimately connected. Carotenoids are the major natural pigments, responsible for yellow to red coloration and are synthesized mainly by plants, algae and some photosynthetic bacteria. The core component of a successful culture of ornamental fish in a limited environment is properly formulated feed. Fish cannot produce carotenoids by own. Hence, diverse sources of carotenoid pigments, including pure carotenoid pigments, animal sources, and plant sources, have been added to fish diets to increase the pigmentation in ornamental fish. The significance of different sources of carotenoids as a dietary supplement for enhancing the pigmentation and coloration in aquaculture has been highlighted in this review paper.

Identification of key regulatory pathways and genes involved in the dynamic progression of pigmentation in Sinibrama taeniatus

IntorductionColoration is a prominent trait in fish that is closely linked to their market value. Fish exhibit a diverse range of body colors, making them an excellent model for studying molecular mechanisms underlying pigmentation. Although regulatory pathways involved in pigmentation have been extensively studied in model fish such as zebrafish and medaka, the presence of varying chromatophore types across different fish species suggests that fish pigmentation mechanisms are not fixed. Therefore, more studies should be conducted on non-model fish. Sinibrama taeniatus is an endemic fish in the upper Yangtze River that is highly valued for its ornamental and edible properties.MethodsIn this study, we identified three chromatophore types in S. taeniatus and investigated changes in body color, chromatophores, and pigments at different developmental stages. Subsequently, RNA-seq analysis revealed that retinol metabolism, thyroid hormone synthesis, purine metabolism, and pyrimidine metabolism pathway are closely associated with pigmentation.ResultsWeighted gene co-expression network analysis (WGCNA) identified several hub genes, including mitf, wnt 9a, wnt10b, wnt11, adcy5, edn1, adcy8, and rdh8, that may play an important role in pigmentation.DiscussionOverall, our findings provide valuable insights into the role of genes and pathways in fish pigmentation and offer useful information for body color-based molecular breeding programs in aquaculture.

Identification and characterization of circRNAs from different body color leopard coral grouper (Plectropomus leopardus)

Circular RNAs (circRNAs) play key roles in several biological processes in animals and their regulatory mechanism in body color formation or pigmentation in fish remains unclear. Here, circRNAs from black and red individuals of Plectropomus leopardus were identified to clarify the mechanism of circRNAs and the competing endogenous RNA (ceRNA) network (circRNA-microRNA (miRNA)-messenger RNA (mRNA)) in body color formation. We detected a total of 1,424 novel circRNAs. Expression analysis of circRNAs in black vs. red P. leopardus revealed 24 differentially expressed circRNAs (DECs), and 11 and 13 of these DECs were up-regulated and down-regulated in red individuals relative to black individuals, respectively (P<0.05 and |log2 Fold Change (FC)|>1). We identified a total of 19 significant miRNA-circRNA-mRNA ceRNA networks through the analysis of DECs, differentially expressed miRNAs (DEMs) and differentially expressed genes (DEGs). Pathway enrichment analyses of the DEGs involved in the ceRNA network revealed that they were mainly involved in melanin metabolism and immune response. Our findings showed the possibility of the regulatory functions of circRNAs and the corresponding ceRNA network in the body color formation process and will aid the breeding selection process of P. leopardus.

New additions to black and white fish mutants

In this short note we present unique and new records of a marine fish pigmentation abnormalities, including a case of an albino-melanistic fish, combining leucism and melanism, the first record of a leucistic individual of the iconic and critically endangered great hammerhead shark (Sphyrna mokarran), first record of leucistic Almaco jacks (Seriola rivoliana) and the first melanistic giant manta (Mobula birostris) in the north Atlantic. We speculate that these new records of pigmentary abnormalities may be related to significant population declines and isolation of remote populations.

Effects of Natural and Synthetic Astaxanthin on Growth, Body Color, and Transcriptome and Metabolome Profiles in the Leopard Coralgrouper (Plectropomus leopardus).

Natural and synthetic astaxanthin can promote pigmentation in fish. In this study, the effects of dietary astaxanthin on growth and pigmentation were evaluated in leopard coralgrouper (Plectropomus leopardus). Fish were assigned to three groups: 0% astaxanthin (C), 0.02% natural astaxanthin (HP), and 0.02% synthetic astaxanthin (AS). Brightness (L*) was not influenced by astaxanthin. However, redness (a*) and yellowness (b*) were significantly higher for fish fed astaxanthin-containing diets than fish fed control diets and were significantly higher in the HP group than in the AS group. In a transcriptome analysis, 466, 33, and 32 differentially expressed genes (DEGs) were identified between C and HP, C and AS, and AS and HP, including various pigmentation-related genes. DEGs were enriched for carotenoid deposition and other pathways related to skin color. A metabolome analysis revealed 377, 249, and 179 differential metabolites (DMs) between C and HP, C and AS, and AS and HP, respectively. In conclusion, natural astaxanthin has a better coloration effect on P. leopardus, which is more suitable as a red colorant in aquaculture. These results improve our understanding of the effects of natural and synthetic astaxanthin on red color formation in fish.

Astaxanthin mitigates oxidative stress caused by microplastics at the expense of reduced skin pigmentation in discus fish

Microplastics (MPs) exposure generally triggers oxidative stress in fish species and vertebrate pigmentation is commonly influenced by oxidative stress, but MPs-induced oxidative stress on fish pigmentation and body color phenotype has not been reported. The aim of this study is to determine whether astaxanthin could mitigate the oxidative stress caused by MPs but at the expense of reduced skin pigmentation in fish. Here, we induced oxidative stress in discus fish (red skin color) by 40 or 400 items/L MPs under both astaxanthin (ASX) deprivation and supplementation. We found that lightness (L*) and redness (a*) values of fish skin were significantly inhibited by MPs under ASX deprivation. Moreover, MPs exposure significantly reduced ASX deposition in fish skin. The total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) activity in fish liver and skin were both significantly increased with the increase of MPs concentration, but content of glutathione (GSH) in fish skin showed a significant decrease. For ASX supplementation, the L*, a* values and ASX deposition were significantly improved by ASX, including the skin of MPs-exposed fish. The T-AOC and SOD levels changed non-significantly in fish liver and skin under the interaction of MPs and ASX, but ASX significantly reduced GSH content in fish liver. Biomarker response index indicated that ASX could improve the moderately altered antioxidant defense status of MPs-exposed fish. This study suggests that the oxidative stress caused by MPs was mitigated by ASX but at expense of reduced fish skin pigmentation.

The genetic basis and potential molecular mechanism of yellow-albino northern snakehead (Channa argus).

Body colour is an important economic trait for commercial fishes. Recently, a new colour morph displaying market-favoured yellow skin (termed as yellow-mutant, YM) of northern snakehead (Channa argus) was discovered in China. We confirmed that YM snakehead is an albino with complete loss of melanin in the skin and eyes by histological and ultrastructural observations, and inherited as a recessive Mendelian trait. By applying genomic analysis approaches, in combination with gene knockdown and rescue experiments, we suggested a non-sense mutation in slc45a2 (c.383G > A) is the causation for the YM snakehead. Notably, significantly higher levels of key melanogenesis genes (tyr, tyrp1, dct and pmel) and phospho-MITF protein were detected in YM snakehead than those in wild-type individuals, and the underlying mechanism was further investigated by comparative transcriptomic analysis. Results revealed that differential expressed genes involved in pathways like MAPK, WNT and calcium signalling were significantly induced in YM snakehead, which might account for the increased amount of melanogenesis elements, and presumably be stimulated by fibroblast-derived melanogenic factors in a paracrine manner. Our study clarified the genetic basis of colour variation in C. argus and provided the preliminary clue indicating the potential involvement of fibroblasts in pigmentation in fish.

Butylparaben Exposure Induced Darker Skin Pigmentation in Nile Tilapia (Oreochromis niloticus)

Butylparaben (BuP), as an emerging contaminant with endocrine-disrupting effects, may exert effects on skin pigmentation in fish by interfering with the neuroendocrine system. Therefore, models of BuP exposure in Nile tilapia (Oreochromis niloticus) were established by adding different doses of BuP (0, 5, 50, 500, and 5000 ng/L) for 56 days. The obtained results showed that BuP exposure induced darker skin pigmentation, manifested as increased melanin content of skin, while genes related to melanin synthesis, including α-MSH and Asip2, significantly changed. In addition, BuP exposure reduced dopamine and γ-aminobutyric acid content in the brain, which is related to the synthesis of α-MSH. Furthermore, the release of neurotransmitters from the brain is affected by light. Thus, the relative gene expression levels in the phototransduction pathway were evaluated to explore the molecular mechanism of BuP-induced darker skin pigmentation, and the obtained results showed that Arr3a and Arr3b expression was significantly upregulated, whereas Opsin expression was significantly downregulated in a BuP dose-dependent manner, indicating that BuP inhibited phototransduction from the retina to the brain. Importantly, correlation analysis results showed that all melanin indexes were significantly positively correlated with Arr3b expression and negatively correlated with Opsin expression. This study indicated that BuP induced darker skin pigmentation in Nile tilapia via the neuroendocrine circuit, which reveals the underlying molecular mechanism for the effects of contaminants in aquatic environments on skin pigmentation in fish.

Monascus sp. Pigment Potency as Simple Preservative in Food Ingredients

Everyday foodstuffs such as tofu, chicken, and fish are ingredients that have a short shelf life if stored outdoors or in the open air. The fungus Monascus sp. is a fungus whose pigment is often used in giving color to food. This study aims to determine the potential of Monascus sp pigment isolated from commercial red rice (Angkak) as a preservative in tofu, chicken, and fish at room temperature. The methods used included isolation of the fungus Monascus sp from commercial red rice (Angkak), macroscopic and microscopic morphological characterization, solid fermentation using rice, harvesting pigments with water solvent, and pigment resistance tests on tofu, chicken meat, and fish. The results obtained from the application of the crude extract of the Monascus sp. pigment in fish survived for two days, chicken meat lasted up to three days, and tofu lasted four days. Each experiment had different results during the organoleptic test and compared to a positive control, namely turmeric, proving that turmeric was still better at resisting food spoilage. This research needs to be investigated further regarding the potential if the pure extract of the Monascus sp pigment is used.

Long-term effect of a short pulse of dietary supplementation with algae on the quality of turbot (Scophthalmus maximus) frozen fillets

This study raises the question of the potential long-term effects of a feeding pulse with diets containing algal biomass on the quality of frozen turbot (Scophthalmus maximus) fillets. A feeding trial was carried out with this aim, in which juvenile turbot were fed during 60 d with six different experimental diets, two of which were enriched with the macroalgaeUlva rigida(U diets), the other two with a microalgae blend (M diets), plus a non-supplemented control diet (CT), and finally, a commercial aquafeed (COM). Two inclusion levels were considered in algae-enriched diets (50 and 100 g kg-1) so that they were designed as U5 and U10 forU. rigida, and M5 and M10 for microalgae-enriched diets. The duration of the feeding pulse with the functional diets was 60 days, and then, all specimens were fed with a COM diet for a further 150-d period until reaching a body size close to the commercial standard (approximately 750 g). Subsequently, fish were sacrificed; fillets were removed from the pigmented flank and kept at -20 °C for 5 months. Then, fillets were thawed and the muscle proximal composition and fatty acid profile were analyzed, and fillet quality parameters were assessed during a 10-d co\ld storage period at 4°C. The possible deferred effects of algae-enriched diets on fillet quality were compared with a control diet without algae (CT) and with a commercial diet (COM). Roughly, the results obtained indicated that a 60-d administration pulse of algae-enriched diets induced some long-term changes in both the nutritional and organoleptic quality of turbot fillets. In this regard, the algae-enriched aquafeeds improved the muscle antioxidant response throughout the cold storage period, prolonging the shelf life of thawed turbot fillets. In addition, in terms of consumers’ acceptability, this feeding pulse on pre-growing stage of the productive cycle was able to modify the skin and muscle pigmentation of fish of commercial size. Namely, the U10 diet increased the protein content, improved muscle texture, reduced fillet total lipid content, and favored muscle selective retention of n-3 polyunsaturated fatty acids. On the other hand, the strategy based on the early administration of a diet rich in fishmeal (CT) for 60 d, followed by feeding with commercial feed, also affected positively the quality of fillets, with values comparable to U10 specimens. Thus, the results obtained indicate that a two-month feeding pulse with algae-supplemented diets during pre-growing phase may represent a promising strategy to improve the nutritional and organoleptic quality of frozen turbot fillet, as well as to extend their shelf life during the post-thawing cold storage.

CRISPR Knockouts of pmela and pmelb Engineered a Golden Tilapia by Regulating Relative Pigment Cell Abundance.

Premelanosome protein (pmel) is a key gene for melanogenesis. Mutations in this gene are responsible for white plumage in chicken, but its role in pigmentation of fish remains to be demonstrated. In this study, we found that most fishes have 2 pmel genes arising from the teleost-specific whole-genome duplication. Both pmela and pmelb were expressed at high levels in the eyes and skin of Nile tilapia. We mutated both genes in tilapia using CRISPR/Cas9. Homozygous mutation of pmela resulted in yellowish body color with weak vertical bars and a hypopigmented retinal pigment epithelium (RPE) due to significantly reduced number and size of melanophores. In contrast, we observed an increased number and size of xanthophores in mutants compared to wild-type fish. Homozygous mutation of pmelb resulted in a similar, but milder phenotype than pmela-/- mutants. Double mutation of pmela and pmelb resulted in loss of additional melanophores compared to the pmela-/- mutants, and also an increase in the number and size of xanthophores, producing a golden body color. The RPE pigmentation of pmela-/-;pmelb-/- was similar to pmela-/- mutants, with much less pigmentation than pmelb-/- mutants and wild-type fish. Taken together, our results indicate that, although both pmel genes are important for the formation of body color in tilapia, pmela plays a more important role than pmelb. To our knowledge, this is the first report on mutation of pmelb or both pmela;pmelb in fish. Studies on these mutants suggest new strategies for breeding golden tilapia, and also provide a new model for studies of pmel function in vertebrates.

Marine yeast Rhodotorula paludigena VA 242 a pigment enhancing feed additive for the Ornamental Fish Koi Carp

Skin colour is an important criterion in determining the aesthetic appeal of ornamental fishes, and thus their market worth. Hence the pigment enhancement in ornamental fishes has been the subject of extensive research by using various synthetic as well as natural pigment sources. Dietary composition is one of the most important elements that influence the development of pigmentation in fish. This study is an attempt to assess the possibility of using carotenogenic marine yeast as pigment enhancer in fish diet for Koi carp, Cyprinus carpio. The 60 days feeding experiment was done by using feed incorporated with mangrove associated marine yeast Rhodotorula paludigena VA242. Greater pigmentation in the scales of fishes fed with experimental feed was observed than that fed with the control diet (normal pellet feed). Furthermore the improved growth rate and general wellbeing in fishes fed with experimental feed provides scope for further studies in this field with respect to the growth and survival of fishes.

Effects of Nitrogen and Light Intensity on the Astaxanthin Accumulation in Motile Cells of Haematococcus pluvialis

The dietary supplementation of Haematococcus pluvialis is a natural, safe, and sustainable method for fish pigmentation. However, astaxanthin-rich H. pluvialis cysts have a poor effect in pigmenting salmonid flesh due to their rigid and thick cell wall. H. pluvialis thin-walled motile cells have recently attracted attention due to their potential advantages in maintaining compound stability, easy digestion, enhancing the bioavailability of carotenoids, and reducing production costs. This study aimed to investigate the effect of various nitrogen concentrations and light intensities on astaxanthin production in motile cells. We first investigated the effect of four different concentrations of nitrogen on astaxanthin accumulation in motile cells. According to the results, the motile cells had the highest astaxanthin concentration and content under the 0 N condition. Then, we compared the differences in astaxanthin production in motile cells under three different light intensities under 0 N conditions. The results showed that after four days of treatment, the protoplasts of the motile cells in the medium light (ML) group and the high light (HL) group had distinct granularity. The cell mortality rate in the HL group reached more than 15%, which was significantly higher than that in the low light (LL) and ML groups, indicating that high light intensity was not suitable for inducing motile cells to accumulate astaxanthin. There were no significant differences between the LL and ML groups in astaxanthin content, motile cells percentage, and cell mortality rate. Considering these indicators, we recommended inducing motile cells to produce astaxanthin under low light conditions because it is more economical in terms of electricity consumption. This study added to the knowledge that nitrogen and light affects the accumulation of astaxanthin in H. pluvialis motile cells. The results would help determine the optimal nitrogen and light conditions in astaxanthin production from motile cells.