Journal of Innovation in Applied Research (eISSN: 2581-4206)

1. Introduction

Microalgae are unicellular photosynthetic organisms and capable of converting light energy, nutrients and carbon di oxide into new algal biomass. Polysaccharides, proteins, lipids, pigments and vitamins are some biologically valuable components which are produced by microalgae through the utilization of carbon di oxide with the help of sunlight (Gouveia et al., 2009; Bellou et al., 2014; Moha-Leon et al., 2018). A good amount of protein, carbohydrate and oil deposition in microalgae depends on algal strain and their growth environment (Draaisma et al., 2013). So, microalgae play a vital role in fish larval, molluscs and crustaceans direct nutrition (Muller-Feuga, 2000). Cultivation of photosynthetic microalgae have received great interest in the field of aquaculture due to their high nutritional profile which makes them good sources of high-quality proteins, sterols and PUFAs like, EPA, arachidonic acid, linoleic acid and DHA etc (Muller-Feuga, 2000; Hemaiswarya et al., 2010). Antioxidant content also present in microalgae (Hemaiswarya et al., 2010), are essential for increasing larval growth, development, survivality and metamorphosis (Muller-Feuga, 2000; Hemaiswarya et al., 2010). Nannochloropsis sp. are unicellular microalgae which possess only one chloroplast and have cell wall consisting with polysaccharide. They are considered as a high nutritional species widely used in aquaculture for hatchery grown herbivores, such as larval and juvenile bivalves (Okauchi, 2004). It is recognized as the potential algae for industrial applications as a consequence of its capability to build up high levels of polyunsaturated fatty acid. Chlorophyll a, astaxanthin, zeaxanthin and canthaxanthin are some valuable pigment components which are found abundant in Nannochloropsis sp. (Lubian et al., 2000) and also regarded as a potential source of essential ω-3 PUFA, EPA (20:5ω-3) (Sukenik et al., 1990; Renaud et al., 1991; Renaud et al., 1994). Gbadamosi and Lupatsch (2018) concluded that fatty acid profile of Nannochloropsis salina increases the ω-3 PUFA in edible fish and enhances the essential nutrient components for diet of human beings. Tetraselmis sp. are unicellular flagellated chlorophytes with rapid growth rate and can withstand with broad range of temperature and pH (Khatoon et al., 2014). They are known to have a promising nutritional profile containing sufficient amount of protein, carbohydrate, lipid and fatty acids which are vital for cultured organisms. Different bioactive compounds such as vitamin E, carotenoids etc. are abundantly found in Tetraselmis sp. (Ismaiel et al., 2016). According to Pereira et al. (2019) Tetraselmis sp. contain PUFA, EPA and α-linolenic acids, which are important for different nutritional applications. Tetraselmis chuii is a widely used microalgae that is thought to be an excellent source of long-chain PUFAs, particularly EPA (Meseck et al., 2005; Zaki & Saad, 2010). Carotenoids are considered as one of the most important group of pigments which provides various colors like yellow, red and orange to fish, crustaceans, animals and plants skin and tissues (Kop & Durmaz, 2008). Different plant species, various fungi, heterotrophic bacteria and photosynthetic prokaryotes can produce lipophilic pigments regarded as carotenoids. They highly contribute in photosynthetic activity because carotenoid contains different pigments which harvests lights and prevents photo oxidation (Hirschberg, 2001; DellaPenna & Pogson, 2006; Walter & struck, 2011). Many fish deposit carotenoids in their integuments and gonads but in case of salmonids, they accumulate carotenoids in muscle. According to Torrissen and Nsevdal (1988) reported that, in matured fish species high quantity of carotenoids are observed in its integument and ovaries, almost 90% carotenoid was also observed as free form in fish flesh. Different aquatic species like fish and other animal species could not able to produce carotenoid pigments in their skin and muscle tissues as a result they are completely dependent on dietary carotenoids which regulates coloration in fish and other animal species. Teimouri et al. (2013) concluded that dietary supplements with Spirulina platensis increased pigmentation in rainbow trout.

Nile tilapia is considered as one of the most important farmed fish species around the world because of its high commercial significance. Nile tilapia is well accepted due to presence of high amount of nutrients like proteins, minerals and essential fats. Thus, this study is aimed to evaluate the dietary influence of selected Nannochloropsis sp. and Tetraselmis sp. microalgae on the pigmentation, nutrition and biochemical composition of Nile tilapia fry.

2. Materials and Methods

2.1. Microalgae strain collection and study area

Tetraselmis sp. and Nannochloropsis sp. isolates were chosen and obtained at the Faculty of Fisheries live feed research corner laboratory at Chattogram Veterinary and Animal Sciences University. Seawater was obtained from the neighboring Sagorika Sea Beach (Kattoli in Chattogram) in order to make medium for microalgae cultivation. Seawater was brought into laboratory and stored for overnight in plastic tanks to settle down the solid particles of water. Initially, a filter bag was used for filtering the sea water avoiding the settled solid particles. After that, in a vacuum pump Whatman paper (GMF Circles 4.7 cm) was used for fine filtration and then filtered seawater was sterilized using autoclave for 15 minutes at 121__degreesignC. For microalgae cultivation filtered and sterilized seawater was used. Sufficient freshwater circulation facilities were ensured to conduct the feeding trial. For UV sterilization freshwater was stored into two 80 L (each) plastic containers so that sterilized water can be circulated into the entire culture system. This method was carried out for 8 weeks in the Chattogram Veterinary and Animal Sciences University's Faculty of Fisheries' Wet Laboratory, in accordance with the water requirement in the fish culture tank.

2.2. Microalgae mass cultivation

Tetraselmis sp. and Nannochloropsis sp. were mass cultured in separate 20 L clear plastic jars in indoors at 25__degreesignC. Following the proportions provided by Tompkins et al. (1995) Conway medium was prepared so that microalgae strains could grow within sufficient nutrient enrich environment. To prepare 1 L Conway media, 1 mL of solution A, 0.5 mL of solution B, and 0.1 mL of solution C were mixed together in filtered and sterilized saltwater. The microalgae culture volume was gradually increased from a starting stock culture volume of 20 mL to a final culture volume of 20 L. In each flask for batch cultivation, 20 mL of microalgal stock was combined with 30 mL of culture media. and the total culture volume was 50 mL. Then the volume of culture was scaled up gradually such as, 0.25 L, 0.5 L, 1 L, 2 L and at the end expanded up in plastic container of 20 L, following the batch cultivation method. During the exponential period of development (Islam et al., 2021) the cultures were shifted into next batch. Microalgae cells were centrifuged for 5 minutes at 5000 rpm by using centrifugation machine (HERMLE Z 206A, Germany), after reaching the microalgal growth into the stationary phase (Islam et al., 2021). The wet biomass was collected after centrifugation and then dried into oven for overnight at 60__degreesignC temperature. A hot air oven (JSR Korea's Natural Convention Oven LNO-150) was utilized for oven drying, and a mortar and pestle was employed to ground oven-dried microalgae biomass into small particles (0.4-0.5 mm in diameter). The powdered microalgae were then kept in a standard freezer at 4__degreesignC until further usage in feed preparation. The feeding trial was conducted when sufficient dried biomass of each microalga had been obtained through batch culture.

2.3. Experimental diets

Five experimental diets with different percentages of microalgal biomass (N25%, T25%, N50%, T50%) were prepared using local feed ingredients depicted in Table 1, and feed with no microalgae (0%) was used as control. All the feed components were grounded, sieved, and oven-dried during the process of feed preparation. Commercialized fish meal was replaced up to 25% and 50% with microalgal dried biomass of Nannochloropsis sp. and Tetraselmis sp. In the following Table 1, the proximate composition of five experimental diets for fry Nile Tilapia is given away.

2.4. Fish source along with experimental design

Nile tilapia fish fry were taken from a commercial tilapia hatchery called "Niribili Tilapia Hatchery" (located in Cox's Bazar). To conduct the feeding trial experiment for 8 weeks, 270 Nile tilapia fish fries (0.023±0.0001 g of mean individual weight) of 14 days old were used. Fries were allocated randomly in 15 transparent, glass aquariums (45×30×30 cm) with a capacity up to 30 L water. To conduct this experiment five treatments were designed namely CF, T25, T50, N25, N50 in triplicate form. Prior to stocking, the fish were acclimatized in a large tank under laboratory conditions for two days. To maintain optimum O₂ level in rearing tank constant air circulation was supplied using aerator pump with perforated air stone in each tank. Fish were fed commercial starting feed for two days during acclimation. Towards the end of the conditioning period, according to the experimental design, 18 fish per tank were stocked encompassing 18 L water in each rearing tank. Diet prepared with Nannochloropsis sp. and Tetraselmis sp. were fed to Nile tilapia fry, in addition to a control feed containing no algae replacements. Prepared 5 categories of diet were grounded and given to the fish at 8 AM, 11 AM, 2 PM, and 5 PM on a day, based on 15% according to their body weight. Fish waste and residual meals have been regularly sifted out from the bottom of each aquarium. Daily, 1/3 of the culture water in the experimental tank was replaced with new and purified (UV-sterilized) tap water. Physical parameters (temperature, pH, O₂) were checked daily and chemical parameters (TAN, NO₂-N, SRP) were analyzed weekly to check the variables of rearing environment.

2.5. Determination of carotenoid concentration in fish tissue

After feeding experiment for 8-weeks, fish were sampled, and three fish were collected from each tank to measure the pigment density and the level of color enhancement of fish tissue due to microalgae fed diet. Fish were starved for 24 h before sampling. Olson (1979) method of pigment extraction and determination was followed. Excluding the alimentary canal and head, 1 gram body tissue of Nile tilapia fish was removed as a sample from each tank and stored in a screw-capped transparent glass vials with a volume of 10 mL. The glass vial was then filled with sodium sulphate (2.5 g anhydrous Na₂SO₄). Then the sample was homogenized with hand-homogenizer and 5 mL chloroform was added in that vial and left at 0⁰C for overnight. When a clean layer of 1-2 cm was produced above the caked residue, optical density was measured using a spectrophotometer (T80 UV/VIS Spectrophotometer, UK) at 380 nm, 450 nm, 470 nm, and 500 nm to compare the maximum reading range for computation. Before being read, 0.3 ml chloroform aliquots from each glass vial were collected and mixed to 3 mL ethanol at a concentration of 100%. Similarly for comparison a blank was prepared. For the computation, the wavelength with the highest absorption was utilized. The maximum wave length absorbance was calculated by following formula:

Total carotenoids (µg/g wet wt.) ?

where, dilution factor =10; extinction coefficient= 0.25

2.6. Sample preparation

At first, whole fish samples were oven dried for overnight (Natural Convention Oven LNO-150, JSR Korea) at 40⁰C. Oven dried fish samples were grounded using a mortar and pestle to form into powdered format for the analyses of protein, carbohydrate, lipid content and fatty acids of Nile tilapia fish.

2.7. Chemical analyses of proximate composition

To assess the protein content, the Lowry et al. (1951) method was followed. In addition to solution preparation, 25 mL of deionized water were combined in and placed into a test tube with 5 mg of oven-dried and powdered fish sample. From the prepared sample solution about 0.5 mL aliquot was taken out. Reactive 1 and 2 solution were prepared previously so that mixed reagent can be made. Protein content of fish samples were evaluated by the addition of 1 N sodium hydroxide, subsequently addition of alkaline copper solution and Folin reagent. Using bovine serum albumin at different concentrations, standard solutions was prepared. The absorbance of the prepared sample solution was measured using a spectrophotometer (T80 UV/VIS Spectrophotometer, UK) at a wavelength of 750 nm. Carbohydrate analysis was carried out using the technique developed by Dubois et al. (1956). The samples were tested by adding 1 mL of 5 percent phenolic solution and 5 mL of strong sulphuric acid. The absorbance of the prepared sample solution was measured using a spectrophotometer (T80 UV/VIS Spectrophotometer, UK) at a wavelength of 488 nm. According to the sulfuric acid-charring method of Marsh and Weinstein (1966), lipid analysis was conducted. Then followed the carbonization technique using tripalmitin as standard, after the extraction of lipids according to Bligh and Dyer (1959) methods. At 200__degreesignC for 15 minutes carbonization was performed. The optical density measurement for each solution was done with a wavelength of 375 nm using a spectrophotometer (T80 UV/VIS Spectrophotometer, UK).

2.8. Analyses of biochemical composition

The direct methylation techniques of Divakaran and Ostrowski (1989) was followed to prepare fatty acid methyl esters (FAMEs). To begin, the total lipid content of the sample was determined using the Soxhlet device. As a lipid extraction solvent, diethyl ether ((C₂ H₅)₂O) was used, and the last stage of lipid extraction was carried out at 60__degreesignC. This extracted lipid served as the final lipid sample for the FAMEs study. For the examination of the FAMEs of the samples, a gas liquid chromatograph (GC-2010 Plus, Shimadzu, Japan) with a high sensitivity FID and clean detector gas flows and a capillary pillar (0.25 μm of film width, 0.25 mm of inner diameter, 25 m of length) was employed. The injection volume was 1 μL. The column temperature was: firstly (50-280)⁰C at 3⁰C /min and then (45-180)⁰C at 2⁰C/min. Compared to retention periods of established standards, individual FAME peaks were identified. Initially, the levels of each fatty acid were expressed as ppm and then transformed into percentages of total fatty acids (TFAs).

2.9. Statistical analysis

Microsoft Excel was utilized to compute the mean and standard error mean (SEM) of the acquired data. The significance level (p< 0.05) of total carotenoid concentration, protein, carbohydrate, lipid, and fatty acid concentrations were then determined using one-way analysis of variance (ANOVA). Finally, the Multiple Range Test of Duncan was performed using IBM SPSS software (v.26) to compare the means of each treatment.

3. Results

3.1. Total carotenoid concentration of fish tissue

In this study, microalgae were proven to be an efficient color enhancer and values of five treatments CF, N25, N50, T25, and T50 varied significantly (p <0.05). Between the Nannochloropsis sp. and Tetraselmis sp. microalgae-fed diet Nannochloropsis sp. exhibited amazing color-enhancing performance in Nile tilapia fish tissue in comparison to Tetraselmis sp. Among 380 nm, 450 nm, 470 nm, and 500 nm wavelengths, the highest absorption was recorded in the 450 nm wavelength. As a result, absorption values in 450 nm wavelength were used for the determination of total carotenoid concentration. The highest concentration of total carotenoid content in wet weight was documented in N50 (3.27±0.04 µg/g) and the lowest concentration was recorded in CF (0.87±0.03 µg/g) (Figure 1). Correspondingly, the total carotenoid concentration in T50, N25, and T25 treatment also showed significantly (p <0.05) higher values compared to CF (Figure 1).

3.2. Fish nutrition

After the end of the feeding trial, the protein, lipid, and carbohydrate percentages of Nile tilapia (Oreochromis niloticus) fry of each treatment were determined by chemical analysis process and there were significant changes (p <0.05) in the whole fish sample documented (Figure 2). The observed values for protein, lipid, and carbohydrate ranged from 26.07% to 32.16% (Figure 2. A), 12.4% to 19.8% (Figure 2. B), and 9.59% to 12.78% (Figure 2. C) consequently. In this study, the highest protein, lipid, and carbohydrate nutrient value was documented in CF (32.16±0.06%), N50 (19.8±0.12%), and T50 (12.78±0.02%) accordingly. The lowest value of protein is achieved in N50 (26.07±0.06%), lipid in CF (12.4±0.12%), and carbohydrate in CF (9.59±0.02%) treatment consequently.

3.3. Biochemical composition

The result of percent total fatty acid composition of whole Nile tilapia fish tissue is presented in the following Table 2. The observed values indicating that percentages of different fatty acids are significantly affected (p< 0.05) by dietary microalgae compared to control feed.

Nile tilapia fish fed with control feed obtained the lowest percentage of SFAs such as decanoic acid (C10:0), palmitic acid (C16:0), heptadecanoic acid (C17:0), heneicosanoic acid (C21:0), behenic acid (C22:0), tricosanoic acid (C23:0) and lignoceric acid (C24:0) in comparison to treatment N25, N50, T25 and T50, although lowest percentage of total SFA was observed in T50 (32.87±0.01%) and highest value was recorded in N25 (35.49±0.09%) treatment. In case of total monounsaturated fatty acid (MUFA), 25% Nannochloropsis sp. based diet exhibited the lowest total MUFA. In regards, highest percentage of PUFA, EPA (C20:5n-3) was observed in N50 (22.42±0.02%) treatment. Elevated concentration of Nannochloropsis sp. in fish diet has significantly increased the EPA (C20:5n-3) content in fish tissue compared to other treatment while in case of other PUFAs elevated concentration of microalgae did not significantly increase the PUFA content numerically. Highest total PUFA was recorded in T50 (52.02±0.06%) treatment in comparison to other treatment.

4. Discussion

4.1. Total carotenoid concentration of fish tissue

Fish skin color is an essential predictor of consumer acceptance, and carotenoids are responsible for fish coloration. Carotenoids must be supplemented in the diet of farmed species because fish cannot synthesize them on their own (Gupta et al., 2007). It has been proposed that microalgae such as Nannochloropsis sp. and Tetraselmis sp. can support the aquaculture sector with vital vitamins, pigments, and polyphenols (Brown et al., 1999; Pataroa et al., 2019; Kokkali et al., 2020). Similar results were also obtained in the current study. Carotenoids-rich Nannochloropsis sp. and Tetraselmis sp. (Di Lena et al., 2018) showed considerable significance as natural fish colorants and confirmed the existence of a significant quantity of total carotenoids in the muscle tissue of Nile tilapia (Figure 1). Although the gradual increase in total carotenoid concentration was noticed in both Nannochloropsis sp. and Tetraselmis sp. fed treatment than control however highest performance was exhibited by N50 treatment. Carotenoids are naturally occurring pigments that can serve as provitamin A and are found in microalgae at a level of 0.1-0.2 percent dry matter, and are generated de novo predominantly by photosynthetic organisms (Becker, 1994). Though there are significant differences in the results of carotenoid contents in Nannochloropsis sp. and Tetraselmis sp. fed treatment, similar results obtained in the study of Tulli et al. (2012) and a change in skin pigmentation was detected after feeding Tetraselmis suecica-containing meals to juvenile sea bass. Greenish pigmentation was found to be enhanced in fish-fed diets including microalgae, like what was seen in Carassius Carassius (Gouveia & Rema, 2005). Teimouri et al. (2013) also found that a 10% addition of Spirulina platensis has resulted in a maximum carotenoid deposition in the skin and fillet tissue of rainbow trout (Oncorhynchus mykiss) as a natural pigment source. Another study found that eating a diet high in carotenoids can lower the incidence of free radical-related disorders including atherosclerosis and cancer (Gouveia et al., 2008).

4.2. Fish nutrition

A microalgal diet's nutritional value is directly proportional to its capacity to offer needed macro and micronutrients to the intended animal consumer and fish exhibit its nutritional status in muscle tissue according to the nutrition provided into its diet. In the current study the results of proximate composition of protein, lipid and carbohydrate (Figure 2A-2C) of Nile tilapia Oreochromis niloticus is significantly affected by different diet composition. One of the primary reasons for considering microalgae as a nontraditional source of protein is their high protein content (Becker, 2007) but in the current study among the experimental fish, Nannochloropsis sp. and Tetraselmis sp. based diet, treatment with commercial fish meal-based diet (Control Feed) has shown better protein percentage (Figure 2.A) and this might be due to presence of high fibre content in higher percentage in microalgae which has reduced the digestibility of microalgae-based diet in fish body (Sarker et al., 2018). Sørensen et al. (2021) also found similar results in his study with fish and confirmed that fish meal-based diet has shown higher protein percentage in the whole-body composition of Atlantic Salmo salar than Nannochloropsis oceanica and Tetraselmis sp. fed diet. Tibbetts (2018) documented that, Nannochloropsis sp. has a protein composition that ranges from 18 to 48 percent and lipid composition ranges from 2 to 68 percent besides Tetraselmis sp. contain protein and lipid ranges from 27 to 54 percent and from 3 to 45 percent correspondingly. Between Nannochloropsis sp. and Tetraselmis sp. comparatively higher protein nutrition obtained in T25 and the highest lipid content among all the treatment was recorded in N50 treatment (Figure 2.B). Carbohydrates are the cheapest energy sources for fish diets and gradual increase in carbohydrate content than control was noticed in this study (Figure 2.C). Carbohydrates are added in aquaculture diets, even though they have a negligible contribution in fish nutrition and growth, to minimize feed costs and for their binding action increasing the water stability of diets. The study of Radhakrishnan et al. (2015) is in agreement with the current study and documented that 50% replacement of fish meal with Chlorella vulgaris microalgae can increase the carbohydrate content in Macrobrachium rosenbergii post larvae. For the economic production of healthy and high-quality product good nutrition is essential and in this regard this study suggests to reduce the inclusion of microalgae (Sarker et al., 2020) to get better protein nutrition in whole fish composition.

4.3. Biochemical composition

Fatty acids can be saturated, mono unsaturated and poly unsaturated types. Among different types of fatty acids, the ω-3 and ω-6 PUFA series are two important PUFA groups that are regarded as the most important bioactive molecules for living species (Li et al., 2014). Microalgae contains a variety of nutritional components, including minerals, essential fatty acids ω-3 and ω-6, and other beneficial elements (Tokusoglu & Ünal, 2001). Among PUFAs, notably for EPA and DHA, omega-3 fatty acids are universally acknowledged and proved to be beneficial (Siriwardhana et al., 2012; Tocher, 2015) in prevention or treatment of a variety of illnesses of human beings which includes blinding retinal conditions, cardiac illness, diabetes, malignance and dementia (SanGiovanni & Chew, 2005; Macchia et al., 2013; Shahidi & Ambigaipalan, 2018). EPA and DHA are mostly found in wild fish (Tocher, 2015). Nevertheless, in aquaculture, to obtain PUFAs specially EPA as well as DHA for cultured fish species fish oil along with fish meal is considered as unsustainable source. Because of the rapid expansion of aquaculture, fish oil and fish meal supply will be insufficient in the future to meet the increasing demand. To partially replace fish meal and fish oil alternatives such as soybean oil and soybean meal have frequently been employed because of their ease of cultivation, harvest, availability (Wang et al., 2014) and tolerance to microbes. In this aspect microalgae also can be a potential substitute to mitigate the essential fatty acid supply demand.

In the current study, the addition of microalgae Nannochloropsis sp. and Tetraselmis sp. in diet has shown a significant positive impact on the fatty acid composition of Nile tilapia whole fish (Table 2) and desired results are obtained in this study. According to the presented data the, most abundant SFA, palmitic acid; MUFA, oleic acid was found in T25 treatment. Essential PUFAs, like linoleic acid (18:2n-6), EPA (C20:5n-3) and DHA (C22:6n-3) were found dominant in T25, N50 as well as T50 treatment, respectively. Findings of this study are consistent with the findings of Mohammadi et al. (2015) and he revealed that palmitic acid, oleic acid, alpha-linoleic acid, EPA are consequently the most prevalent SFA, MUFA, PUFA and highly unsaturated fatty acid (HUFA) in Tetraselmis chuii among all types of fatty acids. According to the experiment of Servel et al. (1994) as well as Schneider et al. (1995) the most abundant PUFA, EPA was found in the genus Nannochloropsis which was also confirmed in the study of Tonon et al. (2002). The maintenance of ω-6 to ω-3 PUFAs are regarded as important for human health for their physical development, homeostasis and psychological health (Simopoulos, 2011). In this experiment Nile tilapia (Oreochromis niloticus) fish received SFAs, MUFAs and essential PUFAs from Nannochloropsis sp. and Tetraselmis sp. inoculated diet.

Previous researchers namely, Takeuchi et al. (2002) fed Spirulina sp. to Nile tilapia, Dos Santos et al. (2019) fed Schizochytrium sp. to Nile tilapia, Hossain et al. (2017) fed Chlorella vulgaris and Spirulina platensis to Nile tilapia, Gbadamosi and Lupatsch (2018) fed Nannochloropsis salina to Nile tilapia and found elevated level of PUFAs in fed fish. According to previous studies, both Nannochloropsis sp. and Tetraselmis sp. microalgae are amazing source of some essential fatty acids as well as long chain PUFAs, especially EPA (Servel et al., 1994; Schneider et al., 1995; Meseck et al., 2005; Zaki & Saad, 2010; Gbadamosi & Lupatsch, 2018) which is confirmed in the current research. In this regard, our data show that Nannochloropsis sp. and Tetraselmis sp. may be useful in enhancing the fatty acid profile of whole fish composition. As a result, for the improvement of the deposition of human health-facilitating fatty acids, the addition of Nannochloropsis sp. and Tetraselmis sp. microalgae into fish diet is a smart strategy to boost the nutritional value of whole fish tissue.

5. Conclusion

The total carotenoid concentration and nutritional and biochemical composition of fish mainly depend on the diet provided to fish. The current study revealed that the inclusion of Nannochloropsis sp. and Tetraselmis sp. microalgae in diet has positively influenced the total carotenoid concentration, lipid, carbohydrate, and valuable fatty acids deposition in fry Nile tilapia (Oreochromis niloticus) whole muscle tissue. Lower protein digestibility due to the higher inclusion of microalgae, which is a plant protein source has been noticed. This study suggests lowering the inclusion of plant protein sources, microalgae to improve the digestibility and protein nutrient deposition. However, observing the positive impacts of those two potential microalgae in fish pigmentation and nutrient profile, microalgae can be useful in fish farming.