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Item Evaluation of Growth Performance and Nutritional Profile of Selected Marine Microalgae Cultured in Low-Cost Media(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Rahman Jihad, Md MotiurMicroalgae are emerging as a sustainable and versatile resource for aquaculture, biofuel, and nutraceutical industries. This study investigates the growth performance and nutritional profile of the marine microalga Gonyostomum sp. when cultured in costeffective media formulated with NPK fertilizer, compared to conventional Conway medium. The microalga was cultivated in varying NPK concentrations (7 mg, 9 mg, 11 mg, and 13 mg/L), with Conway serving as the control. Growth parameters, biomass yield, and biochemical composition (protein, lipid, and carbohydrate contents) were analyzed to evaluate media efficacy. The 11 mg/L NPK treatment (G11) supported the highest cell density among the NPK treatments (7.975 × 10⁶ cells/mL), while Conway medium exhibited the overall highest growth and nutritional content. Notably, G11 yielded a slightly higher lipid content (29.5%) than Conway (27.4%), indicating its potential for lipid-rich applications such as biofuel. However, Conway medium significantly outperformed NPK in protein and carbohydrate accumulation. Economically, NPK media were substantially more cost-effective, suggesting promise for scalable microalgae cultivation in resource-limited settings. The study highlights the viability of NPK-based media for mass cultivation of microalgae, particularly when supplemented with essential trace nutrients, offering a practical approach to enhance sustainable aquaculture and contribute to Bangladesh's blue economy.Item Live-feed Enriched with Microalgae as a Potential Diet to Enhance Growth Performance, Survival and Proximate Composition of Shrimp (Penaeus monodon) Post-Larvae(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Mustaquim, Md. SajjadulThe present study investigated the efficacy of Gonyostomum sp. and Tetraselmis sp., respectively as enrichment agents for rotifers and as direct dietary components in the larval rearing of Penaeus monodon post-larvae (PL). Five treatment groups were evaluated over a 30-day period: direct feeding with Gonyostomum sp. (LG), direct feeding with Tetraselmis sp. (LT), rotifers enriched with Gonyostomum sp. (ERG), rotifers enriched with Tetraselmis sp (ERT), and commercial hatchery feed (CF). Growth performance, survival, proximate composition, fatty acid profile, haemolymph parameters, and cadmium (Cd) stress tolerance were assessed. The CF and ERG groups exhibited nearly same performance in most growth parameters with slight elevation in CF (p < 0.05), while ERG significantly enhanced early survival (PL5-PL15) and immune responses, as indicated by elevated total hemocyte count, protein concentration, and triglyceride levels. ERG also showed superior resistance to Cd exposure, with the lowest cumulative mortality at 48 h. LT and LG treatments demonstrated suboptimal growth and survival, suggesting limited nutritional adequacy when applied directly. Fatty acid profiling revealed that ERG group had the highest n-3 PUFA content, correlating with improved physiological performance. These findings highlight the potential of Gonyostomum sp.-enriched rotifers as a sustainable live-feed during larval stages, while emphasizing the necessity of transitioning to formulated feeds during late post-larval or juvenile stages to achieve optimal growth and stress resilience.Item OPTIMIZING SUSTAINABLE 3RD GENERATION BIOFUEL PRODUCTION FROM MICROALGAE: CULTIVATION, HARVESTING AND EXTRACTION STRATEGIES(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Ayoun, Mohammed AbdullahThe increasing requirement for alternative energy sources has created lot of interest in biodiesel from microalgae such that it is a potential alternative to traditional fossil fuels. This study focuses on optimizing the lipid production from Gonyostomum sp., a microalga, cultivated in two media, synthetic (Conway) and biobased (cow dung infused). Four groups of extraction methods of lipids were tested, Hexane-Methanol extraction with Cow dung infused media (HCD) produced the highest lipid content 23.75 ± 0.20. Further, two different types of FAME extraction were used Type 1 (MeOH + H₂SO₄ + n-hexane) and Type 2 (AOAC Method 991.39). FAME yield was 95.58 ± 0.11%, the highest in AOAC Method 991.39 extraction with Cow dung infused media (Type2s). Fatty acid composition was analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) in order to determine the quality of the biofuel of the lipids. Fatty acid profiles of Gonyostomum sp. were dominated by saturated fatty acids (SFAs) like C16:0 (Palmitic Acid), C18:0 (Stearic Acid), and monounsaturated fatty acids (MUFAs) like C18:1 (Oleic Acid), which are of utmost significance for the production of biodiesel. Extraction with MeOH + H₂SO₄ + n-hexane, Conway Media (Type1c) had the maximum amount of saturated fatty acids (31.65%), while AOAC Method 991.39 extraction with Cow dung infused media (Type2s) had the maximum proportion of unsaturated fatty acids (MUFAs and PUFAs). Iodine value (IV), cetane number (CN), and higher heating value (HHV) were also determined to assess the quality of the biodiesel. Cetane number (CN) values ranged between 58.85 ± 0.00945 for AOAC Method 991.39 extraction with Cow dung infused media (Type2s), the highest. Iodine value (IV) values of all the samples were below 120 g Iodine/100g, which are in accordance with the European biodiesel standards. ANOVA and Tukey's post hoc test was utilized to determine the significance of differences between extraction processes. From the results, maximum efficiency for sustainable production of biodiesel from Gonyostomum sp. is achieved through the integration of biobased (cow dung infused) medium with hexane-methanol and AOAC Method 991.39 Extraction.Item Evaluating the Potential of Microalgal Species in the Phytoremediation of Cadmium and Lead Contaminated Waters(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Acharjee, SwapnilThe persistent and bio-accumulative nature of Cd and Pb, two of the most hazardous heavy metals, poses serious risks to human health and the environment. In this study, two microalgal species Tetraselmis sp. and Gonyostomum sp. exposed to Cd and Pb at concentrations of 3, 5, and 7 ppm over the course of an 8-day culture period were examined for their capacity of phytoremediation. At the end of the trial, important metrics like optical density, biomass productivity, lipid accumulation, pigment stability, and metal removal efficiency were measured. Tetraselmis sp. showed much better (p < 0.001) extraordinary resilience and remediation capabilities, with a bioconcentration factor peaking at 56,167.4 L/kg and maximum removal efficiencies of 83.33% for Cd and 71% for Pb. Gonyostomum sp., on the other hand, showed reduced lipid yields and growth resulting more vulnerable to metal-induced stress, especially from Cd. Remarkably, Tetraselmis sp. experienced a hormetic response to low Pb levels, which raised biomass production and lipid productivity. Furthermore, during heavy metal stress, Tetraselmis sp. demonstrated a statistically significant (p <0.001) lipid productivity of roughly 6.35 ppm/day as opposed to Gonyostomum sp., which peaked at just 2.73 ppm/day. According to these results, Tetraselmis sp. is a promising option for dual uses in microalgal biofuel production and bioremediation, while also addressing the gap in comparative performance analysis of underexplored microalgal species.Item EVALUATING ENVIRONMENTAL STRESSORS TO BOOST MICROALGAL LIPID AND BIOMASS YIELD: A COMPREHENSIVE ANALYSIS FOR SUSTAINABLE ENERGY GENERATION(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Dutta, EtuUnderstanding how environmental factors influence microalgal biomass and lipid productivity is essential for advancing sustainable bioresource development. The marine microalga Gonyostomum sp., grown in Conway medium, was used in this study to evaluate the biomass and lipid yield under varying photoperiod, salinity and pH conditions using response surface methodology (RSM) with a Box-Behnken design. The conditions for the control culture are 24 ± 1 °C, constant light (24 h) at 150 μEm⁻²s⁻¹, 8 ppt salinity, pH 7.3 ± 0.1, and mild aeration (4.53 ± 0.53 mgL-1). Seventeen experimental runs were conducted to determine optimal conditions within the tested ranges of parameters: 12 - 20 h photoperiod, 3 - 13 ppt salinity, and 6.5 - 8.5 pH. The results showed that a combination of 15.81 hour (15hour 48 min) photoperiod, 8.50 salinity and 6.86 pH produced the maximum biomass (1.78 gL-1) and lipid content (82.35%) whereas control combination produced 0.55 g L⁻¹ biomass and 27% lipid. Gas chromatography (GC) analysis of the fatty acid composition showed a profile that was highly favorable for biofuel applications: 63.721% monounsaturated fatty acids (MUFA), 9.99% polyunsaturated fatty acids (PUFA), and 26.282% saturated fatty acids (SAFA), with the predominant constituents being oleic acid (58.955%) and palmitic acid (23.614%). Gonyostomum sp. has the potential to be a high-yield, lipid-rich microalgal species for sustainable energy generation, and these ideal growing circumstances offer a strong basis for its large-scale cultivation for a variety of biofuel applications.Item MICROALGAE HARVESTING THROUGH PH MEDIATION AND OYSTER-DERIVED CHITOSAN: EFIICIENCY, FATTY ACID PROFILE AND ECONOMIC CONSIDERATION(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025-06) Debi, DipaMicroalgae are known as sustainable feedstock for biofuel production but efficient and economical harvesting method remain a major challenge for large scale production of algae. This study investigates harvesting efficiency of marine microalgae Gonyostomum sp. using two sustainable flocculation techniques- including Bio-flocculation via chitosan extracted from oyster shells and pH induced flocculation. The effect of different chitosan dosages (100 - 500 mg/L) and varying pH levels (8 - 11) on the harvesting efficiency and fatty acid methyl ester (FAME) profile was assessed. The results demonstrated 90 ± 0.3% efficiency with 500 mg/L single flocculant chitosan and a maximum efficiency of 97 ± 0.1% at pH 11. Lipid content of harvested biomass exhibited that pH mediated and chitosan mediated flocculation exhibited lower lipid yield (15.20 ± 0.9% and 17.80 ± 1.2%) compared to the centrifugation (21.86 ± 0.8%). Fatty acid methyl ester (FAME) profiling showed that there was significant difference (p < 0.05) among the quality of lipids of different harvesting methods. An indicative chemical cost analysis demonstrated that pH-induced flocculation is substantially more economical (2.24 BDT/L or 0.0184 US$/L) than chitosan-based harvesting (57.84 BDT/L or 0.4743 US$/L). These findings imply that both strategies are viable for achieving high flocculation efficiency. Although the usage of chitosan incurs a higher cost than pH mediation, its use encourages waste valorization and environmental sustainability, whereas pH mediation provides a scalable and inexpensive substitute.Item EVALUATION OF CARBON DIOXIDE BIO-SEQUESTRATION CAPACITY, BIOMASS PRODUCTIVITY, AND PROXIMATE COMPOSITION OF SELECTED MICROALGAL SPECIES IN TOTAL DISSOLVED CO2 LEVELS(Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2025) Chowdhury, MethilaIncreased atmospheric CO2 from human activities is fueling global warming. Among all the carbon mitigating approaches, microalgae represent a ground breaking solution for lowering carbon dioxide through sequestration, a recognized method for balancing CO2 via photosynthesis. The microalgal strains Gonyostomum sp. and Tetraselmis sp. are examined in this study to assess their capacity to capture CO2. Protein, lipid, and carbohydrates were then produced from a total dissolved CO2 supply that ranges from 55 mgL-1 (control) to 1000 mgL-1 in increments of 200 mgL-1, all while maintaining constant temperatures and light intensities. The current study focuses on not only capturing CO2 but also the utilization of gas through value addition. Maximum carbon fixation rate found at 2.75 ± 0.155 and 2.04 ± 0.13 gL-1day-1 for Tetraselmis sp. and Gonyostomum sp., at 400 mgL-1 dissolved CO2, respectively. It was found that Tetraselmis sp. was affected by CO2 concentration by lowering its productivity from 11.58 ± 0.67 mg L-1day-1 to 2.88 ± 0.54 mg L-1day-1 at 1000 mgL-1 total dissolved CO2. On the other hand, Gonyostomum sp. exhibited significantly higher (p<0.05) carbon content and a constant sequestration rate of up to 1000 mgL-1 of total dissolved carbon dioxide in the cultivation media. Growth parameters, including biomass productivity and specific growth rate, as well as proximate compositions such as protein, lipid, and carbohydrate content, and chlorophyll content, were measured and discussed. Dissolved carbon dioxide in the cultivation conditions affected the biochemical composition of both species. Gonyostomum sp. showed better protein and carbohydrate content at 800 mgL-1, lipid content at 600 mgL-1 dissolved carbon dioxide. The carbon content was higher in 800 mgL-1 for Gonyostomum sp. and for Tetraselmis sp. the higher carbon content was in 600 mgL-1 dissolved carbon dioxide. Although the maximum protein, lipid, and carbohydrate content of Tetraselmis sp. varied according to the cultivation conditions.Item Comparative Effects of Different Microalgal Diets on Growth Performance, Nutritional Profile and Enzymatic Activity of Edible Oyster Spat (Crassostrea belcheri)(Faculty of Fisheries Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2024-06) Acharjee, Mahima RanjanDiseases, overfishing, and habitat loss are reducing oyster populations constantly. Moreover, environmental pollution and natural disasters also hinder offshore shellfish cultivation. Therefore, filter-feeding bivalves could be cultivated on land-based system to maintain the culture condition and secure food safety. Live microalgal diet influences the growth, environmental quality, proximate, fatty acid, amino acid and digestive enzyme activities were investigated in the juveniles of edible oyster Crassostrea belcheri in laboratory conditions for 35 days. In this study, four different feeding regimes were trialed for Crassostrea belcheri spat culture: starvation, 2 monospecific diets (Chaetoceros sp., Tetraselmis sp.), 1 bispecific diet (Chaetoceros sp. + Tetraselmis sp.). The oyster group fed monoalgal diet showed a significantly lower survival rate in comparison with the other groups (P < 0.05). Unialgal diet Chaetoceros sp. showed highest protein, (41.7 ± 0.38) in oyster whereas, highest lipid (20.7 ± 0.33) and carbohydrate (34.2 ± 0.33) was found in bi-algal diet. The fatty acid composition of oyster was increased significantly when mixed algae was fed (P < 0.05). In the same manner, mixed diet exhibited greater lipase (LPS) and pepsin (PES) activity. On the contrary, amino acid and amylase (AMS) content of oyster was highest in unialgal Chaetoceros sp. diet. In this research, mixed algal diet had outstanding results on growth performance, proximate and essential fatty acid composition of oyster. However, essential amino acid and digestive enzyme activity showed excellent result in single species diet. The findings demonstrated that indoor cultivation system with microalgal diet might be a potential farming technology for the production of nutritionally enriched edible oyster Crassostrea belcheri.Item COMPARATIVE ANALYSIS OF SEAWEEDS, REARED WITH OYSTERS IN CAPTIVE ENVIRONMENT(Faculty of Fisheries Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2024-06) Afrin, SadiaTwo seaweed species, Gracilaria verrucosa and Ulva lactuca, as well as oysters, Crassostrea belcheri, were co-cultured under different treatments for 120 days in captivity. The study assessed the water quality parameters, growth performance, and proximate and biochemical composition of the organisms. G. verrucosa and C. belcheri were co-cultured (T1), U. lactuca and C. belcheri co-cultured (T2), and G. verrucosa, U. lactuca, and C. belcheri were cultured independently (C1, C2, C3), with three replications in each case. The experiment's conclusion involved a comparison of the treatments and control group's oyster growth, survival, and water quality. Apart from that, both indoor and outdoor seaweeds and oysters were compared to assess their proximate and biochemical indices. The salinity ranged from 32.75 to 22.05 psu, the dissolved oxygen from 7.19 to 4.22 ppm, and the pH from 8.72 to 6.45 ppm for each treatment. Significant relationships between salinity, conductivity, and temperature were found using principal component analysis. Significant variations were seen in the growth rates of the two seaweeds, U. lactuca exhibiting the highest live weight gain and specific growth rate in T2. The percentage of surviving oysters varied from 60% to 80%, with T2 showing the fastest growth rates. The seaweeds' moisture, ash, protein, carbohydrate, and fiber contents varied significantly, according to proximate composition analysis, with U. lactuca (indoor) having the highest protein and carbohydrate content (p < 0.05). Biochemical indices indicates that indoor U. lactuca contained the maximum total chlorophyll, carotenoids, and fucoxanthin. Significant variations were found in the fatty acid analysis of the seaweed and oyster samples. The results showed that the outdoor oyster samples had more omega-3 fatty acids (p < 0.05) while the indoor seaweed samples had lower saturated fatty acids and higher polyunsaturated fatty acids. U. lactuca grown indoors exhibited the highest quantities of both essential and non-essential amino acids (NEAA). However, oyster samples did not significantly differ in their EAA content when grown indoors or outdoors, they did exhibit higher levels of NEAA in outdoors. The study emphasizes how culture circumstances affect the nutritional and biochemical profiles of seaweeds and oysters, and it offers indoor co-culture as a workable substitute for bad environmental conditions that yet allow for optimal growth and nutritional quality.Item EVALUATION OF GROWTH, SURVIVAL AND HEMATO-BIOCHEMICAL INDICES OF COMMON CARP (Cyprinus carpio) THROUGH PARTIAL REPLACEMENT OF FISH MEAL BY MICROALGAE POWDER ISOLATED FROM SOUTH-EASTERN COAST OF BANGLADESH(Chattogram Veterinary & Animal Sciences University, Khulshi,Chattogram, 2023-07) Dey, Sumit KantiA feeding trial of 60 days was conducted after the isolation of microalgae from marinewater to evaluate the effects of Chlamydomonas sp. on growth performance, survival, water quality, proximate composition, hemato-biochemical index of common carp (Cyprinus carpio) where the microalgae was incorporated with the fish diet as a partial replacement of fishmeal. Triplicate groups of twenty uniform sized common carp fries were kept in each rectangular glass tank (40 L). In diets, Chlamydomonas sp. was added at different levels-0% (control), 5% (C5), 10% (C10), 15% (C15), commercial feed (CMF) and fed to the fish twice a day at 5% of their body weight for 60 consecutive days. At the end of experiment, random sampling of fish was done for growth parameter assessment and further laboratory analysis. The protein content of fish fry gradually ranged higher to lower from C15(35.6%), C10(33.2%), CMF (29.8%), C5(25.2%) and control (24.8%). C15 group had the highest lipid value (15.7%) and control group had the lowest one (8.4%). However, there were significant differences (p<0.05) observed among the all five treatments in terms of Average Daily Gain (ADG) whereas C15(0.017 ± 0.00 g) and C10(0.015 ± 0.00 g) were found to be significantly higher (p<0.05) respectively. In case of SGR, significant differences (p<0.05) were recorded where C15 (2.82 ± 0.03%) showed the highest SGR among the five treatments. The result revealed the least FCR value (p<0.05) in C15 (2.4± 0.003) and highest FCR value in control group (3.7 ± 0.05). The highest survival rate was found in C15 followed by C10, CMF and C5 respectively (81.67%, 71.67%, 63.33%, 58.33%) compared to the control group (43.2%). The addition of Chlamydomonas sp. to the feed improved and maintained good water quality during the culture period. RBC, Hb, Hct, WBC were recorded higher in 15% inoculation of Chlamydomonas sp. Replacement of fish meal with 15% and 10% inclusion of microalgae reported higher amount of total protein (8.52 g/dl), (7.83 g/dl) respectively followed by CMF (7.46 g/dl), C5(6.82 g/dl) and control (6.27g/dl). This study indicates that partial replacement of fishmeal by microalgae powder of Chlamydomonas sp. can be a potential source of protein and lipid having cost effectiveness and beneficial effects on common carp fry.
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