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EFFECT OF FORMULATED FEED ON GROWTH PERFORMANCE OF MUD CRAB IN SOFT SHELL FARMING SYSTEM
(The thesis submitted in the partial fulfillment of the requirements for the degree of Masters of Science in Aquaculture Department of Aquaculture Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2018-06) Zamey, Hasnat
The commercial farming of soft-shell crab has been going on in Bangladesh for nearly 10 years, little research has been conducted regarding formulated feeds. The present study was conducted to develop practical formulated diets for soft-shell mangrove crab farming. Presently, there is an urgent need to replace “trash fish” with manufactured diets. In this study, growth performances of mud crab were evaluated by providing feeds namely trash fish; commercial shrimp feed and formulated feed. Individual crabs were placed in 54 buckets in the field research facility at the Institute of Coastal Bio-Diversity, Marine Fisheries & Wildlife Conservation of Chittagong Veterinary and Animal Sciences University, situated in Doriyanagar, Cox’s Bazar. A feeding trial was conducted where the feeding frequency was 5% of the body weight at daily, one day interval and two day interval. The growth of crabs fed the trash fish was not significantly different from the formulated diet, both near 0.70 g/day while the growth rate when fed commercial shrimp feed diet was significantly lower, 0.34g/day. Trash fish provided the best weight gain (47.2±8.334 g), carapace width gain (16.1±2.25 mm) and molting performance followed by formulated feed, which was significantly indifferent from trash fish (P >0.05). Crabs fed with trash fish required shortest number of days for molting (26.3 days). Crabs fed with trash fish had a higher survival rate (44.44%) than commercial shrimp feed (38.89%) and formulated feed (16.67%). The results on feeding trial showed, feeding at two days interval was better in survival (61.11%), carapace width gain (13.89± 0.19) and weight gain (67.88± 10.12%). The results of the present study demonstrated that mud crabs accept formulated feeds but they need to be domesticated. Hence, the development of specific diets for crabs is technically possible by conducting further study on the performance of mud crab at different protein levels and by inclusion of different protein sources in artificial feed.
BIO-ECONOMIC EVALUATION OF SOFT SHELL CRAB FARMING SUBJECTED TO THE REMOVAL OF A SINGLE AND DOUBLE CHELIPEDS OF MUD CRABS
(The thesis submitted in the partial fulfillment of the requirements for the degree of Masters of Science in Aquaculture Department of Aquaculture Faculty of Fisheries Chittagong Veterinary and Animal Sciences University Chittagong-4225, Bangladesh, 2018-06) Rahman, Mohammad Redwanur
This study was conducted to develop a sustainable culture technique for soft-shell crab farming in Bangladesh by applying claw ablation. The present study successfully manipulated the moulting duration of crabs by declawing and the production of crabs was significantly higher than non-ablated crabs. A series of experiments were conducted where one groups of crabs remained intact (T1) and in other groups claw/claws (T2, T3 and T4) were removed/ablated. In T2 groups, only one claw was removed, both claws in T3 groups and in T4, two both claw ablated crabs were kept in one culture box. Individual crabs were then allowed for moulting for at least two moulting cycle (120 days). Results showed that, claw ablation significantly reduced the aggressiveness and cannibalistic behavior in the culture condition. Weight gain was also significantly higher (p< 0.001) in the both claw ablated crab than intact one in both 1st and 2nd moulting duration. Carapace length measurement also showed significant difference. Carapace length was 8.57 ± 1.47 cm after 2nd moulting in the non-ablated crabs while in the both ablated crabs it was 9.33 ± 1.46 cm. The moulting duration was also significantly reduced from average 40.28±7.21 days to 29.88 ± 6.59 days by removing claws. The overall production was 2052g, 2436g, 2876g and 3942g respectively for four treatments. Though mortality was little high in the double stocking groups, it can be minimized by harvesting one crab after 1st molting. Cost-benefit analysis showed that, the net profit was almost double in the cheliped removal system which made the techniques more sustainable and profitable one. Mud crab production with claw ablation techniques in the soft-shell farming system could therefore be profitable and demanding culture techniques in Bangladesh.
Antimicrobial Activity of Marine Microalgae against Bacteria Causing Skin Diseases of Pet Animals
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2020-06) Karmakar, Sharnalika
Microalgae play a significant role in the development of new products for medical and pharmaceutical research due to their ability to generate different biologically active metabolites. Microalgae are target organisms in the search for new antibiotic molecules to deal with antibiotic resistance. My results showed antimicrobial activity of three algal species Tetraselmis sp., Nannochloropsis sp. and Chlorella sp. against three pathogenic bacteria from pet dogs by disk diffusion method. Chlorella sp. showed maximum inhibition zone (13.88 mm) against Escherichia coli, whereas, Nannochloropsis sp. exhibited maximum (9.16 mm) against Streptococcus sp. and Tetraselmis sp. against Staphylococcus saprophyticus and Escherichia coli. The minimum inhibitory concentration (MIC) value of Chlorella was 30 mg/ml against Escherichi coli and Staphylococcus saprophyticus and The MIC value of Tetraselmis was 20mg/ml against Escherichia coli and 40 mg/ml against Staphylococcus saprophyticus. The current study also reported that Chlorella sp. was effective at a constant concentration against both the Escherichia coli and Staphylococcus saprophyticus. However, lesser amount of Tetraselmis sp. was required to suppress growth of Gram-negative Escherichia coli compared to Gram-positive Staphylococcus saprophyticus that need exactly double. It can be suggested that Chlorella sp., Tetraselmis sp. and Nannochloropsis sp. could be used as substitutes of antibiotics against pathogenic bacteria of pet animal as they possess bioactive compounds that have antimicrobial properties.
Growth and Nutritional Profile of Chlorella vulgaris Grown in Conway Media and Waste Water
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2020-06) Usha, Sabiha Zaman
Microalgae are sunlight-driven cell factories that convert carbon into potential biofuels, foods, feeds and high-value bio-actives. They can produce valuable lipids, carbohydrates, proteins, pigments, vitamins and other value added products that are promising for present and future feedstocks and pharmaceutical applications in an integrated approach. Chlorella vulgaris is a promising source of protein and lipid due to its higher growth rate and cellular chemical compositions. Hence, the purpose of this study was to determine growth and nutritional profileof Chlorella vulgaris in aquaculture waste water. For the experiment, Chlorella vulgaris was grown in Conway medium as the control and in 25 % ww, 50 % ww, 75 % ww and 100 % ww present from aquaculture pond used respectively to determine growth and nutritional profile. The culture volume was 1.5 L each with triplicates. The results showed that the growth of Chlorella vulgaris, in terms of cell density and optical density was significantly (p > 0.05) higher ( 4.325x106cellsml- 1) (0.400333 Abs) at high concentration of 50% ww compared to other concentration 25 % ww ( 3.358x106 cellsml-1; 0.263 Abs), 75 % ww ( 3.475x106 cellsml-1;0.348Abs) and 100%ww (4.167×106 cellsml-1; 0.312 Abs) respectively. Protein content of Chlorella vulgaris was significantly high (p > 0.05) at higher concentration of Conway medium (42.69 % dry weight) followed by 25%ww(19.88 % dry weight), 50 % ww (41 % dry weight,) 75% ww (24.45 % dry weight) and 100 % ww (22.97 % dry weight) respectively. On the other hand, lipid content (16 % DW) and (17 % DW) was significantly higher (p > 0.05) at 75 % ww and 100 % ww concentration. In case of carbohydrate content (24 % dry weight) conmway medium significantly higher among the different concentration. The study indicates that media enriched with 50% aquaculture wastewater can enhance the cell growth and nutrient values in cultivation of C. vulgaris
EFFECT OF DIFFERENT NITROGEN CONCENTRATIONS ON THE GROWTH PERFORMANCE AND PROXIMATE COMPOSITION OF Nannochloropsis sp.
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2020-06) Hossain, Md. Shahadat
Microalgae are widely recognized in the aquaculture industries as a source of protein and in the oil industries as a source of biodiesel. Nannochloropsis is a promising source of protein and lipid due to its higher growth rate and cellular chemical compositions. Hence, the purpose was to determine the effect of nitrogen concentrations on cell growth and proximate composition of Nannochloropsis sp. For the experiment, Nannochloropsis sp. was grown in 100 g/L KNO3 present in Conway medium as the control and in 50 g/L, 75 g/L, 125 g/L, and 150 g/L KNO3 present in Conway medium respectively to determine stress effects. The culture volume was 1.5 L each. The results showed that the growth of Nannochloropsis sp., in terms of cell density and specific growth rate (SGR)was significantly (p < 0.05) higher (73.65 x 106) (0.772×106cells/day) at high concentration of KNO3 150g/L compared to other concentration 50g/L ( 21.93 × 106cells/ml; 0.451×106 cells/day), 75g/L ( 20.93 × ml x 106 cells/ml; 0.491×106 cells/day, 100g/L 29.03×106 cells/ml; 0.525×106 cells/day and 125 g/L 56.7 × 106 cells/ml; 0.739 ×106 cells/day) respectively. Protein content of Nannochloropsis sp. was significantly high (p < 0.05) at higher concentration of KNO3 (54 % dry weight) followed by 50 g/L (35 % dry weight), 75 g/L (41 % dry weight,) 125 g/L (48 % dry weight) and100 g/L KNO3 (47 % dry weight) respectively. On the other hand, lipid content (36% dry weight) was significantly higher (p < 0.05) at lower concentration of KNO3125g/L KNO3 to higher. In case of carbohydrate content there was no significant difference among the different stresses except the higher nitrogen stress (13% dry weight) of 150 g/L KNO3. Therefore, the effects of nitrogen concentration have an effective approach to acquire protein, lipid as well as higher cell density
ANTIMICROBIAL ACTIVITY OF SOME MARINE MICROALGAE AGAINST COMMON BACTERIAL DISEASES IN AQUACULTURE IN CHATTOGRAM, BANGLADESH
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2020-06) Nahida Jaman Smrity, Nahida Jaman
The present investigation aimed to study antimicrobial activity of indigenous marine microalgae Tetraselmis, Chlorella and Nannochloropsis against Gram-negative Aeromonas hydrophilla and Gram-positive Staphylococcus and Lysinibacillus sphaericus isolated from diseased fish in Chattogram, Bangladesh. The highest antimicrobial activity was found in the extract of Tetraselmis which exhibited an inhibitory effect against Aeromonas hydrophilia (1.99mm). Moreover, Chlorella showed the highest inhibitory activity against Staphylococcus (1.262mm). However, Nannochloropsis showed no sensitivity against any of these three bacteria. Chlorella showed the MIC value of 20mg/ml against Staphylococcus and Tetraselmis at 10mg/ml against Aeromonus hydrophila. The observed antimicrobial activities might be linked to the contents of the algal extracts containing valuable fatty acids, carotenoids, chlorophylls, hycocyanin, phycoerythrin, phycobiliprotein and phenolic compounds that need to be determined. The studied microalgae could be considered as a potential natural source of bioactive compounds with antimicrobial activities.
EFEECT OF DIFFERENT MICROALGAE ON GROWTH, SURVIVAL, WATER QUALITY AND NUTRITIONAL COMPOSITION ON JUVENILE TILAPIA (Oreochromis niloticus)
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2020-06) Jinat Afruj, Jinat
In the present study, two selected marine microalgae were combined to produce a high-performing feed for Nile tilapia (Oreochromis niloticus)—the world’s second largest group of cultivated fish. In this study, a feeding trial was conducted with fry of Nile Tilapia Oreochromis niloticus in which two types of microalgae such as Tetraselmis chuii and Nannochloropsis sp. were used for replacement of fish meal protein. Seven experimental diet containing two microalgae were formulated to replace 0%, 25%, 50% and 75% of fish meal where each assigned to three replicate tanks, and each tank was stocked with 30 fry of Nile Tilapia from their first feeding for 22 days indoor feeding trial. The results of this study showed that two experimental diet T50% and N75% were performed significantly (P < 0.05) to obtain high weight gain / better growth than the formulated feed with 100% fish meal. Survival rate was found significantly (P < 0.05) higher in all treatments than control. SGR and water quality were also significantly (P < 0.05) higher than the formulated diets. In addition, the protein, lipid and carbohydrate content in Nile Tilapia fry reared in tanks with T50% and N75% were higher than for fry grown in control tanks. Therefore, this study suggests that Nile Tilapia fry reared in tanks can gain nutrition from the selected microalgae. Moreover, the presence of microalgae in the tanks has also been shown to maintain low level of TAN and nitrite in the culture system. Thus, microalgae used as feed supplement practice in hatcheries can be considered as a viable technology. Hence, selected marine microalgae could be used as feed supplement in enhancing the growth and survival of Nile Tilapia fry.
COMPARISON OF SPAT (Crassostrea spp.) SETTLEMENT RATE, NUTRITIONAL COMPOSITION, AND ECONOMIC VIABILITY AMONG DIFFERENT SITES IN COX’S BAZAR COAST
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2020-06) Minhaz, Tashrif Mahmud
The spat settlement (spat density, recruitment, and mortality) of edible oyster Crassostrea spp. was estimated for the three sites (Nunia Chara– NC, Chowfoldandy– CD, and Sonadia Island– SI) located at Cox’s Bazar coast in Bangladesh, from February 2019 to January 2020, deploying shellstring. Field observations were made every 15 days to understand the monthly variation of oyster spat settlement more precisely. A number of 50 live oysters were collected randomly from each farms located at the three sites to assess proximate composition and fatty acid contents. Income, and expenditure data of the three farms were collected from District Fisheries Office, Cox’s Bazar to analyse economic viability of the farms. Both spatial, and temporal variability in spat settlement along with their interaction effect, as a function of prevailing environmental conditions were observed (p < 0.05). Highest spat density, and recruitment were observed at NC with a comparatively lower mortality (p < 0.05). On the other hand, temporal variability shows that spat recruitment, and mortality varied monthly with environmental fluctuations resulting in higher spat density from late October to mid-May. Distinct environmental gradients (salinity, temperature, pH, high tide, and low tide water depth, total suspended solids), and fouling organisms (seaweeds, sponges, marine macrophytes and bush like organisms, mussels, barnacles, other oysters, polychaetes, and oyster drills) were observed during the study, which affected the spat settlement. Spat density, recruitment, and mortality were significantly (p < 0.05) related to the environmental gradients. On the other hand, substrates at NC was mostly affected by seaweeds, sponges, other oysters, and sponges; CD was mostly affected by marine macrophytes and bush like organisms, mussels, barnacles, and polychaetes; SI was mostly affected by marine macrophytes and bush like organisms, other oysters, polychaetes, and oyster drills. Oysters of all the three farms had adequate quantity of proximate composition for human consumption, although protein, and carbohydrate content varied among the farms. All the fatty acid groups, and ratios were significantly different among the farms; however, omega-3 fatty acids were adequate at CD, while omega-6 fatty acids were much higher than the recommended level at NC, and SI. Out of the three oyster farms, SI was not economically viable for commercial oyster farming. Therefore, this study concludes that NC has higher potentiality of allocation for spat collection avoiding late May to mid-October both for commercial farming, and oyster restoration efforts; oysters of all the three farms have good quantity of proximate composition; fatty acids of oysters of CD farm shows better health benefits; NC, and CD farms will be economically viable for commercial oyster farming.
DEMONSTRATION OF MARINE MICROALGAE AS AN ALTERNATIVE TO ANTIBIOTICS AGAINST BACTERIAL DISEASES OF POULTRY
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2020-06) TurfatulJannat, Turfatul
Antimicrobial activity of the methanolic extract of dried marine microalgae Tetraselmis sp, Nannochloropsis sp. and Chlorella sp. was studied against Gram-negative Escherichia coli and Stenotrophomona smaltophilia and Gram-positive Staphylococcus saprophyticus. The largest inhibition zone (8.30 mm in diameter) appeared around the disc loading of extract of Chlorella against Escherichia coli. Moreover, Tetraselmis showed strong antimicrobial activity (20mg/ml) against Stenotrophomonas maltophilia, andChlorella against E. coli and Staphylococcus (10mg/ml).The observed antimicrobial activities might be linked to the contents of the extracts in fatty acid, carotenoids, chlorophylls, hycocyanin, phycoerythrin, phycobiliprotein and phenolic compounds that need to be determined. The studied microalgae could be considered as a potential natural source of bioactive compounds with antimicrobial activities
EFFECT OF DIFFERENT NITROGEN CONCENTRATIONS ON THE GROWTH, PROXIMATE AND BIOCHEMICAL COMPOSITION OF FRESHWATER MICROALGA Scenedesmus sp
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2021-06) Mukta, Fardous Ara
Scenedesmus sp. has grabbed attention nowadays due to its nutritious constituents such as protein, lipids, carbohydrates, and other vital trace elements, as well as potential viability as bioresource for application as fish feed, supplement, human consumption and biofuel production. Nitrogen plays an important role in microalgal cell growth, lipid accumulation, as well as production of protein, carbohydrate and pigments. The aim of this study was to enrich the growth, pigment, proximate and biochemical composition of freshwater microalgae Scenedesmus sp. cultured under different NaNO3 concentration. Scenedesmus sp. was cultured in five treatments of different NaNO3 concentrations as 13 g/L (T1), 19 g/L (T2), 25 g/L (control), 31 g/L (T3), and 37 g/L (T4) in Bold Basal Media having stationary phases on day 7, 8, 9, 10, 11 respectively. Significantly (p<0.05) maximum cell density (11.6×106 cells/ml), biomass productivity (0.58g/L), total chlorophyll, protein (23.58% dry weight) and carbohydrate (27.26% dry weight) were found in highest concentration (37 g/L) of NaNO3 compared to control and lower concentration. On the contrary, lowest (13 g/L) concentration of NaNO3 resulted in significantly highest lipid (20.92% dry weight), specific growth rate (0.521±0.01day-1), monounsaturated fatty acids (28.53% of total fatty acids) and polyunsaturated fatty acids (67.37% of total fatty acids). In case of carotenoid and total phycobiliprotein content, significantly (p<0.05) higher value of 6.43 mg/L and 6.14 mg/g, respectively were produced in control (25 g/L NaNO3) compared to other concentration of NaNO3. Significantly (p<0.05) highest value of total saturated fatty acids was found (56.51% of total fatty acids) in 31 g/L concentration of NaNO3. Therefore, higher concentrations of NaNO3 boosted the growth and nutritional profile in Scenedesmus sp. Moreover, lipid production and fatty acid profile were enriched by the lowest concentration of NaNO3 showing economic and sustainable commercial mass culture of Scenedesmus sp.
ISOLATION, MORPHOLOGICAL IDENTIFICATION AND CHARACTERIZATION OF INDIGENOUS MICROALGAE FROM DIFFERENT SOUTH-EASTERN FRESHWATER HABITAT OF BANGLADESH
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2021-06) Nayma, Zannatul
To utilize the enormous potentiality of indigenous microalgae, this study contains indices on isolation of some primordial freshwater microalgae and to determine their growth rate, pigments and proximate composition. For microalgae isolation, streak plating method in agar, serial dilution and capillary pipetting was performed and for the evaluation of growth performance, data were collected in terms of cell density and optical density. Selected microalgae (Nephrocytium sp., Nannochloropsis sp., Selenastrum sp., Sphaerocystis sp., Ankistrodesmus sp., Monoraphidium sp., Pectinodesmus sp. and Scenedesmus sp.) were mass cultured in commercial Bold Basal Medium (BBM), harvested at their stationary phases to determine the pigments content (chlorophyll-a, chlorophyll-b, carotenoid and phycobiliproteins) and proximate composition (protein, lipid and carbohydrate). Results showed that, onset of stationary phase (9–14 days) varied among the eight species where in the stationary phase; cell density was significantly higher (p˂0.05) in Nannochloropsis sp. All microalgae showed chlorophyll-a as the main pigment component, where Monoraphidium sp. showed significantly highest (p˂0.05) chlorophyll-a (11.264±0.065 μg/mL), b (2.082±0.067 μg/mL) and carotenoid content (8.05±0.07 μg/mL). Moreover, total phycobiliproteins was also significantly higher (p˂0.05) in Scenedesmus sp. (6.105±0.12 mg/g) and significantly lowest (p˂0.05) in Pectinodesmus sp. (1.152±0.012 mg/g) and Sphaerocystis sp. (1.296±0.007 mg/g). Significantly higher (p<0.05) amount of total protein was recorded in Nannochloropsis sp. (34.34±1.22 % dry weight) and significantly lower (p<0.05) in Scenedesmus sp. (21.77±2.17 % dry weight) and Ankistrodesmus sp. (24.26±0.78 % dry weight). Similarly, highest and lowest (p<0.05) amount of lipid content was recorded in Monoraphidium sp. (25.28±0.31 %dry weight) and Pectinodesmus sp. (11.79±0.27 %dry weight), respectively. In addition, carbohydrate content was highest (p < 0.05) in Pectinodesmus sp. These findings indicate that the microalgae assessed in this study have potential as multi-nutrient and pigments supplement, as well as can be manipulated for high protein, lipid and pigments production for the sustainable use of native species in aquaculture, pharmaceuticals and nutraceuticals industry
Antimicrobial Activity of Microalgae and Medicinal Plants against Common Bacteria Causing Diseases in Fish and Shellfish
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2021-06) Nusrat Zahan Sraboni, Nusrat Zahan
Antimicrobial activity of the ethanolic extract of dried marine microalgae Chlorella sp., and Spirulina sp. and dried medicinal plant Aloe vera (A. vera) and Clinacanthus nutans (C. nutans) were studied against three Gram-negative bacteria Aeromonas hydrophila, Vibrio sp., Escherichia coli and one Gram-positive bacteria Staphylococcus saprophyticus isolated from local fish, shrimp and crab by using disk diffusion technique. In this study, Spirulina sp. showed the highest inhibition zone of 19.3±0.577 mm against Vibrio sp. isolated from crab, whereas Chlorella sp. exhibited a maximum inhibition zone of 11.41±0.65 mm against S. saprophyticus. C. nutans displayed antibacterial activity against S. saprophyticus and E. coli with the maximum zone of inhibition (14.21±1.075; 15.103±0.214 mm), whereas A. vera against E. coli, Vibrio sp. with significant inhibition zone (14.037±0.903; 15.363±1.11 mm) respectively. The Minimum Inhibitory Concentration (MIC) of the extracts was determined against the test bacteria and the lowest concentration was revealed by Chlorella sp. at 20 mg/ml against all the test bacteria. MIC value of the Spirulina sp., A. vera, and C. nutans was recorded from 20 mg/ml to 40 mg/ml against the test bacteria. These results indicate the presence of promising antibacterial compounds in the plants and microalgae studied. Further phytochemical studies are needed to elucidate the active component responsible for the antibacterial activity of these extracts.
COMPARATIVE STUDY ON THE GROWTH, NUTRITIONAL COMPOSITION, PIGMENT AND HEMATO-BIOCHEMICAL INDEX OF NILE TILAPIA (Oreochromis niloticus) FRY FED WITH SELECTED MICROALGAE
(Chattogram Veterinary and Animal Sciences University Chattogram-4225, Bangladesh, 2021-06) Amira, Kafia Islam
An 8-week feeding trail was conducted to evaluate the effects of two selected marine microalgae strain Nannochloropsis sp. and Tetraselmis sp. on growth performance, water quality, hemato-biochemical index, carotenoid concentration, nutrition and biochemical composition of Nile tilapia Oreochromis niloticus fry (initial weight 0.023±0.0001 g, mean ± SE). Treatments were designed with five experimental diets: CF (0% microalgae which is control feed), N25 (25% Nannochloropsis sp.), T25 (25% Tetraselmis sp.), N50 (50% Nannochloropsis sp.) and T50 (50% Tetraselmis sp.) respectively. Two hundred seventy Nile tilapia fry were randomly assigned in 15 rectangular experimental tanks in triplicate form of each treatment. To find the data of growth performance initial and final body weight was recorded. To check the survivality initial and final number of fish was counted. Physical parameters of water quality were checked daily and chemical analysis of water quality parameters were done weekly. At the end of 8-week experiment, fish were sampled for determination of total carotenoid concentration, hemato-biochemical parameters, proximate composition and fatty acid profile of whole Nile tilapia fish tissue and significant (p < 0.05) changes of values were observed. The results revealed that supplemented microalgae alone could not significantly enhanced the growth performance than control (p < 0.05). Low palatability and antinutritional factors may be responsible. Significant high survival, better TAN, NO2-N and SRP was noticed in T25 than control (p < 0.05). The hemato-biochemical parameters exhibited significant increase of certain parameters within reference range, however significant decrease in some blood parameters was noticed also (p < 0.05). Although higher percentage of microalgae in diet has reduced the protein concentration in whole fish muscle compared to control but high lipid and carbohydrate was recorded in N50 and T50 treatment respectively. Comparatively higher carotenoid concentration was revealed in N50 than control. Increasing dietary Nannochloropsis sp. and Tetraselmis sp. has also significantly (p < 0.05) increased the percentage of saturated fatty acids (SAFs), polyunsaturated fatty acids (C20:5n-3, C22:6n-3 etc.) compared to control. Thus, this study provides significant information about beneficial impacts of Nannochloropsis sp. and Tetraselmis sp. on Nile tilapia fish.
PERFORMANCE CHARACTERIZATION OF SELECTED INDIGENOUS MICROALGAE ISOLATED FROM DIFFERENT MARINE AND FRESHWATER SOURCES OF BANGLADESH
(Chattogram Veterinary & Animal Sciences University, Khulshi,Chattogram, 2023-07) Dey, Proma
This study includes information on isolating some indigenous freshwater and marine microalgae and determining their growth rate, pigmennts, and proximate composition in order to take advantage of the great potentiality of local microalgae. For microalgae isolation streak plating method in agar, serial dilution and capillary pipetting was performed and for the evaluation of growth performance. Selected microalgae (Chlamydomonas sp., Navicula sp., Gonyostomum sp., Nannochloropsis sp., Choricystis sp., Chromochloris sp., Tetraedron sp., Chlorobotrys sp. Coelastrella sp., Kirchneriella sp. Oscillatoria sp1 and Oscillatoria sp4) were mass cultured in commercial Bold Basal Medium (BBM) and Conway Medium, harvested at their stationary phases to determine the pigments content (chlorophyll-a, chlorophyll-b, chlorophyll-c, carotenoid and phycobiliproteins) and proximate composition (protein, lipid and carbohydrate). Results showed that, onset of stationary phase (9–14 days) varied among the fourteen species where in the stationary phase, significantly higher (p˂0.05) cell density was observed in Gonyoatomum sp. All microalgae showed chlorophyll-a as the main pigment component, where Oscillatoria sp2 showed significantly highest (p˂0.05) chlorophyll-a (22.72±0.04 µg/mL). On the other hand, highest chlorophyll b (2.75±0.07 µg/mL) and carotenoid content (6.888±0.08 µg/mL) was recorded in Chlamydomonas sp. Moreover, total phycobiliproteins was also significantly higher (p˂0.05) in Oscillatoria sp4. (89.80±0.12 mg/g) and significantly lowest (p˂0.05) in Nannochloropsis sp. (0.89±0.04 mg/g). Significantly higher and lower (p<0.05) amount of total protein was recorded in Navicula sp. (59.5123±0.78% dry weight) and Krichneriella sp. (17.276±0.76 % dry weight), respectively. Similarly, highest and lowest (p<0.05) amount of lipid content was recorded in Gonyoatomum sp. (27.4±0.695 dry weight) and Oscillatoria sp3 (9.07±0.07%dry weight), respectively. In addition, carbohydrate content was highest (p < 0.05) in Kirchneriella sp. The results on amino acids and fatty acids revealed significant differences (p < 0.05) across these experimental species in numerous instances
ANTIMICROBIAL ACTIVITY OF SELECTED INDIGENOUS MICROALGAE AGAINST COMMON BACTERIA CAUSING DISEASES IN FISH AND SHELLFISH
(Chattogram Veterinary & Animal Sciences University, Khulshi,Chattogram, 2023-07) Nayeem, Jannatul
Antibiotic resistance is recognized as a "One Health subject," comprising human, animal, and environmental interactions, and has become a crucial public health concern. Cyanobacteria, a form of microalgae, recently emerged as one of the most promising sources of natural and eco-friendly antibiotics due to different secondary bioactive compounds. The antibacterial activity of phenolic extracts was assessed using the disk diffusion technique on four strains of Oscillatoria sp. which were isolated from two marine and two freshwater stations in Bangladesh. Three Gram-positive bacteria (Staphylococcus sp. and Streptococcus sp.) and nine Gram-negative bacteria (Escherichia coli, Vibrio sp., Salmonella sp., Shigella sp., Pseudomonas sp., Aeromonas sp.) were isolated from diseased marine fish, Shrimp and Crab and evaluated. Filamentous Oscillatoria sp. indicated higher antibiotic activity than planktonic one. Filamentous Oscillatoria sp. showed the highest inhibition zone 34.06±0.08mm against Staphylococcus sp., while planktonic Oscillatoria sp. showed lower inhibition zone against Pseudomonas sp. about 17.11±0.18mm. Minimum inhibitory concentration (MIC) value was found to be 100µg/ml for filamentous Oscillatoria sp., and 150 µg/ml for planktonic Oscillatoria sp. These findings suggest that, Cyanobacteria contain potential antibacterial substances which could be a better substitute for existing antibiotics and efficiently serve both the aquaculture and pharmaceutical industries. Keywords:
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 Kanti
A 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.
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, Sadia
Two 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.
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 Ranjan
Diseases, 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.
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, Methila
Increased 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.
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, Etu
Understanding 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.