The purpose of the study was to investigate the proximate composition and mineral content of Bangladesh's economically important freshwater and marine water fish. Proximate composition and mineral content was determined according to the Association of Official Agricultural Chemists (AOAC) standard method. All of the factors had a substantial variation (p < 0.05), according to the findings. The maximum protein content was observed in Lates calcarifer (18.673%) and minimum in Pangasius pangasius (15.616%). The content of lipid among the species varied from 0.316% to 13.396%, with Mugil cephalus having the highest lipid content and Channa striata having the lowest. The moisture content ranges from 68.343% to 81.160%. All the fishes have an average ash content of 0.850%–4.350%. The energy content is also significantly higher in marine water fishes. The mineral content was highly variable. Calcium content was lowest in Pangasius pangasius (0.555%) and highest in Setipinna phasa (3.495%). The magnesium content ranged between 0.281% and 1.885%. Phosphorus was lowest in Lepturacanthus savala (0.826%) and highest in Setipinna phasa (2.114%). The amount of sodium, potassium, and sulfur was relatively less for all fish species but there were substantial differences across the twelve samples. The PCA biplot's for proximate composition analyses has demonstrated positive affinity only between Lates calcarifer and Mugil cephalus in case of ash, lipid, and carbohydrate whereas Setipina phasa, Mugil cephalus, Lutjanus lutjanus, and Oreochromis mossambicus were grouped together with magnesium, phosphorus, calcium, and sulfur in the case of mineral content. Overall, the marine water fishes can be a good food item in terms of nutrition which could provide better health benefits for human.

Seaweeds have become the focus of experts in recent years due to their biological characteristics and the variety of uses they have for both humans and animals. Biochemical composition, amino acids, fatty acids, and phenolic components were analyzed to explore the nutritive value of Gracilariopsis longissima, Padina tetrastromatica, and Ulva intestinalis from the Bay of Bengal, Bangladesh coast. Proximate composition and mineral content were determined according to the AOAC method. The high-performance liquid chromatography amino acid analysis system was used for the amino acid analysis and the fatty acid profile of the extracted oils was assessed as their methyl esters. The Folin–Ciocalteu technique was used to estimate the phenolic content and the aluminum chloride colorimetric technique was used to calculate the total flavonoid content. The three different species of seaweed had significantly different proximate compositions (P < 0.05), with G. longissima having the highest protein content. Except for sulfur, the mineral contents were likewise considerably higher (P < 0.05) in G. longissima. Although the amounts of the essential amino acids were greater than 50 % of the total amino acids in the three studied seaweed species, the total amino acid composition of these three species differed significantly (P < 0.05). The findings indicated that lipid levels were low in all the assessed species, but unsaturated fatty acid levels were high, with G. longissima exhibiting the highest amounts. The results showed that, compared to the other species, G. longissima had a substantially higher (P < 0.05) level of total phenolic and flavonoid content. The three studied seaweed appear to be excellent for nutrition based on their overall nutritional profiles. However, due to high protein, unsaturated fatty acid, essential amino acid, and total phenolic and flavonoid content, G. longissima is the most promising seaweed that will be helpful for pharmaceutical and multifunctional food applications.

The aim of the present study was to evaluate the water quality, growth performance, body composition, length–weight relationship, condition factors and benefit–cost analysis of giant freshwater prawn (Macrobrachium rosenbergii) cultured with biofloc system in pond conditions. The experiment was conducted in twelve (12) experimental ponds, each measuring 240 m². The control group was cultured without any biofloc (T₁), and biofloc‐based three treatments were biofloc with 100% feed (T₂), biofloc with 90% feed (T₃) and biofloc with 80% feed (T₄). The biofloc‐based treatments showed significantly higher floc volume, total suspended solids, total heterotrophic bacteria and plankton density than the control (p < 0.05). All the growth parameters were significantly higher in biofloc‐based treatments (T₂, T₃ and T₄) than in the control (T₁). The lowest feed conversion ratio was found lowest in T₄ (1.40 ± 0.02) and highest in T₁ (2.13 ± 0.04), which was significantly different among the treatments (p < 0.05). The significantly highest production was obtained 939.02 ± 6.61 kg/ha in T₂, and the lowest was 779.67 ± 7.50 kg/ha in T₁. The length–weight relationship indicated positive allometric growth in all treatments. The condition factor ranged from 0.95 to 1.07, showing that the prawns were in good health throughout all treatments. The results of the present study indicated that M. rosenbergii can adapt to a biofloc‐based aquaculture system, and the conventional feeding rations can be reduced up to 20% without affecting the growth and production.

In this study, the nutritional and phytochemical components of red seaweed, Gracilariopsis longissima, were assessed in relation to the effects of various drying methods (freeze, oven, and sun). Gracilariopsis longissima’s proximate composition differed significantly ( < 0.05) among the three drying techniques, with freeze-dried samples having significantly greater protein (30.63 ± 0.90% dry weight) and lipids (1.49 ± 0.05% dry weight) contents. Except for phosphorus and sulfur, the mineral concentrations were likewise considerably greater in the freeze-dried samples. The total amino acids (30.48 ± 0.06% dry weight) and fatty acids contents were substantially greater ( < 0.05) in the freeze-dried samples. In freeze-dried samples, the levels of essential amino acids (18.92 ± 0.02% dry weight) and unsaturated fatty acids (54.08 ± 0.07%) were substantially greater ( < 0.05). When compared to oven- and sun-dried samples, the total phenolic content (88.70 ± 2.19 mg GAE/g dry weight) and the flavonoid content (71.46 ± 2.17 mg QE/g dry weight) of freeze-dried samples was also substantially higher. Among the three distinct drying techniques used, the freeze-drying technique kept G. longissima’s higher nutritional and phytochemical components.