The growing global demand for fish necessitates the exploration of sustainable aquaculture practices. This has led to a focus on the quality and sustainable production of fish products with minimal environmental impact. Thus, the objective of this review is to study and evaluate how different aquaculture systems impact the quality and nutritional profile of fish. Fish are rich sources of protein, containing almost 20% protein and essential amino acids and vitamins. The nutritional value and quality of fish products are directly related to the conditions under which they are produced through aquaculture. This article considers various aquaculture systems, including closed-loop systems, pond farming, marine aquaculture, and aquaponic systems. The operating principles, advantages, and inherent limitations of each fish-rearing system are subjected to rigorous critical analysis in this review. Such practices are necessary to meet the growing demand for fish and to maintain the integrity of aquatic ecosystems for future generations.

The foliar feeding of soil-grown plants with essential elements such as molybdate can restore their Nitrate reductase activity. However, the activity of nitrate reductase under the foliar feeding of plants with molybdate and nitrate in hydroponic conditions has not been investigated. Thus, we wanted to investigate the effect of the foliar feeding of molybdate and nitrate on the nitrate reductase activity in the leaves of lemon balm plants under hydroponic conditions. Nitrate and molybdate solutions were applied by spraying the leaves of lemon balm plants and the nitrate reductase activity was determined by the colorimetric method. The results of our study demonstrated that the application of molybdate and KNO₃ solution enhanced the nitrate reductase activity in the leaves of lemon balm plants. Importantly, our results indicate that foliar fertilization with nitrate and molybdate can improve nitrogen metabolism and carbon fixation in the leaves of lemon balm plants under hydroponic conditions.