Matheus Barp Pierozan

This study aimed to evaluate the economic feasibility of implementing an aquaponic system using different stocking densities of tilapia juveniles integrated with arugula production in a Nutrient Film Technique (NFT) system. To gather data for the economic analysis, an experiment was conducted using a completely randomized 3 x 2 factorial design (densities: 20, 40, and 60 fish/m³; filter media volumes: 50 and 70 liters of expanded clay), with three replications. Each experimental unit consisted of an NFT aquaponic module. The economic analysis included calculations of net present value, internal rate of return, profitability index, and payback period. Results showed that fish stocking density significantly affects the economic viability of an aquaponic system integrating tilapia juveniles and arugula production. The price of arugula increased with higher fish stocking densities, while the price of fish remained unaffected. Stocking densities of 40 and 60 fish/m³ were found to be economically feasible, exhibiting similar internal rates of return, both higher than those observed at a density of 20 fish/m³, which was not economically viable.

Fish production faces various challenges throughout its cycle, from rearing to consumption. Organic acids have emerged as an effective fish feed and meat treatment solution. They promote health and well-being, control pathogens, improve digestion, and contribute to food preservation. This study was therefore carried out to evaluate the evolution of publications on the use of organic acids in aquaculture over time, identifying the leading journals, authors, countries, and relevant organizations associated with the publications and determining the keywords most used in publications and research trends on this type of accommodation using bibliometric analysis. For this analysis, the Web of Science (WoS) and Scopus databases were used, with the keywords and Boolean operators “organic acid*” AND (“pathogens” OR “microorganism*” OR “bacteria” OR “fungi”) AND (“fish” OR “fry” OR “pisciculture”). Ninety-six articles were found in 44 journals, with the participation of 426 authors and 188 institutions, from 1995 to 2024. The most crucial publication source with the highest impact factor was the journal Aquaculture, with 14 articles, 2 of which were written by the most relevant author, Koh C., who received the highest number of citations and had the highest impact factor among the 426 authors. China had the most scientific production, with 26 publications on organic acids in aquaculture. However, Malaysia was the country that published the most cited documents, a total of 386. The most relevant affiliation was the University of Sains Malaysia, which participated in the publication of eight articles. The 10 most frequent keywords were fish, organic acids, citric acid, article, bacteria, growth, microorganisms, Oncorhynchus mykiss, animals, and digestibility. The results indicate increased publications on the benefits of using organic acids in aquaculture, highlighting their effectiveness as antibacterial agents and promoters of zootechnical development. However, gaps still require more in-depth research into the ideal dosages, mechanisms of action, and long-term impacts of these compounds.

The preservation of fish and seafood represents a significant challenge for the food industry due to these products’ high susceptibility to microbial spoilage. Essential oils (EOs), classified as Generally Recognized as Safe (GRAS), have become a natural alternative to synthetic preservatives due to their antimicrobial and antioxidant properties. This review aims to analyze the specific potential of EOs in extending the shelf life of fish and seafood products, offering a natural and effective preservation solution. It provides a detailed overview of EOs applications and mechanisms, highlighting their role in controlling spoilage microorganisms while maintaining product quality. The main methods of EOs application include immersion, spraying, and pipetting, with antimicrobial effectiveness influenced by factors such as concentration, exposure time, and food characteristics like chemical composition and biofilms. Direct EOs application shows challenges that can be countered by exploring nanoemulsion technology as an effective strategy to enhance EOs stability and controlled release, maximizing their preservation impact. Additionally, coatings made from chitosan, gelatin, Farsi gum, and carrageenan, combined with EOs such as oregano, clove, and thyme have shown efficacy in preserving species like rainbow trout, mackerel, and shrimp. However, the commercial feasibility of using EOs in fish preservation depends on consumer acceptance and regulatory compliance. This review offers valuable insights for the industry and researchers by highlighting the practical applications and commercial challenges of EOs in seafood products, underscoring the importance of consumer acceptance and regulatory adherence for market viability.

This study investigated the antimicrobial effects of lactic acid (LA) (3%) and peracetic acid (PA) (300 ppm) on tilapia fillets (Oreochromis niloticus) by fogging (15 min) or by immersion (2 s) in a pool of Escherichia coli (NEWP 0022, ATCC 25922, and a field-isolated strain), Staphylococcus aureus (ATCC 25923 and a field-isolated strain), and Salmonella Typhimurium (ATCC 13311 and ATCC 14028), as well as the effects on the physicochemical characteristics of the fillets. Fogging was effective and the best application method to control S. Typhimurium regardless of the acid used, promoting reductions of 1.66 and 1.23 log CFU/g with PA and LA, respectively. Regarding E. coli, there were significant reductions higher than 1 log CFU/g, regardless of the treatment or acid used. For S. aureus, only immersion in PA showed no significant difference (p < 0.05). For other treatments, significant reductions of 0.98, 1.51, and 1.17 log CFU/g were observed for nebulized PA, immersion, and LA fogging, respectively. Concerning the pH of the samples, neither of the acids used differed from the control. However, treatments with LA, and fogging with PA, reduced the pH compared to immersion in PA. As for color parameters, L* and a* values showed changes regardless of the acid or method used, resulting in an improved perception of fillet quality. These results indicate that fogging and immersion are alternatives for reducing S. Typhimurium, E. coli, and S. aureus in tilapia fillets.

Aquaculture produces more than 122 million tons of fish globally. Among the several economically important species are the Serrasalmidae, which are valued for their nutritional and sensory characteristics. To meet the growing demand, there is a need for automation and accuracy of processes, at a lower cost. Convolutional neural networks (CNNs) are a viable alternative for automation, reducing human intervention, work time, errors, and production costs. Therefore, the objective of this work is to evaluate the efficacy of convolutional neural networks (CNNs) in counting round fish fingerlings (Serrasalmidae) at different densities using 390 color photographs in an illuminated environment. The photographs were submitted to two convolutional neural networks for object detection: one model was adapted from a pre-trained CNN and the other was an online platform based on AutoML. The metrics used for performance evaluation were precision (P), recall (R), accuracy (A), and F1-Score. In conclusion, convolutional neural networks (CNNs) are effective tools for detecting and counting fish. The pre-trained CNN demonstrated outstanding performance in identifying fish fingerlings, achieving accuracy, precision, and recall rates of 99% or higher, regardless of fish density. On the other hand, the AutoML exhibited reduced accuracy and recall rates as the number of fish increased.