Interest and concern about rearing methods and their impact on animal welfare have increased. Production evaluation is population-based, and animal welfare analysis should be similar. In fish, the most common welfare indicators are gill state, fin damage, and body condition. The objective of this study was to evaluate the feeding rate effect on the welfare indicators of Oreochromis niloticus using an epidemiological approach. Five growth stages (from 1.2 to 360 g) were studied using four feeding rates as treatments: underfeeding (80%), recommended feeding (100%), and two levels of overfeeding (120% and 140%). The evaluated welfare indicators include the presence of lesions in different body areas and fins, the decrease in body condition index, and their impact on biomass production. Incidence and relative risk were determined for each indicator. Statistically significant associations were found in the indicators of mortality, weight, body condition (K), and presence of evident damage in the caudal and anal fin in all stages. The results showed that the feed rate directly affects the welfare indicators and production. Mortality, weight reduction, K reduction, and caudal and anal fin damage incidence showed to be relevant indicators in all O. niloticus growing stages. As a result of this study, the epidemiological approach seems to be a valuable tool for production. A risk traffic light method is a proposal that could have great potential, with the suggested limits for WI's concerning the individuals present in the culture pond, allowing progressive evaluation and decision-making to correct risky situations.

Introduction: Animal welfare is a critical component of sustainable production systems, affecting ethical practices and product quality. This review aims to clarify the concept of animal welfare, particularly regarding the mental state highlighted by the World Organization for Animal Health.Methods: A comprehensive literature review was conducted, focusing on studies published between 1980 and 2024. Databases used included CAB Abstracts, Scopus, PubMed, ISI Web, Scielo, Google Scholar, and specialized websites for scientific and technical information dissemination. The search incorporated keywords such as animal, sentience, consciousness, intelligence, freedoms, domains, indicators, measurement, hazard, risk factor, and management, all related to animal welfare.Results: This review presents a detailed analysis of the convergence and divergence between the Five Freedoms and the Five Domains, which are widely used for assessing animal welfare. The analysis identifies gaps in addressing the complexities of animal welfare, especially regarding mental states and risk factors.Discussion: This analysis introduces the EPI-DOM approach, a conceptual framework that integrates basic epidemiological concepts (EPI) with a new vision and classification of animal welfare domains (DOM). The EPI-DOM approach separates indicators measured in animals from external factors influencing their welfare, offering a more holistic evaluation that includes physical, mental, and behavioral dimensions. The framework incorporates risk factors, classified into the domains of management, environment, and interaction, making it a versatile tool for improving welfare assessment across species and production systems.Conclusion: The EPI-DOM framework provides a comprehensive and adaptable model for animal welfare evaluation, with potential to enhance management practices and ethical production. Future research should focus on validating and refining EPI-DOM across different species and production environments to optimize welfare and management strategies.

Five experimental diets containing different lipid sources, fish oil (D1), soybean lecithin (D2), corn oil (D3), canola oil (D4) and olive oil (D5), were evaluated in Atractosteus tropicus larvae for the relative gene expression of the enzymes fatty acid synthase (fas), acetyl‐CoA carboxylase 1 (acc1) and carnitine palmitoyltransferase 1C (cpt1c), in addition to their effects on larval growth, survival and cannibalism during a 30‐day feeding trial. Higher growth and survival were obtained in treatments D1 and D2, and lower performance in diets D3, D4 and D5. The highest levels of expression of fas and acc1 occurred in larvae fed with D1, which contained high amounts of n‐3 long‐chain polyunsaturated fatty acids (LC‐PUFA), mainly DHA and EPA FA are regulators of lipogenesis. The higher cpt1c expression in plant‐based diets is attributed to the fact that these diets are rich in α‐linolenic acid (ALA) and low DHA, EPA and ARA levels that favour ß‐oxidation. In conclusion, the diets with fish oil (D1) and soybean lecithin (D2) were the best treatments for larval growth, survival and cannibalism and thus appear to meet both lipid and energy requirements of A. tropicus larvae, meanwhile the use of vegetable oils influences the expression of intermediary lipogenic genes.

Aquaponics can be defined as the integration of hydroponic plant production in a recirculating aquaculture system and has been proposed as a sustainable method to control the accumulation of waste produced by fish farming. The objective of the present study was to determine the biomass production and its feed potential of Myriophyllum aquaticum, Limnobium laevigatum, Lemna minor and Salvinia molesta grown in aquaponics. To evaluate the chemical compositions of these species, dry matter, organic matter, crude protein, neutral detergent ber, acid detergent ber, lignin, ash, ether extract, gross energy, calcium, and phosphorus of the aquatic plants were determined. Based on the results of this study, aquatic plants are considered to fulfll most of the nutritional requirements of productive animal species. Therefore, it is feasible to use them as the main ingredient in whole animal rations, with an emphasis on Myriophyllum aquaticum and Lemna minor as alternative food sources for di erent animal species, opening the way to aquaponic fodder production. Aquatic plants are interesting alternative, unconventional feed sources, especially because their high growth rates and nutritional qualities make it feasible to use them for animal consumption. However, Salvinia molesta has no value as fodder, especially because of its lignin concentration, which could affect the fodder digestibility.