Influence of different DHA, EPA, and ARA ratios on the performance and lipid metabolism of tilapia juveniles kept at optimal and suboptimal temperatures.

• Grant number: 25/11942-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2025
• End date: August 31, 2027
• Field of knowledge: Agronomical Sciences - Fishery Resources and Fishery Engineering - Aquaculture
• Principal Investigator: Bruno Cavalheiro Araújo
• Grantee: Nurian Santos da Silva
• Host Institution: Pró-Reitoria Acadêmica. Universidade de Mogi das Cruzes (UMC). Campus da Sede Mogi das Cruzes. Mogi das Cruzes , SP, Brazil
• Associated research grant: 22/10972-9 - Metabolic and molecular responses of Oreochromis niloticus juveniles influenced by the interaction between temperature and diet composition, AP.JP

Abstract

Oreochromis niloticus (tilapia) is the most farmed fish species in Brazil. Although it has great potential to adapt to different farming conditions, optimal productive performance is achieved at elevated temperatures (27-30¿°C). However, the main production hubs in Brazil are located in the southern (western Paraná) and southeastern (western São Paulo) regions of the country, where temperatures during autumn and winter fall outside the optimal range for the species. This exposure to low temperatures often results in reduced growth and high mortality rates. Previous studies have shown improved growth and survival in fish species maintained at low temperatures and fed diets containing higher levels of long-chain polyunsaturated fatty acids (LC-PUFAs), especially docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3), and arachidonic acid (ARA, 20:4n-6). Similarly, recent studies have reported better performance in tilapia maintained at suboptimal temperatures and fed diets mainly containing DHA. However, the physiological mechanisms responsible for this improvement remain unclear. Additionally, despite promising results obtained in other species, no previous studies have evaluated the influence of ARA on the performance of tilapia kept at suboptimal temperatures. Therefore, this project aims to investigate the influence of different ratios of DHA, EPA, and ARA on the performance and lipid metabolism of tilapia reared at optimal and suboptimal temperatures. To this end, the study will assess productive performance, morphophysiology, and composition of lipogenic and lipolytic tissues, variables related to the immune system, and gene transcription (pathways of energy metabolism, immune response, and thermal stress). The results of this project will be essential for understanding the relationship between temperature and diet composition on the performance and metabolism of this species, supporting the aquaculture industry in developing strategies to mitigate the negative impacts of low temperatures. (AU)