Impact of parasitism on thermal preferences and response to thermal stress in Colossoma macropomum: an ecological and physiological investigation

• Grant number: 23/13869-7
• Support Opportunities: Scholarships in Brazil - Program to Stimulate Scientific Vocations
• Start date: January 04, 2024
• End date: February 23, 2024
• Field of knowledge: Biological Sciences - Physiology - General Physiology
• Principal Investigator: Adalberto Luis Val
• Grantee: Eduardo Kenyu Okido Matsumoto
• Host Institution: Instituto Nacional de Pesquisas da Amazônia (INPA). Ministério da Ciência, Tecnologia e Inovação (Brasil). Manaus , SP, Brazil

Abstract

The student will develop their activities with the project entitled "Impact of Parasitism on Thermal Preferences and Response to Thermal Stress in Colossoma macropomum: An Ecological and Physiological Investigation". Temperature is one of the most important factors for aquatic ectotherms, and in most fish, body temperature is controlled by ambient temperature, so some organisms have developed thermoregulatory mechanisms to survive and optimize temperature-dependent physiological processes. With the current challenges of climate change, understanding the responses of aquatic organisms becomes even more crucial. Increased thermal variability in aquatic ecosystems can have significant impacts on the health and adaptation of these animals. Results with tambaqui indicate that increased temperature and CO2 cause a high level of monogenea parasitism in the gills, causing damage to the immune and osmoregulatory systems. Therefore, this study aims to investigate how parasitism can affect the thermal preferences and response to thermal stress of Colossoma macropomum.The student will develop an experiment where two groups of fish will be used; one infected and one not infected by monogenea, with 10 individuals in each group. Thermal preference will be assessed in a system that offers temperature gradients, allowing fish to choose between different thermal niches. After a period of acclimatization to the ambient temperature, thermal niches will be created using a heating system. During the 6-hour daily experiment for each group, the animals' transition between thermal niches will be recorded every 1 hour to determine the preferred temperature. After the experiment, blood will be collected from the animals for hematological analysis and muscle, liver and gill tissues will be collected for expression analysis of genes related to heat stress (hsp70 and hsp90). This study offers a valuable perspective on how parasitism may interact with thermal preference and stress responses, providing crucial insights into the ecology, survival and conservation of this species. The student will be inserted into a context of ongoing research, which is evaluating the impact of parasitism on thermal preference and tolerance in the physiological, behavioral and immunological responses of Amazonian fish species. Furthermore, the experiment developed should deepen the knowledge base already acquired by the student and expand their set of work tools. (AU)