Effects of acute thermal stress on acid-base regulation, haematology, ion-osmoregulation and aerobic metabolism in Channel Catfish (Ictalurus punctatus)

Authors: ALLEN, PETER - Mississippi State University; STEWART, HEATHER - Mississippi State University; ABOAGYE, DAIEL - Mississippi State University; RAMEE, SHANE - Mississippi State University

Submitted to: Aquaculture Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2019
Publication Date: 5/17/2019
Citation: Allen, P.J., Stewart, H.A., Aboagye, D.L., Ramee, S.W. 2019. Effects of acute thermal stress on acid-base regulation, haematology, ion-osmoregulation and aerobic metabolism in Channel Catfish (Ictalurus punctatus). Aquaculture Research. 50:(2133-2141). https://doi.org/10.1111/are.14093.
DOI: https://doi.org/10.1111/are.14093

Interpretive Summary: Catfish grown commercially in the southern United States can experience periodic acute increases in water temperature, but their physiological response to acute thermal stress is unknown since they appear to tolerate high temperatures. Researchers at Mississippi State University evaluated the physiological responses to different levels of thermal stress in channel catfish. Channel catfish were resilient to high temperature, but show many physiological changes related to responses to a stressor at high temperatures. This information is important for understanding environmental limitations of the species and designing production management strategies.

Technical Abstract: The Channel Catfish Ictalurus punctatus is an important ecological, recreational and aquaculture species. In both natural and pond culture systems, Channel Catfish are periodically exposed to acute increase in temperature, especially in the summer, which may induce a stress response. With the effects of global climate change, the impact of rising temperatures on aquatic systems is expected to be exacerbated in the future. Hence, there is the need to understand the physiological mechanisms controlling the thermal stress response in fish. Acid–base, haematological, osmotic and metabolic regulations were investigated following acute temperature increase from 28°C to either 32°C or 36°C at a rate of 2°C/hr to assess the physiological response of Channel Catfish to temperature increase. Blood was sampled 1 hr after treatment temperatures were reached. When temperature increased from 28 to 32°C, blood bicarbonate (HCO-3) decreased while cortisol, partial pressure of carbon dioxide (pCO2) and glucose increased. When temperature increased from 28 to 36°C, blood pH, HCO-3, chloride, total proteins and mean corpuscular haemoglobin concentration decreased while cortisol, pCO2, haematocrit, haemoglobin, glucose, lactate, mean corpuscular volume and mean corpuscular haemoglobin all increased. The changes observed are characteristic of acute stress responses in fish and suggest that acute temperature increases to both 32 and 36°C are physiologically stressful to Channel Catfish