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

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 (HCO3-) decreased while cortisol, partial pressure of carbon dioxide (pCO2) and glucose increased. When temperature increased from 28 to 36°C, blood pH, HCO3-, 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.

Climate Change Effects on Aquaculture Production: Sustainability Implications, Mitigation, and Adaptations

“…Therefore, prolonged temperature stress may affect aquaculture productivity through various ways centered on lowered output. For example, chronic stress may affect the neuroendocrine and osmoregulatory systems, altering cardiorespiratory performance and aerobic scope as well as immune responses of several economically important species (Brodie et al, 2014;Gazeau et al, 2014;Paukert et al, 2016;Stévant et al, 2017;Stewart et al, 2019;Zhang et al, 2019). Furthermore, metabolism and physiology, as well as feeding behavior and growth performance of most finfish and shellfish species are likely to be affected (Marcogliese, 2008;Akegbejo-Samsons, 2009;Lemasson et al, 2018).…”

Safety assessment of subchronic feeding of insect-resistant and herbicide-resistant transgenic soybeans to juvenile channel catfish (Ictalurus punctatus)

“…p < 0.05 indicates significant differences among the six experimental groups. www.nature.com/scientificreports/ Channel catfish is a valuable species that serve as an ideal model for physiological studies because of its ecological and economical importance 24 . The embryo or juvenile stage is the most important period in the life cycle, especially sensitive to environmental toxins 25 .…”

The effects of temperature and salinity on the blood chemistry and survival of juvenile Atlantic tarponMegalops atlanticus

“…Perhaps the most informative blood variable in this study was pH, which was highest at low temperature and low salinity but also elevated at low temperature and high salinity. Acid-base balance, which is indicated by blood pH, is extremely important to physiological processes, and extreme pH has been related to temperature effects on survival in other species (Dinken et al, 2022;Smit et al, 1981;Stewart et al, 2019).…”

“…Perhaps the most informative blood variable in this study was pH, which was highest at low temperature and low salinity but also elevated at low temperature and high salinity. Acid–base balance, which is indicated by blood pH, is extremely important to physiological processes, and extreme pH has been related to temperature effects on survival in other species (Dinken et al ., 2022; Smit et al ., 1981; Stewart et al ., 2019). Blood pH is known to generally relate inversely to temperature ( e.g ., decrease with increasing temperature) in water‐breathing and air‐breathing fishes (Cameron, 1978; Howell et al ., 1970; Rahn & Baumgardner, 1972).…”