In vitro effects of increased temperature and decreased pH on blood oxygen affinity of 10 fish species of the Amazon

Abstract

Blood-O2 affinities (P50 ) were measured over a physiologically relevant pH range at 31 (highest temperature average of Rio Negro over the last 8 years), 33 and 35° C for 10 species of the Rio Negro, aiming to test the acute effects of temperature foreseen by the IPCC (Intergovernmental Panel on Climate Change) for coming years. The animals were collected during an expedition to the Anavilhanas Islands of the Rio Negro, 110 km upstream from Manaus (2° 23' 41″ S; 60° 55' 14″ W). Hoplias malabaricus showed higher blood-O2 sensitivity to pH changes (Bohr effect, Φ = Δlog10 P50 ΔpH(-1) ) at both 31° C (Φ = -0·44) and 35° C (Φ = -0·26) compared to Osteoglossum bicirrhosum (Φ = -0·54 at 31° C and Φ = -0·58 at 35° C), but lower P50 under most conditions, and a greater sensitivity of P50 to temperature. Two out of the 10 analysed species had significant increases of P50 (lower blood-O2 affinity) at the highest temperature throughout the pH range tested. For all other species, a minor increase of P50 over the assay-tested temperatures was observed, although all presented a normal Bohr effect. Overall, a diversity of intensities of pH and temperature effects on blood-O2 affinities was observed, which seems to be connected to the biological characteristics of the analysed species. Thermal disturbances in their habitats, likely to occur due to the global warming, would impair blood-O2 binding and unloading in some of the analysed fish species. Copyright © 2016 John Wiley & Sons, Ltd.

Weight-Length Relationship and Blood Characteristics of Silver Arowana, a Osteoglossidae From the State of Amapá (Brazil)

“…In O. bicirrhosum, the hematocrit and hemoglobin were similar to the values reported by Johansen et al (1978) for this same fish species. However, the hemoglobin and MCHC were higher that the values found by Val et al (2016). The function of hemoglobin is adapted to the metabolic needs of fish and the environment, including intrinsic changes in oxygen affinity, changes in content of allosteric effects and variation in interaction by the successive joints of the oxygen molecules (Galdames-Portus et al, 1979).…”

“…In addition, the levels of glucose are considered specific indicators of sympathetic activation during stress conditions, and cholesterol, triglycerides and total protein level are important indicators of the biochemical nutrition of fish (Hoseinifar et al, 2011;Rebl and Goldammer, 2018). In wild O. bicirrhosum, glucose levels were lower than those reported by Val et al (2016) for this same fish species, while the total protein, cholesterol and triglycerides levels were similar to those of farmed Arapaima gigas (Tavares-Dias et al, 2007). However, the concentrations of these metabolites may vary, in part, influenced by environmental and non-environmental factors such as feeding and mode of life of the fish, particularly related to locomotivity.…”

“…The hematological profile of a fish population can indicate its physiological status and health, so that hematology combined with other routine diagnostic methods could be used to identify and assess conditions that cause stress and/or diseases in fish (Tavares- Dias and Moraes, 2004;Ranzani-Paiva et al, 2013;Tavares-Dias, 2015;Bosisio et al, 2017;Barbieri et al, 2017;Fazio, 2019). Hence, blood parameters have been studied in different fish species (Wells et al, 1997;Tavares-Dias et al, 2007;Tavares-Dias, 2015;Val et al, 2016). It is known that the blood component values exhibit genetic and physiological variation.…”

“…The genetic variation may be due to interspecific factors between species and intraspecific factors within species. Moreover, changes in these blood parameters depend on several factors such as species, temperature, age, photoperiod, nutritional status, cycle of sexual maturity, health condition, water quality, dissolved oxygen changes, gender, lotic or lentic environment, handling stress and transportation, size, feeding and stocking density, and microbial infection and parasitism (Tavares-Dias and Moraes, 2004;Ranzani-Paiva et al, 2013;Val et al, 2016;Fazio, 2019).…”

“…For O. bicirrhosum from the Solimões River, in the State of Amazonas, Galdames-Portus et al (1979) studied the functional properties of hemoglobin, and Johansen et al (1978) described the hematocrit and hemoglobin. Recently, Val et al (2016) reported glucose level, hematocrit and hemoglobin of O. bicirrhosum from the Negro River, in the State of Amazonas. Since the health status of a fish population can be evaluated through the determination of blood characteristics, as this specifies the ideal physiological condition in a certain population, this study investigated blood and biochemistry parameters of O. bicirrhosum from the Preto River, in the State of Amapá (Brazil).…”