Change of Rheoreaction and Concentration of Thyroid Hormones in Blood of Juvenile Rainbow Trout Oncorhynchus mykiss during Starvation

Changes in the Ratio of Rheoreaction Types during Fish Starvation

“…Therefore, we believe that a decrease in the experimental indicators of the swimming ability of fish at the beginning of starvation may be caused by the appearance of motivation to currentwise movement, and not only by a change in their physiological capabilities. This is consistent with the literature data; for example, in juvenile Alaska pollock Theragra chalcograma, the transition from active search behavior to (Pavlov et al, 2020a) -0.14 -0.57 -0.30 -0.23 -0.25 0.05 P. mykiss (=O. mykiss) (Pavlov, E. et al, 2016) 0.13 -0.21 -0.20 -0.03 -0.15 0.00 S. trutta labrax (Pavlov et al, 2010) -0.08 -0.18 -0.22 -0.09 -0.01 -S. trutta (Pavlov et al, 2018) -0.43 -0.62 -0.68 -0.58 -0.42 a decrease in motor activity occurred on days 30-54 of starvation (Sogard and Olla, 1996).…”

“…The contranatance index (I k ) represents the most vivid assessment of the dynamics of the migrationassociated changes in fish behavior. Table 2 shows the results of both this work and data previously obtained on individuals of the rainbow trout, brown trout, and its subspecies, the Black Sea trout (Pavlov et al, 2010(Pavlov et al, , 2018(Pavlov et al, , 2020aPavlov, Е. et al, 2016). At the beginning of starvation, all fish are characterized by an increased motivation for currentwise movement, and then, by that against the current.…”

“…Furthermore, to analyze and summarize the results, we used the initial data on control individuals, obtained by us in studies of the physiological and biochemical mechanisms of migration of the brown trout (Salmo trutta), Black Sea trout (Salmo trutta labrax), and rainbow trout (Pavlov et al, 2010(Pavlov et al, , 2018(Pavlov et al, , 2020aPavlov, E. et al, 2016). These individuals were not subjected to experimental effects (hormonal drugs or denial of access to shelters) either before or during the starvation.…”