caa a22 4500 606230572 CHVBK 20210128101215.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s10695-014-9999-3 doi (NATIONALLICENCE)springer-10.1007/s10695-014-9999-3 The onset of stress response in rainbow trout Oncorhynchus mykiss embryos subjected to density and handling [Elektronische Daten] [Gholamreza Ghaedi, Bahram Falahatkar, Vahid Yavari, Mohammad Sheibani, Gholamreza Broujeni] The present study made an attempt to measure the cortisol content, as an indicator of stress response, in rainbow trout embryos which were exposed to different densities and handling stress (air exposure) during incubation. The three densities of experimental embryos at early development stages were considered as 2.55embryos/cm2 (low density), 5.10embryos/cm2 (normal density) and 7.65embryos/cm2 (high density). The cortisol content of eggs (5.09±0.12ng/g) decreased to 3.68±0.14ng/g in newly fertilized eggs. Resting level of cortisol dropped at three densities by day 18 of post fertilization. Then, cortisol increased at hatching stage to 1.16±0.11, 1.20±0.12 and 1.21±0.14ng/g at low, normal and high densities, respectively. There were no statistically significant differences between cortisol concentrations in three densities. The acute handling stress test (5-min out-of-water), conducted on embryos (48h post fertilization, organogenesis and eyed stage) in three densities, revealed no differences in whole-body cortisol levels between stressed and unstressed experimental groups. At hatching stage in low-density group, level of cortisol increased but the difference with the pre-stress levels was not statistically significant. Furthermore, significant differences in cortisol levels of stressed and unstressed embryos were detected on hatching in normal and high density groups [1.20±0.12 at time 0-1.49±0.11ng/g at 1hps (hours post stress) and from 1.21±0.14 at time 0 to 1.53±0.10ng/g at 3hps, respectively]. The results showed no difference in profile of cortisol in different densities, but acute stress conducted on embryos, incubated in different densities, revealed differences in cortisol stress response at hatching between normal and high density, which lead to cortisol increase at hatching time. It indicates that the lag time in the cortisol response to stressors immediately after hatching does not occur when the siblings were stressed during the embryo stage. Results, finally, indicated that hypothalamus-pituitary-interrenal axis was active and responded to an acute stressor under normal and high density, but it is unresponsive to a stressor around hatching under low density. Springer Science+Business Media Dordrecht, 2014 Cortisol nationallicence Stress nationallicence Density nationallicence Embryo nationallicence Incubation nationallicence Rainbow trout nationallicence Ghaedi Gholamreza Fisheries Department, Faculty of Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Khouzestan, Iran aut Falahatkar Bahram Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Guilan, Iran aut Yavari Vahid Fisheries Department, Faculty of Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Khouzestan, Iran aut Sheibani Mohammad Basic Sciences Department, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran aut Broujeni Gholamreza Pathobiology Department, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran aut Fish Physiology and Biochemistry Springer Netherlands 41/2(2015-04-01), 485-493 0920-1742 41:2<485 2015 41 10695 https://doi.org/10.1007/s10695-014-9999-3 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10695-014-9999-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ghaedi Gholamreza Fisheries Department, Faculty of Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Khouzestan, Iran aut NATIONALLICENCE 700 1- Falahatkar Bahram Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Guilan, Iran aut NATIONALLICENCE 700 1- Yavari Vahid Fisheries Department, Faculty of Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Khouzestan, Iran aut NATIONALLICENCE 700 1- Sheibani Mohammad Basic Sciences Department, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran aut NATIONALLICENCE 700 1- Broujeni Gholamreza Pathobiology Department, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran aut NATIONALLICENCE 773 0- Fish Physiology and Biochemistry Springer Netherlands 41/2(2015-04-01), 485-493 0920-1742 41:2<485 2015 41 10695