Continuous gastric saline perfusion elicits cardiovascular responses in freshwater rainbow trout (Oncorhynchus mykiss)

AbstractWhen in seawater, rainbow trout (Oncorhynchus mykiss) drink to avoid dehydration and display stroke volume (SV) mediated elevations in cardiac output (CO) and an increased proportion of CO is diverted to the gastrointestinal tract as compared to when in freshwater. These cardiovascular alterations are associated with distinct reductions in systemic and gastrointestinal vascular resistance (RSys and RGI, respectively). Although increased gastrointestinal blood flow (GBF) is likely essential for osmoregulation in seawater, the sensory functions and mechanisms driving the vascular resistance changes and other associated cardiovascular changes in euryhaline fishes remain poorly understood. Here, we examined whether internal gastrointestinal mechanisms responsive to osmotic changes mediate the cardiovascular changes typically observed in seawater, by comparing the cardiovascular responses of freshwater-acclimated rainbow trout receiving continuous (for 4 days) gastric perfusion with half-strength seawater (½ SW, ~ 17 ppt) to control fish (i.e., no perfusion). We show that perfusion with ½ SW causes significantly larger increases in CO, SV and GBF, as well as reductions in RSys and RGI, compared with the control, whilst there were no significant differences in blood composition between treatments. Taken together, our data suggest that increased gastrointestinal luminal osmolality is sensed directly in the gut, and at least partly, mediates cardiovascular responses previously observed in SW acclimated rainbow trout. Even though a potential role of mechano-receptor stimulation from gastrointestinal volume loading in eliciting these cardiovascular responses cannot be excluded, our study indicates the presence of internal gastrointestinal milieu-sensing mechanisms that affect cardiovascular responses when environmental salinity changes.

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The control of blood pressure during external hypercapnia in the rainbow trout (Oncorhynchus mykiss)

Journal of Experimental Biology ◽

10.1242/jeb.202.16.2177 ◽

1999 ◽

Vol 202 (16) ◽

pp. 2177-2190 ◽

Cited By ~ 9

Author(s):

S.F. Perry ◽

R. Fritsche ◽

T.M. Hoagland ◽

D.W. Duff ◽

K.R. Olson

Keyword(s):

Blood Pressure ◽

Cardiac Output ◽

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Vascular Resistance ◽

Venous Pressure ◽

Cardiovascular Responses ◽

Central Venous ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Blood Pressures

Adult freshwater rainbow trout (Oncorhynchus mykiss) were exposed acutely (approximately 20 min) in a stepwise manner to increasing levels of environmental carbon dioxide ranging between 1.7 and 9.0 mmHg (0.23-1.2 kPa). Experiments were performed to examine, for the first time, the influence of hypercapnic acidosis on aspects of cardiovascular physiology including blood pressure, cardiac output and vascular resistance. Fish displayed dose (water CO(2) partial pressure) -dependent increases in ventral aortic (13–39 %) and dorsal aortic (17–54 %) blood pressures that reflected marked increases in systemic vascular resistance (16–78 %); branchial vascular resistance was unaffected by hypercapnia. At the highest level of hypercapnia (9.0 mmHg), central venous pressure was significantly elevated by 54 %. Although cardiac output remained constant, heart rate was significantly lowered by 4–7 beats min(−)(1) at the two highest levels of hypercapnia. To determine whether the cardiovascular responses to hypercapnia were being blunted by the stepwise increase in external P(CO2), a separate group of fish was exposed directly to a single step of hypercapnia (water P(CO2) 8.0 mmHg). The cardiovascular responses were similar to those exhibited by the more gradually exposed fish except that central venous pressure did not increase and the extent of the bradycardia was greater (13 beats min(−)(1)). After confirming the effectiveness of yohimbine in blocking the vasoconstrictory (α)-adrenoreceptors of the systemic vasculature, this antagonist was used as a tool to assess the importance of (α)-adrenoreceptor stimulation in promoting the cardiovascular responses during hypercapnia. Prior treatment of fish with yohimbine prevented the increased blood pressures and systemic vascular resistance during hypercapnia but did not influence the CO(2)-induced bradycardia. Plasma levels of catecholamines did not change during hypercapnia, and therefore the stimulation of the systemic (α)-adrenoreceptors presumably reflected increased sympathetic nerve activity. To determine whether the cardiovascular changes elicited by hypercapnia were related to acidosis-induced hypoxaemia, fish were exposed to hypoxia in a stepwise manner (water P(O2) 65–151 mmHg). The cardiovascular responses to hypoxia were markedly different from those to hypercapnia and consisted of pronounced increases in systemic and branchial vascular resistance, but only at the most severe level of hypoxia; ventral and dorsal aortic pressures were unaffected. The differences between the responses to hypercapnia and hypoxia, coupled with the smaller reductions in blood oxygen content during hypercapnia, support the hypothesis that the cardiovascular responses to CO(2) are direct and are unrelated to hypoxaemia.

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CARDIOVASCULAR RESPONSES TO SCYLIORHININ I AND II IN THE RAINBOW TROUT, ONCORHYNCHUS MYKISS, IN VIVO AND IN VITRO

Journal of Experimental Biology ◽

10.1242/jeb.191.1.155 ◽

1994 ◽

Vol 191 (1) ◽

pp. 155-166 ◽

Cited By ~ 1

Author(s):

J Kagstrom ◽

M Axelsson ◽

S Holmgren

Keyword(s):

Blood Pressure ◽

Cardiac Output ◽

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Systemic Vascular Resistance ◽

Vascular Resistance ◽

Cardiovascular Responses ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Initial Decrease

Changes in cardiac output, heart rate, dorsal aortic blood pressure and coeliac artery blood flow were measured in unrestrained rainbow trout, Oncorhynchus mykiss, following injections of the elasmobranch tachykinins scyliorhinin I and II. The resistance in the coeliac vascular bed and the total systemic vasculature were calculated from blood pressure and flow. In addition, isolated tails were perfused to investigate the effect of the peptides on the somatic vasculature. Scyliorhinin I (SCY I) produced a biphasic change in the coeliac vascular resistance: an initial decrease was followed by an increase. The decrease in coeliac vascular resistance was accompanied by a decrease in the total systemic vascular resistance, leading to an increased cardiac output. The ensuing increase in coeliac vascular resistance caused a slight increase in blood pressure. In the perfused tail, SCY I produced a marked increase in the somatic vascular resistance. Scyliorhinin II (SCY II) decreased the systemic vascular resistance, causing an increase in cardiac output. SCY II also caused a late increase in the coeliac vascular resistance, which led to hypertension and bradycardia. In vitro, SCY II produced a biphasic response in which an initial decrease in the somatic resistance was followed by a larger increase. The results demonstrate that exogenous SCY I and II are vasoactive peptides that act by different mechanisms in the rainbow trout cardiovascular system. Their actions also differ from the actions of substance P previously observed in the cod, Gadus morhua, and possibly involve a neural reflex.

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The predominant role of mucosal immunoglobulin IgT in the gills of rainbow trout (Oncorhynchus mykiss) after infection with Flavobacterium columnare

Fish & Shellfish Immunology ◽

10.1016/j.fsi.2020.01.044 ◽

2020 ◽

Vol 99 ◽

pp. 654-662 ◽

Cited By ~ 5

Author(s):

Pajongjit Tongsri ◽

Kaifeng Meng ◽

Xia Liu ◽

Zhengben Wu ◽

Guangmei Yin ◽

...

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Flavobacterium Columnare ◽

Predominant Role ◽

Rainbow Trout Oncorhynchus Mykiss

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The role of nitrosative and oxidative stress in rainbow trout (Oncorhynchus mykiss) liver tissue applied mercury chloride (HgCl2)

Ege Journal of Fisheries and Aquatic Sciences ◽

10.12714/egejfas.38.3.02 ◽

2021 ◽

Vol 38 (3) ◽

pp. 269-273

Author(s):

Mehmet Reşit Taysı ◽

Muammer Kırıcı ◽

Mahinur Kırıcı ◽

Hasan Ulusal ◽

Bünyamin Söğüt ◽

...

Keyword(s):

Oxidative Stress ◽

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Liver Tissue ◽

Stress Index ◽

Mercury Chloride ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Total Antioxidant ◽

Ld50 Value

The aim of this study was to determine oxidative stress caused by mercury chloride (HgCl2) in rainbow trout (Oncorhynchus mykiss) liver tissue. For this purpose, the LD50 value of HgCl2 on rainbow trout was determined as 551 μg/L. In the study, 40 fish in four groups were exposed to 25% and 50% (138 and 276 µg/L) of the two subletal doses of HgCl2 for 2 and 7 days, with 10 fish (n=10) in each group. To determine oxidative stress; peroxynitrite (ONOO−), total oxidant level (TOS), total antioxidant level (TAS), oxidative stress index (OSI) and malondialdehyde (MDA) were analyzed. In the study, it was observed that the differences between the groups in terms of ONOO−, TOS, TAS and OSI levels in the liver tissues was significant (P<0.05), however, this difference was not significant (P>0.05) in terms of MDA values. As a result, it can be concluded that HgCl2 increases ONOO−, TOS, TAS, OSI and MDA levels in liver tissue and even small doses of mercury are toxic to fish.

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Immune Response of Rainbow Trout (Oncorhynchus mykiss) to Selected Antigens of Yersinia ruckeri

Acta Veterinaria Brno ◽

10.2754/avb200978010145 ◽

2009 ◽

Vol 78 (1) ◽

pp. 145-150 ◽

Cited By ~ 4

Author(s):

Unal Ispir ◽

H. Bayram Gokhan ◽

Mikail Ozcan ◽

Mustafa Dorucu ◽

Naim Saglam

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Metabolic Activity ◽

Control Fish ◽

Phagocytic Index ◽

Control Group ◽

Yersinia Ruckeri ◽

Whole Cells ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Fish Group

In this study, effects of Yersinia ruckeri antigens on the immune mechanisms of rainbow trout (Oncorhynchus mykiss) were examined. The weight of the 120 fish used in this study was 20–30 g. After injecting 1 mg of formalin-inactivated whole cells (FKC) and O-antigen (Ag-O) intraperitoneally, blood was taken from the caudal vein of anaesthetized fish and metabolic activity of leukocytes (Nitroblue tetrazolium (NBT) activities), phagocytic activity (PA), phagocytic index (PI), serum protein and serum total immunoglobulin (TIg) levels were determined on day 30 after the first immunization. The same procedure was conducted in the control group. In all the experimental groups, considerable increases in the immune indicators were found and significant differences detected between the control and experimental groups (p < 0.05). Metabolic activity of leukocytes decreased significantly (p < 0.05) during the following treatment with antigens compared to the control fish group.

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The adrenergic volume changes of immature and mature rainbow trout (Oncorhynchus mykiss) erythrocytes

Journal of Experimental Biology ◽

10.1242/jeb.203.19.3025 ◽

2000 ◽

Vol 203 (19) ◽

pp. 3025-3031 ◽

Cited By ~ 1

Author(s):

T. Lecklin ◽

A. Tuominen ◽

M. Nikinmaa

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Large Fraction ◽

Control Fish ◽

Volume Distribution ◽

Volume Changes ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Before And After ◽

Volume Response ◽

Fluorescence Polarisation

In this study, we examined whether the adrenergic volume response of teleost erythrocytes is related to cell maturity. Rainbow trout (Oncorhynchus mykiss) were made anaemic by reducing their haematocrit to approximately 50 % of the original value. After 3–4 weeks, small, young erythrocytes were seen in the circulation. By measuring the volume distribution of blood samples from anaemic fish before and after noradrenaline stimulation (10 min, 10(−5)mol l(−1) final concentration), we were able to show that the volume response of young, immature erythrocytes to catecholamine stimulation was greater than that of mature erythrocytes. In addition, the membrane fluidity, measured using the steady-state fluorescence polarisation method, was greater in anaemic fish after 24 days of recovery from bleeding than in control fish. Since blood from anaemic fish contained a large fraction of immature erythrocytes, this result indicates that the fluidity of the membrane of immature erythrocytes is greater than that of mature erythrocytes.

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Use of respiratory-cardiovascular responses of rainbow trout (Oncorhynchus mykiss) in identifying acute toxicity syndromes in fish: Part 4. Central nervous system seizure agents

Environmental Toxicology and Chemistry ◽

10.1002/etc.5620100113 ◽

1991 ◽

Vol 10 (1) ◽

pp. 115-131 ◽

Cited By ~ 23

Author(s):

Steven P. Bradbury ◽

Richard W. Carlson ◽

Gerald J. Niemi ◽

Tala R. Henry

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Rainbow Trout ◽

Acute Toxicity ◽

Oncorhynchus Mykiss ◽

Cardiovascular Responses ◽

Rainbow Trout Oncorhynchus Mykiss

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Post-ovulatory secretion of pituitary gonadotropins GtH I and GtH II in the rainbow trout (Oncorhynchus mykiss): regulation by steroids and possible role of non-steroidal gonadal factors

Journal of Endocrinology ◽

10.1677/joe.0.1630087 ◽

1999 ◽

Vol 163 (1) ◽

pp. 87-97 ◽

Cited By ~ 15

Author(s):

J Chyb ◽

T Mikolajczyk ◽

B Breton

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Body Cavity ◽

The Body ◽

Ovarian Fluid ◽

Multiple Injections ◽

Rainbow Trout Oncorhynchus Mykiss

In order to determine the factors of ovarian origin which can modulate the postovulatory secretion of the FSH-like gonadotropin (GtH I) and the LH-like gonadotropin (GtH II), freshly ovulated female rainbow trout were divided into two groups. In the first group the fish were stripped in order to eliminate the eggs and ovarian fluid from the body cavity, while in the second group the eggs were kept in the body cavity. Subsequently, fish from both groups were implanted with testosterone (10 mg/kg), 17beta-estradiol (10 mg/kg) or 17,20beta-ddihydroxy-4-regnen-3-one (17,20betaP) (1 mg/kg) or injected every 2 days with desteroidized ovarian fluid (1.5 ml/kg). The secretion of GtH I dramatically increased in stripped fish, reaching its maximum levels 2 weeks after ovulation. The preservation of eggs in the body cavity led to the suppression of this increase. The profiles of GtH II secretion were opposite to those encountered for GtH I because the increase of GtH II was observed only in unstripped fish. The administration of steroids showed that testosterone is able to inhibit GtH I release and stimulate that of GtH II in stripped fish, having no effect on the release of these gonadotropins in non-stripped animals. 17beta-Estradiol failed to modify GtH I secretion, however it decreased the release of GtH II in fish containing retained eggs in the body cavity. 17,20betaP had a delayed stimulating influence on GtH I release in unstripped fish. Finally, multiple injections of desteroidized ovarian fluid into stripped fish led to a significant decrease of GtH I release and to an increase of GtH II secretion. This study demonstrates that factors, which are present in ovarian fluid, modulate the post-ovulatory secretion of both gonadotropins--their net action is negative on GtH I and positive on GtH II. Among the steroids, testosterone is of major importance, being able to inhibit GtH I release and to stimulate that of GtH II. We also show that non-steroidal factors present in the ovarian fluid can influence the release of both gonadotropins, which indirectly supports the previous findings about the existence of inhibin/activin-like factors in fish.

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