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Acute stress response of Kootenai River white sturgeon Acipenser transmontanus Richardson reflected in peritoneal fluid and blood plasma
Journal of Fish Biology
Abstract
To evaluate whether stress-response indicators in blood plasma (BP) are similarly reflected in the peritoneal fluid (PF) white sturgeon Acipenser transmontanus were stressed by a 30 min air exposure and pH, PCO2, osmolality, cortisol, glucose and lactate levels measured. Changes in certain stress indicators in the BP (pH, PCO2, osmolality and glucose) also occurred in the PF, while stressor-induced changes in cortisol and lactate were restricted to the BP. Data suggest that PF is a modified ultrafiltrate of the blood and potentially a useful indicator of animal stress.
... The cortisol levels increased about threefold after stress in this study. Cortisol increased 2 to 5 times after acute stress in previous studies on different species of sturgeons (Webb et al., 2007;Zuccarelli et al., 2008). Maxime et al. (1995) reported that the amount of cortisol after hypoxia stress in Siberian sturgeon Downloaded by [Bahram Falahatkar] at 07:33 07 February 2014 increased sixfold compared with the prestress level. ...
... In the current study, the amount of cortisol returned to the prestress amount after 6 hr. Similar results have been observed in white sturgeon (Zuccarelli et al., 2008). Nonetheless, in most studies, cortisol returned to the initial level 12 hr to 24 hr after acute stress (Barton et al., 2000). ...
... In contrast to the results of previous studies, a delayed glucose response, compared to cortisol, was not observed in the present research. Similarly, a glucose peak has been recorded for some species including Siberian sturgeon, white sturgeon, and lake sturgeon at 1 hr or less poststress (Allen et al., 2009;Maxime et al., 1995;Zuccarelli et al., 2008). ...
A study was performed to investigate the influence of dietary lactoferrin (LF) on growth and stress responses of juvenile Siberian sturgeon. Fish were fed six experimental diets (0, 100, 200, 400, 800, and 1600 mg LF/kg diet) for 10 wk. At the end of the experiment, fish were exposed to an acute stressor of 2-min air exposure. The levels of cortisol, glucose, and lactate were measured before and at 1, 3, 6, 9, 12, and 24 h after stress. LF supplementation did not influence the fish growth. Cortisol and lactate, but not glucose level, were significantly affected by dietary LF. Cortisol levels in the control group rose twofold 1 h after stress and were significantly higher than that in LF groups. Moreover, the lowest level of cortisol at all sampling times (prestress and poststress) was observed in fish fed 400 mg LF/kg diet. Lactate concentrations in sturgeon fed 400 mg LF/kg markedly rose 1 h after stress, albeit changes in other LF groups were not significant. Results of this study show that dietary LF can suppress the stress responses in Siberian sturgeon, while 400 mg LF/kg diet appears to be an effective dietary level for this species to reduce stress.
... The cortisol levels increased about threefold after stress in this study. Cortisol increased 2 to 5 times after acute stress in previous studies on different species of sturgeons (Webb et al., 2007;Zuccarelli et al., 2008). Maxime et al. (1995) reported that the amount of cortisol after hypoxia stress in Siberian sturgeon Downloaded by [Bahram Falahatkar] at 07:33 07 February 2014 increased sixfold compared with the prestress level. ...
... In the current study, the amount of cortisol returned to the prestress amount after 6 hr. Similar results have been observed in white sturgeon (Zuccarelli et al., 2008). Nonetheless, in most studies, cortisol returned to the initial level 12 hr to 24 hr after acute stress (Barton et al., 2000). ...
... In contrast to the results of previous studies, a delayed glucose response, compared to cortisol, was not observed in the present research. Similarly, a glucose peak has been recorded for some species including Siberian sturgeon, white sturgeon, and lake sturgeon at 1 hr or less poststress (Allen et al., 2009;Maxime et al., 1995;Zuccarelli et al., 2008). ...
This study was carried out to investigate the effect of an acute stressor on the variation of some physiological and immunological parameters of Siberian sturgeon (Acipenser baerii) juveniles. Fish, reared in 3 tanks for 10 weeks, were used for this study. The acute stress of fish consisted of 2 min of air exposure stress. Plasma levels of cortisol, glucose, and lactate as well as lysozyme activity in plasma were measured before stress and 1 hr, 3 hr, 6 hr, 9 hr, 12 hr, and 24 hr after stress. The plasma cortisol significantly increased in the highest level 1 hr after stress, yet it gradually declined after 3 hr. The glucose significantly increased only 1 hr after stress. There was no significant difference between plasma lactate prestress and poststress. Moreover, lysozyme activity was enhanced by stress, thus reaching the highest level 9 hr after stress. The results of this study indicate that Siberian sturgeon not only have a rapid response to acute stress, but also a great capacity for recovery from stress, thus returning physiological parameters to prestress levels after 6 hr.
... This discrepancy points to an influence of sampling stress when evaluating the basal level of this parameter in sturgeons, as occurs in Teleosts (Barton, 1997;Wendelaar Bonga, 1997). Also in sturgeons, cortisol is indeed the main glucocorticoid secreted in response to stress (Webb et al., 2007) even though these ancient fish showed a greater resilience to common stressors than bony fish (Cataldi et al., 1998;Semenkova et al., 1999;Zuccarelli et al., 2008). In this field study, the sampling of these large sized fish involved some unavoidable pre-sampling opera-tions such as confinement, netting, handling, water removal and air exposure prior to blood sampling. ...
... Cortisol values of sturgeon hybrids are found to be similar to the levels reported for H. huso and A. gueldenstaedtii (Askarian and Kousha, 2009;Bayunova et al., 2002) but higher than the values of 2-20 ng ml )1 reported for A. baerii, Fig. 3. Mean values for blood chemistry parameters for 6-year-old hybrid sturgeon A. naccarii female · A. baerii male (closed circle) plotted with literature data for other species (open circle). Literature data were obtained from: Asadi et al., 2006aAsadi et al., ,b, 2009Askarian and Kousha, 2009;Baker et al., 2008;Bayunova et al., 2002;Belanger et al., 2001;Cataldi et al.,1998;Cech and Crocker, 2002;Di Marco et al., 1999;Furne´et al., 2009;Gessner et al., 2009;Gomulka et al., 2008;Hamlin et al., 2008;Knowles et al., 2006;Lankford et al., 2003;Maxime et al., 1995;Sanchez de la Madrid et al., 2000;Shahsavani et al., 2008;Shi et al., 2006;Wuertz et al., 2006;Zuccarelli et al., 2008 Blood chemistry reference values for sturgeon hybrids 587 ...
... A. brevirostrum, A. oxyrinchus and A. transmontanus (Hamlin et al., 2008;Wuertz et al., 2006;Baker et al., 2005;Zuccarelli et al., 2008;Belanger et al., 2001). The reference intervals of glucose (69-84 mg dl )1 ), NEFA (0.23-0.30 ...
Summary Blood chemistry profiles of cultured sturgeon hybrids Acipenser naccarii female × Acipenser baerii male were assessed in order to acquire basic data for evaluating fish health status on-farm. Sixty healthy fish (11.0 ± 3.2 Kg weight; 117.8 ± 8.6 cm total length) were randomly captured from 600 m3 concrete tanks and sampled from April to June. Blood samples were analyzed for the following 22 biochemical parameters using standard clinical methods: cortisol, glucose, lactate, non esterified fatty acids, triglycerides, cholesterol, albumin, creatinine, urea, total bilirubin, total protein, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatine phosphokinase, lactate dehydrogenase, calcium, phosphorus, magnesium, sodium, potassium and chloride. Biochemical values were found to be consistent with data from the parental species A. naccarii. Cortisol, cholesterol, albumin, urea, total bilirubin, CK, LDH and magnesium were significantly affected by sampling time and the differences are probably related to sexual maturation of the fish. Blood chemistry analyses afforded an accurate evaluation of sturgeons’ health status, also providing information on their reproductive conditions. Evidence resulting from cortisol and lactate values indicated that pre-sampling operations, including capture and confinement of these large-sized fish, must be carefully managed in order to minimize handling stress. This study provides knowledge on blood chemistry of hybrid sturgeon A. naccarii × A. baerii and the results corroborate the validity of the test panel performed in evaluating the physiological functions of sturgeons. Reference values for 22 biochemical parameters were identified for the purpose of evaluating health and welfare in cultured sturgeons.
... To assess physiological response to the air exposure, blood plasma samples were collected from each fish. Plasma cortisol levels were measured by radioimmunoassay as a part of the separate study (reported in Zuccarelli et al., 2008). ...
... Changes in the relative abundance of StAR mRNA in response to an acute stressor were assessed using quantitative real-time PCR analysis. Plasma cortisol levels significantly increased about 4-fold after 30 min of stressor from approximately 20 to 90 ng/ml (Zuccarelli et al., 2008) and gradually decreased towards the basal levels during the resting phase. However, the levels of StAR transcripts did not change from the control levels following the acute handling stressor (p = 0.524, Fig. 5). ...
... Li et al. (2003) demonstrated that a significant, but marginal, increase of StAR occurred after 90 min of an ACTH injection in Japanese eel. The present study showed no significant increase of StAR transcripts in yellow corpuscles of sturgeon following an acute stress, although the levels of plasma cortisol significantly increased 5-fold after 30 min post-stressor (see Zuccarelli et al., 2008). One of the fish sampled at 5 min post-stressor showed 5-fold higher StAR transcript levels compared to others at that timepoint, but it is likely that this fish had high StAR transcripts even before the stressor was given. ...
The white sturgeon, Acipenser transmontanus, is a primitive bony fish that is recognized as an important emerging species for aquaculture. However, many aspects of its stress and reproductive physiology remain unclear. These processes are controlled by various steroid hormones. In order to investigate the regulation of steroidogenesis associated with acute stress in sturgeon, a cDNA-encoding steroidogenic acute regulatory protein (StAR) was isolated from white sturgeon. The putative amino acid sequence of sturgeon StAR shares high homology (over 60%) with other vertebrates. Phylogenetic analysis grouped sturgeon StAR within Actinopterygii, but it was clearly segregated from teleost StARs. RT-PCR analysis revealed that transcripts were most abundant in yellow corpuscles found throughout the kidney and weaker signals were detected in gonad and kidney. Very weak signals were also detected in brain and spleen by quantitative real-time PCR. In situ hybridization revealed that StAR is expressed in the cells of yellow corpuscles. No significant changes in StAR gene expression were detected in response to an acute handling stress. These results suggest that StAR is highly conserved throughout vertebrates, but the expression of the functional protein during the stress response may be partially regulated post-transcriptionally.
... In particular, circulating lactate, glucose, plasma osmolality and Cl − were significantly higher in individuals that were treated for longer (Fig. 2). Similar physiological profiles have been demonstrated in sturgeons exposed to varying degrees of stressors (Semenkova et al., 1999;Kieffer et al., 2001;Bayunova et al., 2002;Baker et al., 2005;Zuccarelli et al., 2008;Beardsall et al., 2013). There was not a significant difference in cortisol between treatments, but given that cortisol has been shown to peak in white sturgeon~30 min after exposure to air (Zuccarelli et al., 2008), it is likely that maximal cortisol concentrations were not achieved as a result of blood sampling immediately after the stressor. ...
... Similar physiological profiles have been demonstrated in sturgeons exposed to varying degrees of stressors (Semenkova et al., 1999;Kieffer et al., 2001;Bayunova et al., 2002;Baker et al., 2005;Zuccarelli et al., 2008;Beardsall et al., 2013). There was not a significant difference in cortisol between treatments, but given that cortisol has been shown to peak in white sturgeon~30 min after exposure to air (Zuccarelli et al., 2008), it is likely that maximal cortisol concentrations were not achieved as a result of blood sampling immediately after the stressor. Likewise, a secondary stress response was elicited in sturgeon exposed to longer treatments, as indicated by elevated levels of circulating glucose, lactate, haematocrit, plasma osmolality and Cl − . ...
White sturgeon (Acipenser transmontanus) are anadromous and the largest fish occurring in freshwater habitats in North America. The largest population is found in the lower Fraser River (LFR), British Columbia, Canada where anglers target the species in a catch-and-release (C&R) recreational fishery. Yet, little is known about the consequences of C&R on these wild fish. Sixty-three angled sturgeon had blood samples taken to assess the physiological stress response relative to fight times. Seven sturgeon were also fitted with acoustic transmitters equipped with accelerometer sensors to assess immediate post-release locomotor behaviour. To understand the relationship between accelerometry and fish behaviour, we calibrated the tags in a lab before deploying them in the field. A physiological stress response was apparent (i.e., increased whole-blood lactate and reduced plasma potassium) and was influenced by fight time. Post-release activity profiles showed a general decrease in activity over time. Post-release displacement was 2-75 m from the release site and all 7 sturgeon were relocated closer to shore. The possible preference we identified for nearshore areas after release should be examined in greater detail in the future as this may lend insight into optimal release locations for white sturgeon. Although C&R mortality rates are low for this species, there is some evidence of transient sub-lethal effects emphasizing the need to refine C&R practices to further improve fish welfare.
... On peut noter que le sac vitellin des larves ou le fluide péritonéal pourraient être des sources non létales pour effectuer des analyses physiologiques chez l'esturgeon (Linares-Casenave et al., 2013 ;Zuccarelli et al., 2008). ...
... (3) Blood sampling is invasive but nonlethal. Other invasive and nonlethal samples could be achieved in future from the larval yolk sac or peritoneal fluid in adults, but further research needs to be conducted in sturgeon (Zuccarelli et al., 2008;Linares-Casenave et al., 2013). ...
Sturgeon farming is long and mainly directed toward the caviar production from oocytes. To increase aquaculture productivity, it is advantageous to raise females with little stress and in a good health status and welfare. Indeed, the energy allocation during fish development between different physiological compartments (growth, immunity, allostasis, reproduction) partly determines the growth rate, the risk of disease as well as the quantity and quality of oocytes. This thesis deals with biomarkers of cellular stress response, immunity and oxidative stress to assess stress, health and welfare of sturgeon. An experimentation designed to produce a gradient of welfare conditions which is based on a dietary supplementation and a heat-stress is presented and data analysis using uni- and multivariate analyzes is discussed. These results are also placed in a broader context from experiments in aquaculture conditions.
While it is interesting to raised sturgeon in good welfare, it is also relevant to select females as soon as possible. Currently, it's necessary to wait several years before moving male to the flesh production and to continue the raising of females until caviar production. Indeed, gonads of juveniles are indistinguishable and there is no sexual dimorphism. Meanwhile the sex of sturgeon is certainly determined by genetics and this thesis presents several methodologies to identify a genetic sex marker exploitable on three month old juveniles.
... However, Belanger et al. (2001) found a large cortisol response (increase from 8.6 ng/ml to ∼40 ng/ml) in mature WS, with a peak in cortisol concentrations occurring 30 min after the onset of a water reduction and air emersion stressor. Juvenile WS from the Kootenai River, also had a larger increase in plasma cortisol concentrations (5.6 ng/ml [15.4 nM] to ∼32.6 ng/ml [90 nM]) 60 min following a 30 min air exposure (Zuccarelli et al., 2008). Results of these studies and the current study suggest the cortisol response to stress is quite variable in sturgeons and likely dependent on various factors such as genetics, age, size and species of fish, duration and severity of stressor exposure and sampling time point (Reviewed in: Wendelaar Bonga 1997;Barton 2002;Martinez-Porchas et al., 2009;Pankhurst 2011). ...
... Like cortisol, basal levels of glucose and lactate appear to be variable even within the same species. Basal levels of plasma glucose and lactate in this study were comparable to concentrations in some rainbow trout (Gagnon et al., 2006;Gravel and Vijayan, 2007;Miller et al., 2007), but greater than those found in previous sturgeon studies ( Barton et al., 2000;Zuccarelli et al., 2008). Basal plasma lactate concentrations were also significantly lower in WS compared to trout in the study by . ...
Selenium (Se) is an essential micronutrient, but at low concentrations can be toxic to aquatic organisms. Selenomethionine (SeMeth) is the primary dietary form of Se aquatic organisms are exposed to and is an environmental concern because it persists and bioaccumulates. White sturgeon (WS) might be particularly susceptible to bioaccumulative toxicants, such as SeMeth, due to their longevity and benthic lifestyle. Se exposure is known to have adverse effects on the physiological stress response in teleosts, but these effects are unknown in WS. Therefore, the goal of this study was to determine effects of dietary SeMeth on the ability of WS to mount a stress response. Juvenile WS were administered food spiked with 1.4, 5.6, 22.4 and 104.4μg Se/g dry mass (dm) for 72days. Lower doses were chosen to represent environmentally relevant concentrations, while the high dose represented a worst case scenario exposure. On day 72, fish were subjected to a 2min handling stressor, and they were sampled at 0, 2 and 24h post-stressor. Cortisol, glucose and lactate concentrations were quantified in blood plasma and glycogen concentrations were quantified in muscle and liver. Transcript abundance of genes involved in corticosteroidogenesis and energy metabolism were determined using qPCR. Under basal conditions, WS fed 104.4μg Se/g dm had significantly greater concentrations of plasma cortisol and lactate, and significantly lower concentrations of plasma glucose and liver glycogen, compared to controls. Corticosteroid 11-beta dehydrogenase 2 (hsd11b2) abundance was lower in WS fed 22.4 and 104.4μg Se/g dm, indicating less conversion of cortisol to cortisone. Abundance of the glucocorticoid receptor (gcr) was significantly lower in high dose WS, suggesting lower tissue sensitivity to glucocorticoids. The increasing trend in phosphoenolpyruvate carboxykinase (pepck) abundance, with increasing SeMeth exposure, was consistent with greater cortisol and glucose concentrations in high dose WS. Exposure to an acute handling stressor elicited a typical cortisol response, but the magnitude of the response appeared to be significantly lower than those typically observed in teleosts. SeMeth also did not appear to modulate the cortisol response to a secondary stressor. However, WS exposed to 22.4μg Se/g dm and sampled 2h post-stressor, had significantly higher concentrations of muscle glycogen compared to controls, indicating effects on their ability to utilize muscle glycogen for energy. Overall, the results indicate that chronic exposure to dietary SeMeth concentrations >22.4μg/g can affect cortisol dynamics and mobilization of energy substrates in juvenile WS.
... In particular, circulating lactate, glucose, plasma osmolality and Cl − were significantly higher in individuals that were treated for longer (Fig. 2). Similar physiological profiles have been demonstrated in sturgeons exposed to varying degrees of stressors (Semenkova et al., 1999;Kieffer et al., 2001;Bayunova et al., 2002;Baker et al., 2005;Zuccarelli et al., 2008;Beardsall et al., 2013). There was not a significant difference in cortisol between treatments, but given that cortisol has been shown to peak in white sturgeon~30 min after exposure to air (Zuccarelli et al., 2008), it is likely that maximal cortisol concentrations were not achieved as a result of blood sampling immediately after the stressor. ...
... Similar physiological profiles have been demonstrated in sturgeons exposed to varying degrees of stressors (Semenkova et al., 1999;Kieffer et al., 2001;Bayunova et al., 2002;Baker et al., 2005;Zuccarelli et al., 2008;Beardsall et al., 2013). There was not a significant difference in cortisol between treatments, but given that cortisol has been shown to peak in white sturgeon~30 min after exposure to air (Zuccarelli et al., 2008), it is likely that maximal cortisol concentrations were not achieved as a result of blood sampling immediately after the stressor. Likewise, a secondary stress response was elicited in sturgeon exposed to longer treatments, as indicated by elevated levels of circulating glucose, lactate, haematocrit, plasma osmolality and Cl − . ...
White sturgeon (Acipenser transmontanus) are the largest freshwater fish in North America and a species exposed to widespread fishing pressure. Despite the growing interest in recreational fishing for white sturgeon, little is known about the sublethal and lethal impacts of angling on released sturgeon. In summer (July 2014, mean water temperature 15.3°C) and winter (February 2015, mean water temperature 6.6°C), captive white sturgeon (n = 48) were exposed to a combination of exercise and air exposure as a method of simulating an angling event. After the stressor, sturgeon were assessed for a physiological stress response, and reflex impairments were quantified to determine overall fish vitality (i.e. capacity for survival). A physiological stress response occurred in all sturgeon exposed to a fishing-related stressor, with the magnitude of the response correlated with the duration of the stressor. Moreover, the stress from exercise was more pronounced in summer, leading to higher reflex impairment scores (mean ± SEM, 0.44 ± 0.07 and 0.25 ± 0.05 in summer and winter, respectively). Reflex impairment was also correlated with lactate concentrations (e.g. physiological stress measures related to exhaustive exercise; r = 0.53) and recovery time (r = 0.76). Two mortalities occurred >24 h after the cessation of treatment in the summer. Given that natural habitats for white sturgeon can reach much higher temperatures than those presented in our study, we caution the use of this mortality estimate for a summer season, because latent mortality could be much higher when temperatures exceed 16°C. This is the first experiment investigating the physiological disturbance and reflex impairment of capture and release at two temperatures on subadult/adult white sturgeon, and the results suggest that future research needs to examine the longer term and fitness consequences of extended play and air exposure times, because these are largely unknown for wild populations.
... Stress-induced rises in plasma osmolality have been reported in many sturgeon studies (e.g. Zuccarelli et al., 2008;Allen et al., 2009;Cocherell et al., 2011), although this trend is untypical in freshwater fishes (reviewed in Wendelaar-Bonga, 1997;Seibel et al., 2021). Allen et al. (2009) hypothesized that the rise in plasma osmolality in stressed sturgeons could be the result of less plasma volume due to water moving out of circulation and into tissues (Okimoto et al., 1994), or haemoconcentrations caused by increased urine flow rates (Wood and Randall, 1973;Tervonen et al., 2006). ...
... Parasites that inhabit body cavities or visceral organs of their host are permanently exposed to the latter's protective factors, including humoral and cellular immune responses. Blood is a source of humoral immune factors in the body's cavities because peritoneal fluid is an ultrafiltrate of blood serum (Zuccarelli et al., 2008;Tarn & Lapworth, 2010). Leucocytes also penetrate the body cavities in fish through the walls of blood vessels (Alvarez-Pellitero, 2008). ...
The structural response and plasticity of the cestode tegument in response to the influence of the host organism is not yet well understood. The main aims of our in vitro study were to analyse the ultrastructural mechanisms and kinetics of tegumental secretion in two cestode species, Dibothriocephalus dendriticus and Ligula interrupta, in response to the influence of fish host blood serum. The incubation of plerocercoids in the culture medium, which contained fish host blood serum, resulted in an increased number of secretory products on the tegumental surface. Our study is the first to experimentally demonstrate the formation of plerocercoid protective layers influenced by the host's internal environment factors. The mechanism of the generation of the protective layer included the following: the intensive formation of organelles in the tegumental cytons and their transfer to the distal cytoplasm of the tegument; increases in extracellular vesicles and vacuoles released on the tegumental surface; arrangement of secretory products and fine‐dispersed extracellular matrix in layers; and formation of the protective layer. The structural tegumental response included increases in the glycocalyx layer and structural changes. Our study revealed that the universal mechanism of protective layer formation was intrinsic to different tapeworms. We hypothesize that plerocercoids of cestodes parasitizing fish may use tegumental secretion in the formation of a protective layer and in the release of immunoregulator molecules to evade the host's immune response.
... (3) Blood sampling is invasive but nonlethal. Other invasive and nonlethal samples could be achieved in the future from the larval yolk sac or peritoneal fluid in adults, but further research needs to be conducted in sturgeon (Zuccarelli et al. 2008;Linares-Casenave et al. 2013). ...
Animal welfare science is expanding rapidly. The use of physiological indicators is one of the most investigated ways in which to evaluate welfare. Blood samples are minimally invasive; they enable successive sampling of the same individuals and provide access to a large range of indicators from numerous physiological functions. Thus, they provide all the useful features for welfare research. The welfare of Siberian sturgeon is a very recent consideration. This chapter gathers together indicators from bibliography and our analysis which have been or could be used to assess this. The current research on stress responses and health status in Siberian sturgeon aids in the collation of this extensive information. Blood samples enable monitoring of hormonal response, biochemical and hydromineral indicators, oxidative stress parameters, immune status, hematological markers, and molecular indicators. The integration of these numerous physiological parameters in the context of welfare assessment is discussed throughout this chapter. Measuring physiological indicators from blood samples analyzed by multivariate analysis could be one of the future standards in the monitoring of fish welfare.
... Stress responses have been fairly well studied for WS under conditions such as air exposure and handling, with stress responses noted via increased cortisol levels (Belanger et al., 2001). Recent studies have demonstrated a stress response in peritoneal fluid and identified the potential utility of modern PIT tag technology to provide a non-invasive means of stress monitoring (Zuccarlli et al., 2008). Studies focused on stress in early life stages demonstrated the endogenous production of cortisol and sex steroids during late embryo development and immediately after hatch as well as an increase in steroid levels around the time of first feeding (Simontacchi et al., 2009;Bates et al., 2014a). ...
White Sturgeon, Acipenser transmontanus (WS), are distributed throughout three major river basins on the West Coast of North America: the Sacramento-San Joaquin, Columbia, and Fraser River drainages. Considered the largest North American freshwater fish, some WS use estuarine habitat and make limited marine movements between river basins. Some populations are listed by the United States or Canada as threatened or endangered (upper Columbia River above Grand Coulee Dam; Kootenai River; lower, middle and, upper Fraser River and Nechako River), while others do not warrant federal listing at this time (Sacramento-San Joaquin Rivers; Columbia River below Grand Coulee Dam; Snake River). Threats that impact WS throughout the species’ range include fishing effects and habitat alteration and degradation. Several populations suffer from recruitment limitations or collapse due to high early life mortality associated with these threats. Efforts to preserve WS populations include annual monitoring, harvest restrictions, habitat restoration, and conservation aquaculture. This paper provides a review of current knowledge on WS life history, ecology, physiology, behavior, and genetics and presents the status of WS in each drainage. Ongoing management and conservation efforts and additional research needs are identified to address present and future risks to the species.
... References Siikavuopio & Saether (2006) Lowe & Davison (2005) Welker et al. (2007) Frisch & Anderson (2005) Lowe & Davison (2005) Urbinati & Carneiro (2006) Barreto & Volpato (2006) Barreto & Volpato (2006) Miller et al. (2007) Gagnon et al. (2006) Davis & Peterson (2006) Zuccarelli et al. (2008) ...
Stress in fish has been widely studied. Cortisol and glucose are two of the most common stress indicators. In spite of the extended use of these indicators and their acceptance, some inconsistencies have been reported in the results of several experimental studies, much of them associated to undefined and uncontrolled variables which may alter the response in secretion of cortisol and glucose into the bloodstream. Most of those factors are not considered as direct stressors but have an effect on the intensity of the response which makes them a source of error. Some of those factors are related to metabolic changes in the organisms as an adaptation or acclimation mechanism; other are extrinsic to the fishes; other sources of error are caused unconsciously by the researcher during manipulation or due to inadequate control of variables, and may lead to intrinsic changes. The present paper is a contribution on the review of the most evident factors that may affect results when using cortisol and/or glucose as fish stress indicators. Some suggestions to avoid or minimize erroneous results in such investigations are also presented.
... However, information on how arti¢cial photoperiods may a¡ect haematological parameters is scarce. Environmental disturbances are generally regarded as potential sources of stress (Barton 1997) and blood plasma cortisol and lactate levels are increasingly used as indicators of physiological stress response in sturgeon ¢sh (Cataldi, Di Marco, Mandich & Cataudella 1998;Zuccarelli, Kusakabe, Nakamura, Prentice, Young & Ingermann 2008). Photoperiod changes reportedly in£uence steroid and corticosteroid hormone levels, but stress is not always an apparent consequence (Pickering & Pottinger 1983;Biswas, Maita,Yoshizaki & Takeuchi 2004). ...
The effects of constant light (24L:00D), no light (00L:24D) and two light–dark periods (18L:06D;12L:12D) on the growth, stress and haematological variables were assessed in juvenile great sturgeon, Huso huso. During the 8-week experimental period, juveniles (22.5 ± 0.6 g) were kept under a 150 lx light intensity in fibreglass tanks (0.8 m2, 500 L). Differences in growth were insignificant during the experiment, but lactate levels were higher in the 00L:24D and 24L:00D photoperiods compared with 12L:12D and 18L:06D photoperiods. Cortisol levels did not show differences among the various photoperiods. At the end of the experimental period, fish reared under a 12L:12D photoperiod had higher haemoglobin values and erythrocyte numbers than in the other photoperiods, while no differences were found between groups with regard to haematocrit values or leucocyte numbers. The highest survival rate (89%) was observed in the 12L:12D period in which the levels of lactate and cortisol as stress indicators were minimal. The results indicate that various photoperiods cause different stress levels in juvenile great sturgeon and have no significant effects on growth, at least in short time periods.
Sturgeon aquaculture faces challenges due to global warming, as chronic heat stress (CHS) jeopardises fish health and production sustainability. To tackle this issue, we analysed serum innate components and the cellular composition of the peritoneum in Russian sturgeons (Acipenser gueldenstaedtii) subjected to CHS and challenged with Aeromonas hydrophila. Russian sturgeons exposed to CHS exhibited a reduction in the serum levels of total protein and alkaline phosphatase activity, trending to a higher decrease in sturgeons exposed to both bacterial challenge and CHS. This sturgeon group showed a worsened health status, reduced growth and a higher mortality rate. Under tolerable temperatures, the bacterial challenge increased serum ceruloplasmin, lysozyme and serum amyloid A levels, which tended to be lower under CHS. The naive peritoneal cellular composition of the Russian sturgeon revealed a predominance of myeloid cells, with lymphoid cells present in a smaller proportion. CHS altered this distribution, increasing lymphoid while reducing myeloid cell percentages and A. hydrophila challenge reverted these alterations. Myeloid cells exhibiting the highest phagocytic potential were reduced by CHS, potentially compromising peritoneal bacterial clearance. Principal component analysis revealed that sturgeons' integral innate response varied according to temperature exposure, evidencing CHS's impact on the anti-bacterial response. Overall, this study provides a first picture of the peritoneal cellular composition of a chondrostean fish. Furthermore, it demonstrates the disruption caused by CHS on the sturgeon's early systemic and peritoneal responses mounted against A. hydrophila.
The effect of body size on various hematological variables was examined in juvenile shortnose sturgeon (Acipenser brevirostrum) ranging in mass from 38 to 730 g. The blood was examined for differences in plasma ionic composition (Na⁺, K⁺, Cl⁻), blood oxygen carrying capacities (hemoglobin, hematocrit), and plasma metabolite concentrations (lactate, glucose), before and following a standard 5‐min chasing stress. All measured resting hematological variables were size independent in shortnose sturgeon. After exercise, levels of plasma lactate, potassium, and hemoglobin increased in all fish. Only post‐exercise levels of chloride and hemoglobin changed in a size‐dependent manner; however, the relationships were weak. The general lack of a relationship between body size and hematological variables might reflect the narrow range of fish sizes used in the present study. From a practical perspective, the results suggest that when examining the hematological stress response in juvenile shortnose sturgeon, a range of fish sizes could be used. This is important considering the variability in the growth rates of juvenile shortnose sturgeon under laboratory conditions.
Much of the understanding of the endocrine basis of stress in fish comes from studies of cultured stocks of teleosts; there is comparatively little information on stress responses in wild stock, and less still on chondrosteans and elasmobranchs. This understanding is being refined through increasing understanding of molecular processes underlying endocrine events, with molecular tools offering ready examination of parts of the endocrine pathway that have been resistant to easy measurement of hormone products. An assessment of the timecourse of activation of the hypothalamic-pituitary-interrenal axis shows generally strong independence of temperature, with most teleosts showing measurable increase in plasma cortisol within 10 min of stress. Chondrostean and elasmobranch responses are less well described, but in chondrosteans at least, the response pattern appears to be similar to teleosts. The short latency for increases in corticosteroids following exposure to a stressor means that sampling of wild fish needs to occur rapidly after encounter. Several techniques including underwater sampling and rapid line capture are suitable for this, as is measurement of steroid release to the water by undisturbed fish, albeit possibly with a reduced range of applications. Basal cortisol values in wild teleosts are typically <10 ng mL(-1), but a number of species show values orders of magnitude higher in unstressed fish. Variability in corticosteroid levels arises from a range of factors in addition to stress including, sex and maturity, time of day or since feeding, and season. These factors need to be understood for the sensible assessment of stress responses in wild fish. Studies on free-living birds suggest that environmental stress resides mainly around unpredictable change, and the limited data available for fish support this view. The effect of unpredictable event such as floods or storms are difficult to assess in wild fish due to the difficulty in sampling at these times, and would be predicted to impose environmental stress as in terrestrial systems; however, this has yet to be demonstrated. There is scope for use of stress responses to be used as a measure of environmental quality but only if the basic response to environmental stress is well understood first. Development of this understanding remains a priority for this field of research.
We quantified initial and delayed mortality of largemouth bass Micropterus salmoides during live-release fishing tournaments and identified probable causes of death in order to provide a biological basis for refining tournament guidelines and regulation. Mean estimates for two tournaments on Lake Minnetonka, Minnesota, were 1.42% weigh-in mortality, 3.35% 3-d delayed mortality, and 4.72% total mortality. Catch and total mortality rates during a May tournament were both over 1.5 times those of a September tournament, the difference presumably being related to reproductive behavior and condition. Tournament mortality of the population was minimal relative to other causes of mortality; total tournament mortality estimates for 1992 (11 tournaments) represented 2.3–6.3% of angling mortality and 1.3–3.0% of total mortality in Lake Minnetonka. Means of all water quality variables measured in live wells were significantly different from those of lake water, and relative differences were greatest for ammonia concentration. The percentage of dead fish in live wells was significantly and inversely correlated with pH, which may reflect effects of dissolved carbon dioxide, No relationship between mortality and live-well fish density, equipment, or holding techniques was detected. Our results suggest that most tournament mortality was due to the cumulative effects of sublethal stressors. Among other recommendations, we suggest that alternatives to traditional weigh-in tournaments during the spawning period be explored and that anglers maximize replacement of live-well water with lake water to reduce concentrations of metabolic waste products.
One of the main practical problems in aquaculture is the stress influence on reproduction. General management practices ( capture, handling, transportation) in fish hatcheries induced stress responses. Serum cortisol, testosterone and glucose concentrations were measured in stellate sturgeon ( Acipenser stellatus, Pallas) and Russian sturgeon ( A. gueldenstaedtii, Brandt) under stress conditions: (i) during capture; (ii) forced swimming and (iii) air exposure. The results suggest that the increased cortisol and glucose level noted indicate stress responses. The authors suggest that in general the short-term hatchery practices utilized do not lead to deterioration of gamete quality in sturgeon breeders. However, prolonged hatchery procedures at high spawning temperatures and high loading densities may negatively affect reproduction.
An application of passive integrated transponder (PIT) technology was used to monitor movements of adult American shad (Alosa sapidissima), blueback herring (A. aestivalis) and gizzard shad (Dorosoma cepedianum) in two experimental fishways. Tag reading efficiency was between 88–96%, detection ranges were 50–100 cm from orifices of 3100–9600 cm2, and read rates were 5–7 Hz. The system was limited by the amount of time that tags were exposed to the energize/detect zone, and by simultaneous presences of large numbers of tags within this zone.
General management practices including capture, handling and transportation in fish hatcheries can induce a stress response indicated by a plasma cortisol increase in many species. However, this phenomenon is not well established in cultured white sturgeon (Acipenser transmontanus). We determined resting levels of cortisol and the cortisol responses to two management stressors and to exogenous adrenocorticotropic hormone (ACTH1–24) injections in cannulated mature male white sturgeon. Mean resting cortisol level was 8.6 ng/ml and ranged over 5.8–12.8 ng/ml through a 22-h period. Water reduction and transportation+handling stressors elicited significant cortisol increases above pre-stress and post-stress levels. Exogenous ACTH1–24 injections of 0.5 and 5.0 μM caused dose-dependent peak cortisol increases above those produced by either the water reduction or transportation+handling stressors.
Experiments were conducted to determine the physiological responses to exercise of Atlantic sturgeon (Acipenser oxyrhynchus) and shortnose sturgeon (A. brevirostrum). We measured the rates of oxygen consumption and ammonia excretion in both species and a variety of physiological parameters in both muscle (e.g. lactate, glycogen, pyruvate, glucose and phosphocreatine concentrations) and blood (e.g. osmolality and lactate concentration) in juvenile shortnose sturgeon following 5 min of exhaustive exercise.
In both species, oxygen consumption and ammonia excretion rates increased approximately twofold following exhaustive exercise. Post-exercise oxygen consumption rates decreased to control levels within 30 min in both sturgeon species, but post-exercise ammonia excretion rates remained high in Atlantic sturgeon throughout the 4 h experiment. Resting muscle energy metabolite levels in shortnose sturgeon were similar to those of other fish species, but the levels decreased only slightly following the exercise period and recovery occurred within an hour. Under resting conditions, muscle lactate levels were low (<1 μmol g–1) but they increased to approximately 6 μmol g–1 after exercise, returning to control levels within 6 h. Unlike similarly stressed teleost fish, such as the rainbow trout, plasma lactate levels did not increase substantially and returned to resting levels within 2 h. Plasma osmolality was not significantly affected by exercise in shortnose sturgeon.
Taken together, these results suggest that shortnose and Atlantic sturgeon do not exhibit the physiological responses to exhaustive exercise typical of other fish species. They may possess behavioural or endocrinological mechanisms that differ from those of other fishes and that lead to a reduced ability to respond physiologically to exhaustive exercise.
Serum and coelomic fluid sex steroid hormone levels were measured in the sturgeon (Acipenseridae) at the onset of anadromous migration and maturation. Cortisol and testosterone levels in coelomic fluid were lower than in serum; conversely, progesterone levels were higher in coelomic fluid than in blood. Specific androgen and estrogen binding in the cytosol of different parts of the brain and in the gonads of fish were different in the pre-spawning state and after ovulation. Before spawning, the highest levels of specific androgen binding were in the forebrain, where levels decreased significantly after ovulation. Specific estrogen binding in the hypothalamus was significantly higher after maturation and ovulation. Correlations were established between sex steroid concentrations in the blood and levels of specific binding in the brain and gonads.
Sturgeons are primitive bony fishes and their hearts have structural features found in other primitive fishes. Sturgeons have a pericardioperitoneal canal (PPC), a one-way conduit into the peritoneum. A PPC also occurs in elasmobranchs (sharks and rays) and studies with that group demonstrate that pericardial pressure and pericardial fluid loss via the PPC affect stroke volume. A study of white sturgeon (Acipenser transmontanus) heart function was conducted to test for a comparable PPC and pericardial effects. White sturgeon-elasmobranch heart-function similarities include biphasic ventricular filling, a comparable operational pericardial pressure (-0.03 kPa), and a strongly negative pressure (-0.2 to -0.6 kPa) with complete pericardial fluid withdrawal. Differences include the white sturgeon's relatively smaller atrium and ventricle but a larger conus arteriosus. Although white sturgeon heart size is also smaller, its pericardial volume is disproportionately less (2.4 to 2.7 vs. 3.5 to 5.4 ml kg(-1) in elasmobranchs), meaning it has less scope for increasing stroke volume upon PPC fluid release. These differences may reflect the phylogenetic progression from the less complex operation of the elasmobranch heart, which lacks sympathetic innervation and has a mechanically mediated (PPC) stroke volume, to the condition in the more derived bony fishes which have sympathetic and parasympathetic regulation of both stroke volume and heart rate.
Metabolic scope for activity (MSA) and critical swimming velocity (U(crit)) were measured in green sturgeon exposed to two stressors daily for 28 consecutive days. The results were compared with unstressed fish in an effort to measure the "cost" of chronic stress. Chronic stress was simulated by exposing fish to a randomized order of acute stressors: a 5-min chasing stressor, a 10-min water depth reduction stressor, or a 5-min confinement stressor. The acute cortisol response to each stressor was initially determined, and the maintenance of that response was verified in 7-d intervals during the chronic stress regime. Exposure to the chronic stress regime resulted in a 25% reduction of MSA caused by significantly increased maintenance metabolic rate (0.27+/-0.01 vs. 0.19+/-0.02 mg O(2) h(-1) g(-1), chronic and control fish, respectively) but did not affect the U(crit) of sturgeon. In addition, a 50% reduction in liver glycogen levels and a twofold increase of resting plasma glucose levels were measured in chronically stressed fish. We conclude that our chronic stress regime resulted in a significant maintenance cost to green sturgeon, possibly because of their inability to habituate to the stressors, but did not decrease their swimming performance.
Stress in fish caused by physical disturbances encountered in aquaculture, such as handling and transport, evokes a variety of responses that may be adaptive or maladaptive. The overall effect of stress may be considered as a change in biological condition beyond the normal resting state that challenges homeostasis and, thus, presents a threat to the fish's health. These stress-induced changes are grouped as primary; secondary, which includes metabolic, hematological, hydromineral, and structural; and tertiary or ‘whole animal’ responses. Many of these responses can be used as quantitative indicators of stress although investigators need to be aware of the various ‘nonstress’ factors that can also influence these conditions. A major focus of current research is on the response of the hypothalamic-pituitary-interrenal axis and the resultant elevation of circulating corticosteroids. Stress, through the action of corticosteroids, may (a) reduce immunocompetence by influencing lymphocyte numbers and antibody-production capacity, and (b) affect reproduction by altering levels and patterns of reproductive hormones that influence maturation. Stress may also alter metabolic scope in fish and affect growth, partly as a result of the catabolic or gluconeogenic effect of corticosteroids. Although certain stressors encountered during normal aquacultural procedures may be unavoidable, a number of practical approaches are suggested that would help to alleviate the detrimental effects of stress in fish.
Stress in wild brown trout Salmo trutta was assessed by sampling blood and measuring the concentrations of plasma cortisol and blood glucose in fish collected by electrofishing and immediately anaesthetized with metomidate. In the River Nidelva, Trondheim, Norway, the resting blood plasma cortisol concentration in the juvenile (0 þ year) brown trout was 52 AE 44 nM (mean AE S.D.) in December and 2Á3 nM (detection limit) in January. The corres-ponding blood glucose values were 1Á8 AE 0Á9 and 1Á2 AE 0Á2 mM, respectively. After electrofish-ing, handling and transport to the artificial stream, plasma cortisol and blood glucose levels increased significantly in both experiments. A maximum plasma cortisol level of 239 AE 120 and 71 AE 32 nM and a maximum blood glucose level of 3Á9 AE 0Á9 and 3Á0 AE 0Á9 mM were measured in the December and January stream channel experiments after transport, respectively. After introduction to the artificial stream, the blood plasma cortisol level returned to resting values within 24 h in the January stream channel experiment. The blood glucose levels remained at a higher level compared to the reference group throughout the December experiment, while it returned to resting values after 24 h in the January stream channel experiment. The major difference between the December and January experiments was the temperature within the artificial stream, 15–17 C in December and 7–9 C in January. This may have influenced the blood glucose levels. After dewatering of the artificial streambed there was a significant increase in plasma cortisol both in the December and January experiments, and after 24 h the plasma cortisol returned to the resting level in the January experiment. The blood glucose also increased during dewatering, although not significantly. # 2004 The Fisheries Society of the British Isles
Increased holding time in ponds or tanks of captured sturgeon broodstock can affect serum Cortisol levels, with atrend towards lower levels with increased time. A relationship between Cortisol levels and gamete quality was observed in some females, whereby low Cortisol was linked to poor gamete quality.
The effect of environmental hypercapnia on respiratory and acid-base variables was studied in white sturgeon, Acipenser transmontanus. Blood PCO2, PO2, pH, hemoglobin concentration, and plasma lactate, glucose, catecholamines and cortisol were measured first under normocapnia
(water PCO2 < 0.5 Torr, 1 Torr = 133.32 Pa), then under hypercapnia (25–35 Torr) and a final return to normocapnia at 19 ± 0.5 °C. Acute
(≤ 2h) hypercapnia significantly increased arterial PCO2 (8-fold increase), ventilation frequency (2-fold increase), plasma HCO3
− (2.3-fold) and decreased arterial pH (to 7.15 ± 0.02). After 24 h, norepinephrine, epinephrine and cortisol, were significantly
increased, and arterial pH reached its nadir (7.10 ± 0.03). During the 72- and 96-h-periods, arterial PCO2 (24 ± 4.4 Torr) and ventilatory frequency (105 ± 5 breaths min−1) stabilized, HCO3
− reached its apparent maximum (23.6 ± 0.0 mmol−1), glucose decreased by 32%, and pH increased significantly to 7.31 + 0.03. The return to normocapnia completely restored
arterial PCO2 (2.5 ± 0.14 Torr), HCO3
− (7.4 ± 0.59 mmol · l−1), ventilation frequency (71 ± 7 breaths · min−1), and pH (7.75 ± 0.04). Overall, hypercapnia produced a respiratory acidosis, hyperventilation, a transient norepinephrine
“spike”, and increased plasma catecholamines, cortisol, and arterial PO2. The respiratory acidosis was only partially compensated (35% pH restoration) 96 h after the onset of hypercapnia and resulted
in a significantly decreased blood-O2 affinity (Bohr effect), as determined by construction of in vitro blood O2 equilibrium curves at 15 °C and 20 °C. Prolonged exposure to hypercapnia may lead to acid-base disturbances and negatively
affect growth of white sturgeon.
Data collected on juvenile salmonids tagged with passive integrated transponder (PIT) tags as they migrate seaward through the Columbia River Basin provide fisheries managers and resource agencies with valuable information to evaluate the effectiveness of current management actions and restoration strategies. The development of new technology to route PIT-tagged fish through multiple alternative pathways as they pass through the interrogation systems at the fish bypass/monitoring facilities at hydroelectric dams provides another valuable real-time tool to monitor and evaluate the migration, passage, and survival of PIT-tagged juvenile salmonids in the basin. The authors describe the current computer program and gate-control technology for routing fish, and provide detailed descriptions of three new types of fish-diversion gates. The comparative advantages and disadvantages of each gate are discussed. The prototype of a fourth diversion gate, with only one moving part, is also described.
The addition of bovine serum albumin (BSA) to a solution of lactate and alanine resulted in the disappearance of the 1H-NMR resonances from lactate but not alanine. As temperature is increased lactate becomes increasingly NMR visible and after heating above 65°C and cooling to 25°C lactate binding is reduced. With a concentration of 0.2 mM BSA, there was a linear relationship between NMR visible lactate versus total lactate over a range of lactate concentrations of 0.2–35 mM (slope 0.384±0.003) indicating that approx. 60% of the added lactate is not visible in the 1H-NMR spectrum. With a 0.1 mM BSA solution, however, the slope was markedly higher indicating that under these conditions only 25–30% of the lactate was NMR invisible. The results from this study indicate that decreased NMR visibility of lactate in proteinaceous solutions is due to non-specific binding which is dependent on the tertiary structure of the protein. This has important implications not only for the interpretation of in vivo 1H-NMR experiments but also for 13C, and 14C studies of metabolism.
In the spring of 1996 and 1997, a prototype 400 kHz flat-plate (pass-by) passive integrated transponder tag interrogation (PIT tag) system was installed at the terminus of the downstream migrant (DSM) channel of the Bonneville Dam First Powerhouse, located on the Columbia River. The system was designed to interrogate previously PIT tagged juvenile salmonids migrating down the Columbia River without interfering with the traditional subsampling of fish passing through the facility. In addition, the design enables fish of virtually any size, and debris, to pass over the system's antennas without the port restrictions imposed by traditional pass-through PIT tag interrogation systems. We describe the fish facility in addition to the flat-plate system and its operation. The system tag reading efficiency was evaluated during 1996 and 1997 using a direct method based on the release of known numbers of tagged test fish and an indirect statistical procedure based on tagged run-at-large fish. The results showed that PIT tag reading efficiency during both years using the direct method averaged 97%, while that using the statistical procedure averaged 99% for the dual multiplexed antenna array. During the 1996 and 1997 field seasons 4371 and 14 733 fish, respectively, were recorded. Daily system functionality was monitored using stick tests (i.e., the passing of PIT tagged sticks across the antenna array).
Different taxa of fish have different tolerances to stress. This implies that for a particular stressor, severity may vary depending on the species to which it was applied. Species may differ in the nature of their physiological response and reproductive consequences to stressors. For example, disturbance or handling may affect the timing of reproduction—accelerating or delaying it as the case may be—in species such as rainbow trout (Oncorhynchus mykiss); however, tilapia (Oreochromis niloticus) respond by acceleration or complete inhibition of reproduction, depending on the maturational stage when the stressor is experienced. Strategies for coping with stress affect reproductive fitness either in terms of gamete or progeny quality. The physiology associated with maturation and spawning appears tightly coupled with stress physiology. Environmental variables, particularly nutrition, are ultimately important in affecting gamete quality and reproductive timing. The physiological response to stressors is also quite polymorphic, within and between species. For example, the circulating concentration of the primary stress response factor cortisol varies greatly among resting and among stressed rainbow trout stocks. Immunocapacity can be influenced by stress, reducing reproductive fitness of broodfish. We propose that maternal systems have been developed to buffer eggs from deleterious consequences of stressors, including regulation of transfer of substances of maternal origin to the egg and in mechanisms controlling the timing of reproduction. Effects of nutritional stressors are moderated by effects on timing of first maturity or subsequent reproductive events and/or by maintenance of quality of some eggs via atresia of others. Deleterious overload of eggs with substances such as cortisol is likely prevented by limiting entry of these compounds into the eggs. Barriers to vertical transmission of numerous pathogens seem to exist, while maternally derived immune protection is provided to assist with disease prevention of pathogenic organisms acquired from parents or by direct post-spawning infection. Timing of reproductive events including puberty, atresia, maturation and ovulation are influenced by other physiological variables responsive to stressors. Knowledge of how a stressor might affect the physiology of a species can help in development of management tactics that lessen the impact of a stressor or even in the development of therapeutants.
Data on the concentrations of some blood constituents of captive Adriatic sturgeon, Acipenser naccarii, a primitive bony fish, are reported. Serum osmolality, Na+, K+, Cl−, Ca2+, cortisol, glucose and total protein concentrations were measured. The effects of anaesthesia, temperature, crowding and prolonged handling stress were tested on a group of 12 4-year-old sturgeons sampled repeatedly. The anaesthetic dose of MS 222 (140 mg l−1) induced significant osmolality elevation in the sturgeon. After exposure to colder temperature (17 versus 25°C), cortisol and Cl− concentrations significantly decreased. The cultured sturgeon did not seem susceptible to crowding and prolonged handling stress, since neither the serum cortisol and glucose levels nor the other blood parameters were affected by these stressors. Results are compared with the few available data on other chondrostean fish and with those on teleosts.
Juvenile paddlefish (Polyodon spathula) subjected to various physical disturbances showed significant increases in plasma cortisol and lactate, but little or no change in plasma glucose, chloride or hematocrit. When paddlefish were given a 30 s aerial emersion handling stressor, plasma cortisol increased from 2.2±0.6 to 11±1.8 ng ml−1 in 1 h but had returned to the prestress level by 3 h. Addition of 0.5% NaCl to the recovery tanks had no effect on plasma cortisol changes. Plasma lactate rose from 26±2.6 to 52±4.5 mg dl−1 within 3 h. Plasma cortisol increased to 14±4.8 ng ml−1 and plasma lactate rose to 67±3.7 mg dl−1 after fish were continuously chased in their home tanks for 1 h; plasma lactate remained elevated for 5 h. In fish severely confined for 6 h in cages with intermittent handling, plasma cortisol rose from 6.2±1.6 ng ml−1 to its peak level of 74±6.3 ng ml−1 by 2 h, but approached the prestress value after 18 h of recovery. Plasma lactate levels in confined fish increased from 27±2.7 to 73±6.9 mg dl−1 by 3 h but had returned to near-resting levels by 24 h. The results suggest that paddlefish do not exhibit physiological stress responses to physical disturbances similar in magnitude to those previously documented for many teleostean fishes including salmonids, although cortisol was determined to be the principle steroid released during stress.
In two experiments, a computerized on-demand feeding system coupled with a PIT tag monitoring device was used to continuously record the triggering activity by ca. 50 individual sea bass for 55 days (Exp. 1, initial average body weight and coefficient of variation, CV: 299 g, 15%) and 69 days (Exp. 2, 157 g, 13%). Each group was stocked in 1 m(3) tanks and exposed to a water temperature of 21 +/- 1 degrees C and a light regime of 16:8 LD. Only 5% of the triggering activity was not associated with simultaneous PIT tag detection. Although each individual was detected via PIT tag during the experiment, only 67% and 74% of the fish actuated the trigger at least once in Exp. 1 and Exp. 2, respectively. Moreover, only two fish in Exp. 1 and one fish in Exp. 2 accounted for 82% (43 + 39) and 77% of the total triggering activity, respectively. These three, high-triggering individuals did not exhibit a higher specific growth rate or agonistic behavior as observed by video monitoring. Indeed, zero-triggering fish had either a slightly higher SGR (Exp. 1) or a higher final body weight (Exp. 2) compared with low- and high-triggering fish.
The original Lowry method of protein determination has been modified by the addition of sodium dodecyl sulfate in the alkali reagent and an increase in the amount of copper tartrate reagent. These alterations allowed the method to be used with membrane and lipoprotein preparations without prior solubilization or lipid extraction and with samples containing 200 mm sucrose or 2.5 mm EDTA.
1. Total cortisol concentrations did not differ in sexually matured female, male, and immature rainbow trout. 2. The per cent cortisol bound to a corticosteroid binding protein was greater in mature female fish (48.2%) than in mature male (16.0%) and immature fish (19.5%). 3. The mature female fish exhibited a lower percentage of free cortisol (21.8%) compared to mature males (44.8%) and immature fish (43.2%). 4. Parallel aspects of the teleostean cortisol binding-protein and the mammalian counterpart are compared and commented upon.
Previous studies of cardiac function in elasmobranch fishes have not included the influence of the pericardioperitoneal canal on pericardial pressure and volume and thus on cardiac function. Accordingly, we studied the function of the pericardium and pericardioperitoneal canal in sharks and rays. We found negative pericardial pressure that rose to a plateau of approximately 0 mmHg when fluid was infused into the pericardium with the canal undisturbed. However, this pericardial pressure elevation caused severe cardiac tamponade. After the canal was occluded, the pressure plateau was substituted with an exponential rise. We injected radioisotopes into the pericardial cavity and obtained scintigrams several hours later. The scans and counts of body fluids and tissues indicated absorption, disputing the suggestion that the primary function of the canal may be inadequate absorption of pericardial fluid. We conclude that the pericardioperitoneal canal maintains negative pericardial pressure, which is a prerequisite in elasmobranch fishes and may serve to regulate pericardial pressure level to optimize cardiac function in relation to changes in cardiac size.
1.1. Chronically imposed metabolic acidose markedly reduced the bicarbonate concentration of the normally alkaline pericardial and peritonel fluids of the turtle, Pseudemys scripta elegans.2.2. These data support tje hypothesis that these fluids function as a buffer reserve.3.3. Respiratory compensation was observed in response toboth metabolic acidosis and metabolic alaklosis.
1. The pH, osmolarity, Na+, K+, Ca++, Mg++, Cl-, urea, NH3 and total protein content of the serum (S), pericardial fluid (PC) and perivisceral fluid (PV) of the stingray, Dasyatis americana, were estimated and compared to environmental data.2. The PC and PV were found to be more acid and osmotically less concentrated than S. Although there were no significant differences in either Na+ or urea concentrations in the three body fluids, K+ was significantly reduced in PC. Ca++ and Mg++ were significantly less concentrated in PC and PV. Both PV and PC had elevated Cl- and almost no protein; both contained significantly elevated NH3 concentration. It follows that recipes for synthetic bathing fluids for elasmo-branch viscera should not be based upon data obtained from plasma or serum analyses.3. A few specimens of D. say were collected. The data were similar.
A model was developed to study the fate of the fish pathogen Aeromonas salmonicida in vivo, inside a specialized intraperitoneal chamber implanted in rainbow trout, Oncorhynchus mykiss. Although normally recalcitrant to lytic agents in vitro, owing to the presence of its regular surface array (S layer), A. salmonicida was rapidly killed in the peritoneal cavity by a host-derived, soluble lytic activity present in peritoneal fluid. Peritoneal fluid was also found to kill other bacteria and lyse various types of erythrocytes, but was particularly lytic to A. salmonicida. Intraperitoneal survival of injected (free) A. salmonicida cells was several orders of magnitude higher than survival of implanted (restrained) cells. Injected free cells could evade the lytic activity of peritoneal fluid because they readily spread, initiating lethal infections. One evasion strategy was envisioned to be the penetration of peritoneal and (or) tissue macrophages. In spite of the killing mechanisms of these phagocytic cells, A. salmonicida was still able to survive and even replicate inside head kidney macrophages, thereby supporting the notion of A. salmonicida as a facultatively intracellular pathogen. Intraperitoneal chambers in rainbow trout may constitute a valuable experimental tool for studying the in vivo fate of A. salmonicida, and perhaps of other fish pathogens as well.
The current concept of ventricular filling in the elasmobranch fish (sharks and rays) is that a subambient pericardial pressure establishes a negative diastolic pressure gradient for the atrium and that ventricular end-diastolic volume is exclusively determined by atrial systole. In contrast, recent findings using echo-Doppler and digital imaging techniques have demonstrated two filling phases in the elasmobranch ventricle. In this study, simultaneous atrial and ventricular pressure measurements made on sharks with an open or intact pericardium establish that atrial pressure is above ventricular diastolic pressure until the onset of ventricular systole. A positive biphasic atrioventricular pressure gradient thus ensures ventricular filling during early diastole, as a result of ventricular relaxation, as well as during atrial systole. Although a reduction in pericardial pressure resulted in a decline in the atrial and ventricular pressure, a positive atrioventricular pressure gradient is conserved. The finding that atrial diastolic pressure is not lower than ventricular diastolic pressure, when combined with previous results showing that pericardial pressure is generally at or above ambient and that ventricular filling is biphasic, constitutes a strong body of evidence favoring the operation of a direct venous inflow as the mechanism by which the elasmobranch heart fills.
The carbonic acid-base balance and the concentrations of Na and Cl were studied in 3 fluids, plasmatic, pericardial and peritoneal, sampled from 2 species of amphibians: Pleurodeles waltl and Xenopus laevis. In Pleurodeles the pericardial and peritoneal fluids are in a state of marked metabolic alkalosis, the carbonate alkalinity being up to 10 times higher in the serosal fluids than in the plasma, whereas PCO2's are very close in the 3 fluids. The Cl concentration is markedly lower in the serosal fluids than in the plasma. In Xenopus, the metabolic alkalosis of the serosal fluids also exists, but to a much lower extent than in Pleurodeles. These observations lead to further researches in the field of morphometry, physicochemistry and physiology.
The addition of bovine serum albumin (BSA) to a solution of lactate and alanine resulted in the disappearance of the 1H-NMR resonances from lactate but not alanine. As temperature is increased lactate becomes increasingly NMR visible and after heating above 65 degreesC and cooling to 25 degreesC lactate binding is reduced. With a concentration of 0.2 mM BSA, there was a linear relationship between NMR visible lactate versus total lactate over a range of lactate concentrations of 0.2-35 mM (slope 0.384+/-0.003) indicating that approx. 60% of the added lactate is not visible in the 1H-NMR spectrum. With a 0.1 mM BSA solution, however, the slope was markedly higher indicating that under these conditions only 25-30% of the lactate was NMR invisible. The results from this study indicate that decreased NMR visibility of lactate in proteinaceous solutions is due to non-specific binding which is dependent on the tertiary structure of the protein. This has important implications not only for the interpretation of in vivo 1H-NMR experiments but also for 13C, and 14C studies of metabolism.
Following a 7.5-h transport haul, juvenile pallid sturgeon (Scaphirhynchus albus) showed a small but significant increase in plasma cortisol to 4.7 ng ml(-1) but similar increases did not occur after fish were handled in a net held in the air for 30 s. Subsequent experiments on yearling pallid sturgeon and hybrid pallidxshovelnose (S. albusxplatorynchus) sturgeon using the same 30-s handling stressor failed to evoke increases in plasma cortisol, lactate or glucose. Plasma cortisol increased significantly from about 2 to 13-14 ng ml(-1) in both pallid and hybrid sturgeon during a 6-h severe confinement stressor with handling. Plasma cortisol in 2-year-old pallid sturgeon subjected to the same stressor demonstrated a linear pattern of increase during the initial 1 h. Plasma lactate increased from 1.11 to about 2.11 mmol l(-1) in hybrid sturgeon during the first hour of severe confinement but did not change throughout the entire confinement period in pallid sturgeon. A significant increase in plasma cortisol to 5.4 ng ml(-1) in 2-year-old pallid sturgeon 1 h after being subjected to 30 s handling at 19:00 h but not at 07:00 or 13:00 h suggests that a small diurnal variation in their stress response may exist. Although both pallid and hybrid sturgeons were responsive to stress, they exhibited very low physiological responses compared with those following equivalent stressors in most teleostean fishes or another chondrostean, the paddlefish (Polyodon spathula). Reasons for the apparent low responses to handling and confinement in scaphirhynchid sturgeons are not known but may relate to their evolutionary history, neuroendocrine mechanisms involved in their corticosteroid responses, or anatomy of their interrenal tissue structure.
Maintenance of sperm at pH values less than approximately 7.5 inhibited the onset of motility when sperm were subsequently diluted with water; maintenance at pH values above approximately 8.2 was associated with maximal motility upon dilution with water. Within 5 approximately min of exposure to low pH buffer (pH 6.9), there was a 50% decline in sperm motility upon dilution with water suggesting that exposure to low pH interferes with motility within a time frame that may affect fertilization. In most instances, maintenance of sperm under CO(2) at a pressure of 4-5 kPa almost completely blocked their capacity for motility. Furthermore, exposing semen to increasing partial pressures of CO(2) up to about 1 kPa resulted in a marked decrease in semen pH. These observations are consistent with the findings that the buffering capacity of semen is particularly low at physiological pH, and that this low buffering capacity corresponds to the highest pH sensitivity of the capacity for sperm motility. The low seminal buffering capacity may represent a physiological adaptation in the control of sperm function. It may also represent a vulnerability to environmental hypercapnia or metabolic acidosis.
Motility of salmonid sperm is inhibited by the presence of carbon dioxide (CO2) in vitro; however, whether this occurs in response to challenges to the adult in vivo is not known. To determine whether CO2 negatively impacts sperm function in vivo, mature males were exposed to exhaustive exercise as well as to acute stress, chronic stress, tricaine anesthesia and environmental hypercapnia and sperm motility and semen CO2 tensions and pH values assessed. Semen CO2 rose and pH decreased significantly only in response to exhaustive exercise and environmental hypercapnia (13 kPa CO2). These changes in semen CO2 and pH were associated with reductions in numbers of sperm becoming motile upon water activation. Chronic and acute stress and tricaine anesthesia were without effect on sperm motility or on semen CO2 or pH. The time course of CO2 inhibition and recovery was evaluated in vitro. At least 50 min was required to note 50% of the inhibitory effect of low CO2 tensions on motility when sperm were exposed to 1.6-3.1 kPa CO2. At higher CO2 levels sperm motility displayed 50% of the inhibitory effect of these tensions within about 30 min. Sperm recovered maximal motility within 1 h of being placed in a nominally CO2-free environment. This study demonstrates sperm vulnerability to not only in vitro CO2 exposure but also in vivo exposure during exhaustive exercise and as result of environmental hypercapnia.
Compared to teleosts, little is known about the stress response in chondrosteans, and the glucocorticoid(s) most responsive to stress have never been definitively determined in sturgeon. In terms of cortisol production, pallid sturgeon (Scaphirhynchus albus) have a low physiological response to stress compared to other sturgeons (Acipenser s.p.). Because of this, our null hypothesis was that cortisol is not the predominant glucocorticoid secreted in response to stress in pallid sturgeon. Our objective was to identify the putative glucocorticoids present in the plasma of pallid sturgeon during the stress response. Pallid sturgeon were subjected to a severe confinement stress (12 h) with an additional handling stressor for the first 6 h. Control fish were not subjected to confinement but were handled only to collect blood. Blood plasma was collected at time 0, 6, and 12 h. Gas chromatography/mass spectrometry was used to screen the plasma for the spectrum of glucocorticoids and determine the putative steroid secreted during the stress response. Cortisol was the primary glucocorticoid detected in stressed pallid sturgeon. In addition, the cortisol metabolites cortisone, alloTHE (5alpha-pregnane-3alpha,17alpha,21-triol-11,20-dione), allo-alpha-cortolone (3alpha,17alpha,20alpha,21-tetrahydro-5alpha-pregnan-11-one), and allo-beta-cortolone (3alpha,17alpha,20beta,21-tetrahydro-5alpha-pregnan-11-one) were detected. Plasma cortisol increased from a resting concentration of 0.67 ng/ml to 10.66 ng/ml at 6h followed by a decrease to 6.78 ng/ml by 12 h. Plasma glucose increased significantly by time 6 and 12 h in both stressed and unstressed groups and remained elevated at time 12h, while resting lactate concentrations were low to non-detectable and did not increase significantly with the stressor over time. Cortisol was the primary glucocorticoid synthesized and secreted in response to a stressor in pallid sturgeon. Though the proportional increase in plasma cortisol in stressed pallid sturgeon was lower than many other species of sturgeon, the concentration was high enough to elicit a secondary stress response as seen by changes in plasma glucose.
This is also consistent with the composition of mammalian PF relative to BP (Tortora & FIG. 2. Recovery from a 30 min stressor reflected by blood plasma [BP ( ); BP control ( )] and peritoneal fluid [PF ( ); PF control
- Bernard
Similar to the Elasmobranchii, the composition of white sturgeon PF relative to BP is indicative of a modified ultrafiltrate (Bernard et al., 1966). This is also consistent with the composition of mammalian PF relative to BP (Tortora & FIG. 2. Recovery from a 30 min stressor reflected by blood plasma [BP ( ); BP control ( )] and peritoneal fluid [PF ( ); PF control ( )] (a) osmolality, (b) cortisol, (c) glucose and (d) lactate. Values are mean AE S.E. (n ¼ 10).
The Authors Journal compilation # 2008 The Fisheries Society of the British Isles
# 2008 The Authors
Journal compilation # 2008 The Fisheries Society of the British Isles, Journal of Fish Biology 2008, 72, 1831–1840